Problems with 95 Tahoe after installing new motor.

[rockola1971]

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.

Ahhh didnt catch that. That changes everything.

 

[YukonandtheHOE]

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

what could step up voltage?

Is it possible that 2 relays could make 24v somehow? Or a capacitor unloading to ecm could spike the system?
How about the coil backfeeding though the timing advance module?

This is kind of a puzzle.. missing some pieces tho..

 

[StevenDey92]

what could step up voltage?

Is it possible that 2 relays could make 24v somehow? Or a capacitor unloading to ecm could spike the system?
How about the coil backfeeding though the timing advance module?

This is kind of a puzzle.. missing some pieces tho..

I read in another forum that the System Over Voltage code can be caused by the transmission?

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[SunlitComet]

neither. your battery or your alternator determines you maximum voltage really. a sudden dump of a capacitor happens when a load is put on it and then it is the current that comes out high. hence if the computer says the voltage is to high it leads back to the alternator because each cell in the battery generally can only generate so much voltage where as the alternator without regulation can just go haywire as long as it is spinning sufficiently.

 

[StevenDey92]

neither. your battery or your alternator determines you maximum voltage really. a sudden dump of a capacitor happens when a load is put on it and then it is the current that comes out high. hence if the computer says the voltage is to high it leads back to the alternator because each cell in the battery generally can only generate so much voltage where as the alternator without regulation can just go haywire as long as it is spinning sufficiently.

I sent you a message the other day. Did you receive it?

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[StevenDey92]

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.

Key Off. E-16 - 12.09 V & Red ABS - 12.29


Key On. E-15 - 11.73 V, Brown ABS - 1.61 V, TPS 5.05 V MAP 5.05 V.

Battery Disconnected - A1 - 0.4 Ohms, A2 - 0.4 Ohms, B3 - 0.4 Ohms, B4 - 0.4 Ohms, ABS Black Wire - 0.3 Ohms.

Wasn't sure where the wiring was for the Fuel Pump Relay. Sorry....

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[StevenDey92]

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.

Key Off. E-16 - 12.09 V & Red ABS - 12.29


Key On. E-15 - 11.73 V, Brown ABS - 1.61 V, TPS 5.05 V MAP 5.05 V.

Battery Disconnected - A1 - 0.4 Ohms, A2 - 0.4 Ohms, B3 - 0.4 Ohms, B4 - 0.4 Ohms, ABS Black Wire - 0.3 Ohms.

Wasn't sure where the wiring was for the Fuel Pump Relay. Sorry....

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[SunlitComet]

sorry i don't have time to do calls. i am stretching myself now being here again so this forum will have to do. two more questions? does your cruise control function, hater a/c unit,4wd if optioned and what terminals were connected on the dlc to get those coded?

 

[StevenDey92]

sorry i don't have time to do calls. i am stretching myself now being here again so this forum will have to do. two more questions? does your cruise control function, hater a/c unit,4wd if optioned and what terminals were connected on the dlc to get those coded?

Cruise Control hasn't worked in the 8 years I have had this vehicle. But I believe that is due to a bad wheel speed sensor. Heater and A/C unit work and I am using 4 wheel drive currently and it works just fine. And I hooked a scan tool up to the DLC and got all the codes that way.

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[SunlitComet]

and the brown wire on the abs was for sure 1.6 volts with key on or engine running?