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Wierd Electrical Issue

z32gtr

By z32gtr,
in Engines & Forced Induction

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z32gtr Newbie

z32gtr

Posted
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I have this issue I can seem to figure out. Z32 with Rb26/ z32 maf sensors/stock turbos/750cc inj/jim wolf ecu. Everything else factory. A few months ago this issue came about, basically when I turn ignition to ON the fuel pump would prime continuously, I swapped out the relay by the kick panel and that solved that issue. But even after I did that car would not start, it would flood, sometimes I could even hear injectors clicking with the key on the ON position while I stood by engine. Took me a while to figure out that If I disconnected the maf sensors car would fire right up. But as soon as I connect them back car dies I instantly. When cold, car will sometimes start with both connected, but as It warms up it will eventually die. It will idle fine for as long as I leave it on if both maf sensors are disconnected sometimes with one too. The other thing I found out is that it will not start if the aac valve is disconnected, If I start it and disconnect it car will die instantly. When it is plugged back in with the key on the ON position the fuel pump primes, im not really sure why. Also, when I is unplugged and key in turned to ON it will prime for like 1 or 2 secs, instead of the 5 or so. I did find that I had some stripped wires to where wire come out into firewall (probably the damn mice, I found a bunch of mouse shit in different parts of engine bay, I live way out in the woods)

Anyhow, I have replaced wires to both mafs with new wiring and just about all the wires that go from ecu to sensors/relay box. I have tried 3 different ECUs with same exact results. All 3 ECUs give me code 12. I have also tried brand new MAF sensors with same results. Starting to get pretty frustrated.

Any suggestions on what to try next or has anyone had a similar issue? Any help would be greatly appreciated.

Thanks in advanced!

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sleptema Proficient

sleptema

Posted
Posted

I have this issue I can seem to figure out. Z32 with Rb26/ z32 maf sensors/stock turbos/750cc inj/jim wolf ecu. Everything else factory. A few months ago this issue came about, basically when I turn ignition to ON the fuel pump would prime continuously, I swapped out the relay by the kick panel and that solved that issue. But even after I did that car would not start, it would flood, sometimes I could even hear injectors clicking with the key on the ON position while I stood by engine. Took me a while to figure out that If I disconnected the maf sensors car would fire right up. But as soon as I connect them back car dies I instantly. When cold, car will sometimes start with both connected, but as It warms up it will eventually die. It will idle fine for as long as I leave it on if both maf sensors are disconnected sometimes with one too. The other thing I found out is that it will not start if the aac valve is disconnected, If I start it and disconnect it car will die instantly. When it is plugged back in with the key on the ON position the fuel pump primes, im not really sure why. Also, when I is unplugged and key in turned to ON it will prime for like 1 or 2 secs, instead of the 5 or so. I did find that I had some stripped wires to where wire come out into firewall (probably the damn mice, I found a bunch of mouse shit in different parts of engine bay, I live way out in the woods)

Anyhow, I have replaced wires to both mafs with new wiring and just about all the wires that go from ecu to sensors/relay box. I have tried 3 different ECUs with same exact results. All 3 ECUs give me code 12. I have also tried brand new MAF sensors with same results. Starting to get pretty frustrated.

Any suggestions on what to try next or has anyone had a similar issue? Any help would be greatly appreciated.

Thanks in advanced!

You're going to find a better answer than this, but my 2 cents: It sounds like your AFMs are giving your ECU readings without the car running. Could be wires have corroded the insulation and are touching, or the actual AFMs themselves are cactus. The way to eliminate this would be to get specifications on what the AFM should be reading at certain RPMs, and with the car off, idling and high idle, check the resistance/voltage at the AFM plugs. If you are getting the same reading at idle as you are with it off, you have an issue. Maybe the reason it runs fine with them disconnected is that the engine doesn't pay attention to the values anymore because of the erratic values given, and just relies off the map sensor.

The AAC (auxiliary air control valve) gives the engine a small amount of air while starting and I believe also helps sets your idle RPM. With this disconnected, the mixtures will be wrong and the engine could stop.

I would have thought taking it to your tuner to get him to connect to the ECU would provide quick and reliable results on what sensor is doing what, as we will know what the car is supposed to be doing.

I'm not sure about your fuel pump, but it sounds like it thinks the engine is running so continuously tries to pump, this could be your AFMs giving the car false readings as well, but I am not sure how your ECU knows how the engine is running.

sleptema Proficient

sleptema

Posted
Posted

i've checked readings on both sensors by hot wiring the maf and checking for voltage differences while blowing air through it, and voltage climbs as it should as more air is blown through maf.

The voltage may rise as it is supposed to, but the base reading when the car is off may be out of calibration, as it may think there is air flowing when it is off.. It's just a thought.

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