Dash/Cluster Swaps

[Awesome]

I did use the search and didn't immediately find anything relevant (first 3 pages).

 

Can a later model cluster be swapped to the '86 (Renix) dash without rewiring the entire truck? I saw a few good clusters in the junkyard, and have a complete donor XJ just begging me to grab the cluster out of it.

I know there's the issue of mechanical/electric speedo. I remember there being an adapter available for that years ago for Wranglers.

 

Anyway, if it's not possible I'll just keep the idiot lights. But would be nice to have real gauges in the dash instead of in a console pod.

[eaglescout526]

For the most part, all clusters will swap. 84-86 have a early speedo connection type

87-90 use a later type. 
these two clusters will interchange with each other. 
 

91-96 HO can work but you will not have a speedometer due to it being electrical and not mechanical. 

[Awesome]

Alright so I have a cluster of information that I need to put together.

 

BoxyJeep makes an electronic speedo conversion kit. They say it does not work with the '86 cluster. Ok, why not? Well he says the '86 cluster has the wrong mount for the new speedo, plus the gauges are different.

 

Since I'd be swapping an electronic speedo in ANYWAY (91+ cluster), why would I not be able to use the rest of the 91+ cluster?

 

To get the tach to work it sounds like the pickup needs to be different. I'm assuming that the hall effect sensor actually needs a different flywheel. Ok. Why can't I just buy a 91+ flywheel and swap that in? New ones are kind of expensive but not really all that bad. Actually there's one in a junkpile near me that I could grab really easily. Does the Renix system rely on the hall effect sensor (CPS) for injection pulse timing? If it does then I guess swapping the flywheel would be out.

 

To get the fuel gauge to work I need an XJ sender or I need to add a resistor, right? I went through the trouble to find an MJ fuel pump but I'm not really convinced it really is an MJ fuel pump. I have a sneaking suspicion that it's really an XJ fuel sender that was labeled wrong. I had to bend it a bit to make it work right. I think I have the wires hooked up backwards as well because the gauge reads backwards. Whatever, why wouldn't I be able to make that work?

 

I HAVE an '88 cluster that I can use for the swap, but I kind of want to be able to use the '88 MJ as well later on. I think it just has the idiot lights too so it's not really much of an upgrade besides the electronic speedo. And there is an '87 XJ in the junkyard that I could pull the cluster from....... but again, it only has the idiot lights so it's not really an upgrade for me.

 

I suppose later on down the line I can pull all the Renix stuff out and swap to a later model OBDI system and that would solve the gauge problem. But that's a later problem that is very time consuming and I'd rather not do it if I don't have to.

[89 MJ]

7 minutes ago, Awesome said:

To get the tach to work it sounds like the pickup needs to be different. I'm assuming that the hall effect sensor actually needs a different flywheel. Ok. Why can't I just buy a 91+ flywheel and swap that in? New ones are kind of expensive but not really all that bad. Actually there's one in a junkpile near me that I could grab really easily. Does the Renix system rely on the hall effect sensor (CPS) for injection pulse timing? If it does then I guess swapping the flywheel would be out.

Can’t answer the other questions, I believe the flywheel is different between Renix and HO. I know that’s the case for the 4.0 for sure. 

[Awesome]

Yeah I assume the flywheel is different (it shows different part numbers) but the only difference is the hall effect ring. So is the hall effect ring only used for the tach on an '86 or is it used for ignition? I'm unfamiliar with the details of how the Renix system actually works.

[eaglescout526]

32 minutes ago, Awesome said:

BoxyJeep makes an electronic speedo conversion kit. They say it does not work with the '86 cluster. Ok, why not? Well he says the '86 cluster has the wrong mount for the new speedo, plus the gauges are different.

Correct. 84-86 clusters are based on an old standard across all companies before the newer style. 

32 minutes ago, Awesome said:

To get the tach to work it sounds like the pickup needs to be different. I'm assuming that the hall effect sensor actually needs a different flywheel. Ok. Why can't I just buy a 91+ flywheel and swap that in? New ones are kind of expensive but not really all that bad. Actually there's one in a junkpile near me that I could grab really easily. Does the Renix system rely on the hall effect sensor (CPS) for injection pulse timing? If it does then I guess swapping the flywheel would be out.

Tach signal is based on ignition pulse from the coil(Renix). Not sure about HO but it could be the same. Renix relies on the CPS to run the coil to send spark out. The ECU controls the injector pulses and pulses fuel even if the coil isnt sending spark.

32 minutes ago, Awesome said:

To get the fuel gauge to work I need an XJ sender or I need to add a resistor, right? I went through the trouble to find an MJ fuel pump but I'm not really convinced it really is an MJ fuel pump. I have a sneaking suspicion that it's really an XJ fuel sender that was labeled wrong. I had to bend it a bit to make it work right. I think I have the wires hooked up backwards as well because the gauge reads backwards. Whatever, why wouldn't I be able to make that work?

This doesnt make sense. If its from a Renix and reads at 88 Ωhms when full and 0 when empty, its Renix. 0 full and 105 empty is HO. Now the fuel sending units (FSU) between XJ and MJ are different. The MJ sits more into the tank than the XJ one. The XJ FSU with sock faces to the right when in the tank and the MJ faces to the left. But you shouldn't have to add anything to get the gauge to work. It will just plug n play. its the oil and temp gauges that you need to switch from switches to sensors.

 

Honestly, if youre turned off about using a full 84-86 cluster, do be. You can just get the 86 speedo cable and put it in. Now I do say to be turned off by the 86 cluster because of the age and problems that I have observed with the clusters. 

1. The lamination to keep the printed copper circuit in place is failing hard on these and no one makes any new ones.

2. The tachs are not adjustable but most tachs can be found behind the V6 anyways so youre good there. But the capacitors and resistors might be failing on the tach board.

3. The bulbs can be a pain to get working right. 

 

Now heres one nice thing about the 84-86 gauges, they just plug in and dont get screwed in like the later clusters where you can damage the winding on the guage. 

 

[ghetdjc320]

Renix CPS is a VR sensor. But as stated above, the coil output is what the tach receives and it's the same for HO models. If you swap to the HO cluster, you can use either a fuel level conversion module or just grab an MTS sending unit for a 91-92 MJ. 

[Awesome]

17 hours ago, eaglescout526 said:

Tach signal is based on ignition pulse from the coil(Renix). Not sure about HO but it could be the same. Renix relies on the CPS to run the coil to send spark out. The ECU controls the injector pulses and pulses fuel even if the coil isnt sending spark.

 

Ok so that confirms that swapping the flywheel won't work unless I swap the entire system over.

 

17 hours ago, eaglescout526 said:

If its from a Renix and reads at 88 Ωhms when full and 0 when empty, its Renix. 0 full and 105 empty is HO.

 

I have a feeling that the sending unit I ended up with is post-Renix. The fuel gauge is pegged full when the tank only has a couple gallons in it. Adding fuel makes the gauge go down. Renix sending units are unobtanium. I have 2 old ones now but both are rusted beyond what I believe to be repairable.

 

I don't believe the current speedometer works. I haven't driven the truck on the road in a year so it's hard to remember, but I don't think it was working. So I need to pull an '87-90 cluster from the junkyard and swap it to an electronic gauge. Get rid of the cable altogether. I checked Ebay and they are all quite expensive.

[ghetdjc320]

9 minutes ago, Awesome said:

Renix sending units are unobtanium. I have 2 old ones now but both are rusted beyond what I believe to be repairable

MTS sells new Renix MJ sending units