bmorgan25 Posted January 31, 2016 Share Posted January 31, 2016 I am new to this site, and have spent a lot of time reading the post on here and have found some nice info that has helped me out. Seems you guys are very helpful to each other so I thought Id throw this out there... I have a 1988 MJ 4x4 with a 92 4.0 motor and stick shift swap. I recently purchase this project to go along with another 88 I have. The problem started with no fuel. tested the fuel pump...its good to go. redid all the gounds I could find....even behind the tail light. bypassed the ceramic resister. replaced the relay. checked and cleaned tons of connections. I don't even have power going to the fuel pump. started testing around....I found out I have no spark either. I have been reading about the cps and testing it....I pulled the plug on it and I have the round plug with three prongs in a triangle. tested with the meter and I'm not sure which prongs I should be testing....but I'm not getting any change on the meter no matter which two prongs I test.... the enging will crank, I do have power to the starter...but that is it.. the motor has a fresh cap rotor plugs wires..... I'm kind of leaning towards getting a new cps....any other ideas out there.. your help is much appreciated Link to comment Share on other sites More sharing options...
JCole Posted January 31, 2016 Share Posted January 31, 2016 Does the ECM Relay have power? Link to comment Share on other sites More sharing options...
bmorgan25 Posted January 31, 2016 Author Share Posted January 31, 2016 I have 12 volt to the fuel pump relay in the box.... Link to comment Share on other sites More sharing options...
bmorgan25 Posted January 31, 2016 Author Share Posted January 31, 2016 where would I find an ecm relay...not trying to be dumb here, but don't know what that is... Link to comment Share on other sites More sharing options...
Marine1Texas Posted January 31, 2016 Share Posted January 31, 2016 did you check you ignition? Sounds like nothing is getting turned on Link to comment Share on other sites More sharing options...
HOrnbrod Posted February 1, 2016 Share Posted February 1, 2016 Start with your ignition switch. It or it's connector is probably fried...... http://www.jeepforum.com/forum/f12/basic-maintenance-ignition-switch-1226376/ Link to comment Share on other sites More sharing options...
cruiser54 Posted February 1, 2016 Share Posted February 1, 2016 I am new to this site, and have spent a lot of time reading the post on here and have found some nice info that has helped me out. Seems you guys are very helpful to each other so I thought Id throw this out there... I have a 1988 MJ 4x4 with a 92 4.0 motor and stick shift swap. I recently purchase this project to go along with another 88 I have. The problem started with no fuel. tested the fuel pump...its good to go. redid all the gounds I could find....even behind the tail light. bypassed the ceramic resister. replaced the relay. checked and cleaned tons of connections. I don't even have power going to the fuel pump. started testing around....I found out I have no spark either. I have been reading about the cps and testing it....I pulled the plug on it and I have the round plug with three prongs in a triangle. tested with the meter and I'm not sure which prongs I should be testing....but I'm not getting any change on the meter no matter which two prongs I test.... the enging will crank, I do have power to the starter...but that is it.. the motor has a fresh cap rotor plugs wires..... I'm kind of leaning towards getting a new cps....any other ideas out there.. your help is much appreciated So you have the late model electronics on it? The reason I ask is the 88 CPS is flat and has only 2 wires. Link to comment Share on other sites More sharing options...
bmorgan25 Posted February 1, 2016 Author Share Posted February 1, 2016 my motor and tranny are from a 92...so its the round one... I don't think its the ignition, but could be wrong. I went ahead and bought a new one to to put in since they are inexpensive and easier....won't be able to get to that till tomorrow...also picked up a new cps.... Link to comment Share on other sites More sharing options...
bmorgan25 Posted February 1, 2016 Author Share Posted February 1, 2016 I should say yes, electronics are a 92.....even the whole wiring harness was swapped into the 88..... Link to comment Share on other sites More sharing options...
bmorgan25 Posted February 3, 2016 Author Share Posted February 3, 2016 ok guys....any other advice. replaced the cps and ignition switch...this gave me power to the coil....but yet I still have no power to the fuel pump or to the ceramic resister that I bypassed....any ideas would be much appreciated Link to comment Share on other sites More sharing options...
Marine1Texas Posted February 4, 2016 Share Posted February 4, 2016 basically you need to start from power and work to the pump with a tester. check power in to the fuel pump relay also checking the working of the relay. If you do have power at the relay then jump it over. if the pump comes on, it would be part of the ignition not switching the relay on. If the pump does not come on, then you need to trace the power to the pump from relay. At this point if pump does not come one you need to make sure your ground are good for your pump. Check wiring on connector near pump, and the ground on rear left tail light. Link to comment Share on other sites More sharing options...
bmorgan25 Posted February 4, 2016 Author Share Posted February 4, 2016 I have been over this a million times...but can't hurt to go again....the one thing that I wasn't sure about...is I have power to three of the termainal seats, for the fuel pump relay when key is on....is this normal.? when I jump the fuel relay between 30 and 87 the fuel pump turns on...I just replaced the ignition switch. and the relays....even tested the new relays... i have taken every ground off and reworked them.... i guess i will start over again and go through this one more time..... could it be the ecm causing this? Link to comment Share on other sites More sharing options...
bmorgan25 Posted February 9, 2016 Author Share Posted February 9, 2016 FYI........... well just in case anyone follows this thread, in the future, when they have the same problem......the computer was the issue. a guy let me borrow his matching computer to see if that was the problem, and it was...I have fuel and spark now. thanks again for the help guys Link to comment Share on other sites More sharing options...
Marine1Texas Posted February 9, 2016 Share Posted February 9, 2016 good to know. not often the ecu go's out so far I have seen Link to comment Share on other sites More sharing options...
cruiser54 Posted February 9, 2016 Share Posted February 9, 2016 good to know. not often the ecu go's out so far I have seen True. I've got some spare 87 ECUs for test units. Link to comment Share on other sites More sharing options...
bmorgan25 Posted February 9, 2016 Author Share Posted February 9, 2016 if anyone here has one for a 92, 4.0 manual....id be interested...damn cold out to go scavenge the junk yards right now....and 150 bucks for a remanufactured one Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now