Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: bisleywrangler on February 10, 2015, 10:07:33 PM

Title: 98 ZJ 2.5td speedo jumping around.
Post by: bisleywrangler on February 10, 2015, 10:07:33 PM

I'm struggling to find the fault. 80% of the time it reads correctly, then as the revs rise for example the speedo will jump from 50mph up to like 120, then fall back down. This can happen at any time and speed but is most pronounced at higher speeds. I have changed the instrument cluster and speed sensor. Anything else I can check/change? Thanks, Ian

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: XJ Fan on February 11, 2015, 09:41:02 AM

My assumption would be a lose cable/connection.

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: bisleywrangler on February 11, 2015, 11:13:40 PM

I sort of assumed the opposite, in that as loose connection would send it to zero and not up in speed. Another possibly related symptom is my cruise control won't work properly.

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: gazjeep on February 12, 2015, 01:18:28 PM

Knackered speedo gear attached to the auto box ?

New ones are pretty cheap & easy fix

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: bgbazz on February 12, 2015, 02:46:16 PM

Are these a mechanical (cable) or electronic system?

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: gazjeep on February 12, 2015, 08:51:55 PM

This is what I was on about http://www.quadratec.com/jeep_knowledgebase/article-46.htm

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: bigjeepzj on February 12, 2015, 10:53:12 PM

Check the loom for damage you could have short in the wiring. The other thing it could be the  ecu or the connections to it.

Title: Re: 98 ZJ 2.5td speedo jumping around.
Post by: bisleywrangler on February 13, 2015, 10:17:03 PM

Thanks for the help guys, I found fixed the problem by swapping the ECU out for an xj one I had, I then swapped the original back in and it is working fine, must have been some crap or something in the connection? Anyhow its all good and the cruise control works now to!