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Hard starting, misfiring and sputtering

Posted by Gstclipse69, Jul 4, 2013

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  1. Gstclipse69

    Gstclipse69 Proven Member

    652
    13
    Joined Jun 30, 2006
    Columbia, South Carolina
    I could use some help and or advice guys. I have a 1g that's my dd. Its all stock 2.0 nt AT. I just painted it a few weeks ago and it was sitting for a couple weeks while I worked on it. Anyway, it used to fire right up as soon as I cranked it. Now its gotten harder to start. At first it would catch and idle low for a minute and slowly bring the rpms up to speed. It keeps getting worse and harder to start. As it sits now its very hard to start and it wont start good at all when its warm. Then last week I was driving around and it starts misfiring and sputtering bad. It had a horrible power loss and idled very low. The thing is, the misfiring etc will come and go. I drove it for a couple days and it didn't do it at all. Then out of nowhere it starts sputtering like that. Then it will drive fine for a couple days before it happens again. I will say as soon as it started sputtering I smelt something in the cabin. I got out and looked under the hood and didn't smell anything. Got back in the cabin and I could smell it.

    Now, what I have done so far is put new plugs in that are gapped right. Swapped in new ignition wires. Swapped in new coil pack. Swapped in new power transistor. Pulled the ecu and looked for anything out of whack. It looked fine to me. I swapped the cas for one in my 2g. No change. Because of the hard start I put in a new coolant temp sensor. No change. Still hard to start. Bypassed the fuel pressure solenoid. Checked that the rail is getting fuel. I pulled my codes and it said barometer and IAT was bad. Got a new 1g mas and no change.
    Now what gets me is that I have a palm that I can datalog with. Something is out of whack with it. Like I just put in the new coolant temp sensor and on the datalog its saying my coolant temp is -75 or something crazy. And after I swapped the mas I still get a code for baro and iat. Then I noticed the tps said it was at like 40% when closed. So I adjusted it to get it lower to like 20%. I observed it was at about 20% then a couple minutes later its back at 50% tps at idle. Im like WTF. Im starting to think something is up with the ecu. I know I smelt something in the cabin when this started and I checked it out, but I didn't observe anything too bad I think. But I don't know what else to do.
    Im just frustrated now one because one I don't know what else to do now, and 2 because I fix what the codes tell me to fix and I put a new cts in and I get no change on the datalogger. Like I said, next on the list is to get another ecu unless anyone has any other ideas. Thanks, Chris
     

    601  0

    1999 Mitsubishi Eclipse GSX
    · 2G DSM
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  2. talonracer717

    talonracer717 Probationary Member

    8
    0
    Joined Jan 31, 2010
    denver, Pennsylvania
    i would definitely change your ecu. mine was having similar problems and giving codes for coolant temp sensor, iat, tps, and all the sensors and wiring were fine so i bought another ecu and fixed everything
     

    180  0

    1991 Eagle Talon N/T
    · 1G DSM
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  3. Gstclipse69

    Gstclipse69 Proven Member

    652
    13
    Joined Jun 30, 2006
    Columbia, South Carolina
    Thanks for the reply. Its been very frustrating the last couple days. I decided to take the injectors out and clean them and see what that does. If that doesn't work then I guess I'll be hunting for an ecu.
     

    601  0

    1999 Mitsubishi Eclipse GSX
    · 2G DSM
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  4. Roderick850

    Roderick850 Probationary Member

    9
    0
    Joined Apr 7, 2013
    FortWaltonBeach, Florida
    so did cleaning the injectors help at all any ?
     
  5. Gstclipse69

    Gstclipse69 Proven Member

    652
    13
    Joined Jun 30, 2006
    Columbia, South Carolina
    Cleaning the injectors didn't do anything. Ecmtuning confirmed that the capacitors were leaking and messing up the board. I should have the ecu back by the end of the week so hopefully that will fix things up.
     

    601  0

    1999 Mitsubishi Eclipse GSX
    · 2G DSM
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  6. DKJson2112

    DKJson2112 Proven Member

    44
    0
    Joined Jul 12, 2013
    Vidor, Texas
    Make sure your spark plugs are gapped right. My car was idling bad, but then after I re-gapped the plugs it ran like a champ. Make sure you clean out your throttle body too. It may not be the issue, but it's always good to keep it clean
     
  7. DSM1G90

    DSM1G90 Proven Member

    4,840
    60
    Joined Apr 6, 2008
    Nampa, Idaho
    Prob what happened with Talonracer is that he had blown ground traces on momboard of the the ECU which was giving him CEL's like crazy for about every sensor under the hood. Doing the ECU swapout cured the issue ... and I've been there before with this one on the blown ground traces on the momboard issue and had to do the same thing.

    How you get blown ground traces is by messing with the sensors with the key on, and/or motor running. Live voltage from the ECU went straight to ground blowing the traces off the momboard in a super duty quick.

    If you're going to mess with any sensor, keep the key OFF, or disconnect the negative from the battery.

    Coolant sensor loves to do this esp when age is the main factor and the sensor is the original one.

    They get super tired and will throw a CEL on occasion, even though one does a sensor test and it comes out negative of failure.

    Found this out the hard way with the basic same problems you're having..and I'm a turbo version.

    Swapped out the coolant sensor (not the temp sending unit) and problems above disappeared.
     

    1K  0

    1990 Plymouth Laser RS Turbo
    · 1G DSM
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