Hello all!

Okay so I've been having low idle issues for a little while, I've done a complete tune up recently including a new and tuned in TPS, and a new CKP (Crankshaft Position Sensor) Low idle issue went away.

The new CKP has been in for two days and just last night on my way home the tachometer started jumping around ALL CRAZY, anywhere from 0 RPM to 2000 RPM, the engine was jumping as well (So it's not JUST the tach acting up). Then the engine died, started right back up but on the rest of the way home she kept jumping around, especially when coasting around 50mph. This morning, drove for about 20 min, no issues, but then driving to work today, did the same thing!

Could I have gotten a bad CKP? Should I try putting the old one back in?
Sure don't WANT to do that, must be the worste sensor to replace, so hard to get to!

Thanks all, hope you can help!

 

hmmmm, nothing, huh? After doing some research on other sites, it sounds like it could be the ignition coil/igntion coil module? Hopefully I can figure this out...

 

ok, first question......

is it the speedometer or the tachometer which is swingining wildly....\

Is the engine revving like crazy when this happens or just the needle jumping around?

I ask this as the VSS (vehicle Speed Sensor) on mine went out and it would show 0 mph when I was doing 60, then it would jump like crazy pegging beyond 85, but I was still only travelling 60mph.

if it IS the tach needle going crazy, you might have a marginal or bad CPS (crankshaft Position Sensor) or, the cable connector is not on all the way....

or.......the TPS you replaced is funky....also maybe a marginal part or a looser connection somewheres.

IAC valve is ok too?

just some thoughts, hope it helps.

cpnwrench

 

Hey all,

So I figured it out...
My brand new CKP (Crankshaft Position Sensor) was the problem. The wire was resting right on the exhaust headers
Leason learned, oh mighty Jeep Gods
If any of you put a new CKP in, MAKE SURE you zip tie it so the wire doesn't get melted like mine did!