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Check engine light on. No codes

Discussion in 'ECU's, Electronics, and Tuning' started by d.b.cooper, Jan 4, 2006.

  1. d.b.cooper

    d.b.cooper Mid-life Crisis Swap

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    My CEL is is on.. When jumped it stays steady - no flashes.

    It runs fine but cuts out completely at 2700 RPM. As long as I leave it below that it behaves normally, but with noticeably less power.

    Car is a 92 Hatch
    Motor is 1995 B18C GSR
    ECU (I think) is a P72

    I have done searches looking for similar reported conditions and thought it is in limp home mode because the CPU is not operational. If relevant - the car took a good jarring on a bump and immediately threww this condition.

    There is a current thread today in the hybrid EG>ETC forum that seems like he has a similar problem.

    The only thing I tried was I disconnected the battery, made sure the power was drained by flipping on the headlights, I then reconnected, had no C.E.L. and it revved fine for a block or two then the light came back on and the condition came back.

    Thanks in advance for any help.
     
  2. brian11to1

    brian11to1 Senior Member

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    if the light is on, but there arent any codes... its a bad ECU... replace it with a known good ecu
     
  3. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    i doubt its a bad ECU. ive said it over and over...the possibility of a bad ecu is slim to none. the things are designed to be beaten up, and they RARELY fail
     
  4. skillz2k5

    skillz2k5 Senior Member

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    I disagree... my car did the same thing at 3500 rpms at random. No code... replaced ecu and problem gone.
     
  5. VTECPOWER

    VTECPOWER Senior Member

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    Unless you accidentally touch one of the map sensor wires to the positive battery terminal, [​IMG] aka me on my crx.
     
  6. civicious

    civicious FüK-VTEC VIP

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    Open the ECU and cut the jumper that I've outlined in the image below. I'd be willing to bet the chip just pooped. Cut the jumper and it'll put the ecu back to stock specs, and mail me the chip and I'll reburn it for you, or replace the chip if it's dead...I've still got the same .bin file that I tuned the car with, so it'll have the exact same specs. My address is PO Box 855, Groveton, TX 75845...get it mailed and I'll try to reburn it and get it back in to the mail to you the same day. Self Addressed Stamped Envelopes are key.

    However, if for some reason you cut the jumper and it continues to act up, the ECU is bad...find a P72 or a P30 from a 94-95 Integra or a 93-95 Del Sol DOHC VTEC and plug it in. If the ECU is what's bad (and I highly, highly doubt it is) and you'd like to keep the same tune as before, send me the old ECU and the new one, and I'll rechip the new one the same.

    But, like I said, I'd be willing to bet the chip just took a dump. From time to time the chips will fart for some reason.



    Here's where the jumper is, it's just a little piece of wire that I believe is soldered together in the center...Holding the ECU right-side up with the plugs to your left, this is at the bottom-right.
    [​IMG]
     
  7. d.b.cooper

    d.b.cooper Mid-life Crisis Swap

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    THAnkS!!!!!!!!!

    Allright, without the clear directions I wouldn't have opened the case on a bet. I am clueless about all things electronic. SO I open 'er up and find the chip that is missing in your picture below the jumper (is that the P72 itself?) has FALLEN OUT of its socket!! PLug 'er in and she did 185kph in the time it takes to traverse the long freeway on ramp by my house (maybe 3/8 of a mile). Felt great.

    Found the jumper that you pointed out no problem, and it was soldered. I didn't cut it but either sometime in the past or with the part rattling around in the case (that can't be a good thing) recently, the wire had already come loose. The car felt to me (I realize this is subjective) as strong as before, so I'm wondering if maybe the jumper came loose sometime previously, long before I the car's feel was really familiar to me.

    So, It runs great and if I was smart I'd leave well enough alone. If I however, reconnect that jumper, will it then access your chip, or has it now been reset to stock permanantly?
     
  8. civicious

    civicious FüK-VTEC VIP

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    If you reconnect the jumper it'll access the chip....right now the car is running on the stock program, if the jumper is loose...


    I'd solder it back together...but that's just me

    :mrgreen:
     
  9. d.b.cooper

    d.b.cooper Mid-life Crisis Swap

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    Cool, I'll try it. Be interesting to see if its been off the whole time or not.

    I'll let you know how it goes.
     
  10. civicious

    civicious FüK-VTEC VIP

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    One thing I do NOT miss about that car...converting km/h to mph on the fly...
     
  11. d.b.cooper

    d.b.cooper Mid-life Crisis Swap

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    Ive gotten pretty good at it. ALthough sometimes its hard to look innocent while looking in the rearview with one eye and the calculator on the cellphone at the same time.

    Alright, I connected them, and it was noticibly different. I think the solder on the jumper broke quite a while ago. I had gotten used to that jolt when vteck kicks in. With your program, it actually is slightly less "fun" in that you don't get that little rush from that peaky hp boost from the vtec, however, I was topping out each gear noticably faster. I really noticed it when I went from 4th at 8,000RPM into 5th. I quit at 7,000 rpm because of traffic (gear ratio / tire calculator says 128 mph) I did it on the same stretch of freeway that has no place for cops to hide that I first tried to find the top end, and it was much less distance traveled.

    I think I'm going to solder up a switch. Somday I want to take it up to Firebird Raceway and try it out with each setting. A mecanic that I take some of my other cars to has a 68 SS396 Chevelle, and we have been talking about lining them up. He thinks I'll be faster. I think he's hustling me.
     
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