Hi there!

Well I have almost completed my 85 trans am with the 91 GTA engine. All the wiring has gone well got my VATS bypassed and the injectors pulse. Car runs for about 5-10 seconds then dies.. No engine codes come up and the PCM is brand new. So my guys have concluded on needing injectors.. Is there any recommendations on what would be a good set to use? I see many options online and don't really want the cheapest or most excpencive..but something decent! I am also looking into the ZEX safe shot nitrous kit more so for show then use but also any recommendations on that besides different spark plugs?
Thanks so much!!

 

Before biting off on that:

Explain carefully why your injectors work fine for 5-10 seconds, then stop. Once you have fully worked that out, THEN AND ONLY THEN, worry about buying injectors.

Not saying you don't need injectors; .... only ... that this scenario and the proposed "explanation" doesn't pass the smell test. See my signature for a hint in that regard. In this particular case, the part of that quote you should figure out how to apply is, "all".

 

I have the car at a performance shop that did all the electrical for me. I was basically told that there is no other scenario now. No engine codes come up good spark, good fuel pressure. PCM is new and fuel pump and pretty much everything else but the injectors. Everything is working properly last week or so would run for 30 seconds then 20 then 10 now 5 seconds. This is basically the information that I have got from them is this car needs injectors. So just trying to source out the best options.

 

How does A WHOLE SET of injectors work for 30 seconds then quit, then 20 seconds then quit, then 10 now 5 seconds then quit?

What you suppose they're going to tell you when you hand em a new set of injectors, they charge you to swap em out, and it does EXACTLY THE SAME THING? (which it will)

This is a typical "shop" "mechanic" type of deal: the small text written in the margin in a 2-point font with clear ink is, "we can't figure it out, just keep spending money and we'll keep getting our OJT on your dime until we stumble across it accidentally or your bank account is empty, whichever comes first".

Get THEM to explain to you how A FULL SET of injectors fails like they're trying to get you to spend your money on. Something besides, "we can't figure it out, so go buy the most expensive thing we can think of". Until then, don't fall for it.

In case you wonder, this is why I DON'T EVER take my car to a "shop" for this sort of thing; if I can't do it myself, I take some other path that I CAN do myself. I would recommend that you adopt the same attitude: learn how to work on your own car. If you didn't build it, it's just an appliance that you operate; there's no pride in accomplishment.

 

Well I 100% agree to what you are saying! I did the motor swap myself but ran into issues with the wiring harness getting injector pulse. I tried and struggled throughout the process with the harness change so I had to make the call to send it out to get the pin outs changed. I guess where I went wrong was apparently installed the vats bypass wrong and a few other wires wrong and wiped out my PCM. That being said I am running the 91 tail lights and headlight doors so I needed the relays all changed so that they worked aswell.. That being all said and done.. They correctly wired the pin outs and vats bypass and finally got my injector pulse. Perfect! I said! The motor was just swapped and built so I was low on fluids when I went down there to see what was going on. They fired it up, ran fine then shut it off. Just to show me. Which was fine by me cause that was a lot further then where I left off.. I'll basically call myself a mechanic 101. I am not experienced but enjoy very much working on my own vehicles and my father owns a shop where I am always playing around. His mechanics were unfortunately not experienced with the electrical and told me they could spend 40hrs trying to wire this and still be nowhere. That's when I had to send it out to a shop where they have a GM guy that has built and wired these in the past. So that's the only reason why I'm in this mess to begin with and completely at there mercy. And yes very pricey!! I know that motor ran great in my 91 write off that I bought(rear quarter damage) I unfortunately don't have any other options and no scenarios to what else it could be with everything else running correctly. I don't mean to sound like a complete tool or anything Iv just been doing what they have Ben requesting and everything is making great progress just not getting the results I want..

Thanks so much!

 

You should contact southbay if your dead set on buying new Inj's. Putting new ones in probably isn't a total waste of money. If the old ones have very much age on them, or have sat very long they probably need replacing. I really don't believe the injectors is your problem. You can lookup the procedures on how to check them. IMHO, for what its worth, your still losing something somewhere. If the car was mine I'd go ahead and take it from them and do the rest of the diagnosis from here. It would be good experience for you. It gonna get really expensive once they put the new Inj's in and tell you it's still doing the same thing and further diagnosis is needed.

 

A quick test that you can do is check the resistance on the injectors both hot and cold.
It will at least tell you if the coils are good. Unfortunately that will not give you any indication as to the quality of the spray or if they flow within spec, however if the coils are failing then they will definitely need to be replaced.

www.southbayfuelinjectors.com
516-442-4707

 

So the injectors are overheating?? And that's the only reason that's keeping my car from running? Is the news I got today.. Does that sound logical to anyone??

Cheers guys

 

Since Sofa was trying to lead you water, but you're not biting... Run for X seconds then quit, is how a correctly functioning VATS works.
VATS = Vehicle Anti Theft System.

Your VATS bypass is not complete.

 

You guys are fantastic help so far! To sum it all up now. My father(owner of an auto repair shop) sent this car to a buddy (another owner of a shop) and I'm stuck in the middle here..I unfortunately am nowhere near skilled enough to do the pinout change and wiring of the 91 motor and harness. My dad's guys tried but couldn't quite get it either so bla bla bla hear I am paying an arm and leg trying to get this project running. Which don't get me wrong they have made great progress on the car I hear 2 injectors are crap 2 are poor and 4 are fair.. Yada yada.. I'm just trying to get all the facts straight. My next question for you(coming from my dad's request) can you give me schematics of the VATS system? Whatever you have on it would be fantastic!!!! I am backing you guys up 100% on this and trying to get ahold of my PCM and just get the vats removed completely so I don't have to do that bypass crap and hope it works! There telling me injectors this and injectors that and I'm just trying to open some eyes hear! And all I have is you guys on my side so I really do appreciate all the help that you have been for me and thank you soooo much!!

 

With reference to the VATS why the motor will run and then just die? Keeping in mind I don't run the chipped column anymore cause the body is an 85 and I have the vats bypass installed. Correctly or not I dk. Just anything you have on it, what it does what signals it sends to injectors. Why they crap out, sending false signals? I'm basically just going to copy and paste right to my dad to pass on to them again thank you thank you thank you!

 

No, the injectors would not be overheating. The coil acts like a solenoid which causes the injector to open and close so if the coil is weak the injector is going to malfunction.

 

Fuel pressure is good when primed. What does it do when the engine runs for 10 seconds?

 

Here is how VATS works: https://www.thirdgen.org/vats_passkey_system

1) you can install the proper resistor value in place of the key pellet. This fools VATS into thinking the correct key is being used.
OR
2) Have a chip modified ("burned") for you computer that eliminates the VATS system. Otherwise, the computer will still be looking for an "OK" signal from the VATS module. Not the proper resistor... not OK. VATS module remove... no OK signal can be sent.

 

I'm running the 85 column so I don't have the chipped key or column that requires it. Is that a problem? I have the bypassII wired to the PCM. Car does start and run just not for long..