desbennett004 Posted March 22, 2017 Share Posted March 22, 2017 Hi Guys, just installed an AX15 from a 98 XJ in my 89 MJ. Put in a new flywheel and clutch. Used the original CPS. Now it will start fine, but when I give it gas it backfires and won't rev up. I'm pretty sure you can't install a flywheel incorrectly, or the bolts won't line up. Is that correct? I'm putting a new CPS in tomorrow, hopefully that will fix it, I just wanted to double check. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted March 22, 2017 Share Posted March 22, 2017 Not sure what the flywheel looks like I assume it's got a reluctor type deal spaced around it for the timing the engine via CPS. Did you use the 89 flywheel? Bad CPS is my first thought but it seem like something in the timing . flywheel could be damaged ? Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted March 22, 2017 Share Posted March 22, 2017 PS I'm pretty sure you can only bolt it on one way, so unless it's damaged or you used the wrong year flywheel that should be ok. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
yxmj Posted March 23, 2017 Share Posted March 23, 2017 Is the new wheel a mirror image of the old....do all the "teeth" and notches line up perfectly...if not the flywheel is not sending the right info to the cps Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 Is the new wheel a mirror image of the old....do all the "teeth" and notches line up perfectly...if not the flywheel is not sending the right info to the cpsI didn't check the new one against the old one unfortunately. I'm pretty sure you can only install it one way, I just wanted to double check. I will check my paperwork and get the part number and check that it is the right one. I will be changing the CPS tomorrow, hopefully that fixes the problem. It ran fine before the transmission swap, not sure what else would be effected. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
Jeep Driver Posted March 23, 2017 Share Posted March 23, 2017 Is the new wheel a mirror image of the old....do all the "teeth" and notches line up perfectly...if not the flywheel is not sending the right info to the cpsI didn't check the new one against the old one unfortunately. I'm pretty sure you can only install it one way, I just wanted to double check. I will check my paperwork and get the part number and check that it is the right one. I will be changing the CPS tomorrow, hopefully that fixes the problem. It ran fine before the transmission swap, not sure what else would be effected. Sent from my SM-N900W8 using Tapatalk Renix and Chrysler flywheels are radically different. I doubt the CPS will solve this problem. Renix flywheels, even for the 4.0, will have to be sought out, I suspect your new flywheel is the wrong flywheel. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 I just checked my order, I got the LUK LFW194 flywheel, which is the one to get for Renix engines according to my research. I don't think I could have installed it incorrectly, I think it only goes in one way. I just put a new CPS in it this morning, and it's still running the same, backfiring and popping when you try to get above idle. Anyone have any other ideas? Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted March 23, 2017 Share Posted March 23, 2017 I'd check the MAP the be sure it's all connected. Does any of this change with the clutch engaged or disengaged? Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 I'd check the MAP the be sure it's all connected. Does any of this change with the clutch engaged or disengaged? Sent from my iPhone using Tapatalk Pro I did have a broken vac line to the map sensor, but I repaired it, and it hasn't made a difference. Having the clutch in or out doesn't make a difference. The idle drops out if I disconnect the map sensor, and comes back up when I reconnect, so it seems to be working. I'm stumped. It was running fine before the transmission swap. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 This is the new flywheel I put in. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 On a side note, does anyone know what these connectors are for? They both come out of the harness near the dipstick. I found the 4 pin connector zip tied down near my starter, but can't find a connector for it. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
Jeep Driver Posted March 23, 2017 Share Posted March 23, 2017 Yes, that's a Renix flywheel. One bolt should be out of sequence in the circle, there is only one way to install it. Link to comment Share on other sites More sharing options...
Jeep Driver Posted March 23, 2017 Share Posted March 23, 2017 On a side note, does anyone know what these connectors are for? They both come out of the harness near the dipstick. I found the 4 pin connector zip tied down near my starter, but can't find a connector for it. Sent from my SM-N900W8 using Tapatalk I'll just throw a guess out.......... If it's related to your trans...........could be back up lights and 4x indicator..........otherwise......? Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 I don't thinks it's for the Trans, the only connector I have on it that isn't plugged in is on the transfer case, which I believe is just to control a dash light to let you know if you are in 4x4 or not. Not sure where this one goes. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
87MJTIM Posted March 23, 2017 Share Posted March 23, 2017 I am not sure what you've got. Was you 89 originally an auto? Could the connectors be for a TCU? I don't think it would effect the idling issues you are having. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 I am not sure what you've got. Was you 89 originally an auto? Could the connectors be for a TCU? I don't think it would effect the idling issues you are having. I don't believe it was originally an auto, I've only had it for about 8 months, but I seem to remember the VIN came up as a manual Trans. Maybe they all had a generic harness that would work with both? In any case, I think you are right, don't think it has anything to do with the issue at hand. Still can't figure it out. Might have to see if I can do a code check, that might shed some light on the problem. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
Ωhm Posted March 23, 2017 Share Posted March 23, 2017 Suggestion only: Fuel pump volume test, possible pinched or dented fuel line. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 23, 2017 Share Posted March 23, 2017 On a side note, does anyone know what these connectors are for? They both come out of the harness near the dipstick. I found the 4 pin connector zip tied down near my starter, but can't find a connector for it. Sent from my SM-N900W8 using Tapatalk On an auto the two connectors that look similar to that one near the dipstick are the NSS and TCU connectors......... Link to comment Share on other sites More sharing options...
DirtyComanche Posted March 23, 2017 Share Posted March 23, 2017 On a side note, does anyone know what these connectors are for? They both come out of the harness near the dipstick. I found the 4 pin connector zip tied down near my starter, but can't find a connector for it. Sent from my SM-N900W8 using Tapatalk On an auto the two connectors that look similar to that one near the dipstick are the NSS and TCU connectors......... That's what I think they are too... Might have an auto harness swapped in (perhaps with an engine swap), or the truck was originally an auto. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 On a side note, does anyone know what these connectors are for? They both come out of the harness near the dipstick. I found the 4 pin connector zip tied down near my starter, but can't find a connector for it. Sent from my SM-N900W8 using Tapatalk On an auto the two connectors that look similar to that one near the dipstick are the NSS and TCU connectors......... That's what I think they are too... Might have an auto harness swapped in (perhaps with an engine swap), or the truck was originally an auto. Thanks for the input. Guess I don't have to worry about those connectors then. Still can get the truck to run properly though. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
omega_rugal Posted March 23, 2017 Share Posted March 23, 2017 Harnesses had wires for both manual and auto trannies, also all conectors for accesories even if the truck doesn`t has them, you always find one or two hanging around... Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 23, 2017 Share Posted March 23, 2017 Harnesses had wires for both manual and auto trannies, also all conectors for accesories even if the truck doesn`t has them, you always find one or two hanging around... That's not quite true. During the Renix years, the factory installed different transmission harnesses depending on which transmission was standard equipment on the vehicle. This also applied to the engine and alternator harnesses. During the HO years I guess they figured it was more cost effective to use common harnesses no matter which equipment was standard during the OBD1 and then the OBD2 models. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Author Share Posted March 23, 2017 It feels like my problem is timing, it's popping and backfiring, like the timing is retarded even though it idles fine. My question is, what could cause that? If my knock sensor was bad/disconnected/damaged, would it retard the timing to that extent? Sent from my SM-N900W8 using Tapatalk Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
64 Cheyenne Posted March 24, 2017 Share Posted March 24, 2017 Shot in the dark, but how about TPS? Did you get it wet or otherwise mess with it lately? Link to comment Share on other sites More sharing options...
desbennett004 Posted March 24, 2017 Author Share Posted March 24, 2017 Shot in the dark, but how about TPS? Did you get it wet or otherwise mess with it lately?No haven't messed with it. Everything ran fine until I did the Trans swap, now it runs like Crap. Not sure if it's related or not, the swap is pretty straight forward. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
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