01 4.2 hard start and stalling when cold
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03-13-2018, 08:11 PM
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01 4.2 hard start and stalling when cold
Hello. This is my first post on a forum so I hope this is where it belongs. I have purchased a 01 4.2 from a guy that said it didn't run. He said one of his employees was driving it and it died at a light so he parked it. We have since gotten it to run but it is a really hard start while cold. Will idle really rough and stall. Under throttle it sounds like it is back firing through the intake. As it gets warmer it seems to do better but still dies out if you push the throttle wide open. The iac valve was cleaned and made no change and the mass air flow sensor was cleaned. It did run better after that but the next day it was almost back to square one. Will be doing plugs and wires to rule that out. Anyone else have these issues or any suggestions on where else to look. Thanks for any help.
Last edited by F15001xt; 03-13-2018 at 08:21 PM.
#2
03-13-2018, 08:21 PM
#3
03-13-2018, 08:24 PM
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#5
03-13-2018, 11:48 PM
#6
03-14-2018, 01:28 PM
Look at it this way, you got a truck with unknown issues and can't really trust the previous owner information.
Go through the normal testing such as fuel pressure, ignition service etc.
Depending on the results, the CHT and or the Intake Air temperature Control may not be working. Thermostat could even be problem after warm up.
.
On cold starts, the computer looks at the readings from the coolant sensor and the intake air temp to set ignition timing , fuel injection and Intake air controller opening.
If there is a failure in this routine from any part or low fuel pressure, the start will be difficult and rough.
.
You need to go through all these area from on an unknown like you have.
The compression comes later if needed.
Best to have a Scanner to look at the live data for the best overall check on system operations.
Basically your doing the same as if some one brought the truck to you to fix. You make all the checks and observations and do what's needed.
Good luck.
Go through the normal testing such as fuel pressure, ignition service etc.
Depending on the results, the CHT and or the Intake Air temperature Control may not be working. Thermostat could even be problem after warm up.
.
On cold starts, the computer looks at the readings from the coolant sensor and the intake air temp to set ignition timing , fuel injection and Intake air controller opening.
If there is a failure in this routine from any part or low fuel pressure, the start will be difficult and rough.
.
You need to go through all these area from on an unknown like you have.
The compression comes later if needed.
Best to have a Scanner to look at the live data for the best overall check on system operations.
Basically your doing the same as if some one brought the truck to you to fix. You make all the checks and observations and do what's needed.
Good luck.