bit fuzzy on the whole gauge cluster upgrade.

[Mobius1]

Alright I know i'll need the oil and temp sending units to make a full cluster work in my MJ. What i'm still fuzzy on is the tach and I don't remember an actual answer to this. How do you calibrate the tach so that its as accurate as possible? MY MJ is a 88 2.5L 2wd and if all goes accordingly next wed I might be doing the upgrade. I guess to better answer my tach question because I know some are adjustable and some are not. What are the typical rpms for the 2.5 2wd? Example rpms for 25, 45, 50, and 70mph??

[JeepcoMJ]

Alright I know i'll need the oil and temp sending units to make a full cluster work in my MJ. What i'm still fuzzy on is the tach and I don't remember an actual answer to this. How do you calibrate the tach so that its as accurate as possible? MY MJ is a 88 2.5L 2wd and if all goes accordingly next wed I might be doing the upgrade. I guess to better answer my tach question because I know some are adjustable and some are not. What are the typical rpms for the 2.5 2wd? Example rpms for 25, 45, 50, and 70mph??

 

this is made simple by getting the right tach (from an identical engine-equipped xj or mj)

 

from what I've been able to tell, on the adjuster left is less pulses and for 4 cylinder, right is for 8 cylinder, center is for 6 cylinder.

[Mobius1]

wow I really didn't think it would be that simple to adjust. since we are on the topic. Where is the location of the temp sending unit? I know where the oil one is I believe. Is the temp one right by the fire wall sorta in between the valve cover and intake?

[LocoJeeper]

wow I really didn't think it would be that simple to adjust. since we are on the topic. Where is the location of the temp sending unit? I know where the oil one is I believe. Is the temp one right by the fire wall sorta in between the valve cover and intake?

 

Sounds about right. On the right side if your staring under the hood.

[Tonedef131]

http://www.naxja.org/forum/showthread.php?t=921205

 

I just did this swap yesterday and that link helped give me an idea oh what was behind there since I couldn't see. It also has pics of the temp sensor location.

[Mobius1]

Hey thanks for the Link. That has to be one of the best write ups i've seen in a while. Does it matter what year xj cluster I get or should I just try and get as close to the same year as the truck is? Found a few xj clusters on ebay they were out of a 96.

[fiatslug87]

Hey thanks for the Link. That has to be one of the best write ups i've seen in a while. Does it matter what year xj cluster I get or should I just try and get as close to the same year as the truck is? Found a few xj clusters on ebay they were out of a 96.

I think you'll need one out of an '87-90. The speedometer turned electronic in '91, and I think the speedometer cable connection is different for the '86. Eagle explained all this in an earlier post, try searching by author.

[Tonedef131]

Does anyone know if the low fuel indicator light in a cluster out of a XJ will work in an MJ? I was pretty low on fuel today and didn't notice it come on.

[mjeff87]

I swapped an XJ cluster into mine that has the low fuel light, and have the same question. I never let it get lower than 1/4 tank, but my sending unit isn't very accurate anymore.....I just fill up around the 150-175 mile mark on the odo, about 9.5 gallons every time consistenly :cry:

 

Jeff

[Eagle]

For an '88, I believe you need a cluster out of a mid-87 or newer XJ, up through '90. As noted above, in '91 Chrysler went over to the electronic speedo.

 

You can also use the '84-early '87 clusters, but you'll need to replace your speedo cable with one for that year XJ.

 

For the tach adjustment, it's a potentiometer not a switch, and there is no position for 8 cylinders. My friend put an '89 6-cylinder cluster into an '84 4-cylinder XJ. The '89 cluster has the potentiometer -- the early ones do not, so if you get an early cluster it will need to be from a 4-cylinder to match your vehicle and generate the correct reading.

 

For the potentiometer, what my friend in Greece reported was that the pot (that's short for "potentiometer") was adjusted all the way to one extreme. To calibrate it to the 4-cyl he found that it required turning it all the way to the opposite extreme. I would use an idle tachometer to verify, if you have access to one. In my friend's case he was changing just because he preferred the style of the newer cluster, so he was able to connect both and compare the tach readings.

[fiatslug87]

Does anyone know if the low fuel indicator light in a cluster out of a XJ will work in an MJ? I was pretty low on fuel today and didn't notice it come on.

They're the same gauge so it should work. I replaced the clusters in two of my MJs from what I assume were XJ clusters (what's the chance they both came from MJs? very low) and they both work fine, light comes on when ~2 to 2.5 gallons are left.

[Tonedef131]

Does anyone know if the low fuel indicator light in a cluster out of a XJ will work in an MJ? I was pretty low on fuel today and didn't notice it come on.

They're the same gauge so it should work. I replaced the clusters in two of my MJs from what I assume were XJ clusters (what's the chance they both came from MJs? very low) and they both work fine, light comes on when ~2 to 2.5 gallons are left.

Well today I was down to less than a gallon, and no light came on. Could the light be bunt out? I looked at it while it was out and it didn't look like a replaceable bulb.