Look at the middle of the pic and see the black circle where either a resistor or transister used to be. This is what I think is causing the ecu to not send a signal to my IAB's. Thanx in advance.




[Modified by Guardson3r3, 3:08 PM 3/19/2002]

 

I'm sure it served some purpose at one time or another

 

Thats pretty nasty. However, if someone here told you it COULD be fixed....what value resistor would go back in? And lets say you do get the right resistor....what caused it to burn up in the first place (and thats the kicker)?

Whats the reference designator that is right on top of it? It looks to be 'R'...is it?

What kind of history does this ECU have?

 

If it's R135, (hard to tell from the pic), something caused it to smoke. Maybe a bad capacitor, shorted diode, or a short in the wiring it was feeding. Unless you got a schematic or looked at another ECU, there's no way to guess what the proper resistor value is for a replacement. BTW, the color bands on the resistor indicate the value, the last one (gold, silver,etc) indicates tolerance (+/- 5%, +/- 10%, etc.). Anyway, I guess it wouldn't hurt to replace it with the correct value resistor and see what happens. If it smokes again, you need to dig into the ECU further.

 

Thanx for the reply. My friend and fellow H-T member has the same ecu and we are going to compare both circuit boards this weekend. The transistor/resistor/capacitor is black on his circuit board. We have some soldering to do this weekend. I will keep you guys updated. I think this piece is for the IAB solenoid on the B18C1. It was sold to me over 5 months ago. I didn't notice the problem until 92SleepR helped me wire my IAB's. His 95 gsr ecu sends the proper signal to shut the IAB valve at start up until 4400RPM's unlike mine. Thanx again for all the input. What do I use to get all the black gunk out?

 

You can use alcohol and an old tooth brush to clean the carbon off the circuit board. (carbon can conduct electricity, so you want to get rid of it) If you can, post a pic of the part in your friend's ECU and I'll try to help you figure out what you need. From the printing on the board though, it seems like R135, which would be a resistor. Can you confirm this?

 

You really need to find out why it smoked before you fix it.

 

How would I do this? It was sold to me 4 months ago but I didn't beging to wire my IAB's until this past weekend and that's when I opened the ecu. It's R135 and I will try to take a pic of my friend's ecu this weekend.

 

didnt u get ur swap done from nu image??? take that **** back

 

Yep..
if that's what I think it is...i've experienced that burning R135/Q31 part. It has nothing to do with ecu reprogramming either. I've seen it happen on various stock OBD1 VTEC ECU's (P28, p30, P72 mainly -- but mainly P28's). I have no idea why it happens though, but it only happens once, as far as my experience with this problem goes. I thought somthing was up with my car's wiring, but it turns out it wasn't, because it didn't happen on ALL of the ecu's I've plugged into my car and tried out, while troubleshooting the problem.

I remember the first time it happned too...(dream sequence)
I plugged in a P28 ecu, turned my car on, barely drove down the street and this funky burning odor hit my nose. I just happend to look down at the ecu and see some smoke come out the side, 'wholey ****!' I yelped, pulled over, unplugged the ecu, took the cover off, 'peee yuuu', smoke came out and it was staaaaanky.....but I saw the chipped that burned and it was the R135/Q31 piece. Took a mental note of that issue. Funny thing is, I plugged it back in and it never smoked again....really weird, ECU gremlins.

I've seen it happen in my friends Delsol Si also. Again, really weird though, no idea why it happens.

I have some upclose pics that particular chip that burns too, if anyone is interested.

I've replaced that capacitor/resitor chip that burns (in the pic) before and all ran well. Although, I don't think that particular part controls your IAB's, since all OBD1 civic/integra ECU's have that capacitor/resistor R135/Q31 peice. I have spare obd1 ecu's I use for parts and I can replace that part if need be....if the board itself isn't too burned up.

 

OK, forget my earlier replies. Looking at the pic again, it apears to have 3 holes in the burned area. This would definately be a transistor. If you are lucky, you might be able to get a number off of the good one in your friend's ECU. Even then, it may just be a vendor number and not one easily cross-refferenced. I would definately suspect another component failed on the circuit board to take out the transistor, meaning a replacement would meet the same fate. If you are lucky, it was caused by an external wiring problem that is by now corrected.

 

Yes I did David, but at the time they used a chipped P28, which I traded for this one. THought I got a good deal.

Katman, I have Mike a.k.a. 92SleepR helping me this Sat. I really don't know much about circuitry and both you guys know your stuff. The reason I think it has something to do with the IAB is that we plugged in his ecu to my car and it gave the signal to shut the IAB, I drove around and it was great. I then plugged my ecu back in and the IAB stayed open. We will compare ecu's and I will take pics of his this weekend. Mike think's it's a transistor as well. The rest of the board is fine, this seems to be the only part that has a problem. I just hope we can solder a new one in there and make it work. Mike and I might need your professional help on this one. I really don't have the $300 for a new ecu when mine works with just one flaw.




[Modified by Guardson3r3, 4:58 PM 3/20/2002]