thenewbigmack

Hey guys, first post on the forum, looking for some help. Fiancés Jeep had issues occasionally stalling at stops or around corners. Also, when starting the car cold, her guages sometimes wouldn't turn on until she flicked her blinker on. She took the car in before I could look at it, and the mechanic told her he reset the idle and cleaned the throttle body.

Fast forward to a few days later... Car won't start. Started a few times, but ran horrible and couldn't hold RPMs without dieing. In between the car not starting and the mechanic looking at it, we replaced a blown water pump, but that was it. Checked for fuel at the rail as well as fuel on the spark plugs, all good. Checked for spark at the plugs, white spark easily seen in the daylight. Not sure where to go from here. Spraying carb cleaner in the intake doesn't start her up either.

Ruling out a fuel issue for now as well as a spark issue unless someone on here feels otherwise. Ruling out crank sensor due to the car getting spark. As far as I know, the idle should never be touched on these cars via a CPU, so could the mechanic have damaged something in the process or have straight up screwed her over figuring she wouldn't know any better?

Any help is much appreciated!

thenewbigmack

Morning BUMP... Hoping to get a few suggestions if possible. Its a daily, and making commuting difficult. Thanks in advance!

rangermonroe

It may sound stupid and unlikely, but take both battery terminals loose and clean both the posts and the ends very well.

My 99 GC went haywire like you are describing and it turned out that there was a slight "film" of corrosion on the inside of my positive terminal.

A couple minutes with 80 grit sandpaper and it was back to normal.

thenewbigmack

Much appreciated! I'm up for anything. I'll let you know

Edit: Now that I think about it... Tried to jump the vehicle earlier with no luck. I can rule out the connections. Thanks for the suggestion though.

DebbiD

HAve a 97 Cherokee 4.0 , experienced same non start, but wouldn't crank. My son replaced the crankshaft position scensor.That was a couple months ago. All is good. Not sure if this would apply to a 5.2. I am ar from a mechanic, but am a long time Cherokee owner.

thenewbigmack

Alright guys... still no start and it's getting quite irritating. Installed new coil, cap, rotor, plugs, and wires. Need to get a fuel pressure test done and a compression test, but besides that, what's left that could be wrong. If the crank sensor was bad, I wouldn't be getting spark correct? I suppose it could be the cam sensor, but not sure how to test for that as no codes are being thrown. Engine cranks, so it's not a timing chain, or seized motor. Any help is much appreciated! Mechanic who worked on the car before it stopped running said he "relearned the idle", which makes no since given the car was having issues in the first place with stalling at stops. That's a band aid, not a fix. Could he have screwed us over here hoping to get some extra cash?

czettlera

Hi when you checked the spark, did you removed all the plugs at the same time, or just one by one. The reason why I'm asking is that if all the plugs were removed and the engine had no real compression, the power consumption of the starter is much lower. If you have a bad contact and a higher resistance for example at the battery terminals (or somewhere else at a grounding point or the PCM supply) and the voltage drops, it could cause no spark under load. I only have this feeling as you said that engine haven't started when you sprayed directly in the intake. Normally if you have proper spark it should. Maybe you could check the battery voltage during cranking.

thenewbigmack

Thanks for the reply! When originally checking spark on the old plugs, I went one by one. When I checked for spark on the new plugs, I just checked one and it was a nice bright blue spark. We actually checked voltage during cranking last night, and it definitely dropped off quickly. However, won't the battery drain rather quickly anyways when the engine won't turn over? You are correct, engine did not start when carb cleaner was sprayed directly into the intake. If it had started, wouldn't that be a fuel issue rather than a spark issue?

czettlera

How deep had the voltage dropped? Reading that you changed almost everything in the ignition system, and you have fine spark, I'm not convinced that it's not a fuel issue, though it haven't started when you sprayed in the intake. You should give an other try, maybe the amount was not enough, or the material wasn't good. As for myself in the same situation with my car I used gas though you have to be careful with it. Fuel pressure should be checked definitely, but it's only the rail pressure, that doesn't mean that the pcm controls the injectors and open them. If the fuel pressure is OK, you could remove the injectors and watch them spray. But anyway if it has spark, somehow it has to start even with a few cylinders, if you get fuel in the intake.

thenewbigmack

Thanks again. When I get home, I'll charge up the battery and try to get her started up with some starting fluid or gasoline. I'll also get a reading on the battery as I'm turning it over. If the voltage drops too quickly while cranking, what could that be a sign of?

thenewbigmack

BUMP... still no luck with getting her started. No codes are being thrown either.

czettlera

If it's no sign of the will of starting with gas in the intake, than we are back again to the ignition. It's OK that you have spark, but by any chance haven't the spark cables been mixed? I can't think of anything else, because if it has compression, spark and fuel in the intake, than it should definitely do something. Sorry I haven't got any other ideas.