Jeep stopped running, now long hard crank

Folks-

It's a 97 SE, 4.0, AW4.

I'm driving to work today, and without any reason whatsoever, as I was about to make the turn into the last leg into our industrial park, the truck just shut off.

Luckily I was able to avoid getting t-boned by crossing traffic.

Attempt to restart resulted in long crank cycle and no refire. Kept trying this with an occasional stumble like the truck was going to refire. White "smoke" out the tailpipe. Presumably this was raw gas hitting the catcon and clouding out (hey, my truck has a milspec smoke generator!).

Kept trying, after about 5 minutes the truck refired, but only with me giving it some gas and grinding away at the starter. Once that happened, it stumbled a little, then finally caught.

Pulled into work, now the truck has long crank cycles and will not catch and run unless I give it some gas (this shouldn't be required of an EFI vehicle).

Thoughts as to what the issue might be? I'm kind of thinking maybe a fuel pump issue.

Im more familiar with the early HO XJ but for those symptoms I'd look at Throttle position sensor, oxygen sensor, crank position sensor, and fuel pump
Fuel pump you can test with a fuel pressure tester, there's a valve to attach it on the fuel rail. Easy to test, I'm not sure the exact pressure for 97 up but it ought to be somewhere in 40-50 psi range.

CPS can cause all kinds of trouble cranking and running, it's a very common problem but I thought it would keep the injectors from firing and coil from sparking, this may be over simplified.

On the 91-95 XJ a bad O2 sensor could cause all kinds of problems like this, used to be able to test it by disconnecting the sensor not sure if this works on the 96 up OBD II jeeps.

I've heard of bad TPS when the throttle had to be opened for the engine to run.

Just a few groggy first impressions.

BTW White smoke makes me think headgasket, blue is oil, black is fuel and white is coolant.
But blowing the headgasket on these engines is not easy so if it smelled like fuel that probably what it was.


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By pushing the throttle pedal you aren't necessarily giving it gas. One likely scenario is by giving it a little pedal you are giving it air. If the IAC sticks shut it will stall every time you release the throttle pedal.

Too much fuel and not enough air may be your issue? A quick look at your air filter is also wise, packed with dust or wet or both (mud).

Sometimes cleaning the iAC helps.

Sometimes low voltage is the issue. A sticky IAC may get really sticky if you have a battery or charging problem. I've had my IAC mess up a few times weeks before I finally noticed a charging or battery problem.

May be something else but the IAC is worth a look.

Th easiest way to check is to get a spray can of carb cleaner, with a nozzle tube firmly attached to the noozle so you don't loose it down the TB. And spray some carb cleaner into the IAC opening with the motor running and working the throttle by hand. Brake cleaner, quick start or even spray oil will also work, carb cleaner works better. I almost lost the nozzle extension down the TB the first time I tried this, learn from my screw up. Doing this usually loosens up the worst of the sticky stuff.

Thanks Green-

I agree, there is "no such thing as white smoke"... but this did smell like fuel.

On refire, there was no smoke.

I can get the truck to run if I grind away at it for probably 3 times the normal length of crank time, with the gas pushed about halfway down. Once it catches, let off and it runs fine and gives every indication it will for a long time (this just happened and I'm at work so I haven't had an opportunity to verify that yet, other than to go to the parking lot and turn it off and restart).

Immediately on shutdown, I will try to refire and get the same as above. Since I know how to get it to refire now, and am not repeatedly grdinging away at it, there is no longer any white smoke.

Really do believe the white smoke was just raw fuel vaporizing.

I have had the vehicle for about 3 months and have been driving it in preparation for giving it to my 17 year old son (slingshot505 on this board, I think- he'll be along shortly). I got an occasional long crank and had been planning on replacing the fuel pump at some point. This also seems to be pointing in that direction so I will likely go ahead and expedite it.

Of course you know this has to happen when I just filled the fuel tank. Murphy is a sumbitch.

I am going to go out at lunch and see if the "turn the key on, wait for fuel pump to shut off, do it again three times" bit to see if the truck refires without issue afterward. I don't believe this is the usual "bad check valve" issue on these fuel pumps, although that has been an issue in the past when the weather was cooler. I say this because I can literally get the truck to run, shut it down, immediately try to refire and I have the same symptom again. There is no way the fuel rail/hoses loose pressure that quickly.

8Mud said:

By pushing the throttle pedal you aren't necessarily giving it gas. One likely scenario is by giving it a little pedal you are giving it air. If the IAC sticks shut it will stall every time you release the throttle pedal.

Click to expand...

Concur. Once I refire I let off the gas and it runs just fine at idle.

Too much fuel and not enough air may be your issue? A quick look at your air filter is also wise, packed with dust or wet or both (mud).

Click to expand...

Filter is brand new, maybe 2 months old, and truck has not been more than down a wet dirt road. The filter looks clean (it's a cone type, will go ahead and clean/retreat it

Sometimes cleaning the iAC helps.

Click to expand...

Will check that out tonight

Sometimes low voltage is the issue. A sticky IAC may get really sticky if you have a battery or charging problem. I've had my IAC mess up a few times weeks before I finally noticed a charging or battery problem.

Click to expand...

I do need new battery terminals. The ones on there are loose.

Th easiest way to check is to get a spray can of carb cleaner, with a nozzle tube firmly attached to the noozle so you don't loose it down the TB. And spray some carb cleaner into the IAC opening with the motor running and working the throttle by hand. Brake cleaner, quick start or even spray oil will also work, carb cleaner works better. I almost lost the nozzle extension down the TB the first time I tried this, learn from my screw up. Doing this usually loosens up the worst of the sticky stuff.

Click to expand...

This is for cleaning the IAC? I will do this at lunch.

Went to lunch, did the wait to start and prime the engine three times trick.

Truck cranked right up... AH-HAH, I says...

Went to the Advanced and put new battery terminals on (not so much because I thought they were causative of this issue, but because they were very loose and in poor condition- and yes, could contribute.

New terminals on and tight, same issue occurs.

I'm 99.8% sure it's the fuel pump now. Got a Delphi fuel pump module on sale at Autozone for $165 all up. Not crazy about spending the money, but it needs to be done, and I still don't have a car payment.

One more thing soon to be scratched off the list so I can hand this over to my son....