Problems with 95 Tahoe after installing new motor.

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StevenDey92

StevenDey92

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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.
When I pulled the codes with a scanner. Code 53 is High System Voltage- ECM is getting 17.7 Volts for more than 2 seconds.

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StevenDey92

StevenDey92

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The only thing I haven't tried yet is putting in a different PROM chip. But finding one has proven to be difficult.

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99Vortec

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Could leaving his old Knock sensor behind cause problems?

(If in fact that did happen?)
 
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SunlitComet

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the over voltage code triggers if higher then 19.5v for more then two seconds.

would you be willing to probe some sensors and wires?
 

SunlitComet

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with key on: voltage numbers on grey wires of map and tps and fuel pump relay. pink wire cavity e-15 of computer. brown wire on abs unit

with key off: voltage numbers on orange wire cavity e-16 on computer. red wire on abs unit.

engine running as best as you can: green/white wire and again the grey wire both on the pump relay.

battery disconnected: map black wire ohms to b4 on computer. same with tps but on cavity b3. black/white a1 to battery cables negative terminal. tan/white a2 as well. black wire on abs unit too. test each separately.
 

rockola1971

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is the motor a Vin R 5.7L? If it is then you CANNOT use a regular code reader to measure the Zeroing of the distributor for base timing. The counts have to be in a very tight window otherwise your engine will either run like crap and/or die alot or it just wont start. As the engine warms and goes into closed loop the timing gets even further off and it all goes downhill from there.

The fix: Reinstall distributor and zero it out with a shop quality scanner that can read and do alot more than a basic scanner. While doing the zeroing you have to make fine adjustments and wait about 15 seconds or so for an update to see where you are at during the zeroing procedure.
 

SunlitComet

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he has a tbi so the scanner play no role in setting the base timing. it uses a single connectable wire to initiate that mode. the vortec did not come about till 1996. he has a 1995.
 

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