LS1 swap DIED, can't figure it out.
05-11-2013, 04:06 PM
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LS1 swap DIED, can't figure it out. Hey everyone!
I have a bit of an issue. It's a 2001 LS1/T56 swapped into a 95 240sx, running a stock camaro tune on an '0411 PCM, disabled emissions, vats, skipshift, done by poconojoe (who seems MIA) It has been my daily for over a year and it ran like a champ. i use an OBDlink MX hooked up to a tablet as my dashboard.
it all started with electric fans. here is the outline, last weekend:
- stock 240sx fan relay wiring uses a 7.5a fuse on the interior fuseblock. AC is also on that circuit, but i'm not using it. fuse was pulled until i began wiring.
- i wire up the fan relays to the ECU, instead of a manual switch. (i left the battery plugged in while i rewired
) worked great, but it threw a TPS circuit low code and another for coil F. i still haven't driven it at this point.
- i diagnose and see it's a bad coil, i remove the PCM connectors and the TPS wiring to ECU seems good, although the resistance falls slowly to 0->.1ohm from 2-3ohm but it might be my meter. nothing seems shorted. i plug the ecu back in. not sure if it matters but the battery is still hooked up at this point.
- cleared codes, drive to auto parts store, skip shift seems permanently engaged and no speedo readings! WTF??
- got back home, replaced coil F, no more code, replaced TPS, but still have TPS circuit low code. shitty performance tho.
- looked under car, noticed that reverse lockout was actually plugged in the skip shift (because a buddy helped me with some work. he plugged the connectors back in, i didn't verify). BUT IT'S BEEN THIS WAY FOR 6 MONTHS!!!
- unplugged reverse lockout and left it unplugged, no more skip shift engagement.
- drove it to work monday, still have TPS code, shitty performance, and no speedo. on the way home, coil B took a dump. while still on the freeway, the OBDlink stops seeing the PCM altogether.
- i get home, reset a couple of times, remove batt, etc, etc but PCM to OBDlink connection is intermittent.
- i disc'd the batt, and replaced the ecu with a 2000 camaro one i had lying around. not sure what tune was on that ecu, but the wiring that originally came with this PCM had the CKP connector cut off.
- this PCM communicates with the OBDlink, but car doesn't start. throws me TPS low circuit but no coil B code.
- i unplug the TPS, car starts, revs, revs higher, revs higher, dies. again, same thing.
- plug tps back in car won't start. plug the '0411 PCM back in (disc'd the batt all these times), no comms to the OBDlink, no start.
- a couple of days ago i get someone here with HPtuners, but his computer won't see my PCM either.
- i try the old PCM again, this time no start whatsoever with or without TPS. HPtuners can't see it and neither does my device.
- PCM does get power at the pins
;tl-dr - wired up fan relays to ecu a week ago, car gradually reached a point where it won't start.
please help, i no longer know what i'm doing.
I have a bit of an issue. It's a 2001 LS1/T56 swapped into a 95 240sx, running a stock camaro tune on an '0411 PCM, disabled emissions, vats, skipshift, done by poconojoe (who seems MIA) It has been my daily for over a year and it ran like a champ. i use an OBDlink MX hooked up to a tablet as my dashboard.
it all started with electric fans. here is the outline, last weekend:
- stock 240sx fan relay wiring uses a 7.5a fuse on the interior fuseblock. AC is also on that circuit, but i'm not using it. fuse was pulled until i began wiring.
- i wire up the fan relays to the ECU, instead of a manual switch. (i left the battery plugged in while i rewired
) worked great, but it threw a TPS circuit low code and another for coil F. i still haven't driven it at this point. - i diagnose and see it's a bad coil, i remove the PCM connectors and the TPS wiring to ECU seems good, although the resistance falls slowly to 0->.1ohm from 2-3ohm but it might be my meter. nothing seems shorted. i plug the ecu back in. not sure if it matters but the battery is still hooked up at this point.
- cleared codes, drive to auto parts store, skip shift seems permanently engaged and no speedo readings! WTF??
- got back home, replaced coil F, no more code, replaced TPS, but still have TPS circuit low code. shitty performance tho.
- looked under car, noticed that reverse lockout was actually plugged in the skip shift (because a buddy helped me with some work. he plugged the connectors back in, i didn't verify). BUT IT'S BEEN THIS WAY FOR 6 MONTHS!!!
- unplugged reverse lockout and left it unplugged, no more skip shift engagement.
- drove it to work monday, still have TPS code, shitty performance, and no speedo. on the way home, coil B took a dump. while still on the freeway, the OBDlink stops seeing the PCM altogether.
- i get home, reset a couple of times, remove batt, etc, etc but PCM to OBDlink connection is intermittent.
- i disc'd the batt, and replaced the ecu with a 2000 camaro one i had lying around. not sure what tune was on that ecu, but the wiring that originally came with this PCM had the CKP connector cut off.
- this PCM communicates with the OBDlink, but car doesn't start. throws me TPS low circuit but no coil B code.
- i unplug the TPS, car starts, revs, revs higher, revs higher, dies. again, same thing.
- plug tps back in car won't start. plug the '0411 PCM back in (disc'd the batt all these times), no comms to the OBDlink, no start.
- a couple of days ago i get someone here with HPtuners, but his computer won't see my PCM either.
- i try the old PCM again, this time no start whatsoever with or without TPS. HPtuners can't see it and neither does my device.
- PCM does get power at the pins
;tl-dr - wired up fan relays to ecu a week ago, car gradually reached a point where it won't start.
please help, i no longer know what i'm doing.
Last edited by VlaDeMaN; 05-11-2013 at 04:13 PM.
05-11-2013, 06:32 PM
#2
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Maybe you have a bad battery? ALso check and make sure you have power going to the pcm. I would disconnect your fan setup and see if that was causing the problem. Maybe you are feeding power back to the pcm from the fans.
05-11-2013, 07:40 PM
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i did just that today, no power is going to the fans or the fan relays. pcm is definitely getting power but no dice on start.
edit: battery turns the motor fine. it's a yellow top... should i try another battery?
edit: battery turns the motor fine. it's a yellow top... should i try another battery?
Last edited by VlaDeMaN; 05-12-2013 at 03:57 AM.
05-12-2013, 06:27 PM
#6
TECH Fanatic
Just random thought... I was tuning a buddy's car that had retrofit HIDs in it. I turned key to 'ON' and started loading the tune. The HIDs were on and everything is going fine... Then he walks by and flicks off the HIDs. After that it was like your last issue... No start, HPtuners wouldnt read the ECU I hooked it up to 3 other cars to confirm. His ecu needed a TECH2 reprogram but after the reprogram it worked fine Maybe give that a shot if all else fails I guess.
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05-13-2013, 03:17 PM
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I have a few questions for you to try and figure out the problem. Can you explain in detail how you wired in the fans and what fans you used? I wired in my own altima fans when I did my LS 240sx swap. I need to know if you used a negative or positive to trigger your relay to the fan or fans. Verify which terminal on your ecu you used also. On the Blue C1 pcm connector #42 green wire is usually used for fan 1 trigger and Red C2 connector #33 dark green wire is used for the fan 2 trigger. Both are negative triggers. So these should only be attached the negative side of the coil on a relay that controls the fans. These should only be ran to trigger a relay not straight to fan itself. If you need help pm me and I will dig deeper and see if I can help you out.
Last edited by jmac636; 05-13-2013 at 03:23 PM.
05-13-2013, 04:07 PM
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jmac636,
yes negative ground trigger to relays, of course not to the fan directly
i have a 7.5a fuse running a trigger line to the 2 relays. in the fusebox i have a 30a fuse that supplies power to the fans. each fan is on it's own relay, one for low, both for high. using 12" mishimotos.
the fans did come on at my custom temperatures when the whole thing was functional.
currently, i have the relays and the fans completely unpluged, and the 2 wires to the ECU unpinned. still no response from ECU.
last night i bought a replacement ECU, it's being shipped from nearby. let's see how fast this will burn out.
yes negative ground trigger to relays, of course not to the fan directly
i have a 7.5a fuse running a trigger line to the 2 relays. in the fusebox i have a 30a fuse that supplies power to the fans. each fan is on it's own relay, one for low, both for high. using 12" mishimotos.
the fans did come on at my custom temperatures when the whole thing was functional.
currently, i have the relays and the fans completely unpluged, and the 2 wires to the ECU unpinned. still no response from ECU.
last night i bought a replacement ECU, it's being shipped from nearby. let's see how fast this will burn out.
05-13-2013, 04:36 PM
#11
TECH Fanatic
Are you near a GM mechanic who has a tech2? I don't know how much you are paying for ECUs but it might be worth a shot for them to try and reprogram it instead of having to get a new ecu every time.
05-13-2013, 06:06 PM
#14
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