I made a thread a while ago about the idle being high in my car. I'd say about 1100 RPMS with it blipping up and down from 1300-1400. I also noticed my car was harder to start. If its been running then it will usually start right up but when cold it needs 4 or 5 seconds. I already had the fuel filter replaced and am hoping it's not the fuel pump. I was just wondering though if the pump was on it's way out wouldn't it make the car idle lower and want to stall out? Can somebody clear this up for me. I am going to try to get a fuel pressure gauge on the car very soon. What about the fuel pressure regulator? Could this be the problem?

 

Ttt

 

Just trying to help you understand why you may not be getting any responses here:

Sometimes helps for people to see all the details and responses in your previous thread. That way they will know you already replace the IAC motor and TPS, cleaned the throttle body, etc. If you don't tell them that, you'll just get the same comments about things you've already addressed:

http://camaross.com/forums/showthread.php?t=456620

Again, you've failed to tell us whether you have an A4 or an M6, so we don't know how far "off" the idle speed is. Why not add a signature, showing the basic info about your car, including year, model, tranny type and any major mods. When people have to guess about this info, they often don't bother to answer your posts.

 

Okay Injuneer, I usually post that stuff. I made that post at 1:21 AM so I was just trying to get it done so I could see if there was any help by the morning. Car is an A4 with a rebuilt transmission and full exhaust/minor bolts ons. The higher idle came out of the blue. It wasn't after anything was installed. Car ran fine for a year with all the current mods. So I think I am correct to assume something is faulty on the car.

I am a little lost with the fuel part of things. I put a fuel pressure gauge on the shrader valve. Turned the key to the on position and the fuel pressure went up to 40 something and then dropped all the way back down. Sounds right for that part because the pump only stays on for a few seconds. Went and did a WOT run and got 43 psi so the fuel pump is fine. I am just confused on how to check the fuel pressure regulator. I've been reading and that looks like it could be the only last problem. I see people take a vacuum tube off or something.......anybody care to explain this to me?

Sig coming in a few Injuneer.

 

I'm really just trying to help you get an answer, not give you a hard time.

Your fuel pressure should not have "dropped all the way back down" when the fuel pump shut off. The system is supposed to hold pressure when the pump shuts off. Reasons it might not:

-faulty fuel pressure regulator diaphragm - look for fuel in the vacuum line.

-leaking injectors - pull the rails up, injectors intact, pressure the system and see if there are any drips.

-faulty check valve in the fuel pump - hard to pin down, but you should be able to pinch off the supply line the instant the pumpp shuts off. If the system holds pressure its the pump check valve.

Still thinking about the idle issue.

 

I'd like to take a stab at the leaking injectors first. So to get the rail up I unbolt the 4 bolts and then what? I already have the 4 bolts out but the rail doesn't want to come up....... I tried a search already.