Tonight I decided to move the Vette in the garage. I had been having problems in the past with hunting idle and battery low when the car has been sitting. I recently had the TPI open and noticed a smell of gas, which I had never noticed in the past. Tonight I decided to put a fuel pressure gauge on. Approximately 40psi was the reading but within 5-10 minutes of the car sitting it was at approximately 32. Is this normal or a sign of a leaky injector?
Do I replace injectors?
Is this an electrical problem with injectors or should I check the seals?

Help! Must pass the emmission test soon!!!!!

 

Mine leaked down a lot faster than that. My problem was the FPR. Take the vacuum line off the intake after pressuring up the system and see if any gas flows through the FPR line if so replace it.

 

For the pressure to drop a little when the engine is turned off is normal, GM says so right in the Shop Manual.

If it drops dramatically, then there's a problem which may or may not need addressing.

If the drop is at the engine, then repairs are needed either to the injector(s) or the fuel pressure regulator.

If at the pump, you can just ignore it since it won't hurt anything.

Since this comes up so often, I tested mine and wrote down the time it took for my pressure to drop, I believe it was, in minute intervals. I posted it before on the Forum and I think I saved it to a doc file.

But if yours only dropped 8 pounds in five minutes, you're good to go.
Don't worry about it.

Your hunting idle and low battery are problems, though, and they need to be diagnosed. They're probably unrelated.

The hunting idle can be caused by a lot of different things: TPS, IAC, Coolant Temp Sensor, 02, MAF, etc. Could be a vacuum leak, failing injector, etc.

Have you checked for any SES error code? That would be my first step.

Low battery could be just because it's old and needs replacing, a faulty digital dash will pull down the battery, a short somewhere, or alternator problem.

These are all possible causes, a data logger, like ScanTool will show if a sensor is malfunctioning. Without one, it's all pretty much guess work.

Jake

 

Thanks for your advise. The problems are making me crazy!

I have been dealing with the hunting idle for some time. No codes just not running correct.

I have replaced the IAC, TPS, Coolant Temp Sensor, EGR, EGR Temp Sensor, and MAT. I have set these up according to the GM manual with other advise from several forums. All of this grief (and the brand new battery running low) made me look at the injectors as a possible problem.

I have had this one for 3 years. It was great the first year but has been somewhat of a problem since. I want to buy another Corvette to enjoy while I try to figure this one out!

 

My FP bleeds of almost immediately, but I've found it to be at the pump. As Jake says it's no problem. For the hunting idle, have you cleaned the throttle bores? Some times opening the throttle blades slightly will even the idle out. If the car sits for extended times the computer will gradually pull the battery down. As Jake suggested if the battery is getting old it will get weak.