Problems with 95 Tahoe after installing new motor.

[SunlitComet]

then verify the part numbers of the ecm and the prom in it for proper application then wipe the memory thru a 1 minute battery disconnection then retest.

 

[StevenDey92]

I have already verified both ECM and Prom. I put in a new ECM as well and still pulled the same codes. I have disconnected the battery for 10 minutes a few times now and still get the same codes.

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[YukonandtheHOE]

timing issues do not set off prom/vcm or over voltage errors.

I didn't look up the codes. Haha

I have re-done timing like 10 times since I put the new motor in, just to make sure it was right.

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Reason i asked ive seen guys forget to plug the base time wire back together and it runs like shit.

Do you have the wrong rated fuse's in the ecm slots? I know it sounds far fetched, but when i put the wrong fuse in my TCM slot my 94 4l80 wouldn't shift and it threw a ses.. put a 10 amp back in and everything was good again.

 

[StevenDey92]

All the fuses are correct.

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[StevenDey92]

All the fuses are correct.

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These problems only started once I put the new motor in.

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[YukonandtheHOE]

Its gotta be a missing ground, other then that what else could have gone wrong with a engine swap.. other then reversing polarity on the batt with the ignition on for a couple seconds and frying the ECM, but you changed that. Or the engine harness got mashed and a bunch of wires are shorted together.

 

[freik_4518]

Sounds to me like the alternator is over charging shouldnt get over 14v

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[YukonandtheHOE]

14.4v is optimal

 

[StevenDey92]

Sounds to me like the alternator is over charging shouldnt get over 14v

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I already tested the alternator. Doesn't go above 14.8v. How would my ECM be getting over 17.7v?

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[YukonandtheHOE]

I already tested the alternator. Doesn't go above 14.8v. How would my ECM be getting over 17.7v?

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Where did you state your ecm is getting 17v!?
Your voltage regulator is done......
Try a diffrent alternator.. nothing in the truck will step up voltage.