car will not idle

[babbott]

Hi all I've got a 97 2.5 that will not idle and I looking for a little advice.

It started a week ago when my wife was coming home she made one stop and shut the car off. 5 minutes later it refused to start. Note, before this event the car had been running perfectly.

Since the car was close I towed it home and put it in the garage. I've tried a few things to see if I could diagnose the problem. First I tried to start, the car turns over and will fire but immediately dies. I tried disconnecting the battery neg to reset the dme, no change. At first I was suspecting it may be a fuel pump issue as it seemed to me it was quitting as of lack of fuel. I checked the fuel pump fuse which was fine (have not checked the relay as I am not sure which one is for the fuel pump). Also when I turn on the ignition it seems the fuel pump runs continuously (faint electric noise behind dash on passenger side). I don't remeber if this is normal never paid attention to it before.

I then discovered if I started the car with the accelerator pedal depreseed it would start and run. With the pedal slightly depressed I can get it to idle around 1200rpm continously, does this rule out a fuel pump problem? As soon as I released the accelerator pedal it dies.

This made me think it was possibly the MAF sensor, so I opened up the engine compartment and disconnected the MAF. No change.

While I was running the car with the covers off the engine comparment I thought I heard what may be a vacuum leak. I have started looking around the AOS which I replaced about 2 yrs ago. I can't see any obvious problems (last time the bellows on the bottom split wide open). I did pull the J-tube and there were a few drops of oil in each end at the connection. I cleaned it out put it back on and restarted car. Pulled of the J-tube and there again were a few drops of oil in each end.

The car has not been smoking at start-up so I am not sure if this is normal for the AOS.

If anyone has comments on what else to check would really appreciate it.

[rsfeller]

I think you answered you own question on the fuel pump, if it wasn't working then you wouldn't be able to get it to hold and idle with the pedal. Pumps run continuously.

Sounds like a vacuum leak to me. Do you have any error codes?

[babbott]

I did not have a CEL but I used threw my OBDII scanner on and found 4 codes P1691 (faulty indicator light CEL, explains absence of CEL), P0102, P1551, and P1514. Since I was initially unaware of codes were present I ran the scan after having already disconnected the battery once and unplugging the MAF.

I replaced the burnt out bulb which took care of P1691. Since the MAF was unplugged I assume this caused P0102, note I reconnected MAF and cleared the codes and this has not come back.

I thought the other two codes may be significant as they are both related to the idle control air valve. I ended up clearing all the codes. I attempted to start car and it was still not starting properly. I started it with the accelerator pedal depressed and got it started. I then kept it idling for a few minutes and blipped throttle a few times. After this the car would idle without need to hold accelerator pedal. I took it for a short drive and everything seems fine. Scanned for codes again when I got home and all clear. Also it will now start normally without holding accelerator pedal. I have no idea what caused the problem to rectify itself and am worried it may come back at any moment.

Anyone have any ideas? I read in another post something about getting P1551 and P1514 if the dme goes into "emergency" mode. Is this correct? what causes dme to go into "emergency" mode? is it possible to reset dme to go back to normal?

Before resetting the codes I looked around for the IACV and found what I believe is the device under the air intake manifold on the drivers side. Small device with hose running to and from as well as an 2 conductor electrical connector. All the hoses, the connector, and the wiring harness appeared to be in good condition.

[systech]

Sounds like it may have been crud in the idle control valve or the throttle body which have dislodged itself ?