Guys i just baught a 95 TA and the thing is running hella rich. I mean to the point where it makes me sick to have it run. Im not getting a check engine light and i didnt have any fuel leaking out of the vac hose going from the regulator to the manifold. I do have a semi hard start condition where it doesnt fire up right away. It takes a few cranks before it fires.

I was thinking of popping the fuel rail loose and then turn on the ignition to see if any of the injectors are leaking... but they shouldnt be leaking since the fuel is supposed to return to the tank after the car is off right???

I had this problem on a 93 camaro and it turned out to be the fuel regulator..

Any ideas?

 

If the fuel system is healthy, the fuel stays in the rails, under pressure when you shut the engine off. It is kept from returning to the tank by the check valve in the fuel pump and the spring closing the diaphragm in the fuel pressure regulator, on the return line. If you have leaking injectors, the pressure will bleed off quickly.

If you want to see if you have leaking injectors, pull the rails up, and pressure the fuel system, using the fuel pump prime connector, or turning the key to "on" (do not attempt to start).

Does it start any quicker if you hold the accel pedal on the floor when you try and start it, putting the ECM in "clear flood" mode?

 

I would suspect an Injector(s), I just went through the same thing. Long crank times, On startup rich enough to burn my eyes in the garage. Ended up being two injectors, They would leak about 1 drop per second after the fuel pump stopped running. I suspected Fuel pump and FPR was wrong on both accounts. Put two new injectors in and all is good now. Knock On Wood. Also holding accel pedal to floor would start the car almost imediatly.

 

The next time i feel like being gassed i'll give putting the pedal to the floor a shot. I suspect that their are leaky injectors. I pulled a plug -- just doing a post buy inspection and the plug was just black with soot.

I think a good idea will be to put a fuel pressure gauge on the rail and see if the pressure bleeds off quickly .. what do you all think?

DMD95z: How did you know which two injectors were leaking?

P.S. the car has about 109K on the clock.

 

Checking the fuel pressure is always a good idea when you have the problems you are having.

 

How I checked the injectors ? Its a long story, But my 95z has only 60k on it and is still under extended warranty. When this first happened it went to the GM dealer they replaced one injector this helped but didn't solve it. Another trip it went back they said weak spark, I didn't buy it, but under warranty so whatever new opti, I had them do the waterpump and FPR on my dime. Car came home with same problem. I talked to some LT1 guys on another forum and decided to pull out my tools and do some checking on there advice. First I hooked up a fuel pressure gauge and noticed soon as the fuel pump was shut off, pressure would bleed off instantly, Pulled the fuel rail and checked myself. Boom leaking injector, car went back to dealer last week where they also found that leaking injector after I told them I checked myself. They replaced the injector under warranty and boom it has been running great ever since. If you have the fuel rail out of the car under no circumstance attempt to turn over the car, Fuel will spray everywhere, Do not ask me how I know.

 

LMAO!

Oh yea i have not experienced the fuel shower, but thanks for the reminder. I wont ask how you know. Im going to grab a fuel gauge and pop the injectors out to to see if one is leaking.

I got my Blue OBD-II cable from auto X ray so i 'll scan the car to see if it can pin point an injector thats not working properly too... although i know it wont tell me if fuel is leaking from the injector... that would be cool if it could though!

 

Today -- i popped the fuel rail off and none of the injectors were leaking. At this point i dont know what else to check to find out why im having a rich condition. I tried scanning the car for codes, but my stupid Auto X ray thinks its an OBD-II car and wont scan it correctly.

 

I still don't see where you checked the fuel pressure. Consequently, what was the pressure while you were checking the injectors for leaks? How long did you check it?

Did you actually apply a vacuum to the FPR hose?

Did you try flooring the throttle when attempting to start it?

How many plugs show signs of running rich? Less than 4 on a side is usually an indication there is a spark issue.

What's the condition of the air filter and the entire intake tube up to the TB?

What about dead cylinders? Fouled plugs will usually not fire, have any been replaced?

 

Did you try connecting the Auto Xray's 12-pin connector as shown on Shoebox's website?

http://shbox.com/1/xraycable.jpg

Kind of hard to get enthusiastic about helping you with the problem, when you don't seem to want to follow up on the suggestions that people are offering you.