Ok, so I'm trying to figure out the worst problem I ever had with a car. It's a 90 ef with a d16z6 and obd1 pr4. I ripped all the wiring out of the car and built an all new harness. It ran great for a year and then one morning it just stopped working. It wouldn't start at all. The weird thing is that there were no codes at all. I unplugged everything I could find map/tps/ect/iat/iacv/both dizzy plugs/alt/o2/injectors/etc. I can't get the ecu to throw certain codes. The only codes that came on were for the iat, eld, ect, and the vtec oil pressure switch and thats it. No codes whatsoever for anything else.

Here's what I did so far:
-Checked spark -none. I put in a new dizzy; plugs and wires too. Now I only have a weak spark
-Check individual sensors. -fine
-Fuel system was checked -all good.
-Timing -yep
-STILL not running and no codes at all

So I was fed up and just rebuilt the entire electrical system:
-Bought a p28 ECU and made a new harness. The only components I reused from the old harness was the pgmfi relay, resistor box, and the cluster.
-Double checked my wiring and tried the new ecu
-WTF! STILL NO CODES! Same exact situation as before.

Does anyone know what would cause this issue?? What could just spontaneously fail and still not work even after a brand new electrical system? The problem and symptoms are identical to the original setup. I can't even think of a POSSIBLE cause except for a dirty supply voltage or ripple to the ecu. I couldn't find anyone else with this problem. I'm going f$#% insane

 

Did you check fueses, grounds, main relay?

 

Yes, I checked everything I could think of. Plus, I don't have an oem harness. No where near as much wiring in my harness. I'm trying to figure out what could cause nearly all of my unplugged sensors to NOT throw codes. I'm assuming whatever is causing that is the main reason why it won't run.

 

Well your best bet is to try to get your hands on a oem harness to figure out what caused it to stop working.The only thing that doesnt make sense is that it worked ok for a while and then suddenly stopped.That makes me think of something mechanical try checking the resistor box if you have one.

 

I checked everything I could both electrical and mechanical. Compression, timing, fuel pressure, checked continuity and resistance for the sensors, you name it. Now I'm sure its not mechanical because I can't imagine anything mechanical that could cause codes for vital sensors not to be shown. It's like the ecu is always getting a signal from something and thinks that the sensors are connected even though they're not. So I'm guessing that even when they ARE plugged in, the ecu is still getting crap data.

 

Did you check the ecu and can you get your hands on another harness?

 

Heres a video of the problem. Its a lot easier to understand this way. I suck at explaining things. http://www.youtube.com/watch?v=M953Ho4d5IQ

 

The only thing i can think of is if some how some where in the system that corrosion got in to the harness and is shorting out the system some how.. or a few cold solders thats a common problem of both. they like to stick there ugly heads up later on it seems like they KNOW when you have every thing back together and then they like to mess with you. they wiill work for a while then not work.

 

yes but where? Its a new harness and I checked resistances on the leads and if so many sensors are acting up whats the common denominator? thats where im stuck...

 

Damn I hope I never have this problem because i'm be totally ****ed haha -.-.

GL on trying to fix the problem, hope you figure it out soon :S