i checked the sensor it checked good but the connector was dirty i cleaned it out... lets see what tha does... it was 20 degrees here today 2..

 

Here's a coupla things I like to do with any "new to me" or friend's Renix Jeeps:

Renix Jeep ICU/Coil contact refreshing
　
　
The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.
The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner.
Squeeze the springy contacts closer together with some needlenose pliers. Apply some dielectric grease to the contacts and bolt the coil back on to the ICU.
While you’re right there unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier. Apply dielectric grease to the connectors and plug them back in.
I feel this procedure should be performed at least once in the lifetime of a Renix Jeep.
　
Revised 11-29-2011
I suggest unplugging every connection in the engine bay you can find, spraying it out with a good electronics cleaner, visually inspecting the terminals, and adding dielectric grease before plugging it back together.
All of the relays should be removed, the terminals wire-brushed until shiny, and the receptacles sprayed out with contact cleaner. Then dielectric grease should be added before plugging them back in. I do this on every Renix era Jeep I purchase or work on for someone else.

 

i check this has been done already they all have grease in them...

 

all the relays i checked are still shiney inside under the dl grease..

 

Consider all that stuff as maintenance and improving a minimally designed system.

Just takes a bit of time and then you know what ISN'T causing your problem. You will reap the benefits for years to come.

I'm intersted in what progress is made with each step. Do one thing, ie ground refreshing, then ICU/Coil stuff and report back.

 

That's unusual!!!

 

My Dad worked for Jeep during this time period until about 2008 or so when he got sick.... and he only like Renix era Jeeps... This was his Jeep before he passed so i am not that surprised for the 20 years we have had it.. this is the 1st time it has done something like this... to my knowledge.. I wish i could have pick his brian about it... but now I am learning from you thank you..

 

I'll bet he cleaned the relays then. Cuz I never find them clean.

Do the other stuff first as a preventative maintenance thing just so we know it's been done and is not an issue. That stuff was supeer important on all the Jeeps we worked on in Arizona so I can't imagine how much more important it is to you guys who live in areas of the country where rust and corrossion are a big issue.

 

My flex plate has 4 cut outs some have 3. The slots have nothing to do with the cylinders in their relationship to one anyother. Thnk of it as a timing strobe light. Everytime the CPS detects the break in the magnetic field, the slot in the flex plate, a signal is sent to the ECU. The more signals that are sent to the ECU, the more accurate the information regarding engine timing. They could have done this with as littla as 3 slots on the flex plate, but 3 is better that 2, and 4 is better than 3 and so on. Todays car's have a minimun of 8 slots on the flex plate. But the only two that really matter are the slots that determine TDC on the flex plate & CPS and distributor & CKS aka Cam position sensor.

 

Have you read the renix efi manual?

 

The ecu uses the input for ignition timing and fuel injection. And four doesn't make sense, its not a v8...divisibility. The manual even shows three notches. 12 teeth after a notch is tdc for a pair of cylinders. It's a speed and timing value...

 

CKP is the crank position sensor, commonly known as the CPS.


https://www.cherokeeforum.com/f51/he...ix-links-1397/

http://www.jeep4x4center.com/knowledge-base/index.htm

http://www.greatlakesxj.com/tech.html

 

BAM! So much...information...at once...my head is....going to burst! Get a drill...please...while I still have time...

 

Norsk, yours is HO. Ours are Renix. Different flywheel/flexplates.

Anyway, with Renix you need at least .5 volts AC to have a good signal to the ECU.

 

< (I wonder why they put those there for us to use, then move them around so it's hard to find what you want?)

Rooster, just in case it wasn't made clear somewhere....A Renix Jeep ALWAYS cranks a few seconds. It's the "nature of the beast". Two, three or four seconds. Unlike say, with points, the ECU needs a second to make sense of the sensor inputs before there is spark.

Not sure but it seems to me 2 revs. does it. Bigger-better starter, cables, and battery speeds THAT up.