RMACE

I have a 1994 Camaro Z 28 convertible that is having an issue that neither the dealer nor a performance shop can figure out. The engine is rebuilt with a new distributor .500 intake .510 exhaust lift comp cam. It's running extremely rich and has been under diagnostics three times and nobody can find the problem. However, it has been discovered that there are 47 # injectors installed in the car. The computer has been re-flashed and reprogrammed with new info yet doesn't want to run smoothly and seems to be flooding constantly. Premier automotive in West Jordan Utah has guaranteed they will find the problem or will not release the car, however, they have tried everything they can think of and now are claiming that the cam is causing it to lose vacuum which is causing the car to run roughly. I have $10,500 into restoration of this car and have come to the end of my rope! Any help and advice would be very much appreciated!

Injuneer

TTT - post got "stuck" because someone "moderated" it.

my94blackz

47# injectors wow. Plus no mention of a tune.

slopokrodrigez

So put a cam in it they can guarantee.

KW Baraka

Those 47LB injectors are a huge problem; they are of no benefit on a 'cam only' engine and will only serve to waste fuel. Installing/running them without a tune just makes it that much worse.....it's no wonder you're running rich and flooding.

You really need to have 24LB injectors installed.....and then go from there.

KW

Injuneer

Doesn't really matter... he hasn't been back to the site since November 7th, 2 days after he made the original post.

The original post got stuck in a "moderation" queue because it contains a word that triggers the spam filter.

RMACE

Thank you KW. i put 36# injectors in, and it has been tuned for everything but the injectors. Still runs like dog meat. checked everything that i can think of and it still doesnt make sense. have been told a hundred different possible causes but none have panned out.
new opti
new TPS
new wires and plugs
new Idle air control
new map
re checked tune
Checked compression
3 different mechanics have checked valve timing
new temp sensor

Injuneer

Now you have 36# injectors but not tuned for them. Why are you surprised it runs poorly? Why would you even install injectors that are good for 500 HP when you are nowhere near that level? Who is telling you to do make these changes?

RMACE

I put used 36s in to see if it would help. this is all new to me so im doing whatever i can think of to make this thing run! after reinstrall it ran awesome now runs like ****! PCMforless said the tune they did to it would handle 47s so i figured 36s would be better. any other insults you wanna throw at me?

RMACE

ok now i have 24s in it and it sounds like 3 or 4 cylinders are firing randomly. Next suggestion?

Matts97camaro

Everytime you change injector sizes you need to get a tune if you want it to run properly. A tune for a 47 # injector is not going to be the same for 36 # much less a 24#. Get it tuned for the 24#s. Sounds like there may be other issues with the motor, but if you get the injectors tuned that will be one problem eliminated and is a must.

Injuneer

It's really hard to take this thread seriously. Tune... no tune.... 47# injectors..... 36# injectors..... 24# injectors. But will not listen to any advice.

RMACE

Ok to my knowledge the PCM was set for stock injectors. I purchased the car not knowing it had 47s. It's possible that the previous owner had it tuned for 47 but I don't know. This is my FIRST LT1 and my first project involving computers. I just want to get it to start and drive it. Also I don't have the resources to tune it everytime I do something to it it to make it start. I would appreciate a little education on this system and some advice on where to look to identify the problem and no judgement on my ignorance on this car. I admit ignorance and request knowledge. Please someone guide me step by step in troubleshooting OR tell me what's wrong with it. FYI THE ENGINE IS NEW (REBUILT 2013)

Injuneer

I thought pcmforless tuned it for 47# injectors. Now, to your knowledge, it's tuned for stock injectors. Do you not understand why we are having a hard time helping you. How do you know it's tuned for stock (24#/HR) injectors? Because if it isn't nothing we tell you will help.

timnfxr

A great place to get a good understanding of the LT1 is right here on this site. There's a wealth of knowledge and experience here and an excellent source of reference and how-to's at:

4th Gen LT1 F-Body Tech Aids

If you have a PC or laptop, you should consider getting the monitoring and tuning software (read the second "Sticky" at the top of this message forum).

There isn't one magic thread that has all answers, so it will take some reading, logical, systematic diagnostic testing, and patience. And its very important to provide as much info about your problem(s), and what tests you've performed, as well as parts changed.

Good luck.