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Thread: Idle Woes...AGAIN!

  1. #1
    Join Date
    Oct 2002
    Location
    Lincoln, NE
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    Idle Woes...AGAIN!

    Okay, I'm at my witts end! I don't know where to go from here. My idle trouble began several months ago and I have been seemingly throwing parts at it since then and nothing is working. Here's what the cars does, (the small version). It dies. Whether in gear or 'N' or 'P' it doesn't matter. I have to keep my foot on the accelerator and keep the RPMs above 1k (in gear) or about 2k (in 'P' or 'N'). It doesn't die right away, though. In 'P' it will idle for 3-4 minutes, fluctuating between 700-800 RPM and 100-500 RPM. It acts as if it is missing, but only when below 1k RPM. The symptom are about the same when in drive as well.

    Here's my car in a nutshell:
    '89 auto
    92,XXX miles

    Here's what I have done to try and fix this idle problem:
    Pulled codes (O2 Sensors bad)
    new O2 sensors (about three weeks ago), on the way home new CE code!
    Pulled codes (Canister Purge Circuit Failure)
    new canister purge solenoid
    NO NEW CODES

    Things that I have done about 5k miles prior to any idle trouble:
    New plugs and wires
    New DIS module

    Mods and upgrades to the car at about the same time:
    '95 supercharger
    1.73 roller rockers
    New radiator
    New thermostat
    Removed Air Silencer
    and other minor fixes that don't come to mind right now

    The things that I have thought about and checked:
    All visible vacuum lines--all seem secure, no leaks found
    All electrical connections firmly together (plug wires secure)
    Engine mounts check out ok
    MAF checked for cleanliness (ok)

    Thoughts that I have about what may be wrong:
    Fuel Pump: No loss of top end power, so I'm guessing it is ok for now
    Fuel injectors: Could be one or two not working properly, but again, no problems when about 1k RPM
    IAC: Not too sure about this one. From what I have seen, when the IAC goes, 90% of the time, the idle goes up, not down.

    My car runs great at WOT. No hesitation, not missing. Just power. And under normal highway driving it runs great. No symptoms there what-so-ever. Problem is only evident when I am at a stop.

    Does anyone have any thoughts or suggestions? I really don't have the $$ to continually throw parts at it until I get it right. And this is my daily driver to boot, so I really need it running.

  2. #2
    Join Date
    Sep 2002
    Location
    Effingham.IL
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    I have had a missing problem for about three month. I have been chasing this problem like you.
    thursday i removed my dis and put some dielectric grease under the dis module and the miss
    was gone.So I put on a new dis. The car runs just fine ,but i still get a check engine light,and codes.
    I have more money in finding the miss than what i payed for the car.
    you may want to try some dielectric grease under the dis.It helped me, but was not a cure all .

  3. #3
    Join Date
    Oct 2002
    Location
    Lincoln, NE
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    2,062
    I gooped it up pretty good when I replaced it. And dielectric grease helps when the car is warm. I have the problem all the time! You reminded me though that I remember a grounding strap that was gone when I resealed the upper 1/2 of my engine. Maybe that is what my problem is...

    Who knows! It's going to be way too cold the next few days to check it out! Thanks for that line of thought though! Hopefully that is my problem.

  4. #4
    Join Date
    May 2002
    Location
    Dallas, TX
    Posts
    5,648
    Next time you start the car, while its running, unplug the IAC. If its doing anything, the car will die. My best guess is the IAC has carbon build up and is sticking closed. You could try removing it and cleaning it up, just don't touch the nylon diaphragm with anything including your fingers. Use brake parts cleaner and shake it around and see if it helps.

  5. #5
    Join Date
    Jan 2003
    Location
    México
    Posts
    9
    hey I had the same problem but now is worse, the car lose power when i gas it and i got a chek engine, I don't get codes so I tried with new oxigen sensors, plugs and wires, another dis module, the rpm's still fluctuating between 500 and 750 or less,
    Now the water is cold here and the rpm's are some better but when the engine gets its temperature, starts the erratic idle!!!
    in this case may be the dielectic grease helps, don't you think?

    so I post the problem and told me to check the Cam Position Sensor, im still wating because I need my car running too!

    I hope you fix it,

  6. #6
    Join Date
    Jun 2002
    Location
    Los Angeles
    Posts
    210
    Just a guess that you have probably explored was that maybe a ground is bad somewhere or a frayed wire on the ground side. Since some of the symptoms you mentioned are related to systems that need to have steady voltage present, just a thought.

  7. #7
    Join Date
    Feb 2003
    Posts
    10
    I had the same problem, and changed the DIS, it worked fine, and had another problem down the line again. I wound up changing my thermostat, and temprature sensor. My car thought it was running hotter than it was, and cut out. It wasn't showing up in my dash because my

  8. #8
    Join Date
    Oct 2002
    Location
    Lincoln, NE
    Posts
    2,062

    update...

    Finally took the SC to the Mechanic today. He only had about an hour to look at it, but what he found is that the car is running lean at idle. I'm taking it back on Wed for him to get into the specific sensor readings. He is thinking that it has something to do with the fuel management system. He hasn't ruled out the fuel pump, but think that it is not likely. Does any one here have any thoughts?

  9. #9
    Join Date
    Sep 2002
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    Effingham.IL
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    007 Did the wrench tell you what code numbers he got.

    Next you need to check fuel pressure at the schrader valve on the fuel rail
    if thats not it, go and check the 02 sensors in the exhaust.if you got a 41R
    or a 41C and a42R might be the 02 sensors left & right sensors or just one
    sensor left or right.
    Last edited by Randy N Connie; 03-03-2003 at 09:25 PM.

  10. #10
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    Just that the O2 sensors were registering lean. I have brand new O2 sensors (about 500 miles) so I doubt that it could be those. I got them from Car Quest, who I trust to get quality parts more than other parts stores. It is possible though. Wed he's going to check the individual codes (sensor readings) that the EEC is receiving and go from there. I just want to see if anyone else has had this issue and has an idea what it could be.

  11. #11
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    Sep 2002
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    Effingham.IL
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    oo7 I put new 02 sensors in mine. Didnt help so I took them back out
    and put the old ones back in.I now have another shop looking at it .He
    has went over ever thing .He is putting in new 02 sensors again.it looks
    like I may have bought a bad 02 sensor.will find out tomarrow.
    Igot mine running great but it throws 41r 41c &42.

    So I am hoping i put a bad 02 sensor in the right side.and allready had a
    bad 02 sensor.when i find out I will let you know
    Last edited by Randy N Connie; 03-03-2003 at 10:01 PM.

  12. #12
    Join Date
    Oct 2002
    Location
    Lincoln, NE
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    Does yours have a problem with running at idle? That is where mine is right now. Under 1k RPM and it dies. Over that it runs great. And at higher RPMs, it isn't running lean. So I'm baffled. I don't know enough about the fuel management system yet to be able to think if what it may be. And to boot, the car is not throwing any codes that would cause a CE light. So that is why I'm at the mechanic now. I'll keep you posted though.

  13. #13
    Join Date
    Apr 2002
    Location
    Albany, NY, USA
    Posts
    999

    It may sound simple but...

    Fuel Filter? Could be clogged and starving the flow at idle. The pump is still a possibility though. Aren't our pumps 2 stage pumps?

    Clogged injector could be the culpirt

  14. #14
    Join Date
    Oct 2002
    Location
    Lincoln, NE
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    Haven't ruled out the pump yet, it just seems unlikely. The fuel filter may be an option, (I haven't changed it yet), but I'd think that I'd have a problem at the whole rpm range, not just at idle. And I've thought about a clogged or just plain non-functioning injector. My thought there would indicate a "miss," especially under hard acceleration. The car doesn't miss at all. My thoughts actually reside with the IAC, (stuck shut) but that would indicate a rich situation, not lean. The other thought is that my cam sensor is starting to go. I'm not too sure about that one, as I'm not in complete understanding about how the cam sensor fits into the overall engine function picture. But based upon what my "wrench" told me today, I'm totally lost.

    I will replace the fuel filter though. I've only had the car for about 8k miles, but based upon the other maintenance (lack of) I'm sure it needs to be replaced. Thanks for the thoughts.

  15. #15
    Join Date
    Sep 2002
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    Effingham.IL
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    I think i had more than one problem.mine had a ruff idle.
    it would throw a 14 code bad cps. But it still ran so i looked
    for something else .Found a crack in the top ic tube fix that.
    It ran better but still mist.So I fix the 14 code replaced the cps
    put a BHJ balancer and under drive pulleys on. then it still mist.
    put new plugs wires on .It started to miss more. then I found spark plug wire
    came loose fix that.now it runs great but started to throw codes for running
    lean change 02s still runnig lean .put the old 02 back in still shwing lean.
    So i am back to putting in 02s again.the new 02 was bad and the old 02 was bad.
    So I am hoping that I get new 02s in that are good.

    mine mist at idle all the time and some time at all RPMs.
    Last edited by Randy N Connie; 03-03-2003 at 10:39 PM.

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