Hey guys,

I'm having this issue and it's making my car undrivable. I have a 95 with the h23a1.

My car started running terribly and wouldn't idle. It will start and stall. If it does manage to stay running, it misfires badly. It throws a code 6 (ECT), but I've replaced that sensor many times and I've replaced the connector. I also tested it with a multimeter and it looks good. I finally cracked the ecu and sure enough, it's popped. I thought it was just bad luck and purchased another p14. I installed it and boom! Popped again.

The car runs decently on my basemap tuned phearable p28, but I really want it to run perfectly on the p14.

Its blowing the Q27 Transistor which corresponds to pin A17 (intake air bypass control solenoid). I checked and it's the right connector at the IAB vacuum box (black and pink wires). I think it doesn't blow my phearable because it doesn't have a transistor for IABs since civics didn't come with them.

What could be causing this? I've done everything I can think of.

Thanks!

 

It's gotta be shorting somehow. I would run a new wire from the iab connector straight back to the ecu connector. You can just pop open the back of the ecu connector and slide the new one in after removing the old.

 

And here is what holmesnmanny is referring to as far as pinning a new wire to the ecu connector.

 

So I took the ecu to work today and had my coworkers (electrical engineers) take out my bad transistor. They said everything else looked fine and we just left the space open. They told me since I didn't care if my IABs worked or not, leaving the space open was fine since there were no driven components from that transistor. I plugged it in and it's still acting up.

I'm going to put a new transistor in on Wednesday, but I'm wondering if that transistor failure isn't related to my code 6. I smelled burning components when I first installed the new ecu, but it ran fine, so I figured it was dust or something burning up. It just randomly started acting up again last night when I was changing the slave cylinder. I was close to the ect, but I never touched it directly.

The connector has been replaced, the sensor is new, and it seems to be getting a 5v source just like the service manual indicates.

How does my car not see this input!? This is driving me crazy! Thanks for the help so far guys.

 

im wondering if somehow ur reading the code wrong .. also there is another intake solenoid ... its at the end of the air filter

 

I just install a paper clip in the blue 2 pin connector behind the radio and turn the ignition on. It flashes 6 short pulses and repeats. That corresponds to ect sensor. I've had the car for 4 years and rebuilt the engine and suspension. I know it pretty well and that's why I'm so frustrated.

Also, the other solenoid has been long gone since before I owned the car. It has a short ram intake.

 

once I was having repeated issues that were tough to explain, and ev ery time I would stop the car and re-start, it seemed to be gone for a bit.

Finally tracked it down to a rubbing solder on a wire, it was either grounding out, or somehow causing the pin to lose contact with the ecu. I took out the jumper harness and it was fine.

In your situation, I am thinking you may have a pinched wire somewhere, and it will occasionally rub when the car or harness moves, and cause the problem.

The only way I found mine was pushing my carpet back in place and it made the problem happen, then I knew what to look for. You may have to just experiment with moving stuff while idling, and see if the problem appears, unless you fell like swapping your engine harness and ecu harness and hoping it solves it.

 

I've decided it must be the wiring for the ect because I get the code 6 with my chipped p28 too, so that eliminates the ecu being the problem. I think the busted transistor is unrelated. I'm going to directly rewire the ect to the ecu and hope that's it. I've tried everything else. The car runs a little better on the p28, but I think the screwy fuel maps are causing it to 'accidentally' run better. So doesn't that eliminate everything but the wiring or sensor (which is new).

 

Internal short in the IAB solenoid was surging the ecu, popping a transistor, and overpowering my 5v rail, causing my ect to freak and screw my fuel table up. At least, that's what it looks like. New transistor and unplugged IAB seem to have it working fine right now. Just in case anyone had a similar problem, that was my solution.