wannabeMJ Posted April 18, 2010 Share Posted April 18, 2010 I'm starting to put the interior back in the truck and I'm puting the 90 XJ wirring harness for the motor swap but the cluster for the XJ doesn't have the RPM gage on it just the huge fuel gage but my MJ one got it Ive seen a post for the rear wirring but as anyone done this so far? I'm sure some of you guys have put RPM's in your trucks can some one tell me where the RPM is taken from on the engine maybe after that I will figure out if I can get the cluster to work Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 The "Tachometer" is always wired up. You just need to get yourself a new cluster. Rob L. Link to comment Share on other sites More sharing options...
Geonovast Posted April 18, 2010 Share Posted April 18, 2010 Can't the 86 cluster work with the 90 wiring? Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 Can't the 86 cluster work with the 90 wiring? yeah cuz I got the cluster with all gages on my 86 ( it had the 2,8L) and I don't care about the idiots light lolll Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 Nope, different speedo hookup. Rob L. Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 connectors look about the same but different numbers of pins on the connectors Link to comment Share on other sites More sharing options...
Geonovast Posted April 18, 2010 Share Posted April 18, 2010 Nope, different speedo hookup. Rob L. Doesn't sound like a problem to me. Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 connectors look about the same but different numbers of pins on the connectors It won't work. Simple as that. You can compare how they look all you want, but the only solution to your problem will be a different cluster. Staring at it won't make that happen. Rob L. ;) Link to comment Share on other sites More sharing options...
Geonovast Posted April 18, 2010 Share Posted April 18, 2010 Put the speedo from the 90 cluster into the 86 cluster. Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 here are the 2 cluste the top one is the 86 MJ and the bottom one the 90 XJ Image Not Found the back of the 86 Image Not Found and the back of the 90 Image Not Found 15 pins on 1 and 16 on the other Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 Ok, so now we have pictures of showing it not going to work. :dunno: Get a new cluster. Your killing me smalls. :( Rob L. Link to comment Share on other sites More sharing options...
Geonovast Posted April 18, 2010 Share Posted April 18, 2010 Put the 90 speedometer into the 86's cluster, then plug it in. If it works, great, and all you'll have lost is the tripometer. If it doesn't work, then you'll need a different cluster. I'm fairly certain the electronic aspect is interchangeable. Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 Do what you want. I'd just find a Junkyard, find one out of an '88-'90 XJ/MJ buy it for $10, and call it a job. The speedo's aren't bolt in interchangeable in the clusters. Its going to require cutting. Get a new cluster. Rob L. Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 so ur telling me I need to find a cluster from a XJ that had the RPM in but wirring harness still won't fit the new cluster cuz my harness doesn't have the RPM anyway ?? :huh???: Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 so ur telling me I need to find a cluster from a XJ that had the RPM in but wirring harness still won't fit the new cluster cuz my harness doesn't have the RPM anyway ?? :huh???: THE WIRING ON THE XJ IS FINE. What I AM telling you is that you need to stop obsessing over the cluster, and just go find a new one. All XJ/MJ's with out tachometers still have all the stuff to run one built into the harness. What you will need on the other hand is the coolant temp sensor and the oil pressure sensor on the XJ motor, as right now they are set up for switches for the idiot lights. THE '90 CLUSTER HAS A DIFFERENT PLUG NOT BECAUSE IT DOESN'T HAVE A TACH, BUT BECAUSE ITS FOR A '90, NOT AN '86. Get a new cluster. '88-'90 should work. Rob L. Link to comment Share on other sites More sharing options...
Geonovast Posted April 18, 2010 Share Posted April 18, 2010 The harness has all the wiring in there already. The difference is in the cluster. Idiot light cluster and full cluster circuit boards look very different. You do not need to do any wiring. Simply switch the speedos, and put the cluster in. Either I'm right, or Rob's right. Only way you'll know for sure is to try it. Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 thanks guys Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 18, 2010 Share Posted April 18, 2010 The 90 cluster will work fine in your 86. As mentioned, you will have to modify the speedo cable hookup and calibrate the tach using the potentiometer on the tach circuit board. Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 will I have to had a resistance on the board ?? what do u mean by calibrate ?? never done that before calibrate for the fact that the 2.8 doesn't revolution like the 4.0? Link to comment Share on other sites More sharing options...
Automan2164 Posted April 18, 2010 Share Posted April 18, 2010 Correct. You will just have to change the way the 2.8L tach sees the signal from the harness. Rob L. Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 any advice or tricks on how to do this? Link to comment Share on other sites More sharing options...
Geonovast Posted April 18, 2010 Share Posted April 18, 2010 4.0 are 2.8 are both 6 poppers... why would the tach need adjusting? Link to comment Share on other sites More sharing options...
wannabeMJ Posted April 18, 2010 Author Share Posted April 18, 2010 4.0 are 2.8 are both 6 poppers... why would the tach need adjusting? tought so to ....... anybody else have toughts on this :hmm: Link to comment Share on other sites More sharing options...
Eagle Posted April 18, 2010 Share Posted April 18, 2010 Can't the 86 cluster work with the 90 wiring? Yes but the speedometer cable is different. Also, the '86 cluster doesn't have the adjustable potentiometer, so you have to use a 4-cyl cluster with a 4-cyl engine, or a 6-cyl cluster with a 6-cyl engine. Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 18, 2010 Share Posted April 18, 2010 True, but I'm not sure the 90 and 86 tach pickups are the same. Are you? :D If it reads correctly, that's good. Stick it in there and try it. Link to comment Share on other sites More sharing options...
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