Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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Russ Verbael

(1 posts)

10/11/2016 07:54AM

Main British Car:

1994 GM 3.4L Fuel Injection
Posted by: RussV
Date: December 12, 2016 01:00PM

Help, Help, Help.

I just bought a 3.4 V-6 from a '94 Pontiac and would like to learn HOW the fuel injection system works. My question is: where can I get a comprehensive entry-level manual that describes in detail the 3.4 fuel injection components, features, operation, trouble-shooting, with diagrams, schematics, etc?? This is my first experience with a fuel injected engine and I want to learn enough to be able to deal with all the details.

In other words, a "3.4 Fuel Injection For Dummys" book. Is there such a manual available??

Responses are welcome by phone (406) 781-7233 or by BritishV8 private message.

Thanks for any assistance.


Edited 2 time(s). Last edit at 12/13/2016 02:22AM by Moderator.

Curtis Jacobson
Portland Oregon
(4369 posts)

10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 1994 GM 3.4L Fuel Injection
Posted by: Moderator
Date: December 13, 2016 02:20AM

Welcome to BritishV8, Russ!

I've moved your first post into its own thread and re-titled it in hopes that you'll get more replies that way.

And, I've removed your email from your post in hopes that you'll get less spam emails that way. I strongly recommend never, ever, ever posting your email address on a message board. BritishV8 users who want to contact you can easily use our secure private message system - it works GREAT!

Is it safe for me to assume your 1994 3.4L is the one that looks like this?

More pics and descriptions of the mighty "3.4 SFI" engine may be found in these three articles: James Spradlin's, Charles Long's, and Brian McCullough's. (Photo captions may help you identify components.)

On message boards, it often works best to ask rather specific questions. Otherwise, folks don't know what you don't know.

If you prefer to talk to someone, I'd recommend phoning Brian because he's in the business of selling parts for installing these engines into British sports cars. Look for "BMC" in our vendor directory, which you'll find under the "Contacts" tab at the top of this page. Tell him we sent you.

For troubleshooting specific GM 3.4L components, this website is a good place to start: [easyautodiagnostics.com]

Edited 1 time(s). Last edit at 12/13/2016 02:24AM by Moderator.

Brian Mc Cullough
Forest Lake, Minnesota, USA
(373 posts)

10/30/2007 02:27AM

Main British Car:
1980 MGB '95 3.4L 'L32' SFI V6, GM V6T5 & 3.42 Limi

authors avatar
Re: 1994 GM 3.4L Fuel Injection
Posted by: BMC
Date: December 17, 2016 06:10PM

I have two books to recommend if you are planning to build your own wiring loom:

Chiltons manual for the specific vehicle
Motorbooks Chevrolet fuel injection 124678.

For the 3.4L L32 engine we make the brand new wiring looms that are VERY easy to install. Very little work to it and it can be used to run the engine outside the car if desired such as on a dyno.

I have had people ask me if we could charge less for it and to build it more economically but I don't like leaving people high-and-dry not now or in the future. We build a finished product that you are not left trying to determine what plugs are for, what are not required, where they fit around the engine and so on. I give telephone support where it is needed but if we sold an incomplete and lower priced unit, there would be so many phone calls I would not be able to sustain them. Build a good loom= less issues, less time building, quicker to get the car driving. We also support with photos and other documentation for those purchasing from us. If you have seen what we do you know we want something that looks like it could have come from the factory- and better.

We could leave you with an unfinished product, additional weeks of study and work and charge half as much for it. There would be no support for something like this LS1 V8 loom:

The price of the V8 unit above is just about $200 less than ours (and they build these in high quantities!) plus it does not come in half so if the engine is pulled, you must leave the engine loom dangling over your pain or sitting on the floor between the rails in the engine bay. From the products available on the market, I know we offer a very good price on our parts. If you are interested in all new plugs, high quality new wiring and a loom that is plug and play, keep ours in mind. We used to rebuild the stock engine loom and give it a plug to mate into our graft in section of the wiring loom but a few years ago, the price to continue doing that with all the plugs (even purchased in quantities!) and wire and time got so expensive that we went to new Everything. Most of the wiring looms are either soaked with oil or burned out due to poor wiring location thanks to the engineers.

Here is our wiring loom:

Or if you want to see more about the two separate halves of the above kit, here they are:

Engine to PCM:

Chassis to main engine loom:

Hope this information helps,


David Stephens
(10 posts)

07/14/2017 03:41PM

Main British Car:
Absolutely original custom freak TBD, probably '98 Vortec 7400

Re: 1994 GM 3.4L Fuel Injection
Posted by: KadettB
Date: July 14, 2017 04:49PM

I had a 94 Camaro with the 3.4, had over 300k miles on it when I got it. Over my first year I tried everything to solve a misfire that got worse as it warmed up, and worse at larger throttle openings. Nothing ever solved it. I could get one good wot pull every morning, then the misfire would return. Nothing ever changed that, and I tried it all.
The only thing left to try was the aluminum heads, intake, and sequential port injection from the much higher output front wheel drive transverse 3400 V6. But I gave up and tossed the 3.4 instead. The same money bought me a better V8. No regrets.
If you want a Camaro V6, get the 3.8 from '96-'02

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