P28 ecu trouble
 

I have a P28 ecu i got from a friend it has been chipped he had it in a 00 civic si with a jumper harness. He also had a VFAC and i think that went bad and then the car started running like crap hard to start cel anyway i put it in my car which is a obd1 92 civic hatch with a swap and the chip is for a b-series but the car is hard to start and when it starts it throws a Code 4 which is crank angle sensor well i replaced that and it still doing the same thing. I put in another stock p28 ecu and it runs normal with no cel lights and not hard to start. I was just thought i would see if anyone might know what is wrong with it? I sent to a place that repairs ecus twice but he said he did not know what it was. Plus he did not have the right stuff to test it So if anyone has any idea what it might be please help me out thanks.

Re: P28 ecu trouble
 

On the chipped p28 cut jumper wire J1, this will "unchip" it. If the ecu works fine, there is a problem with the chipping modifications.

http://www.qcwo.com/technicaldomain/...11/image-9.jpg

Re: P28 ecu trouble
 

pmed everyone still need help

Re: P28 ecu trouble
 

Ok, so you're getting a crank angle sensor CEL, and the crank angle sensor is good. You tried another ECU and no crank angle sensor CEL. Call me crazy, but I think you have a problem with the crank angle sensor input in the ECU. I'm not sure what your question is, because the answer seems pretty obvious.

Re: P28 ecu trouble
 

thanks for the advice i kinda figured that much out but where in the ecu is that located thats the question.

Re: P28 ecu trouble
 

Why does that matter, you're not going to be able to troubleshoot and repair that yourself most likely. There aren't schematics of Honda ECUs kicking around, so you'll have to get in touch with someone who is very familiar with repairing them.

You can buy another P28 for about $75, so that's the fast and easy fix.

Re: P28 ecu trouble
 

sounds like you need to test the wires from ecu to sensor. make sure the wire hasnt be crushed.

when you say jumper harness do you mean conversion harness?
2000 ecu is obd2, with chip and conversion harness it changes it to obd1, that conversion harness could be bad, they arent really built that well, its a solid connector plug with pins at both ends thats was originally designed for circuit board applications. each terminal gets the 90 degree elbow cut off and wire soldered to it. the wire could just be broken free or not getting a good connection.

Re: P28 ecu trouble
 

If that was the case the other P28 he tried wouldn't have worked perfectly.

Re: P28 ecu trouble
 

yeah but that one was stock and he didnt say if the he used the jumper harness or not, but hey that why i asked what he means by jumper harness. just throwing another idea out there.

Re: P28 ecu trouble
 

he said he put it in a 92 civic which is obd1. he wouldn't use a conversion harness.


if you threw a code with the chipped ecu but not with the stock one then it sounds like what fabrik8 was tellin you. the crank angle sensor input for that chipped ecu.