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intermitten tps problem?

outlander

NAXJA Forum User
Location
Columbus,Ohio
89 xj 4.0 stick shift.
I have an intermittent problem it seems like it has cropped up since the weather has been in the 90s here.
Sometimes when I start the engine and go to Revit it will only go to 1000 RPM then it starts to spit and sputter.
Then after about 20 or 30 seconds of pushing on the gas and messing around it revs past that point and everything is fine think I should change my TPS?
 
This one's hard to diagnose because it doesn't do it all the time 95% of the time it runs like a raped ape but he does seem to be a factor because up until this hot spell it never did anything like this could it be possible that it's coil?
 
The symptoms you describe sound like vapor lock. Have you tested the fuel pressure and the fuel injectors. Are one or more injectors weeping fuel into the cylinders when the engine is off ? Tested the MAP sensor ?
 
Kind of a classic CPS symptom, except it is usually engine heat that causes issues. Like when you shut it down and try a restart a few minutes later with an already hot engine, the CPS resistance values change.

Might try a CPS ohm test cold and hot. then maybe a CPS voltage test while cranking cold and hot. I never change many parts on a hunch, I usually test then change.

My TPS symptoms were usually very high RPM's at a startup and/or erratic idle, high idle, then low idle, kind of continuously hunts for the sweet spot.

One off the wall problem I had was I had some water in my distributor, I could hardly see it under the sync sensor. Started up fine cold, but when it got hot the evaporating water vapor would mess with my spark.
 
89 xj 4.0 stick shift.
I have an intermittent problem it seems like it has cropped up since the weather has been in the 90s here.
Sometimes when I start the engine and go to Revit it will only go to 1000 RPM then it starts to spit and sputter.
Then after about 20 or 30 seconds of pushing on the gas and messing around it revs past that point and everything is fine think I should change my TPS?


Humid also?

When's the last time you refreshed all the connectors in the engine bay or refreshed the grounds?
 
for craps and grins Ill throw on my spare(new never installed oem)
CPS....
The one thats in there now has about 7 or 8 years on it so its probably about time for replacement from a maintenance standpoint.
 
The symptoms you describe sound like vapor lock. Have you tested the fuel pressure and the fuel injectors. Are one or more injectors weeping fuel into the cylinders when the engine is off ? Tested the MAP sensor ?
Im all too familiar with the renix hot restart vapor lock.....this problem is different.
 
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