Stock '98 4.0 Pinging
07-06-2018, 10:37 AM
#16
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Year: 1997
Model: Cherokee
Engine: 4.0
I agree that the colder plugs are probably masking a bigger problem but it was a cheap stop gap measure for now while I keep trying to track down the actual culprit.
Which scan tool did you buy? I'm wary of the cheap Bluetooth ones they sell on Amazon but if they actually work I'll get one in a heartbeat.
Taking the old plugs out they looked like they were running relatively hot but it couldn't be that accurate since I didn't check them right after it was pinging like you said.
I haven't checked the fuel pump pressure but I should just to eliminate it (need to get a gauge). I replaced the pump with a Carter unit in early 2015 to fix a bad sender so I kinda doubt it's failing or something is plugged but anythings possible.
I've also noticed my overhead console is reporting a drop in the average MPG by about 1... from 21ish to 19.8-20.
Which scan tool did you buy? I'm wary of the cheap Bluetooth ones they sell on Amazon but if they actually work I'll get one in a heartbeat.
Taking the old plugs out they looked like they were running relatively hot but it couldn't be that accurate since I didn't check them right after it was pinging like you said.
I haven't checked the fuel pump pressure but I should just to eliminate it (need to get a gauge). I replaced the pump with a Carter unit in early 2015 to fix a bad sender so I kinda doubt it's failing or something is plugged but anythings possible.
I've also noticed my overhead console is reporting a drop in the average MPG by about 1... from 21ish to 19.8-20.
I wouldn't be complaining about getting 19 or 20 mpg average! Unless you have the manual trans
07-06-2018, 10:54 AM
#17
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Location: Northwest CT
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Year: 1998
Model: Cherokee
Engine: 4.0
07-09-2018, 07:52 AM
#19
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Year: 1998
Model: Cherokee
Engine: 4.0
Bought the same one mannydantyla bought. Should be here tomorrow and I'll try out whatever free apps I can find.
Should be posting more detailed info soon.
Also, it seems like the computer had to adjust to the new plugs because the overhead console is back to showing a 21mpg (although I'm sure it's accuracy can't be trusted)
Should be posting more detailed info soon.
Also, it seems like the computer had to adjust to the new plugs because the overhead console is back to showing a 21mpg (although I'm sure it's accuracy can't be trusted)
07-19-2018, 04:23 PM
#20
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Year: 1998
Model: Cherokee
Engine: 4.0
Well, it doesn't seem to be a fuel related problem as the LTFT was between -5% and 5%. Really not sure what would cause ping at this point. Idles at 10-14 degrees and at speed with no load is at 34-38 degrees. Under load climbing a hill I saw it drop back as far as 16 degrees. Does that sound right for the 4.0?
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