Jackrabbit41 Posted September 13, 2016 Share Posted September 13, 2016 So ever since I swapped my trucks been running horrible. It does every time you let off the gas, at idle its like it had the worlds biggest cam. All the lights dim and brighten as the engine revs up and down and the thing smokes like it's running off sea foam. I never touched the engine. Would could this be? It's making new noises too Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 13, 2016 Share Posted September 13, 2016 I put in the wrong flywheel on so I had to pull out the tranny and swap fly wheels and then put her all back together. Running good and shifting smooth. :hmm: Turned to crap overnight? Link to comment Share on other sites More sharing options...
Jackrabbit41 Posted September 13, 2016 Author Share Posted September 13, 2016 I put in the wrong flywheel on so I had to pull out the tranny and swap fly wheels and then put her all back together. Running good and shifting smooth. :hmm: Turned to crap overnight? Ya lol but just figured it out. Map sensor vacuum hose came out lol plugged her in and she's perf Link to comment Share on other sites More sharing options...
desbennett004 Posted March 22, 2017 Share Posted March 22, 2017 I put in the wrong flywheel on so I had to pull out the tranny and swap fly wheels and then put her all back together. Running good and shifting smooth. :hmm: Turned to crap overnight? Ya lol but just figured it out. Map sensor vacuum hose came out lol plugged her in and she's perfThis post saved me $45. Was just about to order a new CPS, checked the vacuum line going to the MAP sensor. It was broken. Thanks! Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted March 23, 2017 Share Posted March 23, 2017 I put in the wrong flywheel on so I had to pull out the tranny and swap fly wheels and then put her all back together. Running good and shifting smooth. :hmm: Turned to crap overnight? Ya lol but just figured it out. Map sensor vacuum hose came out lol plugged her in and she's perfThis post saved me $45. Was just about to order a new CPS, checked the vacuum line going to the MAP sensor. It was broken. Thanks! Sent from my SM-N900W8 using Tapatalk Pretty common. Here's something to look at: http://cruiser54.com/?p=280 Link to comment Share on other sites More sharing options...
Minuit Posted March 23, 2017 Share Posted March 23, 2017 Rule 1 of troubleshooting sudden drivability issues: it's the MAP sensor line. I've seen it cause all sorts of problems, and in fact the only time I've ever seen the CEL on in my '91 was when it was driven with that line just barely loose for about 2 hours. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Share Posted March 23, 2017 Looks like I still have another problem, but the broken vac line wasn't helping. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted March 23, 2017 Share Posted March 23, 2017 Rule 1 of troubleshooting sudden drivability issues: it's the MAP sensor line. I've seen it cause all sorts of problems, and in fact the only time I've ever seen the CEL on in my '91 was when it was driven with that line just barely loose for about 2 hours. It should be!! Link to comment Share on other sites More sharing options...
cruiser54 Posted March 23, 2017 Share Posted March 23, 2017 Looks like I still have another problem, but the broken vac line wasn't helping. Sent from my SM-N900W8 using Tapatalk Sometimes this stuff is like eating an elephant....one bite at a time. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 23, 2017 Share Posted March 23, 2017 Rule 1 of troubleshooting sudden drivability issues: it's the MAP sensor line. I've seen it cause all sorts of problems, and in fact the only time I've ever seen the CEL on in my '91 was when it was driven with that line just barely loose for about 2 hours. You have an HO, get rid of it. :yes: http://comancheclub.com/topic/41929-installing-a-1996-throttle-body-mounted-map-sensor/ Link to comment Share on other sites More sharing options...
Minuit Posted March 23, 2017 Share Posted March 23, 2017 Rule 1 of troubleshooting sudden drivability issues: it's the MAP sensor line. I've seen it cause all sorts of problems, and in fact the only time I've ever seen the CEL on in my '91 was when it was driven with that line just barely loose for about 2 hours. You have an HO, get rid of it. :yes: http://comancheclub.com/topic/41929-installing-a-1996-throttle-body-mounted-map-sensor/ On the list. Sent from my LG-D850 using Tapatalk Link to comment Share on other sites More sharing options...
desbennett004 Posted March 23, 2017 Share Posted March 23, 2017 Looks like I still have another problem, but the broken vac line wasn't helping. Sent from my SM-N900W8 using Tapatalk Sometimes this stuff is like eating an elephant....one bite at a time. 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 Link to comment Share on other sites More sharing options...
cruiser54 Posted March 24, 2017 Share Posted March 24, 2017 Looks like I still have another problem, but the broken vac line wasn't helping. Sent from my SM-N900W8 using Tapatalk Sometimes this stuff is like eating an elephant....one bite at a time.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 If you had a knock sensor, which you don't according to Hornbrod, since you have an HO, you need to check your fuel pressure. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 24, 2017 Share Posted March 24, 2017 If you had a knock sensor, which you don't according to Hornbrod, since you have an HO, you need to check your fuel pressure. That wasn't directed to the OP or desbennett004. Go back four posts and read it again........... :shake: Link to comment Share on other sites More sharing options...
cruiser54 Posted March 24, 2017 Share Posted March 24, 2017 If you had a knock sensor, which you don't according to Hornbrod, since you have an HO, you need to check your fuel pressure. That wasn't directed to the OP or desbennett004. Go back four posts and read it again........... :shake: Too much bull$#!& here. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 24, 2017 Share Posted March 24, 2017 I don't have a HO, it's Renix. I'm pretty sure it had a knock sensor, but I'm not sure if there is a limit it will retard timing if it's not working right. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted March 24, 2017 Share Posted March 24, 2017 I don't have a HO, it's Renix. I'm pretty sure it had a knock sensor, but I'm not sure if there is a limit it will retard timing if it's not working right. Sent from my SM-N900W8 using Tapatalk This thread has become so contaminated with bull$#!& it's hard to tell any more. I'd love to help. A bad knock sensor will not cause major driveability issues. Let's get back to basics like what the problem is. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 24, 2017 Share Posted March 24, 2017 If you had a knock sensor, which you don't according to Hornbrod, since you have an HO, you need to check your fuel pressure. That wasn't directed to the OP or desbennett004. Go back four posts and read it again........... :shake: Too much bull$#!& here. Yep. Just eating an elephant....one bite at a time. :rotfl2: Link to comment Share on other sites More sharing options...
cruiser54 Posted March 24, 2017 Share Posted March 24, 2017 If you had a knock sensor, which you don't according to Hornbrod, since you have an HO, you need to check your fuel pressure. That wasn't directed to the OP or desbennett004. Go back four posts and read it again........... :shake: Too much bull$#!& here. Yep. Just eating an elephant....one bite at a time. :rotfl2: Whatever. Are we here to help people or get into a pissing contest? Egocentric bull$#!& or contributing to the community? Link to comment Share on other sites More sharing options...
desbennett004 Posted March 24, 2017 Share Posted March 24, 2017 Just did a AX15 swap from a 98 XJ into a 89 MJ, 4.0. Swapped flywheel, clutch, and Crank Position Sensor. Now it will start and idle fine, but once you try to give it any throttle whatsoever, it starts popping and backfiring, like the timing is out. Flywheel is correct, CPS is correct. Not sure if it's related to the Trans swap, or its just coincidental. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted March 24, 2017 Share Posted March 24, 2017 Just did a AX15 swap from a 98 XJ into a 89 MJ, 4.0. Swapped flywheel, clutch, and Crank Position Sensor. Now it will start and idle fine, but once you try to give it any throttle whatsoever, it starts popping and backfiring, like the timing is out. Flywheel is correct, CPS is correct. Not sure if it's related to the Trans swap, or its just coincidental. Sent from my SM-N900W8 using Tapatalk Which flywheel did you use? The 98 will not be compatible with the Renix system. Link to comment Share on other sites More sharing options...
desbennett004 Posted March 24, 2017 Share Posted March 24, 2017 I used a renix flywheel from LUK. Double checked part numbers, it's compatible with the 89 4.0. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
desbennett004 Posted March 24, 2017 Share Posted March 24, 2017 Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted March 24, 2017 Share Posted March 24, 2017 Have you tested the CPS output per this? http://cruiser54.com/?p=50 Link to comment Share on other sites More sharing options...
desbennett004 Posted March 24, 2017 Share Posted March 24, 2017 Have you tested the CPS output per this? http://cruiser54.com/?p=50 No sir, I have not. I will do that in the morning for sure. I was wondering about the distance from flywheel measurement, and whether having the 89 CPS in the 98 bell housing might somehow increase the distance from the flywheel. I'm going to slot those holes tomorrow also, just to make sure I get a good signal. Thanks for the advice, I will report back with my results. Sent from my SM-N900W8 using Tapatalk Link to comment Share on other sites More sharing options...
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