Home » Public Forums » GMCnet » Wanted: Fuel Injection Impressions
| Wanted: Fuel Injection Impressions [message #196392] |
Thu, 24 January 2013 16:25  |
Dave Wilson
Messages: 94
Registered: September 2009
Location: Livonia, MI
Karma: 0
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Member |
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Hi All,
We are considering making the change (finally!) to fuel injection. I've been trying to sell my father on this for some time, and the latest tank of gas running poorly through his carburetor may be the last straw for him. He's also noticed the carburetor gasket getting eaten much quicker lately and is convinced it's due to today's gas mixtures (and we put in 93+ octane and additives).
That's the background, now the reason for this post: can anyone that has the time and an EFI system please comment on their personal experience with it? A couple of things we'd be interested in hearing are: 1) what type of EFI system you're using; 2) how many miles do you have with the system in place; 3)do the GMC gas tanks present any "fuel starvation" issues when travelling through the hills; 4) 4 "barrel" throttle body or 2; 5) finally, did you add a manually adjusted spark control or if you let an ESC system plug into your ECM to manage both spark and fuel.
Thanks in advance for all responses! Feel free to "unload" good and bad stories- we need to hear!
Dave Wilson
'77 Eleganza II
Photos @ http://www.gmcmhphotos.com/photos/member.php?uid=2183&protype=1
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196397 is a reply to message #196392] |
Thu, 24 January 2013 18:46  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Dave,
Probably the best place to find such information & ask questions is:
https://groups.google.com/group/gmcmh-efi?hl=en&noredirect=true&pli=1
In the left column of that page, you'll find a link to join the GMCMH-EFI
Google Group -- a mailing list much like GMCNet, but dedicated to EFI.
You'll certainly want the information and assistance available there after
making the leap.
Ken H.
On Thu, Jan 24, 2013 at 5:25 PM, Dave Wilson wrote:
>
>
> Hi All,
> We are considering making the change (finally!) to fuel injection.
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196404 is a reply to message #196397] |
Thu, 24 January 2013 21:41 |
rvanwin
Messages: 325
Registered: April 2007
Location: Battlefield, MO
Karma: 6
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Senior Member |
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| Ken Henderson wrote on Thu, 24 January 2013 18:46 |
Dave,
Probably the best place to find such information & ask questions is:
https://sites.google.com/site/gmcmhefi/
In the left column of that page, you'll find a link to join the GMCMH-EFI
Google Group -- a mailing list much like GMCNet, but dedicated to EFI.
You'll certainly want the information and assistance available there after
making the leap.
|
I have had a number of requests to gain access to the sites efi site. Actually, everyone should go to the Google Group that Ken mentions first in order to get authorized. Once authorized for the Google Group then you will automatically gain access to the Google site efi site. This is set up this way in order to have only one gate keeper for access to GMC EFI information.
Please go here: <https://groups.google.com/group/gmcmh-efi?hl=en&noredirect=true> Over on the right hand side is a link to request membership to the group. Once you receive authorization, then you can navigate to the sites link given. Google is updating groups to a new format which is here: <https://groups.google.com/forum/?fromgroups&hl=en#!forum/gmcmh-efi> Unfortunately, you have to be signed in with a google account in order to get a link to join the group. I've complained to Google but probably won't do much good.
So, for new members to the EFI discussion, we should be directing folks to the Google Groups forum location as the first place to go in order to get set up to join in EFI discussions.
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196407 is a reply to message #196404] |
Thu, 24 January 2013 22:50 |
Phantom2
Messages: 94
Registered: September 2012
Location: Springfield, IL
Karma: 0
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Hi, BAD News. You have to have EFI installed on your motor home in order to join. A bunch of help for someone wanting to change over. You have to do it before you can get help.
NOTICE on sign up page.
Quote
Owners of '73-'78 GMC TZE motorhome with EFI are eligible for membership. Requests for membership MUST include the year and model of your GMC, your location, and the type of EFI you're using. (You may also include additional comments to the manager.)
Larry Hopkins
75 Avion
Springfield, IL
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196409 is a reply to message #196407] |
Thu, 24 January 2013 23:02 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Weeelll...That statement is not quite accurate. We (I) really mean the
restriction to be to those with a GMC (or serious interest in them) and at
least interested in EFI. I'm pretty lenient, but don't intend for the site
to be wide open for all EFI stuff on every 'rod in the country. MAYBE I'll
re-write it, but I doubt that many qualified GMCers from GMCNet will be
deterred by the current wording. :-)
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Thu, Jan 24, 2013 at 11:50 PM, Larry wrote:
>
>
> Hi, BAD News. You have to have EFI installed on your motor home in order
> to join. A bunch of help for someone wanting to change over. You have to do
> it before you can get help.
>
> NOTICE on sign up page.
> Quote
> Owners of '73-'78 GMC TZE motorhome with EFI are eligible for membership.
> Requests for membership MUST include the year and model of your GMC, your
> location, and the type of EFI you're using. (You may also include
> additional comments to the manager.)
>
> --
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Wanted: Fuel Injection Impressions [message #196411 is a reply to message #196392] |
Fri, 25 January 2013 00:00 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| Dave Wilson wrote on Thu, 24 January 2013 14:25 |
Hi All,
We are considering making the change (finally!) to fuel injection.
That's the background, now the reason for this post: can anyone that has the time and an EFI system please comment on their personal experience with it? A couple of things we'd be interested in hearing are: 1) what type of EFI system you're using; 2) how many miles do you have with the system in place; 3)do the GMC gas tanks present any "fuel starvation" issues when travelling through the hills; 4) 4 "barrel" throttle body or 2; 5) finally, did you add a manually adjusted spark control or if you let an ESC system plug into your ECM to manage both spark and fuel.
Thanks in advance for all responses! Feel free to "unload" good and bad stories- we need to hear!
|
I will answer the questions as best I can. It appears there is some difficulty getting on to the EFI forum. Please, everyone, understand the EFI forum is not mysterious, closed group. It is run by Ken Henderson and Randy Van Winkle. 99% of the folks there are on this forum also. Google just keeps changing the rules, but they will get it straightened out.
1. Many are using the Howell system. Quite a few made up their own kit, usually using a GM TBI. Some get a wiring harness from a supplier to save the hassle of making that up.
I personally have a Howell kit to which I added distributor control and eventually the EBL add-on computer.
2. I have 32K on my EFI in this coach and probably 15K when the kit was in the previous coach. (Yes, I took it with me when I changed coaches.)
3. I think the tanks are OK. I have never starved for fuel. Like any system, crud will plug filters and plugged filters don't work worth beans. My tanks had Ethanol in them for years and looked like they came from the factory. Shiny.
As far as hills, we have been over some mighty steep hills... Rockies at least twice a year... going and coming. Raton pass in New Mexico will get any coach's attention. I have never had any kind of starvation related to heat, evaporation of fuel, etc. I did have to change my fuel pump under "the tree" that is along 80 in Nevada.
4.The Howell is a two barrel, 2" each. My 455 coach goes pretty well. When it is wide open at 3000 RPMs the MAP shows little or no vacuum. I think it is breathing OK.
The injectors have concerned the EFI group. Howell changed to injectors with less capacity. Most of us have turned up the fuel pressure to get enough fuel. GM TBIs came with larger capacity injectors and those folks run less pressure. (13# vs 18#)
The EBL shows us the duty cycle of the injectors and at 18# or so, the system has adequate reserve for extreme duty.
5. This one I feel very strongly about. What ever system you get, I would make sure it has complete distributor control. By this I mean knock sensor, computer controlled distributor _and_ that spark is adjusted with the current mixture the computer is sending to the engine. This is why many have gone to EBL. EBL adjusts spark for lean cruise and for power enrichment, all the while watching knocks, MAP (Altitude adjusted "vacuum"), temperature, etc. Spark control will probably yield the biggest increase in gas mileage. You are not going to get 14 mpg. Too much weight and too much air to shove out of the way.
Many of us have fiddled with or had some help fiddle with spark, fuel and many subtle settings. This is not because EBL or Howell or whatever is a bad kit. It is because our engines are all different not to mention final drives, transmissions and locale. Once it is dialed in it is not something that needs continual adjustment.
Folks on the EFI forum help new EFIs get up and running all the time. Nothing but fun.
Hope to see you soon on the EFI discussion.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Wanted: Fuel Injection Impressions [message #196413 is a reply to message #196392] |
Fri, 25 January 2013 01:08 |
rvanwin
Messages: 325
Registered: April 2007
Location: Battlefield, MO
Karma: 6
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Senior Member |
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| Dave Wilson wrote on Thu, 24 January 2013 16:25 |
Hi All,
We are considering making the change (finally!) to fuel injection. I've been trying to sell my father on this for some time, and the latest tank of gas running poorly through his carburetor may be the last straw for him. He's also noticed the carburetor gasket getting eaten much quicker lately and is convinced it's due to today's gas mixtures (and we put in 93+ octane and additives).
That's the background, now the reason for this post: can anyone that has the time and an EFI system please comment on their personal experience with it? A couple of things we'd be interested in hearing are: 1) what type of EFI system you're using; 2) how many miles do you have with the system in place; 3)do the GMC gas tanks present any "fuel starvation" issues when travelling through the hills; 4) 4 "barrel" throttle body or 2; 5) finally, did you add a manually adjusted spark control or if you let an ESC system plug into your ECM to manage both spark and fuel.
Thanks in advance for all responses! Feel free to "unload" good and bad stories- we need to hear!
|
Dave,
There are many that have been running efi for many years without any issues. Most of the early adopters opted to go with a kit supplied by Howell, Turbo City or Affordable EFI. These systems used the mid 80s ECM developed by GM and were mainly based on the 7747 ECM.
I opted for the Howell kit during a group buy about 6 years ago. My 403 was running good with the carb. I installed the kit (which only provided fuel management) and on the first test drive, I said "wow". A few months later, I installed the Computer Controlled Distributor (CCD)and on the first test drive, I said "WOW". Initially, I relied on others to help me get a chip that was good for my 403. I then obtained the equipment to "burn" my own chips and did some additional tuning on my engine and a few others. That tuning process was painful so about 3 years ago, I added the EBL system which greatly improves the tuning capability and, in fact, makes it a fun activity.
I have over 60,000 miles using the TBI and have had little problems with the system. A module and a coil caused a little problem (but that occurs on non efi systems as well). I also had a filter problem once but, again, non efi systems suffer from this problem. And I did have an O2 sensor go bad and that component is unique to efi. The engine still ran just fine but was in Open Loop. The only way I noticed was that I was not going into Lean Cruise.
I have never had any problems with fuel starvation (unless I ran out of fuel in the main tank before switching) either with the pump external to the tanks or now with in-tank pumps. I do take some precaution when I'm going to be in major hills to insure I don't run the tanks down too low.
A 2 barrel with 2" bores provides more than enough air flow for our applications.
There are several ways of getting to efi. Build your own by collecting all the piece parts. The most difficult part is probably the 2" bore TBIs. They were on the Chevy 454 (late 80s and early 90s) but are getting to be hard to find. This approach is the cheapest way but involves more work and understanding. The kit approach with the older GM ECMs with a possible upgrade with EBL. Then there is a several aftermarket EFI kits that work great and can be easier to install and tune but at a higher price. Further, there is another small segment who are doing port injection which requires a little more work.
No matter what you do, you will probably get between 8 - 10 mpg so don't look for mileage improvement to pay for investment. I believe I have gotten between 1 to 2 mpg improvement, but it starts ever time, doesn't diesel on shutdown, has no problems at different altitudes, makes some adjustment to the varying gas mixtures we are faced with these days, is more responsive (the wow factor), and with the EBL provides instantaneous mpg display, trip info, plus all the gauges that the ecm monitors as well as displaying WB O2 info and fuel pressure info.
If you come to Dothan, I will be leading a roundtable discussion about efi trying to answer any questions anybody has about efi.
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196419 is a reply to message #196413] |
Fri, 25 January 2013 06:37 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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Randy is the man
listen to what he says
(don't forget to talk about the "new" and "old" injectors)
and
what is available today
and the free "Randy install ":>)
gene
On Thu, Jan 24, 2013 at 11:08 PM, Randy Van Winkle <rvanwin@yahoo.com>wrote:
>
>
> Dave Wilson wrote on Thu, 24 January 2013 16:25
> > Hi All,
> > We are considering making the change (finally!) to fuel injection. I've
> been trying to sell my father on this for some time, and the latest tank of
> gas running poorly through his carburetor may be the last straw for him.
> He's also noticed the carburetor gasket getting eaten much quicker lately
> and is convinced it's due to today's gas mixtures (and we put in 93+ octane
> and additives).
> >
> > That's the background, now the reason for this post: can anyone that has
> the time and an EFI system please comment on their personal experience with
> it? A couple of things we'd be interested in hearing are: 1) what type of
> EFI system you're using; 2) how many miles do you have with the system in
> place; 3)do the GMC gas tanks present any "fuel starvation" issues when
> travelling through the hills; 4) 4 "barrel" throttle body or 2; 5) finally,
> did you add a manually adjusted spark control or if you let an ESC system
> plug into your ECM to manage both spark and fuel.
> >
> > Thanks in advance for all responses! Feel free to "unload" good and bad
> stories- we need to hear!
>
> Dave,
>
> There are many that have been running efi for many years without any
> issues. Most of the early adopters opted to go with a kit supplied by
> Howell, Turbo City or Affordable EFI. These systems used the mid 80s ECM
> developed by GM and were mainly based on the 7747 ECM.
>
> I opted for the Howell kit during a group buy about 6 years ago. My 403
> was running good with the carb. I installed the kit (which only provided
> fuel management) and on the first test drive, I said "wow". A few months
> later, I installed the Computer Controlled Distributor (CCD)and on the
> first test drive, I said "WOW". Initially, I relied on others to help me
> get a chip that was good for my 403. I then obtained the equipment to
> "burn" my own chips and did some additional tuning on my engine and a few
> others. That tuning process was painful so about 3 years ago, I added the
> EBL system which greatly improves the tuning capability and, in fact, makes
> it a fun activity.
>
> I have over 60,000 miles using the TBI and have had little problems with
> the system. A module and a coil caused a little problem (but that occurs
> on non efi systems as well). I also had a filter problem once but, again,
> non efi systems suffer from this problem. And I did have an O2 sensor go
> bad and that component is unique to efi. The engine still ran just fine
> but was in Open Loop. The only way I noticed was that I was not going into
> Lean Cruise.
>
> I have never had any problems with fuel starvation (unless I ran out of
> fuel in the main tank before switching) either with the pump external to
> the tanks or now with in-tank pumps. I do take some precaution when I'm
> going to be in major hills to insure I don't run the tanks down too low.
>
> A 2 barrel with 2" bores provides more than enough air flow for our
> applications.
>
> There are several ways of getting to efi. Build your own by collecting
> all the piece parts. The most difficult part is probably the 2" bore TBIs.
> They were on the Chevy 454 (late 80s and early 90s) but are getting to be
> hard to find. This approach is the cheapest way but involves more work and
> understanding. The kit approach with the older GM ECMs with a possible
> upgrade with EBL. Then there is a several aftermarket EFI kits that work
> great and can be easier to install and tune but at a higher price.
> Further, there is another small segment who are doing port injection which
> requires a little more work.
>
> No matter what you do, you will probably get between 8 - 10 mpg so don't
> look for mileage improvement to pay for investment. I believe I have
> gotten between 1 to 2 mpg improvement, but it starts ever time, doesn't
> diesel on shutdown, has no problems at different altitudes, makes some
> adjustment to the varying gas mixtures we are faced with these days, is
> more responsive (the wow factor), and with the EBL provides instantaneous
> mpg display, trip info, plus all the gauges that the ecm monitors as well
> as displaying WB O2 info and fuel pressure info.
>
> If you come to Dothan, I will be leading a roundtable discussion about efi
> trying to answer any questions anybody has about efi.
>
> --
> Randy & Margie
> '77 Eleganza II '403'
> Battlefield, MO
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196452 is a reply to message #196450] |
Fri, 25 January 2013 13:05 |
Dwayne
Messages: 418
Registered: October 2007
Location: White Rock BC
Karma: 0
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Senior Member |
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I just received my latest Good Guys Magazine. INside is an ad "Best
Selling Self Tuning EFI in the World. www.fuelairspark.com anyone
familiar with this?
Dwayne Jacobson
White Rock , BC
77 Kingsley
On Fri, Jan 25, 2013 at 10:25 AM, Larry Engelbrecht
<lengelbrecht@sandi.net>wrote:
>
>
> Waiting to be allowed access (btw I'm lengelbrecht at sandi dot net).
>
> I'm interested in doing a Megasquirt but want to hear what the community
> says about it first.
> --
> Larry Engelbrecht
> '73 26' ex-Glacier
> TZE063V100319 030773
> _______________________________
>
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Dwayne & Sharon Jacobson
White Rock, BC
77 Eleganza II
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196454 is a reply to message #196452] |
Fri, 25 January 2013 13:44 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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| Dwayne wrote on Fri, 25 January 2013 13:05 |
I just received my latest Good Guys Magazine. INside is an ad "Best
Selling Self Tuning EFI in the World. www.fuelairspark.com anyone
familiar with this?
Dwayne Jacobson
White Rock , BC
77 Kingsley
|
I'm pretty sure that's a typo, it should be "The most expensive Fuel injection system in the world"
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196482 is a reply to message #196464] |
Sat, 26 January 2013 01:11 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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With so many knowledgeable people running the Howell system, you have the
best technical support of any EFI unit on the market.
Ease of obtaining parts at any parts place is a plus.
If your ECM develops on the Howell, you can get another from any automotive
shop. If you have the EBL option, you do not want to turn it in as core, we
will warranty it and buy back the ECM .
On Fri, Jan 25, 2013 at 1:55 PM, Bruce Hislop <bruce@perthcomm.com> wrote:
>
>
> I purchased my Coach in the spring of 2008 and installed EFI in the late
> fall (Drove it home in a snow storm that evening!) Next spring it would
> start and run fine but everytime I let my foot off the gas then stepped on
> it again, the engine would bog.
>
> The issue turned out to be that Holley had reduced the size of the
> injectors in their TBI from 80 pounds of fuel per hour @ 13psi to approx
> 63pph. No where is this mentioned in any Holley literature I can find, nor
> did Howell seem to know this.
>
> Alot of people that purchased a Howell kit around that time were having
> the same issue. Yet guys with older kits (with 80pph injectors) were having
> no issues. There was alot of discussion on the Forum and EFI was getting a
> bad rap.
>
> Now that we have figured out the issue with the 63pph injectors and fixed
> that by increasing the fuel pressure, we've moved on to adding more
> upgrades like the EBL that offers more advanced improvements like spark
> control and deceleration fuel cut off.
>
> Things are pretty quiet on the EFI forum lately because everyone have
> their engines running so well now.
>
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
> Hubler 1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196519 is a reply to message #196450] |
Sat, 26 January 2013 14:53 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| LarryInSanDiego wrote on Fri, 25 January 2013 10:25 |
Waiting to be allowed access (btw I'm lengelbrecht at sandi dot net).
I'm interested in doing a Megasquirt but want to hear what the community says about it first.
|
Larry,
There are a several GMCers using Megasquirt. I believe one has upgraded to EBL.
I do not have Megasquirt, so I am ready and expecting corrections to what I am about to write. Sorry this is so long.
I believe Megasquirt to be a high quality unit. My concern is spark control. Looking at the spark control table, I see a "flat" table. By this I mean that it is one dimensional. It is a curve-able table in that you can pre-set the distributor to advance given RPM, MAP. According MegaSquirt throttle and temp is figured in somewhere. All, good stuff.
I would say that if you had Dick Paterson's spark table plugged into the Megasquirt you would have a distributor that worked pretty much like Dick's, and Dick's distributors have gotten us a zillion miles with great performance. He knows what he is doing.
EBL's spark control is built heavily on the GM EFI systems. The spark is not a flat table but rather a series of tables and "adders" that make fuel and spark interactive.
As an example of detailed spark control, EBL allows Lean Cruise. Lean Cruise turns down the fuel when cruising at say 65. This is a good thing. _But_ it also allows us to advance the spark when the fuel leans out. Lean mixtures burn slower. We are adding 3 and 4 degrees to the lean cruise. Every time my coach goes into lean cruise the MPG jumps one mile per gallon.
(Obviously I am not in lean cruise all the time and I am not getting 14 MPG)
EBL allows DFCO. (Deceleration Fuel CutOff) Now days, all cars shut off the injectors when coasting. (above a certain speed and RPM) If I could coast everywhere, I _would_ be getting 99 MPG. Ha.
So, if MegaSquirt, or any other of the good companies out there can do this kind of thing... having the computer watching fuel _and_ spark and making decisions about both from the information gathered from both I would be most interested.
EBL has a nice computer interface to change tuning, but MegaSquirt also has a great interface.
If MegaSquirt TBI can be run with a 7747 computer with EBL added, then I would think it a viable solution. It appears that MegaSquirt has 4 injectors on 4 ports. That might be attractive and an EBL 7747 can handle the 4 injector system.
Remember the wiring harness. My biggest hassle with this whole conversion has been wiring. No one's fault. I started with a Howell and realized I wanted (or could have) computer controlled spark. More wires. Then I got EBL and wanted to add a Vehicle Speed Sensor. More wires. Then I wanted to put a WideBand on the display. More wires. Then, just for fun, I wanted an Intake Air Temperature (IAT). More wires. Then I wanted Fuel Pressure on the display. More wires.
Don't do it the way I did. Find out _everything_ you eventually want, because rewiring is like rewiring a house after you built it because you are unhappy with phone jacks or electrical outlets. I am embarrassed by the "Beckman Wadup" that is under Ruth's seat... and running under the back of the hatch. Maybe someday I will rewire the whole thing like Ken Henderson did with little tags on each wire. It is beautiful to behold.
I want:
Fuel management
Spark Control (and the two interrelated)
Lean Cruise
DFCO
WideBand O2 sensor
Fuel Pressure
This means the following sensors: O2, throttle position, MAP, Engine Temp, Vehicle Speed, Wideband, and possibly Intake Air Temp.
Decide what you want. Think the moon. You don't have to add it all now, but you can plan for it so the addition is neat and easy.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Wanted: Fuel Injection Impressions [message #196523 is a reply to message #196464] |
Sat, 26 January 2013 15:16 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| rf_burns wrote on Fri, 25 January 2013 13:55 |
Things are pretty quiet on the EFI forum lately because everyone have their engines running so well now.
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I have thought of another "concern" perhaps not discussed here.
Carburetors have "power valves" that increase the amount of gas going in the engine. I am almost sorry the term Power Valve came into use as it makes some of us think that it is only for power. It is used when the engine is making lots of power and does add to the amount of power being made.
The real effect of the extra gas is that it cools the combustion chamber. If the power valve is not working valves and pistons can suffer catastrophically.
So, when getting an EFI kit we need to think about 12,000 pounds of coach and creature comforts plus perhaps a towed.
When I got EFI from Howell I didn't know beans. I decided to add exhaust temperature gauges to my coach because some were telling me I was going to burn up my engine with Lean Cruise. (As a side bar it turned out things got cooler when in Lean Cruise)
Since I have added EBL I have had occasion to have the benefit of BobR's (developer) comments on several aspects of EFI. One is that I know EBL (and probably any 7747 based EFI) have Power Enrichment. When we push down the peddle, the "Power Valve" opens. BobR told me that the longer you are on a hard pull, the richer it goes.
This is not BobR's invention. GM figured this one out. Important in a car. I am thinking _very_ important to a GMC pulling the Grapevine or Raton Pass.
As a side bar, I delayed the Power Enrichment on my coach. Exhaust temperatures went up _fast_. Very fast. Like 200 degrees in 30 seconds. I put the EBL back to the GM Power Enrichment settings and have not touched that since.
You folks with carbs, this is important for you too. Unless you _really_ know what you are doing, don't start bending things and changing jets to get better mileage... you might need new valves and pistons. (another reason the GMC Motorhome carb is _not_ the same as the car version.)
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Wanted: Fuel Injection Impressions [message #196550 is a reply to message #196519] |
Sat, 26 January 2013 20:45 |
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wally
Messages: 643
Registered: August 2004
Location: Omaha Nebraska
Karma: 5
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| George Beckman wrote on Sat, 26 January 2013 14:53 |
| LarryInSanDiego wrote on Fri, 25 January 2013 10:25 |
Waiting to be allowed access (btw I'm lengelbrecht at sandi dot net).
I'm interested in doing a Megasquirt but want to hear what the community says about it first.
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Larry,
There are a several GMCers using Megasquirt. I believe one has upgraded to EBL.
I do not have Megasquirt, so I am ready and expecting corrections to what I am about to write. Sorry this is so long.
I believe Megasquirt to be a high quality unit. My concern is spark control. Looking at the spark control table, I see a "flat" table. By this I mean that it is one dimensional. It is a curve-able table in that you can pre-set the distributor to advance given RPM, MAP. According MegaSquirt throttle and temp is figured in somewhere. All, good stuff.
I would say that if you had Dick Paterson's spark table plugged into the Megasquirt you would have a distributor that worked pretty much like Dick's, and Dick's distributors have gotten us a zillion miles with great performance. He knows what he is doing.
EBL's spark control is built heavily on the GM EFI systems. The spark is not a flat table but rather a series of tables and "adders" that make fuel and spark interactive.
As an example of detailed spark control, EBL allows Lean Cruise. Lean Cruise turns down the fuel when cruising at say 65. This is a good thing. _But_ it also allows us to advance the spark when the fuel leans out. Lean mixtures burn slower. We are adding 3 and 4 degrees to the lean cruise. Every time my coach goes into lean cruise the MPG jumps one mile per gallon.
(Obviously I am not in lean cruise all the time and I am not getting 14 MPG)
EBL allows DFCO. (Deceleration Fuel CutOff) Now days, all cars shut off the injectors when coasting. (above a certain speed and RPM) If I could coast everywhere, I _would_ be getting 99 MPG. Ha.
So, if MegaSquirt, or any other of the good companies out there can do this kind of thing... having the computer watching fuel _and_ spark and making decisions about both from the information gathered from both I would be most interested.
EBL has a nice computer interface to change tuning, but MegaSquirt also has a great interface.
If MegaSquirt TBI can be run with a 7747 computer with EBL added, then I would think it a viable solution. It appears that MegaSquirt has 4 injectors on 4 ports. That might be attractive and an EBL 7747 can handle the 4 injector system.
Remember the wiring harness. My biggest hassle with this whole conversion has been wiring. No one's fault. I started with a Howell and realized I wanted (or could have) computer controlled spark. More wires. Then I got EBL and wanted to add a Vehicle Speed Sensor. More wires. Then I wanted to put a WideBand on the display. More wires. Then, just for fun, I wanted an Intake Air Temperature (IAT). More wires. Then I wanted Fuel Pressure on the display. More wires.
Don't do it the way I did. Find out _everything_ you eventually want, because rewiring is like rewiring a house after you built it because you are unhappy with phone jacks or electrical outlets. I am embarrassed by the "Beckman Wadup" that is under Ruth's seat... and running under the back of the hatch. Maybe someday I will rewire the whole thing like Ken Henderson did with little tags on each wire. It is beautiful to behold.
I want:
Fuel management
Spark Control (and the two interrelated)
Lean Cruise
DFCO
WideBand O2 sensor
Fuel Pressure
This means the following sensors: O2, throttle position, MAP, Engine Temp, Vehicle Speed, Wideband, and possibly Intake Air Temp.
Decide what you want. Think the moon. You don't have to add it all now, but you can plan for it so the addition is neat and easy.
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We have a Megasquirt 3 installed. It does all these things. Paul Lamke ran Megasquirt. One other by the name of Wayne was working toward it.
A GM ecm with EBL would be the way to go to take advantage of the combined experience of the EFI group. George and Randy have shared their excellent timing table which will certainly get you on the right track. It did me.
Megasquirt has a large array of user choices on how it is implemented and configured. Presently I'm running speed density like a 7747 ecm with the option of going to Mass air flow instead. I did have a 7 pin HEI distributor but changed to wasted spark so I can use a modified distributor body as a cam position sensor. Presently I'm using two injector drivers on port injection as batch fire. The plan is to use all eight injector drivers when I get the cam sensor installed and have sequential fuel injection. There is an option for individual cylinder fuel trim if I could ever figure out how to use it. There are also eight ignition outputs that can be used if you want coil on plug ignition also with individual cylinder spark tables. There are at least two ways megasquirt handles knock retard. The latest version uses "windowing" where the sensor is only active during the crank angles that spark knock would occur. This eliminates other noises from triggering retard.
I do have DFCO set in the fuel table. Also lean cruise is set in the AFR and fuel tables and the wide band trims to the lean cruise AFR setting real time. Lean cruise is immediate and continuous rather than after a time like a 7747 would do. Squirt does the same things only in a different way. You get to figure out how to make it do what you want.
EBL and Megasquirt will both tune fuel tables automatically with software. For megasquirt this got way better with the release of Tuner Studio.
All of this and only 8 to 10 mpg!
Wally Anderson
Omaha NE
75 Glenbrook
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