Rockfrog Posted January 31, 2015 Posted January 31, 2015 So, I picked up a 92 XJ and in the back just so happens to be two 2.8L GM V6 boat anchors (extra scrap weight value I guess). So I start looking at what I can scavenge from them, alternator, throttle bodies for future projects ... Wait a minute ... That GM tps looks awfully familiar ... Unfortunately my stock TPS died (old AMC manual version) and got hacked during the HO head/TB conversion. But the GM tps' on the 2.8's looks and feels just like the old AMC/Renix tps... Even the same arm actuators. The plug orientation is different, but if it fits and works the same.... They are only $28 on rockauto... 1988 Camano 2.8L tps is what I have two of. Am I loosing my marbles or is it just possible I can bolt these on?
jimoshel Posted January 31, 2015 Posted January 31, 2015 Why don't you just try it and see? Report back and let us know.
gogmorgo Posted January 31, 2015 Posted January 31, 2015 You never know. AMC had their hands pretty deep into GM's parts bins towards the end. Throttle position sensors are also all very similar in both form and function.
Rockfrog Posted February 1, 2015 Author Posted February 1, 2015 Tried it, got an idle of 2500rpm, and if I relaxed the sensor, a no start. So much for the cheap and easy ... It was too good to be true. Unless the junkyard throwaway sensors were junk, since my stock sensor did the same thing when it went out. But I doubt it.
Rockfrog Posted February 1, 2015 Author Posted February 1, 2015 Just checked the test specs ... .2 -.9V at idle, ranging to 5V at WOT ... Sound familiar? Maybe my sensors were shot. Might check the local parts store prices and test a new one if I get a decent enough deal.
Rockfrog Posted February 1, 2015 Author Posted February 1, 2015 I think I found it, GM sensor - A - ground B - SIGNAL C - 5V reference Renix - A - Positive 5V reference B - ground C - SIGNAL SO... Assuming I have this right, I just need to re-arrange the wires in the connector and the cheaper GM sensor ... That is roughly $100 cheaper ... And readily available ... Is a doable thing. Makes sense why my idle went off the charts now. Gonna try this when I get the chance. In other news I got my ebrake working again, made me feel better after round 1 cheap tps fail.
Rockfrog Posted February 1, 2015 Author Posted February 1, 2015 I'm going to wire a simple adapter harness and try it again, cross yer fingers.
gogmorgo Posted February 2, 2015 Posted February 2, 2015 Hope it works out. In the pits at FSAE Lincoln last year we though we had some issues with our TPS, and we couldn't find our spare. We went to the pit next door, and their spare bolted up and plugged right in. Slight recalibration (we always recalibrate for new sensors) but it worked great, even though ours was off a '90's GM truck and theirs was for a 2000's Suzuki. Like I said, TPS's are pretty similar in form and function.
Rockfrog Posted February 2, 2015 Author Posted February 2, 2015 Yeah, the issue is the way the Renix reads voltage, and the way it is wired internally it seems. It may read voltage (climbing) the same as the GM sensor, but the internal pinout of the sensor is different making them a direct swap incompatible. And Suzuki and GM have had a long relationship over the years, I would suspect a considerable compatibility there. From my research a simple wire swap should allow use of the 86-91 2.8L TPS (86-87 are physically the same as the Renix, 88-91 point the connector straight up but function the same). I'm making and quickly adapter harness right now. If it works, and 87 s10 tps is a direct swap with a simple wire rearrange on the plug. And they run $21-32 on rockauto, vs $118 for the Renix manual version and $60 for the auto.
Rockfrog Posted February 2, 2015 Author Posted February 2, 2015 So ... The crossover harness ... WORKS PERFECTLY! SO ... The GM 2.8L TPS (and pretty near all GM engines) from 86-91 (and possibly later as GM TPS still work the same) will work to replace the 5spd renix sensor. Use the 86-87 S10 version for a correctly angle plug, 88-91 will have the plug straight up. You will only need to rearrange the wires in the plug once and it's a direct swap. Picture of my hacktastic adapter harness in a minute. Just have to let the phone charge. But I did drive around the block and back again.
tugalo Posted February 2, 2015 Posted February 2, 2015 The TPS connedtor is a Weatherpak, and you could buy a pin removal tool and just change over the connectors without having to make a harness..........look on ebay for the tool
Rockfrog Posted February 2, 2015 Author Posted February 2, 2015 I have the tools, I made the harness as a tester, I didn't want to rearrange the connector before I proved function. Hell, I didn't even adjust the TPS or even add the second spacer, it's just quickly popped in place. Idle is better than my current Renix TPS. Now that I have proven it works, I'll rearrange the wire order in the stock connector and on the Renix side of the adapter harness . And the harness will now become a test/adjuster harness. I didn't want to futzing with it too much if it wasn't going to work.
Rockfrog Posted February 2, 2015 Author Posted February 2, 2015 The two TPS' side by each. The conversion harness to test it all. Stock wires re-arranged in the plug to GM pattern. The old adapter harness reset for use as a test dongle. The wire nuts simply cover the wire leads used to test and adjust.
Knucklehead97 Posted February 3, 2015 Posted February 3, 2015 This is fantastic. But why is your TPS on the back of the throttle body?
Rockfrog Posted February 3, 2015 Author Posted February 3, 2015 Because it's on an HO throttle body. I did an HO head (92) and manifold (99 intake) back in October-ish. Been driving around for the last day, the GM TPS even got rid of a hesitation when starting in first, always thought it was another unrelated issue.
Knucklehead97 Posted February 4, 2015 Posted February 4, 2015 Well if I have to change my TPS AGAIN then I know what I'm doing. :D
Crash Posted February 7, 2015 Posted February 7, 2015 The TPS for an auto trans is plug n pray for a manual trans. Just has an additional plug. I work at a Carquest auto parts, and the computer did not even show a listing for a manual trans. Auto trans TPS prices that I have seen have always been significantly cheaper.
Rockfrog Posted February 7, 2015 Author Posted February 7, 2015 yes, but the GM TPS is cheaper still ... and a bazillion times more likely to be found in a Wrecking Yard (how many 2.8L manual trans cars/trucks left the GM factories between 1986 and 1991? Compared to 4.0L Comanche/Cherokee's from 87-90?). Last check the Auto trans sensor was ~$60 on rockauto, the GM sensor is $21 on rockauto. Only takes a quick wire swap to work, and is completely reversable. If I had an auto .... wouldn't have even crossed my mind, but I just happened to have a manual, and happened to get saddled with these two 2.8L efi engines in the back of my parts XJ so .... now there is a source for 5spd manual TPS's compatible with the Renix system. FYI - the sensor next to the GM takeoff is an auto TPS that used to reside on my engine until I tried the GM sensor (AMC on the left, GM on the right). it had a flat spot on take off, and when I got it the wiring wasn'f sealed properly (hence the RTV) ... since I had these two sensors, and the inkling to try ... I have now put just over 500kms on it without even a hiccup, flat spot, hesitation or burp. I just wanted to share my findings was all, and add another JY source for parts (the original Delphi sensor is still going to be the more reliable one).
Rockfrog Posted February 19, 2015 Author Posted February 19, 2015 Just an update, another 1000km's with zero issues and a better idle. Going to start looking for these when I JY crawl now. Just to clarify, the only modification needed is to re-arrange the wires in the stock plug. Simple as that. I still have my renix TB I can mount one to and snap a pick if anyone is remotely curious.
Rockfrog Posted November 4, 2016 Author Posted November 4, 2016 So, Just a long term update. This GM TPS has been working for the last 1.5yrs now. Recently picked up a spare for $25. So pretty much cheap and easy. Going to start looking at compatibility for 2.5L (pre 92 so renix TBI) next. Looks like I should be able. To utilize the same GM TH32 with a simple wire swap again.
HOrnbrod Posted November 4, 2016 Posted November 4, 2016 I guess you use Photobucket, thus no pics. Damn Photobucket is down more than it's up. :fs1:
87MJTIM Posted November 4, 2016 Posted November 4, 2016 ...Photobucket is down more than it's up. :fs1: Perhaps it needs a prescription for Viagra. (Sorry, couldn't resist.)
Rockfrog Posted November 6, 2016 Author Posted November 6, 2016 Pictures seem to be working for me on the web, but not in Tapatalk. I downloaded the pictures and will re-add them when I get home Tuesday.
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