JeepGuy61

So I picked up an 89 XJ last week. Has a long Crank issue I'm having trouble diagnosing. Sometimes will Crank no start. Has new plugs, wires, cap and rotor. Also checked fuel pressure its within spec and injectors are good. Getting good spark from coil so I'm running out of ideas on what to check. Any help would be much appreciated.

cruiser54

It's common to the system to crank longer than you're used to.

Your CPS may be weak causing the "crank-no start".

Here's how to test it.
also, go to www.cruiser54.com and complete Tips 1,3,4, and 5.



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 itself as shown in Figure 2 as Connector A, 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 the upper mounting hole to 3/8″ from the stock 5/16″, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

Another little tip to save tons of aggravation is to stick a bit of electrical tape to your 11mm socket and then shove the bolt in after it. This reduces the chances of dropping that special bolt into the bell housing.

JeepGuy61

Thanks for the information I'll give that a shot

cruiser54

Keep us in the loop.

JeepGuy61

Thanks for the advice not sure what the actual problem was did a good tune up cleaned some sensors seems to be running fine now

cruiser54

That's what we like to hear!!!

JeepGuy61

Hello all. So the long Crank problem started happening again today only this time after about a mile of driving the jeep stalled on me at a red light. If I keep on the throttle it will stay running no problems. I put a new Crank sensor in it. Did not fix the problem so I got another one put that in still happening. It's got a fresh tune up plugs, wires, cap, rotor all new. I also fixed the battery ground it was bad at the block. I'm kind of figuring it's a fuel issue at this point. I'm wondering if the fuel pump is weak or if the injectors are bad. I have good pressure at the fuel rail currently. Until I have time to do some more testing and diagnostics I'm at a bit of a loss. Any input would be greatly appreciated. Thank you

BillyBoy

Cruiser, you are a god.

BillyBoy

Really, I should be sending you money every time you save my jeep.

cruiser54

There is a donation button on my website.......LOL

cruiser54

Check the intake manifold bolts to see if they are loose.
Check where the tube from the throttle body to MAP sensor fits in the throttle body and if the tube itself has any cracks.

JeepGuy61

Thanks for the advice hopefully I have a chance to look at it after work today.

Jeepwalker

I've had the same problem. Vehicle is warmed up and driven, shut it off ....won't start. Only occurs once, twice, maybe 3x a year, usually in the winter. Sometimes it just won't start. I let it sit for maybe 10-15 minutes, go get a coffee or whatever, come out and boom, takes off like normal. I kick myself, I had the intake manifold off this summer, literally looking at the CPS and DIDN'T replace it (what a dope I am!!). I'd forgotten about the long-start problem till you raised it. I'll check the connectors and voltage when I get it running here again soon.

Let us know what you find out.

cruiser54

Next time it happens, unplug the CPS and plug it back in. see if it starts.

Jeepwalker

Good idea. Thanks for the tip!