Home » Public Forums » GMCnet » [GMCnet] throttle body fuell injection
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| Re: [GMCnet] throttle body fuell injection [message #196734 is a reply to message #196727] |
Tue, 29 January 2013 05:48   |
Jim Bounds
Messages: 842
Registered: January 2004
Karma: 0
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Guys, I've pretty much left this thread alone, hey many of you guys have and are dealing with FI modifications and that's fine-- more power to ya.
My post however is maybe for those lurkers out there that are starting to feel to be "with it" they must jump into the deep end of the pool and try and figure out fuel injection even though they really don;t want to and do not have the background to do it. Everytime the prez get on natl. TV there is a rebual so here is one for this thread.
If you see your coach as an extension of the hot rod you built in high school and part o the lure for getting it is to screw around with it and you not only want to but must be the one to keep her on the road and maintained, fuel injection and a pile of other cool "KPD's", that's "knobs per dollar" is something you would never do without.
If you, however, do net see yourself with a big grin through a greasy face loving life with a wrench in your hand, I would not suggest fuel injection and here is why:
1. New cars have millions of dollars spent in matching the computer engine management systems to optimize a motor, reading the entire manual and lurking on mailing lists will not give you that input modifying your old big block American iron to FI.
2. Be sure to have a complete list of replacement parts and a clear understanding of the diagnostic tree of how to maintain and repair the system because out on the open road YOU will probably be the one heading up any repairs. In general, mechanics and service writers who run the business for dealerships and even B line repair centers do not see themselves getting into a liability loop of aftermarket mods made to drive trains. If you break down on the road, it can be a scary place out there trying to find mechanical help, it makes no sense in complicating your situation.
3. To date, I have not seen an economic upside to spending the time, money and risk at installing fuel injection. Purly economically speaking-- not cause you like it but just the dollars and sense of it-- there is not a large pickup in economy, it starts and stops nice but a well maintained carb will too. It will adjust for altitude but a carb will not drop to let you down, it will just not be as efficient-- it will usually keep working if you take care and adjust your driving. When something goes wrong, if you can find someone to mess with it, there will be time for them to discover what you have so any work done will usually take more time and cost more.
4. I am not saying it is bad Juju for many, it's just an additional liability if you are not going to be the one first person in figuring it out when there is a problem. To those that have had no problems with theirs-- super-- the question is not if there will ever be failure but when and when it does happen, what assets will you have to get going again?
5. While it's true all vehicles today use FI and many mechanics today have no ide about carbs but there will usually be someone who does understnad them and even if not, the learning curve and diagnostics of a carb system is no big deal. If somethiing craps out in an original ignition or fuel delivery system, it will be much easier to find a repair. Heck, you can spray WD 40 into a carb and get the motorhome out of an intersection-- try that with an FI system!
OK, so there is my rebutal-- no need to rebute my rebutal, I feel though for the lurkers to get a full view of the issues-- there must be a contrasting view to keep things real. I do not want to put my customers in harms way, I do not want them to be out on the road with few options other than a tow. I am building machines for a nn-technical person or someone who does not want to get down with the motor themselves. We build coaches that take people places and they do things with. Largly speaking, you guys who go for FI do not do business or want the machine we build mainly because you have personal things you feel you must have. You do not need those things to produce a reliable machine and chances are it will be better if you did not have all of that modified stuff in your engine compartment if "bubba" will be your mechanic to solve your problem!
If you fee the enthusiast hair stand up on the back of your head on what I say here-- you really should get FI. If on the other hand you seek simply a reliable, servicable, easier maintainable vehicle where you are not "big daddy" when it comes to fixing it, you may want to push yourself away from the FI table.
This rubutal message has been brought to you by the bassomatic-- makes a good floorshine, mmmm makes a good whipped topping...
Jim Bounds
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From: Dan Gregg <gregg_dan@hotmail.com>
To: gmclist@temp.gmcnet.org
Sent: Monday, January 28, 2013 11:42 PM
Subject: Re: [GMCnet] throttle body fuell injection
Bob, Sent you an email a couple of days ago. You thinking you will do the door before Dothan? If so, get ready for lots of lookers during open house.
See you there.
Dan
--
Dan & Teri Gregg
Dexter, Mo.
http://danandteri.blogspot.com/
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| Re: [GMCnet] throttle body fuell injection [message #196752 is a reply to message #196734] |
Tue, 29 January 2013 10:29 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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Senior Member |
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| Jim Bounds wrote on Tue, 29 January 2013 04:48 |
... hey many of you guys have and are dealing with FI modifications and that's fine-- more power to ya.
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I wonder if Jim's pun was intentional... 
I do have to agree with Jim though. FI isn't for everyone. Having an essentially custom installation on your rig could possibly cause problems if/when a paid tech is crawling around trying to trace down a problem. Of course, most of the systems (i.e. Howell) use the ubiquitous 80's GM computers and throttle bodies, so won't really be that foreign to most techs, though the devil is in the details.
OTOH, it can be "interesting" to get a carb tuned and optimized for your engine, too... though once it's set up, it should be very reliable (within the limitations of what a carburetor is designed to do, of course).
To me, you have to balance the pros and cons to determine if installing a FI system is worth it or not...
Pro:
1) Better starting
2) Better high altitude performance and efficiency (might not matter if you never "go high").
3) Potential for more power and/or better efficiency (both are entirely different discussions)
4) You can outfit many FI systems with EBL, which will give you real-time feedback, diagnostics, and potentially better fuel economy (at the cost of $$$ and more time)
5) There are fewer parts to wear out in a throttle body than a carb (a lot less fiddly)
6) Serious "car nuts" probably won't have huge problems installing a system, and will have something new to play with.
Con:
1) Will the advantages above really "pay back" the investment in time and money you put into the installation? You can buy a LOT of gas for the price of a typical FI system.
2) Potential for "interesting troubleshooting experiences" if you break down on the road (though a carburetor failure on the road has its own potential for difficulty).
3) Your rig might be off the road for weeks (or longer) if you hit snags in the installation of the FI system.
4) If you live in California, the friendly folks at the Bureaucracy of Vehicle Inspection Bureaucracy might deem that you've broken various laws of nature and insist that you put a smoggier carb back on.
Me? I've got a cobbled-together system laying on my office floor. I found a used (read "cheap") Howell TB FI system that was set up for a big block Chevy. The reason I went that way was because it's set up to control the distributor (which I liberated from a car at the men's mall), which is really crucial if you're trying to get more gas mileage and the best performance (most of the Howell systems don't control the distributor). Will I run into "interesting things" during the installation? Almost certainly. But just like this forum, there are other online resources out there where very knowledgeable people are willing to help (and I'm a "car guy", and a "computer / electronics guy", so have a pretty good head start). OTOH, I'll end up with a one-off system that's not quite like any other. Pray for me. 
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: [GMCnet] throttle body fuell injection [message #196757 is a reply to message #196734] |
Tue, 29 January 2013 11:56 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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When faced with replacing my carb on The Pig or updating to fuel injection I opted for the Howell system with EBL which I bought from Applied along with a Patterson dist. The existing carb was a non motorhome Quadrajet which means I did not even have a good core for a quality rebuilt. Once the system was installed and functional I have not had to touch it. The Pig starts up quickly without any throttle english and runs smoothly no matter what elevation or vehicle load. I did have a few issues getting the system on line but that was the result of trying to tie in an oil pressure cut off switch for the fuel pump. After a few phone calls to Jim K at applied and tech support at Howell I removed the low oil pressure switch from the system and everything has been fine. I am not computer or electrically fluent but after installing the system myself and following the trouble shooting chart supplied with the system and a few phone calls to tech support at Howell and Applied the system is all of what was promised. Installing and trouble shooting the system myself forced me to understand how it works and how to systematically trouble shoot problems with it should they occur. The Howell system from Applied may not be the cheapest way to a complete system but it is a truly complete plug and play system which did not require deep system knowledge necessary to build a system from scratch parts. If a problem does occur I am confident that it can be fixed over the phone and all of the system parts are common Gm parts ( such as the fuel pump relay I kept smoking while trying to integrate the low oil pressure safety switch) stocked at all National chain auto parts stores.
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] throttle body fuell injection [message #196776 is a reply to message #196760] |
Tue, 29 January 2013 16:15 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Carl,
The fuel injection systems such as Howell, Holley, Megasquirt are all throttle body FI systems.
The throttle body is the same as a carb body (venturis and throttle plates).
The FI system injects the fuel into the throttle body venturis whereas the carb uses vacuum to suck the fuel into the venturis.
Squirting WD-40 or gasoline into the throttle body venturis or carb venturis will get you out of an intersection.
The problem is getting it fixed if you're not technically savvy after that! ;-)
BTW Double Trouble has a Paterson Q-Jet and dizzy, The Blue Streak has a Holley Commander 4 barrel EFI and a MSD dizzy. Double
Trouble runs well (except at altitude); The Blue Streak lives up to its name and goes like a shower of s#!t!
Regards,
Rob M.
Sydney, Australia
AUS '75Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of noi
Sent: Wednesday, 30 January 2013 5:31 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] throttle body fuell injection
Greetings JimB:
Not looking to rebut your rebuttal, but;
Heck, you can spray WD 40 into a carb and get the motorhome out of an intersection-- try that with an FI system!
Computer controlled FI&Dist combo aside (only FI and normal Dist), why would spraying WD40 into a carb; supplying; fuel WORK and
spraying WD40 into a FI; not ejecting; NOT work?
Looking for enlightenment, not arguing with you :p
Carl P.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] throttle body fuell injection [message #196829 is a reply to message #196785] |
Wed, 30 January 2013 07:06 |
Jim Bounds
Messages: 842
Registered: January 2004
Karma: 0
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Senior Member |
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I sort of got carried away when I made that statement-- you may be able to do it but with most of the FI systems folks are using that ties the ignition to the fuel system varying it all together that they really do work well when they work-- heck, that's not the question the problem is when something goes wrong it seems they really fail hard with little driver alternatives.
Really, I'm not being totally down on the systems-- that might be looked at as short sighted on my part but for the coaches we see, the customers we work with and the scenarios I see people having on the road-- I cannot tell you how many people have been stranded with few option other than a huge tow bill. Once Jim K. saved one guys bacon by driving 4 hours 1 way and did it 2 times only to find that the non weatherproof connectos on the cpu mounted under the coil pack on the back wall of the engine compartment were corroded causing nothing to happen by way of the coach starting. No one would help so Jim K. made it happen for this guy. Those are the things I see with fuel injection.
I kinda feel bad some think of me as backward on this but after installing and working with many systems -- throttle body, direct port and all-- when a carb is involved, if all else fails in one day I can have a brand new distributer for $195 anywhere in the lower 48 the next day. If the motor isn;t locked up we can make it run and that's everything when I'm trying to help someone long distance.
I hade once a direct port FI system in my coach (Larry), coming back from a music festival I threw a fan belt and the motor just stopped! Turns out the fan belt nicked the wires on the front mounted crank trigger and I bought property right there. I should not have been put in harms way, something as small as throwing an AC belt which I should have been able to continue to motivate, the FI system I had put me in harms way. These "unexpected results" are what I do not want to expose my customers to. Then when I finally beat out of the guy I got the *&^%$ system from what the crank sensor was from, it was off of a Beretta-- if I would have known that yea, I might have been able to fix it but I or no one else had any idea what the part was. This is why I say really know your system, know the part numbers and how to fix the thing yourself. If you do then OK, if you don't-- don;t leave home without it!
Don't hate me because I no longer FI. I've been to that mountain-- fell of the other side and if I can keep someone else from falling like I did then I've done my job. KNow what you have and be prepared to use your knowledge...
Jim Bounds
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________________________________
From: noi <v76_Birchaven@yahoo.com>
To: gmclist@temp.gmcnet.org
Sent: Tuesday, January 29, 2013 7:19 PM
Subject: Re: [GMCnet] throttle body fuell injection
Greetings Emery,
My statement/question was prompted by JimB’s thoughts about Fuel Injection – I was not questioning or taking him to task about it, but was curios why he would say:
“Heck, you can spray WD 40 into a carb and get the motorhome out of an intersection-- try that with an FI system!”
As he did not say if he was discussing a FI or FI/CCD setup, I preferenced my question (or at least tried to) to ask…. If you just had a FI system (say MSD Atomic) with a regular distributor (say Paterson), would not spraying WD40 into that setup work equally as well?
I fully agree with you that a FI/CCD system would not work for the very reason you said.
Carl P.
76 Birchaven
South of Fremont
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| Re: [GMCnet] throttle body fuell injection [message #197049 is a reply to message #196718] |
Fri, 01 February 2013 09:33 |
MIGUEL MENDEZ
Messages: 179
Registered: August 2004
Location: Montclair, California
Karma: 3
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Senior Member |
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After reading all of this, I thought, hell, why not give it a try, i got 22 MSD Atomics on the road as of now with no problems but, what if i do get stuck in an intersection, hmmmm, so, off to the yard i went, got a can of brake cleaner, yes, i said brake cleaner, sprayed into the msd TB and voom, fires right up, however, if your using the spark controller, won't happen, so far, the 22 installed are running just fine with the stock HEI system, and no problems, however, the MSD, and the Howell systems, both do go into limp mode so yes, you'll still be able to drive across the street if need be
Miguel
1978 Royale Pain in the %$@, side bath w/ a 403 that i love.
GMC name : The other woman
http://www.mgmgmc.com
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| Re: [GMCnet] throttle body fuell injection [message #197052 is a reply to message #196718] |
Fri, 01 February 2013 09:46 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Can someone explain why the spark controlled system won't run with external fuel?
Does it check fuel pressure???
Other wise how does it know??
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] throttle body fuell injection [message #197061 is a reply to message #197052] |
Fri, 01 February 2013 10:06 |
rvanwin
Messages: 325
Registered: April 2007
Location: Battlefield, MO
Karma: 6
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Senior Member |
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| Keith V wrote on Fri, 01 February 2013 09:46 |
Can someone explain why the spark controlled system won't run with external fuel?
Does it check fuel pressure???
Other wise how does it know??
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I have also been thinking about this. I'm not sure it won't fire and run. The only problem is that you couldn't "fill the bowl" and get some run time so you would have to continuously dribble in your choice of flammable liquid. The ECM will shut down the injectors if it is not getting a positive return from the distributor, so no spark, no injector firing. But I don't know of anything in the programming that would know if the injectors are not getting fuel. While fuel pressure is a possible display item when running the EBL, FP is not a sensor input into the ECM.
Would be good to know this. A little test seems appropriate?
Randy & Margie
'77 Eleganza II '403'
Battlefield, MO
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| Re: [GMCnet] throttle body fuell injection [message #197076 is a reply to message #197063] |
Fri, 01 February 2013 12:43 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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Matt,
What I am asking is from the comments that a TBI engine with spark control won't run if you spray WD-40 in the Throttle body.
I'm wondering how the ECU knows that the injectors arnt supplying the fuel?
If theres no Fuel pressure sensor, I don't see how the ECU would know and I'm thinking the TBI engine would run just fine...well as well as anything:)
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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