eaglescout526 Posted May 28 Share Posted May 28 Oh and im not asking you to test the sensors again, I’m just asking if they all got 5V when you did test them. If they didn’t then the ECU is at fault. I’m going off what AMC said in the books that the ECU should be the absolute last thing to replace when having these issues. Link to comment Share on other sites More sharing options...
I_s2k Posted May 28 Author Share Posted May 28 5 minutes ago, eaglescout526 said: Oh and I'm not asking you to test the sensors again, I’m just asking if they all got 5V when you did test them. If they didn’t then the ECU is at fault. I’m going off what AMC said in the books that the ECU should be the absolute last thing to replace when having these issues. Ah okay gotcha, I wanna say yes when I did test them. If I remember correctly the only concerning one might’ve been the MAP connector but I don’t remember what its values were, I do know for sure that CPS/TPS are good. I did actually see the date code, it’s a little faded haha and you’re correct, 85. I’m still at a loss, I can’t believe I’m this stumped haha, i have the ECU cracked right now and don’t see anything alarming. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 28 Share Posted May 28 Nope. That’s mostly why AMC preached that it should be the last thing to be replaced as it’s built pretty well and reliable. I have one ECU in my possession where the fuel circuit doesn’t work. I need to do more component testing as to why that is. The voltage regulator was replaced on it and it didn’t make a difference other than it could crank again. Link to comment Share on other sites More sharing options...
I_s2k Posted May 28 Author Share Posted May 28 3 minutes ago, eaglescout526 said: Nope. That’s mostly why AMC preached that it should be the last thing to be replaced as it’s built pretty well and reliable. I have one ECU in my possession where the fuel circuit doesn’t work. I need to do more component testing as to why that is. The voltage regulator was replaced on it and it didn’t make a difference other than it could crank again. Sounds like a heap of fun haha. Well at this point I’m at the verdict of gut it and new body style swap it, which was always the plan, but I was really hoping I could figure something out to be able to at least drive it around a bit while I finish up my one ton project. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 28 Share Posted May 28 I have two spare ECUs if you want to test and see what’s going on. Link to comment Share on other sites More sharing options...
I_s2k Posted May 28 Author Share Posted May 28 2 minutes ago, eaglescout526 said: I have two spare ECUs if you want to test and see what’s going on. I appreciate it but I’m willing to take your word that it’s more than likely not an ECU issue, you have a much better idea than I do haha and I wouldn’t wanna burden ya with your extra parts! I need to spend more time with it but I’ve been wrapped up in my Cherokee as of recently when I’m not at work 😒 Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 29 Share Posted May 29 2 minutes ago, I_s2k said: I wouldn’t wanna burden ya with your extra parts! Hahahahaha I’ve already done that to myself. I think I’ve got two or three throttle bodies, I had 5 intake manifolds at one point and I believe I’m down to one or two now. Link to comment Share on other sites More sharing options...
I_s2k Posted May 29 Author Share Posted May 29 2 minutes ago, eaglescout526 said: Hahahahaha I’ve already done that to myself. I think I’ve got two or three throttle bodies, I had 5 intake manifolds at one point and I believe I’m down to one or two now. Oh sheesh hahaha, I’ve tried the spare parts game but I can’t do it, the only things I’ve been holding onto are random BS things such as visors, mudflaps, etc. I have a Lund moon visor on my one ton XJ as well as 2 non lighted visors sitting on the shelf, an aluminum rear visor, fiberglass rear visor for new body style, and a plastic rear visor for old body style. I have a set of OE Cherokee mudflaps and now a set of OE Comanche mudlflaps. I essentially collect all the non important stuff haha. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 29 Share Posted May 29 Lol that’s not terrible at all. I think we all shun but encourage everyone to hang on to parts. I took on the 2.5L parts roll and that’s what I mostly have. But I’m as stumped as you are with this issue. Now you said the ISA does work as in you have seen it move or heard it? Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 29 Share Posted May 29 Wild thought. Every vacuum line is routed correctly right? I can’t remember if the MAP is routed to the base of the throttle body or the port at cylinder 3/4 on the manifold. Nevermind it’s an 86. It’s obvious where it goes. Link to comment Share on other sites More sharing options...
I_s2k Posted May 29 Author Share Posted May 29 39 minutes ago, eaglescout526 said: Lol that’s not terrible at all. I think we all shun but encourage everyone to hang on to parts. I took on the 2.5L parts roll and that’s what I mostly have. But I’m as stumped as you are with this issue. Now you said the ISA does work as in you have seen it move or heard it? Yes, the ISA does work as far as I know. I can audibly hear it tap the throttle everytime it dies and I have seen it spin open/closed when I was messing with the diaphragm in the EGR. And the vacuum line for that connects to one of the metal tubes that in turn connects to the TB where the 4 collect if I remember correctly but yes, it is obvious haha. As far as touring goes, everything looks right. I thought about replacing every hose as it wouldn’t hurt but I can’t seem to get a straight answer in which diagram is accurate for an 86 with the 2.5. I’ve seen multiple diagrams out there but I’ve heard people say multiple were wrong, 0 help to me lol. I also do not know what size of hose was used for everything, I just haven’t looked. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 29 Share Posted May 29 Does your firewall still have the tag on it that shows the vac diagram? Link to comment Share on other sites More sharing options...
I_s2k Posted May 29 Author Share Posted May 29 14 minutes ago, eaglescout526 said: Does your firewall still have the tag on it that shows the vac diagram? No unfortunately the sticker faded away… Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 29 Share Posted May 29 Well damn. Ok I think I have a general idea as I had to make 86 vac set up with 87-90 set up minus the 2 ports on the TBI as two of them go to the crank case if I remember correctly. Link to comment Share on other sites More sharing options...
I_s2k Posted May 30 Author Share Posted May 30 On 5/28/2024 at 7:43 PM, eaglescout526 said: Well damn. Ok I think I have a general idea as I had to make 86 vac set up with 87-90 set up minus the 2 ports on the TBI as two of them go to the crank case if I remember correctly. Sorry man my day was busy as hell yesterday and I didn’t even get a chance to look at the forums! Do you have any pictures of said diagram or anything of that sort? I may double check it this weekend if I can find the time. How important is the vacuum lines “if that’s what they are” in the Airbox? I mean I know most vacuum lines are important obviously but there’s 2 if I remember correctly in the Airbox that some unwelcome guests chewed up. I managed to kinda rig them back together but obviously the problem I’m having is still there. Link to comment Share on other sites More sharing options...
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