Ok, so I'm trying to figure out the strangest problem I ever had with a car. It's a 90 ef with a d16z6 and an auto OBD1 pr4 converted to manual and vtec. Last year, I ripped all the wiring out of the car and built an all new harness. I only wired what was essential for it to move. It ran great for a year and then one day it just stopped working. It wouldn't run at all. This setup never had any problems AT ALL before this, and the weird thing is that there were no codes being displayed. The pump primes and I can enter service mode too. I did some troubleshooting and it seemed like I wasn't getting any spark. I got a new dizzy and now I have spark. It seems a little weak, but that could be just because I don't have another identical setup to compare it to. Even after that, it still doesn't run. I have spark, fuel delivery, and my timing is dead on.

I checked as everything I could from the ecu connectors. Power/grounds/map/tps/ect/iat/iacv/dizzy/alt/o2/injectors/etc. Everything seemed OK from my dmm.
What's weird is that I can't get the ecu to throw certain codes. I disconnected all the sensor plugs I could and the only codes that came on were for the IAT, ELD, ECT, and VTP and thats it. No codes whatsoever for anything else.

So, I figured the ecu just went bad. I bought a manual p28, and while waiting for it, I made a much nicer tefzel harness to replace the old one. The parts I reused from the old harness were the main relay, the injectors/resistor pack, and sensors.

New harness, new ecu, new dizzy... STILL doesn't run and it behaved exactly like it did at first. Plus, it doesn't matter if I use my ghetto, hacked up pr4 or the new p28. I get the same issue. No codes are being displayed for anything even when sensors are unplugged. (with the exception of the IAT, ELD, ECT, and VTP)

Does anyone know what could cause this issue?? What could spontaneously fail and still not work even after a brand new electrical system and ECU? The symptoms are identical to the original setup regardless of which ecu I use. I figure that whatever is causing this is why it won't run, but I can't even think of a POSSIBLE cause. For example, both the MAP and TPS won't throw a code when unplugged. The MAP's wiring is isolated from everything else (it has it's own separate +5v, signal, and gnd wires) and it goes straight to the ECU. The only thing in common between the sensors is the ECU itself. I couldn't find anyone else with a problem like this. Anybody have an idea? I'm going f$#% insane

 

i have had a problem with my resistor box on my obdo and no codes were showing up. when i had this problem my car was broken down for a month i no how bad it sucks. it seem strange that even tiring to make the car throw codes it wont. if you still have the box or if you put the resistor in line id maybe check them with a voltage meter make sure they are in range

 

lol the resistors? Well, that would explain why the new ecu was acting exactly like the old one. So you just replaced the pack and that took care of it? Or did you do away with the pack and use saturated injectors?

 

New or used? I'm assuming used.

Instead of swapping complete distributor assemblies, you should have isolated the no-spark to either the ignition coil or the ignitor by testing, and replaced the offending part in your existing distributor.

I'd be willing to place money on your problem still being related to the coil or ignitor.

 

o.k technically you no longer run a ressitor box right? did you install the jumper harness, this basiclly jumper all the wires that used to go the resister box together, this is a pic of it. this plug may go bad from time to time so make sure they are all jumpered to each other.
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if you have fuel pressure verify by letting the pump cycle and lossen the banjo bolt at the end of the fuel rail to make sure. now if you do the only thing left if you do have spark are the injectors the black/yellow on the inector plug should get 12vdc when you first cycle the ignition. check black/yellow to a know ground if you have 12 volts then go from black/yellow to the other wire to the injector harness for each individual injector. remember cycle the ignition everything you are going to check so have someone helping you. the black/yellow is the hot side and ground side comes from your ecu. so if you have 12vdc to a know ground but not from wire to wire on the plug well your problem is there. your injector is not injecting at all.
if you want to find out fast if your injectors are to blame spray starting fluid in the trottle body then crack if the car comes on or feels like it is going to come on then you just reduced your possible issues to the fuel side.

 

Well, at first I didn't have spark. My old distributor was a piece of crap. It was rusted inside and the tdc ferrite was loose. It didn't have much life left anyway when I put it on so I just thought it finally went dead. I bought a new distributor and now I do get a spark, but I'm still not getting any codes if I unplug it. I have no clue why the ecu(both my old one AND a new, tested one) is thinking that everything is plugged in and working correctly even if they're not. The only sensors that throw codes when I unplug them are the ECT, IAT, ELD, and the vtec pressure sw. I can't find out why the others ones aren't giving me a CEL when they're unplugged. I don't know what could cause that to happen even after a new ecu and harness.

no I still have it, my injectors are peak and hold. I do have fuel pressure and I even tried them in another manifold to directly see if one was stuck or something. I'm gonna go and check each injector circuits right now. I'm skeptical about how a resistor box gone bad would cause the ecu to not report CELs, but if it happened on k20rex's obd0 ecu, it might with my obd1 too. I ran out of things to replace or test around november 20th :/

 

the obd1 swap requires you to replace the resistor box with the jumper plug... technically it is just a jumper that you have, the plug sometimes has a bad connection althought not often.

 

Yeah, if I had an SI, an obd0 to obd1 ecu jumper and used obd1 injectors; but I don't.
I made an all new harness so it's pretty much electrically identical to a factory obd1 harness. I'm using p+h injectors from an obd0, so I have to use a resistor pack. I checked the injector circuits' resistance from directly from the ecu plug, 10±.5 ohms all around. I also unplugged the injectors, still no codes. So I think all that kinda rules out the injectors causing the ecu to not report any codes.
I still got NO idea what could cause two good ecus to not report codes. I'm about to sell this damn shell. Its got be haunted or something. :/

 

 

Even when the dizzy's unplugged, neither ecus show any codes except for eld, iat, ect, and vtp.