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2G Severe power loss. Please help! Searching 6 months

Posted by bibdrums, Jun 10, 2019

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  1. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    1996 Gst spyder A/t, Hallman MBC, MHI big 16g, 3” turbo back exhaust, IPT retorqued converter, IPT shift kit, Autometer boost gauge, 20K on stock rebuild


    About 6 months ago I was cruising on the highway doing about 70 when the car had a bad miss-fire and started feeling like it was running on 2 cylinders and sort of chugging. I pulled over and the car idled fine. So I gave it some gas and it sounded normal but was lacking a lot of power. It moved so slowly from a stop that it was hard to pull out into traffic. When I got home I checked for codes and had a p0300.


    I have been chasing this problem for 6 months. Yesterday, out of nowhere, the car ran amazing for about an hour. Then, just as suddenly, it started running like crap again. Feels like it’s pulling timing or not getting enough/too much fuel. Also, the exhaust manifold is getting MUCH hotter than ever before. It melted the condenser fan. Builds boost very well though and holds it.


    This is what I have checked or replaced:

    Fixed ALL boost leaks
    Checked timing (like 5 times)
    Checked compression (all good)
    New knock sensor (was leaking black goo)
    Swapped in known good coils
    New coolant temp sensor
    Swapped in known good ECU
    Turbo had play so had it rebuilt
    Checked fuel pressure
    New FPR
    New egr
    Salvaged power transistor
    New alternator
    Ran open exhaust to rule out catalytic converter
    New O2 sensor
    New exhaust manifold (was cracked and leaking)
    New plugs ngk bpr6es gapped properly
    New wires
    New tps
    New crank position sensor
    New MAF


    When I checked the fuel pressure it was a little high - 43 with the vacuum line connected and 50 disconnected, that’s why I changed the FPR but the new one is showing almost the same so it may be the gauge? Or a clogged return line maybe?


    Does anyone have any other ideas on what to check next. I don’t have link, a wideband or anything to log with yet but I am getting link and a wideband in the next month or two. Does anyone have any ideas of stuff I may have missed in the meantime?


    Thanks!
     
    Last edited: Jun 11, 2019
  2. d1prospect

    d1prospect Proven Member

    208
    25
    Joined Mar 14, 2004
    Glen Bunie, Maryland
    Did you set the fuel pressure with the line off ?

    I’ve had a hot manifold before, which turned out to be a restricted cat. Turn my housing and manifold red. Removed cat and np ever since
     

    Drag Race Build 3K  15

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  3. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    Thanks for replying.

    I don't have an adjustable FPR yet. I ran the car with the downpipe disconnected to rule out the cat. There was no change in how it ran.
     
  4. Mello

    Mello Proven Member

    907
    203
    Joined Jul 4, 2003
    Albuquerque, New Mexico
    May not be the problem but check the plug wires. Small cracks in the insulator or plug boot could let the spark arc over & short out. Run the engine at night in the dark and you may be able to see if there is some arcing issues.
     
  5. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    Yes, thanks. I knew I would forget stuff. I have been battling this for so long. I changed the wires and plugs (ngk bpr6es). Thanks, any other ideas please keep them coming.
     
  6. ThunderChild

    ThunderChild Supporting VIP

    2,518
    683
    Joined Jan 5, 2012
    Rathdrum, Idaho
    Check wiring for anything melted/chewed on, it presents like an electrical or ECU issue.

    Have you verified the CAS is functional and stable? Do you have ecmlink so you can post a log?
     

    Street Build 164  3

    1990 Plymouth Laser N/T
    fwd · manual · 1G DSM

    257  8

    1987 Toyota Pickup/Hilux
    awd · manual · Misc Vehicles

    Street Build 792  7

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    Street Build 1K  1

    1992 Eagle Talon TSi AWD
    manual · 1G DSM

    Street Build 2K  10

    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  7. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    I have not really checked the CAS I will have to look into doing that. I don't have ecmlink, I should be getting it pretty soon.

    I found a black wire that had been rubbed through in my harness that I assume was a ground and checked the continuity to ground and there was continuity. I'll have to go through it all better. Thanks!
     
  8. ryan_c2g

    ryan_c2g Probationary Member

    6
    0
    Joined Jan 2, 2013
    corpus christi, Texas
    Check your MAFS. I similar problem years ago. The pins were contacting properly. Check all of your connection for exposed wires.check the ECU connection pins as well.
     

    281  0

    1997 Mitsubishi Eclipse Spyder GST
    · 2G DSM
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  9. ryan_c2g

    ryan_c2g Probationary Member

    6
    0
    Joined Jan 2, 2013
    corpus christi, Texas
    Weren't *
    Sorry stupid phone is autocorrecting
     

    281  0

    1997 Mitsubishi Eclipse Spyder GST
    · 2G DSM
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  10. tk106

    tk106 Supporting Member

    1,338
    257
    Joined Sep 11, 2017
    Cincinnati, Ohio
    Make sure the plug wires are in the correct order and confirm your O2 sensor is working. Also check the connector on the coil
     

    88  3

    2000 Jeep Cherokee Sport - Classic
    awd · automatic · Misc Vehicles

    116  4

    93 Civic 4 Door -sold-
    fwd · manual · Misc Vehicles

    Street Build 2K  6

    1992 Eagle Talon TSi AWD
    12.625 @ 111.42 · 1G DSM
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  11. Clipsoe

    Clipsoe Proven Member

    62
    16
    Joined Apr 22, 2015
    Fort Lauderdale, Florida
    I had a similar issue a while back, ended up being the OEM Mass Airflow sensor. Replaced it, car ran perfect after that.
     

    398  6

    1997 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
    Loading...
  12. ohlegend

    ohlegend Proven Member

    550
    40
    Joined Apr 2, 2012
    Pemberville, Ohio
    Check you crank sensor too, I had the same thing happen to my car. car would run and drive great, then the crank sensor would get warm and quit working. It wouldn't get spark, but it would fuel. Does it smell like gas under the hood? and check to see if your plugs are wet! I Couldn't get the car to run again until it cooled down. I switched to a 1G black top and it solved the issue.
     

    Street Build 6K  14  6

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
    ohlegend

    732  0

    1998 Mitsubishi Eclipse GST
    automatic · 2G DSM
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  13. TSiAWD666

    TSiAWD666 Freelancer

    2,139
    554
    Joined Aug 15, 2003
    Herndon, Virginia
    I didn't see these as replaced: MAF, and cam angle sensor. Check the wiring for these while you're at it.
     

    Road Race Build 13K  12  371

    1999 Mitsubishi Eclipse GSX
    377 whp · 416 lb/ft · 2G DSM
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  14. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    Thanks guys. Then next two things on my list to swap out are the maf and the cam sensor. First the maf because the cam sensor is tough to get at. I did check all the wires going to the maf and they all have the proper voltages and the ground is good. These are 23 year old parts so changing them definitely can't hurt.

    I noticed accidentally, by dropping a ratchet on the maf while it was running, that if I tap the maf while it's running the rpm's go up for a second or two and then fall back down. Not sure if that is a sign of anything.
     
  15. curt-s

    curt-s Proven Member

    740
    202
    Joined Dec 21, 2008
    Winterville, MB, Canada
    if the plugs werent on the right coils, the engine wouldnt run at all. in our wasted spark, since 1/4 and 2/3 always fire simultaneously, the only wrong way is coiling 1/2 and 3/4 together. at that point you have totally wrong spark timing.
    however, checking the plugs for proper contact is ok and especially check the connectors for the transistor unit and coil pack as they can break over time. been there, a bi*** to track down.
     

    Street Build 2K  1

    1991 Eagle Talon TSi
    fwd · manual · 1G DSM
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  16. rEclipserGST

    rEclipserGST Proven Member

    1,552
    44
    Joined Nov 17, 2007
    Columbus, Ohio
    Confirm your timing is correct. When my exhaust manifold would go cherry red, it was because timing was off. Advanced.
     

    Street Build 568  25

    1995 Eagle Talon TSi AWD
    187 whp · 200 lb/ft · 2G DSM
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  17. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    Well it wasn't the MAF. I just changed it and its still running awful. I'm gonna start going through the wire harness to look for broken, melted or shorted wires. If anyone has any suggestions on which ones to start with or any good procedures I'd love to hear about it. Thanks again everyone for all your suggestions and help!

    Also, I've been searching for ways to test the cam position sensor and I can't really find a definitive way. Can anyone help with that?
     
  18. rEclipserGST

    rEclipserGST Proven Member

    1,552
    44
    Joined Nov 17, 2007
    Columbus, Ohio
    Rent a timing light or buy dsmlink.
     

    Street Build 568  25

    1995 Eagle Talon TSi AWD
    187 whp · 200 lb/ft · 2G DSM
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  19. motomattx

    motomattx Proven Member

    1,686
    495
    Joined Dec 9, 2010
    wampum, Pennsylvania
    Sounds like it might have jumped time a tooth or two, that or maybe a clogged catalytic converter.
     

    Drag Race Build 2K  16

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  20. bibdrums

    bibdrums Probationary Member

    9
    0
    Joined Apr 29, 2009
    Milltown, New Jersey
    I checked both of those and they were both good. Maybe the cam position sensor is sending a bad signal to the ECU causing the timing to get wacky. That's the next thing I'm going to swap out. I just took a really good look at it and the wires don't look so good. Definitely looks to be the original so I'm gonna replace it.
     

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