Wild Comanche Posted April 30, 2016 Share Posted April 30, 2016 I have a 1989 Comanche with a 1992 or 1993 rebuilt block and head, 1999 intake, 60mm bored throttle body, 22 lb. 4-hole injectors, aftermarket headers, and the existing Renix computer with the 4-spd. auto tranny. It idles good, but has terrible throttle response. I finally took it to a shop that has a scan tool. He asked me what flywheel is installed as he has got some odd scope readings. The old 1989 flywheel or the 1992 or 1993 flywheel? Since the engine was rebuilt at a custom rebuild shop I did not have an answer right off the top of my head. After some phone calls I believe it has the '92 or '93 flywheel. Are these different year flywheels interchangeable? Or is there a compatability issue between the different computer systems? If not, could this explain the throttle problems? Any help will be appreciated. Thanks............................... Link to comment Share on other sites More sharing options...
gogmorgo Posted April 30, 2016 Share Posted April 30, 2016 Pretty sure it wouldn't run at all with the wrong flywheel. Completely different mechanism. The Renix flywheel has a bajillion windows consistently around the edge, the HO has three fairly spaced out groups. Should be pretty easy to verify by pulling off the inspection cover. Link to comment Share on other sites More sharing options...
FrankTheDog Posted April 30, 2016 Share Posted April 30, 2016 If you have the renix computer you should have an 87-90 flexplate. Surprised it runs at all but I've never compared the two to see how close they are. Link to comment Share on other sites More sharing options...
Eagle Posted April 30, 2016 Share Posted April 30, 2016 Pretty sure it wouldn't run at all with the wrong flywheel. Completely different mechanism. The Renix flywheel has a bajillion windows around the edge, the HO has three. Should be pretty easy to verify by pulling off the inspection cover. You are correct -- an XJ or MJ with the Renix ignition/injection system simply won't run with the 91+ Chrysler HO flywheel (or flex plate). Link to comment Share on other sites More sharing options...
Wild Comanche Posted April 30, 2016 Author Share Posted April 30, 2016 Thanks for that info.. Well it does run, but not that you could consider it driveable in the least. I have been trying to figure this problem out for about 6 weeks. Link to comment Share on other sites More sharing options...
mikekaz1 Posted April 30, 2016 Share Posted April 30, 2016 Do you mean throttle response in general? Like in park or neutral? Or while driving? Your TV cable could be out of adjustment if its while driving. Link to comment Share on other sites More sharing options...
Wild Comanche Posted April 30, 2016 Author Share Posted April 30, 2016 The throttle response issue is when it is parked. Trying to actually drive the vehicle is next to impossible. Link to comment Share on other sites More sharing options...
mikekaz1 Posted April 30, 2016 Share Posted April 30, 2016 I'm guessing the throttle body is clean since its brand new but what about the sensors? Are the new? Old? Mounted correctly? You said you went to a 99 intake. That means you can't use the renix TB (3 bolts right?) so are your factory sensors even compatible? Does it change if you disconnect the throttle cables? I swore they routed differently between renix and HO... but haven't been around a renix recently Link to comment Share on other sites More sharing options...
cruiser54 Posted April 30, 2016 Share Posted April 30, 2016 How are the grounds at the dipstick tube stud on that shiny new motor? http://cruiser54.com/?p=19 Distributor indexed correctly? http://cruiser54.com/?p=68 Link to comment Share on other sites More sharing options...
Wild Comanche Posted April 30, 2016 Author Share Posted April 30, 2016 The throttle body is off a 1996 jeep. It is spotless and was bored to 60mm. The guy that rebuilt the throttle body did a nice job. All of the sensors are "Renix" system sensors and some but not all are new. The throttle cable (s) have been changed from the 1989 year as they wouldn't work with the 1996 throttle body. The list of replaced ignition parts and sensors : New distributor, new coil, new ignition wires, remanufactured cpu, new ignition control module, new TBS sensor (dual plug for auto tranny) and a new MAP sensor. All the grounds have been checked at least twice. The distributor is installed correctly. The engine was rebuilt by M & S Engine Works in Sandpoint, Idaho. He has been in business a long time and does a really professional job. It was balanced and blueprinted. As he does this to every engine rebuild. He has rebuilt hundreds of engines in his shop. I spent hundreds of hours on the internet researching this very conversion before deciding to go ahead. Even after trying to cover every base of a conversion like this it seems that the "flywheel snafu" was something overlooked. I will know next week if the later flywheel (1991 and on ) is actually installed on this engine. I looked at the two flywheels on the internet and the windows are completely different. The jeep is in a mechanics shop presently and I haven't taken possession of it as I didn't want to void any warranty on the rebuild. I will know next week on the flywheel issue. Thanks for the advice. This is a great website.................... Link to comment Share on other sites More sharing options...
cruiser54 Posted April 30, 2016 Share Posted April 30, 2016 You might even be able to see which flywheel it is by looking through the inspection cover where the engine and trans meet. Did the rebuilder get a "new" Renix flex plate? If so, he could have gotten a defective one. It has happened. All this said, if the distributor is not indexed correctly per tip 13, you could be chasing your tail. I wouldn't skip over it no matter who is the engine builder. Link to comment Share on other sites More sharing options...
Rockfrog Posted April 30, 2016 Share Posted April 30, 2016 So after going through all of that, has anyone check fuel pressure at the rail? Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted April 30, 2016 Share Posted April 30, 2016 So after going through all of that, has anyone check fuel pressure at the rail? Sent from my SGH-I337M using Tapatalk LOL. Thanks Captain Common Sense for slapping us all back into reality...... Link to comment Share on other sites More sharing options...
Rockfrog Posted April 30, 2016 Share Posted April 30, 2016 I kinda does fit the symptoms, and I have been stuck in that trap of dancing around the simple issue plenty of times myself. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted April 30, 2016 Share Posted April 30, 2016 I kinda does fit the symptoms, and I have been stuck in that trap of dancing around the simple issue plenty of times myself. Sent from my SGH-I337M using Tapatalk Agreed. Link to comment Share on other sites More sharing options...
Wild Comanche Posted April 30, 2016 Author Share Posted April 30, 2016 Thanks for all the input. And comments. After this much time scratching my head, it's almost entertaining. This project has definitely went over budget. In both money and time. But you have to love it or what's the point. As to the fuel pressure at the rail, It was checked when the engine was installed and it is close to 39 psi. As to indexing the distributor, it can be rechecked and verified. As I think back I believe the engine builder scraped the old 1989 engine, as it disappeared out of the bed of my truck where it had been sitting for a while. The engine had 267,000 miles on it and had seen better days. The crankshaft bearing surfaces had severe ridges in them and it was impossible to get a new rear main seal to stop oil leaking. And a rod bearing was starting to knock. I ended up putting 2 quarts of "Lucas Heavy Duty Oil Stabilizer" in the last oil change but it was headed for the graveyard by then. I later thought he should have saved the 1989 engine for later reference or examination. Obviously hind sight is usually right on the money. Thanks again..................... Link to comment Share on other sites More sharing options...
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