riftonthemind057

Okay I have a d15b2. I'm having electrical issues. The car when it starts reads a 12 volt reference into the ecu then 5 volts at the tps, the iat sensor and eagr sensor like it should ,after about a couple seconds the voltage raises on all of those sensors in turn shutting off the car. Now I have checked some of my grounds throughout the car tried replacing the ecu with a known good one and still does the same thing. I'm in the process of checking my dizzy right now. Not sure what to check and where to check it. I'm using a pm6 ecu. its also a 1990 civic dx with a dpfi to mpfi swap. Someone plz help me.. I've heard to check the thermostat housing ground by jumping wires in the ecu but not sure which ones to jump. I'm soooo stumped.

Blanco

Voltage regulator in the alt is bad. Have it tested first and then replace it if it truly is the problem.

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riftonthemind057

He has unhooked the alternator thinking that may have been what it was and still getting this surge throughout.

Blanco

You're getting spikes in power which means that something is supplying too much power. The obvious answer would be the voltage regulator and it's inside the alternator.

If the alt itself was bad and easy test is to start the engine and then pull the ground from the battery. If the engine keeps running the alt is fine and if it dies the alt is bad. But, you're getting power...just too much of it.

Also, if there was something wrong with the thermostat ground, power spikes would be the last thing you'd get.

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riftonthemind057

what else would you think would be supplying to much power other then the alt?

Blanco

Well, you have to ask yourself what supplies the electrical power to the car.

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riftonthemind057

I'm kind of a noob man I'm an amateur body man and looking to make this a hopped up ride eventually. I'm thinking battery, ecu, alternator thats about it.

Blanco

The alternator is what supplies all of the electrical energy to the car. Not only can it fail and undercharge, it can also fail and over charge. Which is why I suggested having it tested. Check the under-hood fuse box to make sure that all of the connections are clean and tight and that none of the fuses are blown. But that alt is the both the beginning of the equation and the most obvious answer. I know next to nothing about body work but I assume that it's the same in that the obvious answer is usually the correct answer. If it was just one or two sensors getting high voltage I'd say that just those would need to be replaced, but it's all of them and the car shuts itself off after that happens.

If the thermostat ground were bad you wouldn't get any power at all, not voltage spikes.

Check the Reference Section for the ECU trouble codes list. That'll you how to pull any possible codes and then what they mean. But, if you're not getting a CEL (check engine light) you won't have a codes either.

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riftonthemind057

thank you for all the info I will let my mechanic know to check all of thee above. he had the same question with the alternator so he disconnected it and still the spike. So then he thought it might be the distributor. Now I will definitely have him check the main under hood fuse box for everything. thanks again I've been having lots of trouble finding someone to at least give me a little bit of help.