- Joined
- May 3, 2013
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- 70
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- 563
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- Upstate South Carolina
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This one is a real head scratcher!
96' FZJ80 that has ran great for years but started having intermittent staring issues. Primarily the issue was the clicking starter but not turning the engine over but after dozens of attempts sometimes it would finally start. The current issue now is that it turns over fine but wont fire. Here is whats I have done up to this point.
Fusible links replaced
Starter has been replaced a couple times and isnt the issue
Replace the fuel pump at GSMTR 2 years ago when the truck shut off and would not start a couple miles before we got to the event. Now thinking it may have been this current issue just getting started. The new fuel pump fired right up and the truck ran but still had intermittent starting issues.
Just put a factory Toyota fuel pump back in it today.
Fuel pump currently not getting 12+ from the FPR.
FPR not getting 12+ from COR
COR is getting 12+ from ignition when in on postition
COR is getting 12+ from ECM (Yellow wire)
COR is getting ground signal during cranking from ECM (Red-White wire)
COR bench tested and functions properly sending voltage to terminal for Red-Green wire to FPR but does not send the 12+ to the FPR while installed in the truck.
Tested continuity between the ECM and COR wires as well as between the COR and FPR and eveything is good.
Tested 12+ to the ECM from the ignition (Black-Blue wire) and its good.
Truck starts and runs with starting fluid so spark isnt an issue.
I used a power probe to bypass the COR and put 12+ to the FPR (Red-Green wire) and the truck starts and runs fine but as soon as you remove the 12+ within a few seconds it slowly starts to stumble and then dies.
Two problems I see here are that the main high load wire on the FPR (Red-Green) isn't getting 12+ from COR. The second issue is that the low load wire (Red-white) that runs through a resistor in the FPR to reduce 12+ to around 9+ so the fuel pump doesnt run as hard did not get 12+ after the truck fired up.
Haven't researched yet if the ECM tells the FPR to run on the red-white wire after the initial start up and if the ECM stops sending ground to the COR so it opens the circuit and stops sending 12+ to the FPR for the high load start up and acceleration.
My thought is that the ECM isnt getting an input signal needed to tell it to fire the fuel pump. I know it needs the STA signal from the Ignition/starter and the crank postion signal. Since the truck runs when I supply 12+ to the FPR I ruled out the crank position sensor.
What am I missing!
96' FZJ80 that has ran great for years but started having intermittent staring issues. Primarily the issue was the clicking starter but not turning the engine over but after dozens of attempts sometimes it would finally start. The current issue now is that it turns over fine but wont fire. Here is whats I have done up to this point.
Fusible links replaced
Starter has been replaced a couple times and isnt the issue
Replace the fuel pump at GSMTR 2 years ago when the truck shut off and would not start a couple miles before we got to the event. Now thinking it may have been this current issue just getting started. The new fuel pump fired right up and the truck ran but still had intermittent starting issues.
Just put a factory Toyota fuel pump back in it today.
Fuel pump currently not getting 12+ from the FPR.
FPR not getting 12+ from COR
COR is getting 12+ from ignition when in on postition
COR is getting 12+ from ECM (Yellow wire)
COR is getting ground signal during cranking from ECM (Red-White wire)
COR bench tested and functions properly sending voltage to terminal for Red-Green wire to FPR but does not send the 12+ to the FPR while installed in the truck.
Tested continuity between the ECM and COR wires as well as between the COR and FPR and eveything is good.
Tested 12+ to the ECM from the ignition (Black-Blue wire) and its good.
Truck starts and runs with starting fluid so spark isnt an issue.
I used a power probe to bypass the COR and put 12+ to the FPR (Red-Green wire) and the truck starts and runs fine but as soon as you remove the 12+ within a few seconds it slowly starts to stumble and then dies.
Two problems I see here are that the main high load wire on the FPR (Red-Green) isn't getting 12+ from COR. The second issue is that the low load wire (Red-white) that runs through a resistor in the FPR to reduce 12+ to around 9+ so the fuel pump doesnt run as hard did not get 12+ after the truck fired up.
Haven't researched yet if the ECM tells the FPR to run on the red-white wire after the initial start up and if the ECM stops sending ground to the COR so it opens the circuit and stops sending 12+ to the FPR for the high load start up and acceleration.
My thought is that the ECM isnt getting an input signal needed to tell it to fire the fuel pump. I know it needs the STA signal from the Ignition/starter and the crank postion signal. Since the truck runs when I supply 12+ to the FPR I ruled out the crank position sensor.
What am I missing!
