Home » Public Forums » GMCnet » Caddy 500 Fuel Injection / Ignition Systems
| Caddy 500 Fuel Injection / Ignition Systems [message #369795] |
Tue, 24 May 2022 17:34  |
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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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G'day,
As noted in my other email I am keeping the Avion I have Downunder and would like to change from the Quadrajet to a fuel injection system and better ignition system.
What's the consensus of opinion on what systems to use.
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: Caddy 500 Fuel Injection / Ignition Systems [message #369797 is a reply to message #369795] |
Tue, 24 May 2022 20:03  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Personally. Rochester 454 throttle body. With affordable efi kit and ebl ecu.
Very proven. and easy to source parts and troubleshoot. Randy can help you tune it for the caddy.
Larry and Bob Miller run fi-tech’s on their caddy’s. But larry just went through some issues. I am constantly hearing issues with all the other units. (Fi-tech, and sniper). When they work they work though.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369799 is a reply to message #369795] |
Wed, 25 May 2022 06:57 |
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RF_Burns
Messages: 2276
Registered: June 2008
Location: S. Ontario, Canada
Karma: 3
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I forgot to mention, the GM/EBL system also integrates the ignition control (ESC) system using an Olds ESC HEI distributor from a mid '80's 307.
EFI makes the engine start and run like a modern engine, but ESC really wakes it up!
If you elect no to go with ESC from the start, you need a small circuit board that reduces the 12V pulses from the distributor TACH output down to 5V pulses. Howell came with this circuit in the wiring harness, but I'm not sure about how Affordable EFI handles this. The google group can help if you need this.
Don't worry about all the tuning capabilities, there are downloadable files on the Google group. They are very easy to flash into the EBL if not preloaded. If you want to get into the meat of the system, the EBL makes that easy as well. Or you can just let it do its thing, no worries.
Since you a higher pressure electric fuel pump for EFI, many of us have gone to dual pumps at the tanks. This eliminates the tank selector valve and gives redundancy with a second fuel pump.
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
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
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369800 is a reply to message #369799] |
Wed, 25 May 2022 08:29 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Affordable EFI can do the harness with the ignition control, ect.. they offer a turn key kit, and I know GMC folks that only run one of their complete kits. I believe they utilize a Holly TBI, but I am not positive. they also seem to program chips to applications.
The EBL adds much more to the equation especially if you have funky cams, or other things with the engine you can tune a little more and do the VE learning. Plus the "whats up display" and the digital dash are only available with the EBL. with the affordable you just have the blinky light for diagnostics, unless you can find an old OBD 1 scanner.
so if you do not want to source all the different parts, affordable EFI seems to be a simple way to go. if I was to do mine over, I would at least buy their wiring harness, rather then all the modifications I had to make to the GM one.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
[Updated on: Wed, 25 May 2022 08:31] Report message to a moderator |
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369802 is a reply to message #369795] |
Wed, 25 May 2022 22:02 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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I would think it would be easiest?? I do not know Australia at all, but it is 99%
Parts from any gm based truck from 88-94.
The ebl ecu is proprietary, but rarely an issue and you can substitute in another ecu to limp by.
I would buy the affordable kit with ecu. And buy the ebl ecu. Then you can keep the affordable ecu as a spare.
The other efi systems i know people who have trouble getting parts in the states. You have to ship the whole unit in for repair.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369803 is a reply to message #369795] |
Thu, 26 May 2022 07:10 |
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RF_Burns
Messages: 2276
Registered: June 2008
Location: S. Ontario, Canada
Karma: 3
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Rob,
For a number of years GMCer's were having excellent results with the Howell EFI kits which they built for the GMC Motorhome. Around 2009 (the time I purchased my kit) Holley changed the injectors from 80 pound per hour (PPH) fuel rate to ~63pph. Howell seemed unaware of this and the change threw the fuel calibrations out of kilter. The fix was to increase the fuel pressure so the smaller injectors would flow 80PPH. However the pressure regulator in the Holley throttle body (TB) could not regulate at the desired pressure so there was still fueling problems. While trying to fix issues with the smaller injectors, I came across the EBL system. It made fixing the fueling tables a snap. Ken Henderson also installed the EBL and soon a number of people with the smaller injector problem were installing EBLs.
Since the Holley could not regulate to the desired pressure and was unstable, many of us have changed to Rochester TB's from a 454 which had the higher flow injectors. I don't know if Holley brought back the higher flow injectors, or if Howell is using an external pressure regulator to make the smaller injectors flow at 80PPH. Maybe Randy Van Winkle would know. We do know the Rochester TB from a 454 does flow at the desired rate and works well.
As far as parts, the GM TB EFI system was used on millions of vehicles over many years. The sensors are readily available from many aftermarket sources. They are analogue output sensors (0-5 volt) mostly variable resistance so I would think other manufacturers sensors might also work. Did Holden use GM engines?
The sensors are:
-Coolant Temperature: thermistor
-O2 sensor: common part to many manufacturers
-MAP sensor: aka vacuum sensor. This might be harder to get down under, but is a common GM part.
-Throttle Position sensor: part of the TB, it's just a variable resistor, so more of a wear part.
-Ignition module for spark control: Common part, but good to have a spare.
I have never had a sensor failure (touch wood). Fuel pumps being mechanical, seem to be the main failure. I changed to dual pumps and kept my original EFI for a spare (10 years old and was still working). With dual pumps, I have redundancy.
As Jon said, the aftermarket kits use proprietary parts and require you to return it for any repairs. That pretty much forces you to carry a whole spare system with you. My biggest issue with them was they had the electronics housed in the TB. Heat is a big enemy of electronics and caused issues. I now see some aftermarket systems have moved the electronics to a separate box to install inside the coach.
I carry my original ECM from Howell as a backup, but have never needed it. Except for my original issues with Holley's smaller injectors, I haven't had any real issues with the GM based EFI system.
This document has all the common GM sensor part numbers. You could see if they are available either OEM or aftermarket down-under.
http://www.gmceast.com/technical/Swartzendruber_Generic_TBI_SlidesNotes.pdf
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
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
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369805 is a reply to message #369803] |
Thu, 26 May 2022 09:23 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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That reminds me of one important fact. Fuel delivery is the #1 issue with EFI. That is where you need to really spend your thoughts on how you want to accomplish that. There is not one true method to do this. I copied randy van winkles document and using 2 fuel pumps. Some systems use sumps. Fi-tech has their fuel command that seemed to cause all sorts of issues at first but people now claim those issues are fixed and it is the solution.
So really how you decide to get fuel up to the engine is just as varied of a decision as what efi you bolt on.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369807 is a reply to message #369802] |
Fri, 27 May 2022 03:01 |
cadelec
Messages: 303
Registered: September 2011
Location: Brisbane Australia
Karma: 1
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Senior Member |
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Hi Rob
I have Bobby Moores old system. he soucered a harness from Turbo city. i have only had a few problems
1 was an O2 sensor this was a universal part and easily sourced here
Fuel pimp was replaced around 3 years ago i just purchased a spare it came from rock auto in 10 days
i needed a oil pressure switch i found one off of a 90s commodore
i chamge my fuel filter (at the input to the fuel pump) once a year it always has crud in it but its easier than dropping tanks
i also have another filter between the pump anf the throttle body
in my view the whole system is very simple and any parts are only 10-14 days via rock auto
i also assume the parts that may fail wilould be relitively cheap and you culd justify carrying a spare of nearly everything
also there is a large following of chevs here in OZ so places like
All American Autos https://www.allamericanautoparts.com.au/parts/
Eagle Autos
Bruce Jones had problems with his Holly sniper which left him staranded in Toowoomba
i have a fair bit of confidence that if something goes wrong i can diagnose or find someone who can help
Trevor
Brisbane Australia
Siesta Koala 76 Edgemont (old Bobby Moores)
71 Cadillac Eldo Convert
58 Cadillac Eldorado Brougham Project
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369821 is a reply to message #369795] |
Mon, 30 May 2022 12:25 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Rob, my coach has the Atmonic MSD injection system, currently owned and supported by Holley although how much longer they will offer support is open to question since they developed and sell the newer holley sniper system. Miguel Mandez fitted it for the PO, likely because it was at the time accepted by CARB, and it was a California coach. Trouble free so far.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Caddy 500 Fuel Injection / Ignition Systems [message #369826 is a reply to message #369795] |
Tue, 31 May 2022 21:53 |
Scott Nutter
Messages: 782
Registered: January 2015
Location: Houston/San Diego
Karma: 4
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Senior Member |
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Welcome back Rob! I got to agree with Johnny…. I have the MSD Atomic set up on my coach and I have had ZERO issues with it the last 5 years and 25,000 miles. It is absolutely amazing for a $1,200 hit. But that was the complete system.. every issue I’ve had with my 2 previous carbs are gone. I especially love it when I’ve been at a campsite for 2 weeks and go to start it! No stalling, smoke, rich gas smell, or hesitation. It runs better than most other campers tow vehicles.
I would really like to do the full blown Howell ebl etc etc, but right now, I don’t have a reason to.
BTW, there is a SD carb that can update the computer in the module unit when there is a update, but it won’t hurt anything if you don’t. But if you do, it’s all over the Internet.
We will talk soon! Scott
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI
Houston, Texas
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