Political_Man

I have a 1986 Jeep CJ-7 with a 4.0 l6 from a 1996 Jeep Grand Cherokee. I posted in the Tech forum about another problem before but the response was so-so.

Long story short, I'm still learning to work on cars. I've fixed a few problems here and there but I've got a problem that is a little over my head. Basically I had a problem with the fan control unit. The circuit board was getting so hot that that the solder connections were coming loose. I ordered a new one and followed the instructions EXACTLY for for connecting it. It worked properly for about 15 minutes. I put away my tools as I was testing. After a little bit the fan wouldn't shut off. I tried turning the engine off, got out my test light, then turned on the engine again. Turned off the engine and then the engine wouldn't start up again. It turns over but won't start.

Here is what I've done. I've replaced the ignition switch (it was only $10 at Advance Auto.) No dice. I got my test light out and tested all the fuses, all good. I pulled the cable off the coil and tested the positive side. Good. I pulled the cable off that goes the the distributor put a nail in between the rubber and metal connector and turned it over and tested it against a ground. No spark. (hopefully I tested it right) The coil was replaced a couple of months ago.... Another thing... I can't hear the fuel pump click on like normal either.

I was wondering if

a) if anyone had an suggestions from here and

b) if someone wanted to come over for a few beers and help me work on (and teach me a few things) and maybe earn a few bucks...

Puto

Did you disconnect the neg batt terminal prior to starting this? If not try that now.

Sneakin Deacon

well, if its not firing its not getting fuel or spark...put a test light on the plug wire and see if its hitting, and then make sure the timing is right. if that doesnt work make sure you have fuel pressure. im not firmiliar with jeeps so i dont know if the fan control is integrated to the ECU or what. there is no reason for a board to get so hot that connections unsolder themselves

Road Rage

id take it to Besco, sounds like you have an electrical problem...

power2weight

I'd buy a cheap digital voltmeter (seriously the $3 one I have from Harbor Freight is still working while the $70 one from radio shack has bit the dust (and no radio shack dude, a sample rate of 1HZ does not mean it can work as an oscilloscope)).

You should be able to put a screw driver near the coil with the coil to dizzy wire off and see if it throws a spark. Then test the coil leads and see if there is 12V across it.


Since you cannot also hear your fuel pump prime it sounds like the relay that controlls the ECU is probably shot.

Can you probe your TPS sensor and see if that has powered?

I have a sneaking suspicion that your ECU isn't powered.

SmokinS13SR20

Check the main fuses/realys that are usually located under the hood, I agree with P2W, sounds like the ecu is powered.

Political_Man

I will buy a voltmeter tomorrow. As I said before I am still learning so I don't know that I totally understand what you are saying but I will give it a shot. The offer is still up for anyone who wants to drink some beer and earn $ to show me what the hell I'm doing...

Thanks for all the suggests so far...

P057

Try not letting your jeep roll into lakes.


Preventative maintenance is the best kind of maintenance.

Graves

Political_Man

No more lakes for me.

Just for the record, the problem with the fan control unit was happening before that little episode. In fact, the person who owned it before me said he soldered those connections together more than a few times himself. Something obviously happened when I hooked up the fan control unit. A lot of this stuff is custom and I'm not even sure how well this control unit integrates with the ignition system. I also noticed the control unit had some differences than the one that was originally in there, with everything being custom, who knows. Once I get the thing started again, I'm going to rethink the whole fan control piece. I know something was going with it because when the fan was hooked up I was getting some feedback and it would take a couple of seconds after turning the key for the jeep to shut down. With the fan disconnected, everything ran fine. I was hoping the new fan control unit was going to fix everything but obviously it did more damage than help.