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Weird Random NO Start_usuals have been tried NEED advice!

ItZaJeePThiNG

NAXJA Forum User
Location
Pennsylvania
I have a 90XJ and I'm randomly getting a no start no spark from the coil.

the CPS is almost two years old. the cap, rotor, plugs, wires, ICM, coil, battery, battery wires, terminals are NEW.

I dont know if the temp. is making a difference but i cannot solve this problem since it happens randomly and all the searches i've been doing are related to the cps/ half of those posts they say that didnt fix the problem.

I replaced the cps on top of the bell housing a couple years ago which actually was the problem back then however it was because the manifold burned it and the wires melted, I now have it wire tied so it cannot happen again.

can someone list everything that can cause the no spark condition from the coil.
i have replaced the coil 3 times, and the ICM twice. probably never needed to do so but since its is random and it solved the problem then it was replaced.
 
ItZaJeePThiNG said:
I have a 90XJ and I'm randomly getting a no start no spark from the coil.

the CPS is almost two years old. the cap, rotor, plugs, wires, ICM, coil, battery, battery wires, terminals are NEW.

I dont know if the temp. is making a difference but i cannot solve this problem since it happens randomly and all the searches i've been doing are related to the cps/ half of those posts they say that didnt fix the problem.

I replaced the cps on top of the bell housing a couple years ago which actually was the problem back then however it was because the manifold burned it and the wires melted, I now have it wire tied so it cannot happen again.

can someone list everything that can cause the no spark condition from the coil.
i have replaced the coil 3 times, and the ICM twice. probably never needed to do so but since its is random and it solved the problem then it was replaced.
http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm
Start testing sensors. It's fairly easy with most Renix problems to diagnose with a voltmeter.
 
88 Wagonman, Thanks for the info. I'm going to check the cps sensor with my meter now, aside from the camshaft position sensor(which was not mentioned in that link) i checked the other sensors yesterday when the jeep did run and basically just pulled & cleaned thoses sensors.

The TPS and IAC i pulled before and during cranking and both acted exactly how they were supposed to. when re-connected after idling they brought the idle back down.
The EGR valve is brand new since was broken a couple months back and failed state EM.

how and what is the correct way to test the cam sensor in the dissy? I pulled the cap and rotor yesterday and checked for excessive carbon-none. i took the two 8mm bolts that held down some metal plate off and thought the sensor would come out, it does not. The Haynes manual states the entire dissy needs removed. true of false and is this really worth doing?
 
CPS sensor was reading 1 million plus on meter! new part was reading 222 ohms. took a long fkng time to replace(for the second time!) and would have went a little smoother if the one bolt and washer didnt fall into the transmission!
Next time if i ever have to do this im cutting the hole on the sensor and making a half moon so the bolts would then only need un screwed a little bit then the sensor could slide right out.
I cant believ this new/old sensor i had in their was bad

The jeep is lives again!
 
The cam position sensor in the dizzy won't cause a no spark condition, without it the ECM will guess which half of the rotation it is on. When it does this it will either run fine or run horrible, but should still run.
 
Dead cam pos sensor will not cause a no start, only causes a sloooow start.

Dizzy must be pulled to replace. It controls fuel injection timing, not A/F ratio but the when to initiate opening the injector timing.
 
88 Wagonman said:
The cam position sensor in the dizzy won't cause a no spark condition, without it the ECM will guess which half of the rotation it is on. When it does this it will either run fine or run horrible, but should still run.

Somebody was recently pulling their hair out here with that exact start up problem. Ran fine on start up, then ran like sh*t the next start up, totally random!!!!!!
 
Is it normal for the 90 xj or even the renix engine itself to have a long crank-to-start time?
I do the usual prime the fuel pump a few seconds berfore starting but there is a significant delay, as if all 6 cylinders need to compress first or so there is adequate oil pressure built up first before firing.

My brother just got out of the Marine Corp and I let him drive this jeep after we fixed the no start CPS, and when he went to start it he almost let out the key early, i just had to tell him keep cranking it needs to build up oil pressure first! Is this true?
my 94 xj starts up very fast almost on the first stroke.
 
ItZaJeePThiNG said:
Is it normal for the 90 xj or even the renix engine itself to have a long crank-to-start time?
I do the usual prime the fuel pump a few seconds berfore starting but there is a significant delay, as if all 6 cylinders need to compress first or so there is adequate oil pressure built up first before firing.

My brother just got out of the Marine Corp and I let him drive this jeep after we fixed the no start CPS, and when he went to start it he almost let out the key early, i just had to tell him keep cranking it needs to build up oil pressure first! Is this true?
my 94 xj starts up very fast almost on the first stroke.

Renix is always slow to start. It also needs a good battery voltage and good starter to reach a critical minimum cranking speed for the ECU to let it start at all, IIRC (per 5-90).
 
I don't know if the older models have this but i was having a VERY similar problem. I didn't replace the CPM but did replace the cap, rotor & coil as they were in rough shape and still had the problem.

Some poking around proved that the ASD (Automatic Shut Down, whatever that is) relay was bad. Replaced the 5.00 relay and problem went away.
 
ok let's see if my answer helps you out. As mentioned in numerous threads the #1 culprit of a crank no start on a renix XJ is a bad CPS. I was having the same issue with my 89 for quite some time. Start up bitchin for a couple of months then crank, crank, crank, nothing. I would pop the hood & wiggle the cps connector & voala good for another couple months. I recently found a chrysler tsb (Jeep reference J007 I believe). It involves replacing the CPS & installing a patch harness which is a shorter direct link to the 32 pin connector.
I recently performed this ordeal in my back yard on 08/23/08. It also states to make sure that the ECM/TCM grounds are clean & tight (oil dipstick tube area). I recommend this repair to any renix jeep owner if it hasn't already been performed. Also the OEM sensor is made by siemens & is made in France just like the Bendix ECU. It has what appears to be 18 ga wiring as opposed to many aftermarket sensors having really thin gauge (22?) wiring. I also wanted to add that the if your sync sensor in the distributor goes bad you will experience abnormally long cranking times because the ECU doesn't know the positions of the #1 or #6 cylinders used to synchronize fuel injection timing. So it gang or batch fires three injecors at a time until the engine runs. Mine went bad cracking where the vane passes through the hall-effect device. Standard part #LX234 I believe. Hope this helps anyone out there with renix starting problems.
 
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