Speedometer Spike??

[valleyxj]

Driving home I noticed my speedometer spike twice, once at 65 and later at 55. There was no noticeable change in speed, no hesitation, or pre-stalling. I think that both times I had either accelerated slightly or just let off of the gas a bit. Again there was no change in speed and I didn't see what the tach did.

Will look under the hood to make sure no hoses are loose or off. This happened once before 4-5 months ago. Recent work included a new exhaust system (cat, Magnaflow muffler and pipes, and a new O2 sensor).

Appreciate any insight.

[Mudderoy]

I wonder if the speedo gear in the transfer case is worn or out of alignment.

[valleyxj]

Had new transfer case seals put in about a month ago.

[4.3LXJ]

This can happen when you have a sticky or worn out speedo cable. It develops some friction and sticks a little and then winds up a little and then lets go. When it does, the speedo reads a sudden change in speed

[valleyxj]

Thanks all. 43XJ I'll take a look at that, plan on cleaning engine and undercarriage this weekend. How hard is it to access?

[4.3LXJ]

The speedo cable is easy to pull on the tcase. Might take a pair of channel locks to unscrew it. However under the dash it is a little tougher. Before you get to far into it you might want to pull the tcase end and twist the cable with your fingers. It should twist fairly easily.

[oderdene]

clean with WD40 and add some ATF on this, they will solve all

[valleyxj]

Will try that. On the drive in to work today it did the same thing, it started when I would hit bumps in the road (noticed both speedo and tach this time), and once it just went crazy (all the left, then right) again with a little acceleration, but I felt no change in speed and it went back to normal after a few seconds. Oil pressure, battery, cooler gauges are all fine. Should I get an engine diagnostic done?

[4.3LXJ]

Yup, speedo cable.

[valleyxj]

Just read another forum with similar problem. One guy said his battery wazs failing and after replacing his gauges started to work OK. Funny, the tech did a diagnostic on my battery when I got the muffler replaced and said it was down to half the amps it used to have. Could be the problem possibly.

[xj4life2]

Doubt very seriously its the Batt, I agree with Steve , its the cable, lube it with graphite and you should be good.

[Mudderoy]

This can happen when you have a sticky or worn out speedo cable. It develops some friction and sticks a little and then winds up a little and then lets go. When it does, the speedo reads a sudden change in speed

So the 1995 XJ still used a physical cable that turned connected to the speedometer? Mine is electronic.

[4.3LXJ]

So the 1995 XJ still used a physical cable that turned connected to the speedometer? Mine is electronic.

Correct. OBDII went all electronic

[xj4life2]

Correct. OBDII went all electronic

Ya its called drive by wire in the "industry"

[valleyxj]

Thanks again all. Will also clean and check the grounding wires.

[prcjeep]

Okay so old thread but im having an interesting issue similar to the above.

My XJ is a 96 so its obd II. My speedo either doesnt work or is just jumping all over the place all the time. I havent been able to determine my speed by it for a few days now as its been all finiky. I pulled the plug and the gear out of the tcase and all looks well...

I have two CEL messages right now, 24 and 42. I already took care of the TPS(24), im not really sure about 41.

Would either of these CEL's be related to the speedo? Also my Odometer is not going either when the speedo isnt.

[prcjeep]

Okay so old thread but im having an interesting issue similar to the above.

My XJ is a 96 so its obd II. My speedo either doesnt work or is just jumping all over the place all the time. I havent been able to determine my speed by it for a few days now as its been all finiky. I pulled the plug and the gear out of the tcase and all looks well...

I have two CEL messages right now, 24 and 42. I already took care of the TPS(24), im not really sure about 41.

Would either of these CEL's be related to the speedo? Also my Odometer is not going either when the speedo isnt.

Okay so i replaced the TPS last Saturday. and since then my CEL's have gone away.

My speedo is steady and correct most of the time but randomly will jump all over the place.

The other issue I'm having is that in every gear, if i try to go past around 2800-3000 rpms it "cuts out" like it lost fuel or spark. it wil also do it when in neutral and i try to rev past 2800-3000, it cuts out and once the rpms drop below say 2300 it resumes again...

Any ideas?

[4.3LXJ]

My first guess is that the CPS is marginal. Any codes for this?

[prcjeep]

My first guess is that the CPS is marginal. Any codes for this?

Nope, Ive been lucky enough not to have CPS issues before.... Ive replace my 4.0 more times than ive replaced the CPS lol

This all started about two days after our last trip to creekside.... it was quite muddy.