87 F-150, 6-cyl engine problems
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87 F-150, 6-cyl engine problems
Hi All,
Been trying to fix this problem for many months now. I have an '87 F-150, 6cyl, 5-spd and it is very hard to start. Once it does start it doesn't attempt to run at the proper cold idle speed. It goes down to about 800, then sputters and stalls. Once the engine is warmed up it idles fine. When I press the accel the engine responds reasonably but if I take it on the road and try to run it, it runs real rough. If I lightly lay into the accel, the truck will run and go to higher RPMs without a problem, but if I try to apply more accel, the truck fights for a while until I lay off the assel, then it will finally make it to higher RPMS. I've tested and/or changed the following:
Fuel pump, filter, and pressure regulator - replaced
Coil, TFI, cap, rotor, wires, plugs - replaced
EGR, EVP, and EGR control solenoid - replaced
All temp sensors tested OK
Throttle position sensor tested OK
Vacuum system, including can, is intack and 'sucking'
Intake air bypass solenoid is functioning 100%
I cleaned the entire intake manifold, no issues there.
Air filter is replaced
All hoses are intack.
All wiring is intack from what I can see
Additional notes:
1. When I run the KOEO test I get a '31' code for low voltage in the EVP sensor. First off, will an EVP error cause what I am seeing? Secondly, I checked the EGR system from head to toe and it functions properly, good voltage on sensor, good voltage swing when I apply vacuum, the connections are good to the PCM module. This has me completely baffled.
2. When I run the KOER test I get 31, 41, and 77. 31 as above, and 41 for an O2 sensor detects the system is lean. Will the '41' error cause what I am seeing? Is there any way to adjust/test the mix? I'm assuming that the 77, operator error, is because I didn't hold the power steering or brake long enough during the test.
3. I've tried to run the cylinder balance test, but I cannot get the truck to perform it. Once I get the codes I wait a few seconds then press and release the accel. I've tried pressing the accel about 1/4 the way down, tapping it, and pressing it all the way to the floor. Nothing I do seems to trigger the cylinder balance test.
I know this is lengthy but I've put alot of time into solving this problem and it's driving me nuts!!!
Thanks for any help
Mark W.
Been trying to fix this problem for many months now. I have an '87 F-150, 6cyl, 5-spd and it is very hard to start. Once it does start it doesn't attempt to run at the proper cold idle speed. It goes down to about 800, then sputters and stalls. Once the engine is warmed up it idles fine. When I press the accel the engine responds reasonably but if I take it on the road and try to run it, it runs real rough. If I lightly lay into the accel, the truck will run and go to higher RPMs without a problem, but if I try to apply more accel, the truck fights for a while until I lay off the assel, then it will finally make it to higher RPMS. I've tested and/or changed the following:
Fuel pump, filter, and pressure regulator - replaced
Coil, TFI, cap, rotor, wires, plugs - replaced
EGR, EVP, and EGR control solenoid - replaced
All temp sensors tested OK
Throttle position sensor tested OK
Vacuum system, including can, is intack and 'sucking'
Intake air bypass solenoid is functioning 100%
I cleaned the entire intake manifold, no issues there.
Air filter is replaced
All hoses are intack.
All wiring is intack from what I can see
Additional notes:
1. When I run the KOEO test I get a '31' code for low voltage in the EVP sensor. First off, will an EVP error cause what I am seeing? Secondly, I checked the EGR system from head to toe and it functions properly, good voltage on sensor, good voltage swing when I apply vacuum, the connections are good to the PCM module. This has me completely baffled.
2. When I run the KOER test I get 31, 41, and 77. 31 as above, and 41 for an O2 sensor detects the system is lean. Will the '41' error cause what I am seeing? Is there any way to adjust/test the mix? I'm assuming that the 77, operator error, is because I didn't hold the power steering or brake long enough during the test.
3. I've tried to run the cylinder balance test, but I cannot get the truck to perform it. Once I get the codes I wait a few seconds then press and release the accel. I've tried pressing the accel about 1/4 the way down, tapping it, and pressing it all the way to the floor. Nothing I do seems to trigger the cylinder balance test.
I know this is lengthy but I've put alot of time into solving this problem and it's driving me nuts!!!
Thanks for any help
Mark W.
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