mattbuch96 Posted December 7, 2016 Share Posted December 7, 2016 A few days ago I upgraded my "base model cluster" to the most upgraded one. I followed these directions http://www.naxja.org/forum/showthread.php?t=921205. And my tach isn't working. Any idea? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
AMC86Kid Posted December 7, 2016 Share Posted December 7, 2016 with out any pics of how it looks hooked up in the vehicle i can't really determine what could have went wrong when you say your Tach isnt working do you mean that all of the gauges work but the RPM gauge does not work? also tell us what year your MJ is the guy in your link did it in a 87 XJ so he might have already had a RPM gauge even in his old dash witch made the swap to the new one super easy for him Link to comment Share on other sites More sharing options...
mattbuch96 Posted December 8, 2016 Author Share Posted December 8, 2016 Its a 1990 2.5l ax4 rwd The cluster on the top is my old one with the "idiot lights" and I swaped in the more upgraded one I switched my oil pressure sender and engine temp sender to sensors. After driving it around all other guages work except the tach. Link to comment Share on other sites More sharing options...
AMC86Kid Posted December 8, 2016 Share Posted December 8, 2016 ok that help me out so i believe since you have a in line 4 motor and your vehicle is 2 wheel drive you have no sensor from your tranny telling the dash what your rpm is i think the only way to get it to work is to take the tranny to a tranny shop and have them put in a sensor so that you can hook it up to your rpm dash gauge now i may be wrong but I'm pretty sure that since the original dash did not have an rpm gauge then why would they install a tranny that has a rpm sensor in it ??? on the other hand you might be lucky they might have the sensor in the tranny and they just never ran the wire for it up to the dash i would look at the tranny and see if there is any evidence of an electrical connection and go from there Link to comment Share on other sites More sharing options...
Minuit Posted December 8, 2016 Share Posted December 8, 2016 ok that help me out so i believe since you have a in line 4 motor and your vehicle is 2 wheel drive you have no sensor from your tranny telling the dash what your rpm is i think the only way to get it to work is to take the tranny to a tranny shop and have them put in a sensor so that you can hook it up to your rpm dash gauge now i may be wrong but I'm pretty sure that since the original dash did not have an rpm gauge then why would they install a tranny that has a rpm sensor in it ??? on the other hand you might be lucky they might have the sensor in the tranny and they just never ran the wire for it up to the dash i would look at the tranny and see if there is any evidence of an electrical connection and go from there This is incorrect. The tach should work out of the box. The signal comes from the ignition system and every MJ is equipped for it, whether it originally had the tach or not. I've converted two trucks now and the tach has worked correctly both times. Check that the two plugs are snapped in all the way (on my '89, sometimes they won't go in completely and the gauges won't work) and check the ground under the dashboard. You mentioned everything else works fine, so neither of those are probably the issue but they're still worth checking. Other than that, I've never personally had a tach go bad but if everything else checks out I'd start suspecting the tachometer gauge itself may be bad. You might also want to look for any nicks or tears in the cluster's printed circuit board. Let me know what you determine. I have quite a few parts for these Renix clusters (no complete ones, sadly) so if you need another tach or a printed circuit board I could probably help you out. Link to comment Share on other sites More sharing options...
AMC86Kid Posted December 8, 2016 Share Posted December 8, 2016 well there you go check and make sure it is connect and grounded well then if it still don't work take it back and try a different one if it still does not work then let us know and i can look up some schematical specs for you Link to comment Share on other sites More sharing options...
mattbuch96 Posted December 8, 2016 Author Share Posted December 8, 2016 Thank you, I do not see any imperfections on the circuit board, where is the ground under the dash located? I will have to check that. Link to comment Share on other sites More sharing options...
Minuit Posted December 8, 2016 Share Posted December 8, 2016 On the left side of the dash above the hood release cable. Should be a 5/16" bolt. You might have to take the knee panel off to see it. http://cruiser54.com?p=110 Link to comment Share on other sites More sharing options...
mattbuch96 Posted December 8, 2016 Author Share Posted December 8, 2016 I will check that tomorrow morning and let you know, i really hope it works its self out. thanks again! Link to comment Share on other sites More sharing options...
Eagle Posted December 8, 2016 Share Posted December 8, 2016 If I remember correctly, there are two contacts where the tach head attaches to the printed circuit. Under the hood, there are two small, yellow "thingies" (highly technical term there) with flip caps on them. Inside, there are contacts for running some basic diagnostics. The smaller of the two has six terminals (receptacles). That's the one with the feed for testing the tach. You can check it by taking the cluster out of the dashboard and running jumpers from the test terminals to the tach head. I'm not set up to scan the diagram of the diagnostic connector. As drawn, it shows two columns and three rows. The right side of the block has two notches cut out of it. Oriented that way, top right is #1, #2 below that, #3 bottom right ... then #4 top left, #5 below that, and #6 bottom left. #1 is the positive tach feed. #3 is the ECU ground -- you can use that for the tach ground, or just ground it to the engine block. Link to comment Share on other sites More sharing options...
buckwheat Posted December 8, 2016 Share Posted December 8, 2016 My assumption would be in using a tach from a 6 cylinder engine in a four cylinder engine doesnt work. Since it is based on the ignition system, wouldn't that change based on how many cylinders are firing? Sorry if this is incorrect information. Link to comment Share on other sites More sharing options...
DirtyComanche Posted December 8, 2016 Share Posted December 8, 2016 My assumption would be in using a tach from a 6 cylinder engine in a four cylinder engine doesnt work. Since it is based on the ignition system, wouldn't that change based on how many cylinders are firing? Sorry if this is incorrect information. It will 'work' even if it's the wrong one. It just reads incorrectly. Link to comment Share on other sites More sharing options...
Eagle Posted December 8, 2016 Share Posted December 8, 2016 My assumption would be in using a tach from a 6 cylinder engine in a four cylinder engine doesnt work. Since it is based on the ignition system, wouldn't that change based on how many cylinders are firing? Sorry if this is incorrect information. It will 'work' even if it's the wrong one. It just reads incorrectly. ^^^ What he said. Link to comment Share on other sites More sharing options...
AMC86Kid Posted December 8, 2016 Share Posted December 8, 2016 what exactly do you guys mean when you say it runs off of the ignition system Link to comment Share on other sites More sharing options...
Eagle Posted December 8, 2016 Share Posted December 8, 2016 what exactly do you guys mean when you say it runs off of the ignition system The tachometer is electronic, not mechanical. It receives electrical pulses and "counts" them, converting that into an RPM reading. The electrical pulses for the tachometer come from the ignition. What it's doing is counting how many times the coil sends a spark to the spark plugs. Link to comment Share on other sites More sharing options...
mattbuch96 Posted December 8, 2016 Author Share Posted December 8, 2016 Thank you guys for all the input, i ended up just taking it out and plugging it back in and everything works! I must have not had it all the way plugged in :doh: Link to comment Share on other sites More sharing options...
AMC86Kid Posted December 8, 2016 Share Posted December 8, 2016 congrats bro at least you figured it out and got it to work does it work correctly or is the reading off at all ? Link to comment Share on other sites More sharing options...
Eagle Posted December 8, 2016 Share Posted December 8, 2016 congrats bro at least you figured it out and got it to work does it work correctly or is the reading off at all ? Good news that he got it working. If the "new" cluster came from a 6-cylinder, the tach probably doesn't read correcttly. The good news is that that style cluster is the newer style ("newer" as it relates to the Renix years, with the mechanical speedometer), and those have a potentiometer on the back of the tachometer that can be used to adjust it to read correctly for a 4-cylinder. If it came from a 4-cylinder, no adjustment should be required. Link to comment Share on other sites More sharing options...
Minuit Posted December 8, 2016 Share Posted December 8, 2016 Thank you guys for all the input, i ended up just taking it out and plugging it back in and everything works! I must have not had it all the way plugged in :doh: Always the simple stuff! :thumbsup: Sometimes those plugs don't want to go all the way in for whatever reason. Link to comment Share on other sites More sharing options...
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