FourCJsOneXJ
NAXJA Forum User
- Location
- In The Sticks
Appears the CKS in my ‘95 Sport 4.0L 5 spd went away.
It was a slow intermittent mix of symptoms. All began with IAC like intermittent junk, the rough idle, dies while idling, stalls when coming to stop sort of stuff. IAC tested fine, measured the proper tip-to-base distance and throw, so I cleaned the IAC plunger, spring, tip and its home in the TB orifice as I’ve done on so many other vehicles, this is the only time this didn’t cure the problem.
The symptoms gradually moved on to "cranks but won’t start", acted like a fuel issue and for a while and a shot of gas into the intake manifold via the brake vacuum canister hose would get it fired, ended up being coincidence, the time preparing to do it apparently allowed the CKS to cool sufficiently so it worked properly once again.
Measured the CKS, it checked fine cold or warm, given its intermittent nature I never could measure it quick enough while heat soaked to get a bad test result.
Then it began just shutting down at speed, no notice, no codes, nothing! Just dead at 55 mph on curvy narrow mountain roads with blind corners and no shoulders . . . nice!
I’ve read about thermal issues causing the CKS to get squirrely with age, mine has 158k on it so I ordered an OEM Mopar replacement.
While waiting for the UPS dude to deliver it I yanked the suspect, fun stuff there! Pulled the thing out, the rubber grommet came with it and disintegrated mid air (placed ANOTHER order).
Upon inspection, the CKS tip looked all caked with grease and dirt. Just inspecting, I cleaned the thing up and tried to scrape what I thought was dirt build up from the perimeter of the tip, wouldn’t budge!
That’s when I realized it was the tip itself, all melted and mushroomed. Hard to believe the thing measured fine when cold and actually still worked until heat soaked but it did. The sensor housing/body was nearly an 1/8th inch shorter than the new one due to the mushrooming; there was no sign of abrasion on the tip face . . . just odd!!!
Mine is the non-adjustable two bolt variety so I temporarily covered the opening in the bell housing and reinstalled the bolts leaving enough gaps for the CKS bracket to slide in and after opening (cutting out) the bottom portion of the bracket holes on the old one, slipped it in. With less than two turns each bolt was secured so I could at least move the rig out of my way without installing the new CKS until the grommet arrives.
Problem solved for now but what a journey and lesson learned!!!
Has anyone experienced the "melting" and "deformation" I found? I've never seen this before and am guessing it's due to thermal shorting of the guts??
It was a slow intermittent mix of symptoms. All began with IAC like intermittent junk, the rough idle, dies while idling, stalls when coming to stop sort of stuff. IAC tested fine, measured the proper tip-to-base distance and throw, so I cleaned the IAC plunger, spring, tip and its home in the TB orifice as I’ve done on so many other vehicles, this is the only time this didn’t cure the problem.
The symptoms gradually moved on to "cranks but won’t start", acted like a fuel issue and for a while and a shot of gas into the intake manifold via the brake vacuum canister hose would get it fired, ended up being coincidence, the time preparing to do it apparently allowed the CKS to cool sufficiently so it worked properly once again.
Measured the CKS, it checked fine cold or warm, given its intermittent nature I never could measure it quick enough while heat soaked to get a bad test result.
Then it began just shutting down at speed, no notice, no codes, nothing! Just dead at 55 mph on curvy narrow mountain roads with blind corners and no shoulders . . . nice!
I’ve read about thermal issues causing the CKS to get squirrely with age, mine has 158k on it so I ordered an OEM Mopar replacement.
While waiting for the UPS dude to deliver it I yanked the suspect, fun stuff there! Pulled the thing out, the rubber grommet came with it and disintegrated mid air (placed ANOTHER order).
Upon inspection, the CKS tip looked all caked with grease and dirt. Just inspecting, I cleaned the thing up and tried to scrape what I thought was dirt build up from the perimeter of the tip, wouldn’t budge!
That’s when I realized it was the tip itself, all melted and mushroomed. Hard to believe the thing measured fine when cold and actually still worked until heat soaked but it did. The sensor housing/body was nearly an 1/8th inch shorter than the new one due to the mushrooming; there was no sign of abrasion on the tip face . . . just odd!!!
Mine is the non-adjustable two bolt variety so I temporarily covered the opening in the bell housing and reinstalled the bolts leaving enough gaps for the CKS bracket to slide in and after opening (cutting out) the bottom portion of the bracket holes on the old one, slipped it in. With less than two turns each bolt was secured so I could at least move the rig out of my way without installing the new CKS until the grommet arrives.
Problem solved for now but what a journey and lesson learned!!!
Has anyone experienced the "melting" and "deformation" I found? I've never seen this before and am guessing it's due to thermal shorting of the guts??
