background:

i have a 93 cx with a b16a and i was using an unchipped p28 to run it for a while (bought it this way, never seemed to notice anything other then 5k vtec and 7600 redline)

i purchased a phearable ecu chipping kit, i had my friend do it and he did an okay job getting it in but it wouldnn't work. i kept getting cel's and i was unable to pull the codes. i contacted phearable and they told me to disconnect the jumper to return it to stock so we did and we also clean up all the soldering from the chip better.

i started the car and did not get a cel, everything was acting just as if it was before we tryed chipping the p28. vtec works, i can rev above 4k. so i drove it for a while about 15 minutes and the cel come back on, i pulled over shut it off and was going to pull the code when i turned the ign back on the cel was gone. so i drove back home and it stayed off till i got home.

it has been doing this on and off since i did this, the car was running fine before hand. no cel's or anything like that. its getting pretty annoying and since the cel goes away i cant seem to be able to get the cel to flash to pull the code.

is it possible that i fried my ecu and that is what is causing this to happen, i would ask a friend to borrow their ecu to test but no one has an ecu that would run my car.

thanks
derek

 

anyone have any ideas?

 

I would say swap it with a known good ecu, but since you dont have any, you have to start from the begining. You are gonna want to check all your fuses. If you ECU/memory fuse is blow, the car will run fine but when a CEL pops up, the light will go away after the car is turned off. Physically look at the ECU for burn marks, and smell it, yes, smell it. Does it smell burnt? Try to get a different ECU and swap it in. There arent many ways to diagnose a bad ECU, but the best way is to swap it out.

 

You ruined it. You probably burnt the board somewhere too severely. Get a new ECU.

 

are you trying to say that if the ECU/Memory fuse is blown the car will drive fine no CEL's but will throw a CEL every once in a while but it will clear out after you shut off the car?

gtfo... seriously if you don't have any good information then keep your mouth shut... why would a burnt ECU run PERFECT no CEL's nada for like 20-60 minutes no CEL's and then just pop one randomly, then it clears out after i shut off the car? how much sense does that make. you sound like the kind of person that works at a parts store... ya know the person that throws parts at cars to fix problems... errrr

 

The reason I know this is because it happened to me... bought a Phearable chipping kit, didn't do such a great job, burnt the board a little, and it ran fine for a little while and starting throwing a CEL randomly. I would turn the car off and the CEL would go away. Tried to check the code, nothing. The CEL would go on and off for no reason.

Bought a new ECU and it fixed the problem.

I was trying to provide you with good information, I don't understand why you got so pissed off. The same exact thing happened to my ECU and I guarantee you it's the problem.

It does make sense though. It's caused by a weak connection at one of the soldering joints or a weak connection in one of the circuits from burning it a little bit. Vibrations from driving the car can cause the loose connection to randomly weaken or strengthen.

 

+1

 

i didn't get pissed :-) you actually put more information down this time around. i would just rather not get... "burned ecu; replace and move on"

yeah it does make sense... how ever what i am noticing is my CEL is coming on at wierd times, not really when i am driving but like for instance i drove 2 hours this morning, and when i stopped at the ATM my CEL came on. after i shut it off and turned it on it was gone.


i found a socketed p28 that looks like it was installed good. i am going to try switching my chips over to that board and see how it goes.

also currently the p28 that i tried to chip has had the jumper at j1 cut, so according to what phearable told me that should revert the ecu back to stock and not use the chips that were installed. rahh ecu problems.

 

I cut the jumper J1 first also like Phearable said and it ran fine. But since I wanted it chipped I replaced the ECU.

I know exactly what you mean though about the CEL coming on at weird times, it's annoying as hell, trying to drive and all of a sudden CEL comes on and you're in limp mode. What I noticed, is that if I tapped on the ECU lightly while the engine was running, it would trip the CEL. If I tapped it again, sometimes the CEL would go back off, and sometimes not. However, every single time I turned off the car, regardless of whether the CEL was on or not when I turned it off, the CEL would be gone when I turned the car back on.

Good luck with that other ECU, hopefully it works.

 

i am not even going in limp mode... with the jumper attached i am in limp mode. but disconnected i get no CEL to start and when it does get one i am most definitely not in limp mode.

when the CEL comes on everything works fine, i can rev to 7600 like it used to, i get vtec. i just have this annoying *** cel, maybe ill try tapping the ecu like you said haha.

where did you get your new ecu from?

thanks too by the way sorry about kinda being a dick i just wanted to get some more information on this rather then hearing... its NFG get a new one. :-) thanks!!!

 

I got my new ECU from Phearable, this time already chipped. I didn't want to risk messing it up again.

 

hows the new ecu i was thinking of chipping my own but i dont wanna risk it

 

bad idea... in my opinion atleast. it will cost less after you mess it up like me.

 

In the future I wouldn't chip my own unless I had a nice soldering iron. So my advice is not to chip it yourself unless you are skilled with a soldering iron and have a decent one to use, preferably one that you can adjust the heat.

 

yea honestly the only way i would try this again would be if i had:

- a nice soldering iron (heat adjustable & small tipped)
- plenty of desoldering braid
- solder sucker (idk what its called but its a hand held tool to suck up solder)
- an extra ecu...(but at that point you might as well just buy a chipped one)