1990 YJ coil, voltage, ICU, something ISSUES

Ignition power I assume it's that point when you turn the key all the way forward to start the motor (cranking power). Those drawings were something I copied from stuff i found on line that I had a hard time reading because of poor picture quality. I believe the issue is that some of these wires ran through the ignition control module while others ran through the ecm, and you have to figure out where to pull wires from to make it work.

I have one question That big red wire, is it always 12v hot, or is it hot only when cranking. If it is always hot then the (I) should probably come from a cranking hot wire, not a switched. If the big red wire is a hot only when cranking then the (I) should probably be a switched hot from the ignition.

 

Great you got it! Post your video on youtube then post the link to youtube video on here and it will pop up as a video to watch on this page. I think thats how it works.

 

Without the ecm you'll probably want to set your timing at 6-8* BTDC. Your carbed so 6 would be good, 8 might be too much. Only you will know that when tuning. I'm fuel injected on my CJ and I run 8* BFTD. remember to disconnect the vacuum from the distributor and plug the vaccum line when setting your timing.

 

So this is it all buttoned up cleaned up comma it starts and runs unfortunately as mentioned it does only start on the let off which causes issues sometimes because as I turn it over it feeds gas and if it doesn't start it will essentially backfire through the carburetor that issue was solved at one point so I will have to figure that out but the fact that it's running again makes me very happy with this new system and all the wiring removed. I'm very pleased with the overall outcome and cleaning up all of the various connectors from the old ECM system I have a few manifold sensors to remove and plug and I need to finish my AC TO OBA conversion but other than that it's almost ready to roll.
The voltage meter also is not reading at the moment so I will have to trace that one down hopefully it wasn't somehow connected to the ECM but if all I lose out of this is a voltage meter I'm fairly comfortable with that I can always add an additional better gauge for that.

And I have determined there is truly no good way to run plug wires on an inline 6 engine as a matter what you do it kind of looks like a Rat's Nest hahaha

 

So I have the cause of the start on key turn release figured out. As it stands when I turn the key for start it kills power to the yellow switched wire that I ran to the distributor so on key turn no power is going to the distributor there is simply just enough RPM left from the starter that when I release the key and the power comes back to the distributor that it fires off most of the time.

I am running through my head various scenarios of wiring the distributor to get power during key turn but short of adding a secondary relay somewhere it seems that wiring the distributor to the key turn power would only backfeed to the starter once it was running. My old starter relay had additional posts that I am going to try to check and see if that was originally feeding the distributor during start and not allowing it to feedback to the solenoid while the engine is running.

Any thoughts would be greatly appreciated. being this close to the end of the tunnel is an encouraging Prospect

 

Did you have a switched power coming from the plug on the firewall in front of the driver going to the ignition module. Mine was red with a white stripe and about 10g. This is a switched power that stays on even when you crank. It is the one I used to feed the distributor. You've got to have one. It may not be the same color and it is probably the thickest wire going to the Module.

 

Well so i figured out the solution....just took a minute of quiet introspective....yah not really more of a "IM GONNA TAKE THIS THING TO THE DESERT AND BURN IT IF I DONT FIGURE THIS OUT" moment.
My old starter relay had an additional post marked BAL (i assume balast) . Which on key turn gives 12v from the battery post. So ill be putting my old relay back in and everything should be good inda hood.

Pics to follow

 

But you still need power going to distributor when you're cranking. Hooking your old relay up probably won't fix that. Did you read my last post?

 

Yes, Im investigating that situation now.

When i tested my old relay the post marked BAL got power on crank and lost it on switch. So if i cant find the wire youre talking about i think if i have the hei wired to switch for running and the relay for start it should work. It would be great to have just the one wire so fingers crossed that i can find it, but like ive said....RUNNING is my goal...even if its a little unorthodox.
Thankfully when it starts it is RUNNING very well.
Oh just thought of this too, whats your thought on gapping the plugs out? Im set at the OEM reqs...but everyone sais i should gap them wider now.

 

I would stick with OEM gapping. You haven't changed anything in the spark system itself. You are still cap rotor spark plugs etc. You haven't increased you spark voltage. Specifically you changed the location of the coil.

 

Ok, final outcome......

Went back to my original starter relay after not being able to locate a switched power that didnt die on crank. I simply had to splice a wire from the BAL post on the relay into the (yellow) switched power running to the HEI. EVERYTHING IS RIGHT AS RAIN NOW..
Went for a cruise and had no starting problems at all.
Seems the voltage gauge was just loose or something after reinstall , because it suddenly came to life after a few bumps.
So things are good in JEEP land , ill be posting a couple more photos once its 102% complete.

Next project ,,,finish the OBA conversion and installing the ARB LOCKER( that ive had for about a decade) in the rear....now that ill have air.....

 

Hey all I to got rid of most of the ECM junk and didn't happen to run into any of the issues discussed here. Installed the HEI as per OffGrids advice and it just worked right out of the gate, thank you sir for your advice and help with that!, but, theres always a but with a Jeep! Have a new issue and not actually related to Electrical but maybe you all can send me your thoughts on it. Installed a header and during the install had to plug the EGR connection between the exhaust and intake manifolds at the intake as the distance between the two with the header was greater than stock so being that most of the EGR stuff had been eliminated with the previous webber carb/ nutter by-pass I figured that wasn't a critical issue, so I eliminated it and plugged the opening in the intake. reinstalled everything and now the engine is running really rough and acts as though it is not getting fuel, have to pump the throttle linkage to keep it running. Fuel pump is fine filter fine, fuel lines fine. Do ya'll think that the elimination of that EGR pipe between the intake and exhaust manifolds would cause an issue like this? I'll be back at it in the AM to check timing, carb air/fuel mixture and pull some plugs to see how they look. Any insight into this issue that others have had with header installs and subsequent issues relating to same will be greatly appreciated!

 

Can you shoot me a few pics of your carb and intake and post for me. My cj is 10 years older and set up differently. Sounds like your sucking air from somewhere under the carb. This would make it feel lean. If it was the same as mine. The egr was mounted on the exhaust manifold (EM). The EM was bolted to the intake manifold (IM). The egr rerouted exhaust gases back to the a plate under the carb. Was yours set up like that? So you plugged that hole. On the bottom of the IM where the two bolted together I had to make a plate to bolt seal off the square hole left by the missing EM and I sealed it with high temp RTV.

My first thought can you remove the egr spacer plate and set the carb straight onto the IM.

 

I'll take some pics and post later this evenin so ya'll can see but no the EM was not "bolted" to the IM, they where connected to each other by a tube about .5 inch dia. I t ran from under the IM to the face of the EM just above the exhaust pipe connection. I plugged the hole with a screw in plug and also used red hi temp sealant. Another possible leak point is that the IM isn't flush with the block on the underside of the IM but it doesn't appear that way and the attaching bolts were torqued to factory specs of just over 20 ftlbs. Hopefully later today we will have figured it out, probably something simple were just not seeing as the motor ran fine before these most recent mods. Thanks for all your input and help it is much appreciated.

 

I had no problems after removing and plugging that connector tube. I did it while doing my gasket replacements.
So fsr i have noticed no more issues since my wrap up and a small tap on the guage brought my voltage gusge bsck to life.
I also finished my OBA conversion to my AC compressor ... so for the moment its time to just drive it for a while before the next project........ SYE AND REBUILT TRANS....

 

Worked on it for most of the day but got frustrated and have decided that since I'm only a shade tree mech and this issue is beyond my realm I will take it to this shop here in central Va they call the Jeep Doctor and have him sort it out. I do appreciate all the advice and help, but I think it's time to call in an expert! I'll keep y'all informed on what the doctor comes up with. He's done work on this Jeep before and he's good and prices are reasonable. Once it's running well I can finish the painting lighting upgrades and new seats, will also post a pic or two

 

Thanks for the quick reply! I will try it out and let you know. I am unsure of the wiring cause most of its gone, and I also have a question about the starter relay wiring. Should there be a wire from relay to starter? Also there is a push button starter of that has any effect... thanx again, this forum is awesome, and if I ever get out from under the hood I'll be sure to get more in depth with it!

 

Your welcome. This thread also goes into some starter relay wiring too.

 

Just a quick question to OffGrid or JTHM71 when we were talking about ECM removal did JTHM71 take out and eliminate both the ECM located on the driver side wheel well under the radiator reservoir and washer tanks and the MCU located under the dash on the passenger side, or was only one eliminated? The pics posted showed the MCU removed but didn't actually show the ECM removed. I'm currently in the process of trying to take my 89 YJ totally old school but am concerned that the ECM may have some kind of voltage regulator in it that prevents the alt from putting to much amps thru the ignition circuit thus the question of did he eliminate the ECM and the MCU. It sounds like he did from re reading thru the threads but just want to be sure. Any and all help and assistance would be greatly appreciated!