Jeep starting problems

[CFMopar]

Hey guys question about my 96 xj 4.0L 5spd

Sometimes its hard to start. It wont go unless i hold down the gas while cranking it. Monday i was getting out of "PARKING SPACE" in some snow and it stalled. I took almost 10 tries of cranking it over to get it started again. It would sputter and die and never get over 1000 rpms. probably 3-500 rpms and then die

Today It would rev up to 1500-2000 rpms in netural sometimes and I still need to hold the gas to kick it over..

I've tried some fuel injector cleaner.. Gonna do the plugs tomorrow... Anything else? Could it be the TPS?
Any input?
Thanks
Vic

[Back N Black]

Fuel Filter?

[NMike]

it sounds like a fuel or idle circuit problem

if there is no check engine light, then there is no sensor acting up, except maybe the crank.

you may have a fuel pressure problem. not enough will actually cause the engine to seem flooded. a weak fuel pump or maybe ice in the fuel system could do this.

could also be the idle air motor. if it is very dirty or inoperative will give the same symtoms you described.

[NMike]

also check the output from your auto-shutdown/fuel pump relays. an old relay might supply nbot enough power to the fuel and ignition systems

[CFMopar]

You dont happen to know where thoughs relays are and how do i check them? Im not very good with electircal stuff 

[CFMopar]

Gonna try fuel filter tomorrow checked the plugs and wires there ok

[NMike]

the relays are in the relay box by the battery. (on the Passenger side) when you open the lid, the inside will have a disciption about which relay is what. the relays are all the same. just swap the fuel pump one with the a/c relay. then swap the ASD relay with the starter relay.

[SeattleCharger]

if not any of those things, what about a fuel injector relay?

[NMike]

that would be the ASD (auto shut-down) relay. also powers the ignition and charging systems

[CFMopar]

I changed the fuel filter.. Seems a bit better on start up but now i noticed rpms seem to go up to 1500 at idle in netural after it warms up a bit...

[NMike]

which end of canada you in?

[CFMopar]

Ontario

[CFMopar]

swapped the relays no help...

[firefighter3931]

Vic, it's either a weak fuel delivery problem or weak ignition. Pull a plug wire and crank it over while looking at the spark....if you see a dull orange arc the ignition system is weak. How does the cap & rotor look ?



Ron

[Plumcrazy]

Chrysler had some problems with the Jeep fuel pumps in 95-97.  They would cause the problems you have described.  If you don't find any problems with the ignition system, it's probably the fuel pump.  Chrysler released a new and improved fuel pump module to fix the problem. It's P/N 4798941.  If you do replace the pump, make sure the gas tank is cleaned out also. 

[CFMopar]

would either of those problems cause a random increased idle and run on sometimes?

[firefighter3931]

would either of those problems cause a random increased idle and run on sometimes?

Not likely.....try throwing some gas line anti freeze in there. You might have some water in your fuel. Winter-grade gas also sucks !

The fuel pumps are a known issue. 



Ron

[CFMopar]

Ok so maybe the run on is bad gas...

Just to better describe the issue... If the heep has been sitting for a while it will start no problem.. If its been running for a bit and i try to start it I gotta keep my foot on the accelerator....

I'll look at my rotor and cap tomorrow if i get the chance between work. If its not that its more than likely the fuel pump... right?

[firefighter3931]

Ok so maybe the run on is bad gas...

Just to better describe the issue... If the heep has been sitting for a while it will start no problem.. If its been running for a bit and i try to start it I gotta keep my foot on the accelerator....

I'll look at my rotor and cap tomorrow if i get the chance between work. If its not that its more than likely the fuel pump... right?

Usually, when the fuel pump is on it's way out the the engine will begin to run rough. Yours seems to run fine when it's been sitting for awhile but has hot starting problems which would indicate the pump is not the problem. It almost sounds like vapor lock from what you're describing.

Check the cap and rotor...and also see what color the spark is when you ground out the ignition sysytem. Dull orange spark is weak. It could also be the coil on it's way out....defective coils usually act funny when they get hot. 


Throw some gas line anti freeze in there and a few gallons of high test fuel. 



Ron

[andy74]

check the exhaust also, we had some that the cat was plugged that acted like that too, i usually drill a hole in the pipe ahead of the convertor,if it acts better then weld the hole shut and move on

[firefighter3931]

check the exhaust also, we had some that the cat was plugged that acted like that too, i usually drill a hole in the pipe ahead of the convertor,if it acts better then weld the hole shut and move on

Yep....excellent point Andy ! 

There was a huge recall on Jeep & Ram catalytic converters....my 96 5.2 L 1500 cat was junk and had to be replaced. This recall covered the 96-99 model years and thousands of vehicles.


Worth looking into 



Ron

[CFMopar]

Its a new cat... replaced it a few months ago...

[CFMopar]

So i finally get around to changing the cap and rotor today and of course nothing can go easy.... One of the bloody bolts breaks off on the rotor... (why couldn't they just use clips like in the charger i don't know.... SO then i go to drill it out and use a screw extractor.... As im drilling im thinking this just might work... But of course i get ahead of myself cause when i try the extractor it breaks off in the bolt... SO now i got a broken hardened extractor in the hole which cant be drilled out.. So looks like i gotta replace my distributor now too..

For once it would be nice if things just worked with no problems...

[Back N Black]

A friend of mine had a 1990 jeep that had spark issues and he replaced the distributor with a HEI type out of a 6 cylinder GM. it worked great.

[NMike]

his distributor is more a cam sensor. the ignition is controlled by the PCM.

an to thin k i just tossed a whole load of jeep parts a couple months back. at least i got $120 in scrap metal for it...

[CFMopar]

Just a question with reinstalling the distributor... I got the old one out now and marked where the rotor was pointing so that im not a 180 degs off.. When i drop the new one in it should be pretty close to the proper timing if not bang on right?

[NMike]

the timing is a calculation from the crank sensor. the cam sensor (distributor) just tells the PCM which cylinder at TDC is on the power stroke or overlap stroke. it can be out alot and the PCM would still fire the cylinder at the right time.

like a grenade, close is good enough.

[CFMopar]

I cant get it to fire up now. I've set it tdc set the rotor to the num1 plug and and cranked it. It turns and just before it fire it stops

[NMike]

well the most important signal the PCM needs is the crank sensor. all the distributor is , is an ON-OFF signal for the PCM. if you have access to a scan tool, you could look up the "SYNC STATE". that is the timing between the crank and cam sensors. it is either good or not in the PCM's eyes.

is there fuel pressure while you are cranking? spark?

[Back N Black]

Are you TDC on the Compression stroke or the exhaust stroke? If your on the exhaust stroke it will be 180 degrees out and it will backfire.

[CFMopar]

I fliped it 180 to make sure I wasent out... I put my finger over the #1 hole and cranked it until it pushed it off then turned the crank with a ratchet until it lined up on the marker. So it should be compression stroke side.

[CFMopar]

I shifted all the wires over counter clockwise and it ran but ran rough... does it mean my distributor is out a bit now?

Its weird to cause the #1 on the cap is not where the #1 was on the old cap...

[CFMopar]

got it stupid pos      now check engine light is on.... might be a stored code im guessing

[Steve P.]

More than likely a misfire code. Clear it an go from there..