well my friend's got a chipped p28 in his hatch. It has been running just fine up until now. Now it has been acting up and randomly throwing a code 0 that would go away eventually and then come back. Then today it happened again and the code would not go away. We plugged my chipped p28 into his car and it ran fine and didn't throw the code anymore. So obviously his ecu is messed up. He resoldered all of the connections in the ecu and it still isn't working right. What could have happened to make his ecu all of a sudden go bad when it was working fine?

 

anybody?

 

i would try a different chip, that one could have went bad...if it had a cold solder joint that was good enough to make contact but occasionaly offer to much resistance. Ive seen happen in small electronics before, but those were SCR's and logic controllers.

 

nah its not the chip. We tried swapping chips from my ecu and it didn't work. Then we tried just swapping the whole ecu for mine and it did work. Definantely something messed up with his ecu.

 

Could be something that went wrong in the chipping process, make sure none of the points that you soldered are loose.

 

I'm with the cold solder joint crowd.

Cut J1 to verify if the ECU is good. If it is, reflow the joints on the socket and the latch.

 

when you say reflow do you mean resolder?

We are going to try this tonite. thanks for the input

 

And if all else fails sell it to me for $5

I'm gonna agree with JD on this one.... Actually, my initials are JD too, so i'm gonna agree withmyself.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">I'm with the cold solder joint crowd.

Cut J1 to verify if the ECU is good. If it is, reflow the joints on the socket and the latch. </TD></TR></TABLE>

sorry should have thought to mention that earlier.

like j Davis said if it doesnt work when you bypass the chipping circuit by cutting J1 then its safe to say its the solder job. make sure your using rosin core solder or some type of flux, something to clean the contact as your soldering...in the mean time you could post a pic of the joints so some of us could see if you poped a trace or something applying to much heat etc.

 

yea i told him to get a pick of the joints...he sais he doesn't think it will come out well enought. I have seen the joints and they don't look bad at all. I don't see why it shouldn't be working. Hopefully tonight or tomorrow he will cut the j1 jumper and see if that helps.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by toolowsol &raquo;</TD></TR><TR><TD CLASS="quote">Actually, my initials are JD too, so i'm gonna agree withmyself.</TD></TR></TABLE>

Hehe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">I have seen the joints and they don't look bad at all. I don't see why it shouldn't be working</TD></TR></TABLE>

It's not just shape and size, but color - if they are a bit dull, it's a good sign of a cold joint that isn't making good contact. I've even had one or two over the past couple years with nothing I could see wrong that worked fine after reflowing the joints.

 

well he sais he cut the jumper and it works so i guess his joints do need resoldering.

 

 

hey guys I resoldered everything, but When I cut the jumper it still threw a code 0. Do I need to reset the ecu when I do this, because I just cut it while it was still in the harness. I can go and disconnect the battery but havent had time.

I just dont understand why it will run sometimes, and then other times it throws code 0

 

wait so it didn't work? I thought you said it did.

 

You might have burned up the 74hc373 IC, Those have pretty low heat tolerance, epecially the surface mount variety (which I doubt you have). This is why I tell people without any electronics soldering experience to leave it to someone that knows what they are doing and has the right equipment. Another possability is that you pulled up a trace somewhere or burned through one. Let me know if you don't figure it out, I can probably repair it for you for a small fee.

 

he should be able to solder it correctly. He is about to finish engineering school

 

Well i am going to try and transfer my chip to my dx ecu and see what happens. I think a transitor has gone bad since the ecu was not throwing a code when I clipped the uberdata jumper the first time, but it did throw a code 0 the second time I clipped the jumper.


ARRR I hate this!

 

now you got worse things to fix...

 

yeah i know, i dont think its the headgasket, I think it may just be low on coolant and a bad fuel map

 

Send your ECU to me, I can probably fix it for you...