Couple issues, need some input

veedubin

Official SM Decals
87 Turbo 5 spd JDM 7M with JDM auto ecu.

Car ran great right after swap, and for about 3 weeks after. then it popped the CEL. Code 51 and 52. I have already rewired the knock sensors prior to installing engine.
I am fighting with both of these codes and I am now losing the battle.
Code 51 is there from the time the engine is started. If i clear the ECU by the fuse or batt disconnect, I can start the car just fine. as long as I don't rev it, the CEL will remain off. I can check the codes while the light is off and it shows 51. I have replaced and adjusted the TPS with a known working unit. When I rev the engine, say about 3k ish, it'll pop the light on and code 52 is there. I checked the rewire, no cont. to ground on either wire. less than 30mv at the ground for the KS wire. I replaced the knock sensors last night with 2 known working ones I had laying around. The cel popped on soon as I revved it, code 52.

Now the wierd part; I got fed up with the car and decided to drive it home from the shop with 52 still present. So I backed the car out of the shop, turned it off, then restarted it. I let it idle to warm it up while I was locking up. ran for about 5-7 minutes. I get in the car to go home, and the whole ride there, the light never came on! The ride was about 10 minutes and I was laying into the throttle pretty heavy just to see when/ if the light would flash up. After stopping inn at wal mart for milk, I came back to the car started it and drove the rest of the way home. Before I could get out of the parking lot the light came back on.

This morning I checked the codes again, 51 and 52. cleared codes for the hell of it, took my kids to school. light popped soon as i hit 3k rpm. when I left the school the light stayed off for about 10 minutes until I pulled into Wawa for my coffe. On the way home the light was back on......... WTF

So that is the whole story, a bit lengthy, but I want to make sure I have all the details straight.
I spent the better part of yesterday searching the code 52 threads and found all the typical " rewire it" or "replace it" threads. Not too much on this type situation.

I've got 2 options to try for the 52 code:
I just ordered 2 new KS connector from yota, they will be in tomorrow morning. So I can do another rewire. I know repitition is stupid but hey.
I am also thinking of putting my USDM 5spd ECU in the car and see what happens. I am not sure if the pinouts are different between the JDM A/T and the USDM 5spd. I do not have EGR so I know that will throw a code, I just want to make sure if I plug the US ecu in i'm going to have all the pins going to the right wires.

Thanks to all for wasting your day reading that novel. Any input is greatly appreaciated.
 

Kevin

7mgte -> 7mgte swap done.
Apr 20, 2009
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Windsor Ontario Canada
i had the code 52 too.. i used Shaeff's re-wire kit. and code went away forever!! lol. check your connectors etc.. (i bet u probably did)
i guess you could try re-wiring it again... not hard to do anyway.

as for the code 51... are you saying it shows when you rev? because it is supposed to do that..
 

veedubin

Official SM Decals
Kevin;1505452 said:
i had the code 52 too.. i used Shaeff's re-wire kit. and code went away forever!! lol. check your connectors etc.. (i bet u probably did)
i guess you could try re-wiring it again... not hard to do anyway.

as for the code 51... are you saying it shows when you rev? because it is supposed to do that..

Yea, I doubled checked the connectors, depinned them to make sure no wires got broke or anything. They were both fine.

Code 51 does not set the light. when I rev the car past 3k, code 52 will set, and the light pops on.
 

Kevin

7mgte -> 7mgte swap done.
Apr 20, 2009
865
0
0
Windsor Ontario Canada
ya same thing for me.. code would be gone.. (code 52) then when i drive or rev.. it comes back. could be a knock sensor.. i would say most likely your wiring but you say u double checked everything so ya it might be the ks itself. well one of them atleast.
 

veedubin

Official SM Decals
Kevin;1505471 said:
ya same thing for me.. code would be gone.. (code 52) then when i drive or rev.. it comes back. could be a knock sensor.. i would say most likely your wiring but you say u double checked everything so ya it might be the ks itself. well one of them atleast.

Last night I actually replaced both sensors with 2 known working units. And then that's when the wierd shit started happening.
 

Kevin

7mgte -> 7mgte swap done.
Apr 20, 2009
865
0
0
Windsor Ontario Canada
idk what else to tell u man lol.
either the ks or the wiring.

maybe u touched the wiring and accidentally screwed somethin when you replaced them.

check both again and see what happens. other then that idk why else will it be doing that.. maybe the ecu? idk.
 

veedubin

Official SM Decals
Kevin;1505479 said:
idk what else to tell u man lol.
either the ks or the wiring.

maybe u touched the wiring and accidentally screwed somethin when you replaced them.

check both again and see what happens. other then that idk why else will it be doing that.. maybe the ecu? idk.

I'm really thinking the ECU could be a culprit in this case..... I'm not sure though. Once I get the new KS connectors in tomorrow I'll re-re-wire them and see what happens. If that doesn't work I need to look at ECU. I have the US 5sp turbo ecu from the last motor, I just don't know iff I can plug that into a JDM auto turbo harness. Not sure if all the pins are the same. Besides, this motor is not equipped with EGR, so I'de have that code to deal with....... f*cking cars.
 

gaboonviper85

Supramania Contributor
Jan 13, 2008
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Northeast Philly
veedubin;1505583 said:
I'm really thinking the ECU could be a culprit in this case..... I'm not sure though. Once I get the new KS connectors in tomorrow I'll re-re-wire them and see what happens. If that doesn't work I need to look at ECU. I have the US 5sp turbo ecu from the last motor, I just don't know iff I can plug that into a JDM auto turbo harness. Not sure if all the pins are the same. Besides, this motor is not equipped with EGR, so I'de have that code to deal with....... f*cking cars.

I am 99% sure it's not the ecu....ecu's rarely ever go beat in these old cars!

Think you should rewire the sensors using shaff's kit....
 

veedubin

Official SM Decals
gaboonviper85;1505630 said:
I am 99% sure it's not the ecu....ecu's rarely ever go beat in these old cars!

Think you should rewire the sensors using shaff's kit....

ECU, yes I agree, I've never really heard of onegoing bad. But just like every other electronic device, It's possible.

If my re-re wire fails, I'll be contacting shaeff about his kit. I really forgot he did that until i read that post. Could have saved some time. Oh well. life moves on and the supra is still slower than a civic........ :nono:
 

veedubin

Official SM Decals
FIXED!!!

purchased new KS connectors from yota and rewired and viola!
Last night could not have went any better car wise..... oh wait yes it could. I could have remebered to put the rad cap on. Drove 12 minutes with no rad cap..... surprisingly she started to get a little hot. Damnit. oh well all those little details are straight, and the car runs great! Now i need to adjust the TPS and she should be like new.
Thanks to all that threw in thier advice.