darknezz

So I Have had My jeep for 2 years now and before the last few months it has done this only a few times. Once after a long freeway trip then stop and go traffic and once on a very hot summer day stop and go stuff.

What happens is it will stall while sitting/idling, then maybe try to start but just rev up to 3k then die out or just crank forever and not start at all. Wait 5 mins and it starts but runs loud with almost backfiery noises for a few secs, i have no exhaust though so its loud anyway, then its all good again while driving.

In the last few months its been doing it every few times I go out now and just getting worse, depends on how much I drive and how much stop and go, its also taking more and more sitting time.

It has ALWAYS taken (i think) an abnormally long time cranking to start after its warmed up, remember its a renix though.

So where to start before my jeep wont start at all one day.

I keep my intake and all the parts real clean and did spark, cap/rotor, fuel filter and other stuff not to long ago.

My thoughts are, in order, CKP, ECM, fuel pump, some relay/resistor. Being on the road when it always happens I haven't had a chance to see if its a no spark or no fuel situation. Maybe my engines just had enough and losing compression :S

Thanks for the help!

ol'DixieJeep

try your crank position sensor. then try a tune up. distributor CPS and plugs and wires.

UJSLOST

Check fuel pressure when this is occurring if possible. Im having a similar issue but I know what whats causing mine. I have rust in my fuel tank and when the fuel is low the "sock" is getting saturated with rust particles and runs like hell. When I add fuel it "washes" the sock off and runs fine.

darknezz

I Can test the ohms of the ckp right? i dont want to buy one if its not bad, but Ive been thinkin it might need one for awhile, and i said its all tuned up.

Yea next time it happens ill check at the rail if theres pressure, it doesnt seem to matter how full my tank is though. the seal around the tank is leaking so i need to get in there anway though, and its prolly rusty.

ol'DixieJeep

when this happened to me it ended up being my cam position sensor. i have one where the distributor normally would be. (coil pack engine) if you have a distrubutor then its inside of there.

glad i got a plastic tank... lol

darknezz

yea, thats the first thing i was saying (ckp is the right abbreviation for the crank position sensor)

mine is at the bellhousing between the engine and trans right?

uhgg i like when theyre on the front crank shaft pully

what should it measure?

ol'DixieJeep

i dunno. i had a spare so i swapped em lol.

but add cps to your list... i had this happen twice due to the cps and not CKP but still both are viable reasons.

UJSLOST

This is what I used to check OHMS on mine and found it to be bad.

http://www.lunghd.com/Tech_Articles/...iagnostics.htm

darknezz

oh i didnt see u said CAM, alot of ppl call the crank position sensor cps.

does my renix even have a cps?

UJSLOST thanks for the link! looks like great info ill go over it

ol'DixieJeep

yes i believe its in the distributor... anyone else confirm?

ZINGGG

My cam position sensor is in my distributor (right underneath the cap) in my 96. I'm not sure about the renix though. Get in there and take a look. Look for a wire that comes out of the middle of the distributor

ol'DixieJeep

if not then it could be your distributor...

cruiser54

This is how you test a Renix CPS:

Renix CPS Testing and Adjusting
　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
　
Revised 11-29-2011

　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
　
Revised 11-29-2011

cruiser54

Renix has no Cam Position Sensor. It has a sync generator in the distributor. You can unplug the dizzy and it will still run, the injectors will not fire sequentially. Not an issue here. Test the CPS using the voltage method, not the ohms test.

darknezz

the site UJSLOST posted has all the right terms and info but thanks cruiser54 . and thats the ckp once again miss naming

im def gonna replace it, sounds like whats causing my problems