2000 Cherokee 6 cyl

2000 Cherokee (Post #1)
My 2000 Cherokee refuses to restart after I shut it off, 2 hrs into my mail route. Runs hotter than normal when on my route. When I try to restart engine, it acts like it wants to vaporlock. It then blows black smoke and almost catches. After less than a minute of cranking it catches, but will not accellerate until gas is cleared out of cylinders.
Tried running water over the radiator-it seemed to help it restart. Dealer read code: Misfire on cly. #4, EVAP code on emmissions. Jeep dealor diagnosed plugs(had platinum in it), and throttle body cleaning(lots of carbon). Did not fix problem. New diagnosis-weak valve springs?????
All fluids have been flushed and filled. Maintenance has been preformed on a very regular basis. Can any one help on this one?

First thing, has your timing been checked, when was the last time you had the timing chain and gears changed. If your timing is drifting , it will be hard to start if your timing is out enough, especially on a hot engine.

2000 Cherokee (Post #1)
My 2000 Cherokee refuses to restart after I shut it off, 2 hrs into my mail route. Runs hotter than normal when on my route. When I try to restart engine, it acts like it wants to vaporlock. It then blows black smoke and almost catches. After less than a minute of cranking it catches, but will not accellerate until gas is cleared out of cylinders.
Tried running water over the radiator-it seemed to help it restart. Dealer read code: Misfire on cly. #4, EVAP code on emmissions. Jeep dealor diagnosed plugs(had platinum in it), and throttle body cleaning(lots of carbon). Did not fix problem. New diagnosis-weak valve springs?????
All fluids have been flushed and filled. Maintenance has been preformed on a very regular basis. Can any one help on this one?


Hi, it sounds ike you should check the MAP sensor its mounted on the throttle body. It has a small ruber elbow which sometimes cracks and Map sensor adds extra fuel. Pick up bottle if TECHTRON injector cleaner add to tank Dale :rolleyes:

Jeep has an appointment for Mon. Dealer wants to change out valve springs. Already in for $300. Needs another $350 to do this. Is this really necessary, or would that problem show up in road driving? It runs fine at all other times. Problem only occurs when route hot. Jeep has 86,000 mi. on it. Full half are on route.

Jeep has an appointment for Mon. Dealer wants to change out valve springs. Already in for $300. Needs another $350 to do this. Is this really necessary, or would that problem show up in road driving? It runs fine at all other times. Problem only occurs when route hot. Jeep has 86,000 mi. on it. Full half are on route.

HI, IF IT RUN FINE ALL THE OTHER TIMES I DON'T KNOW WHY THEY WANT TO CHANGE VALVE SPRINGS. IF THEY WERE BAD IT WOULD RUN CRAPPY ALL THE TIME. DALE [email protected]

That's what I thought. I know just enough to be dangerous about engines. Can do simple things myself. Have had 3 6 cyl DJ5's. This is my second Cherokee. The first was a 95. This one has the coil paks on top.Been driving right hand drive Jeeps since 91. Could change the plugs in my 75, 76, and 77 in a heart beat. I know this Jeep with my eyes closed. Spend about 5 hours a day in it. Could tell the sound the old sixes made when they were a quart low, but this one has got me
puzzled on several things besides this problem.
Have used Techtron since day one with this Jeep. Use 90% BP Amoco unleaded. Very rare to use off brands and never use gasohol. Change oil at 2500, never more than 3000.
There was a tech bulletin that said to reprogram the computer because of it's inability to dissipate extra heat in engine. reprogramming would cause the fan to turn on more often. Sounds more like my problem and a possible cure than anything the dealor has come up with. Does this sound true?

Went to dealer today. Reset computer to kick fan on more often. I now have a co-pilot to record (??) 30 seconds before and after no start incident. Dealer mentioned gasahol usage could add to hot start problems. 99% BP Amoco unleaded with no alcohol run through since day one. Has anyone else had this problem?

How much hotter is it running? There is a safety shuutdown to prevent damage to the engine in severe overheating conditions but you'd need to be in the temp red zone.

Did the TB cleanout and plug change clear the cyl misfire code? Check the #4 ign wire, cap, rotor and fuel injector. Maybe #4 is not firing correctly and loading up with fuel. Also check it's compression to make sure everything's seating properly.

Not sure if it cleared code at that time. If it did it came back the next time I tried to start and it wouldn't catch. It is not running in the red, only slightly above 210. Average temp on road is just below. Temp rises to about 215 or 220 when shut down during route. Would check cap rotor and wires if this model had them. It has a coil pack for each cyl.

Not sure if it cleared code at that time. If it did it came back the next time I tried to start and it wouldn't catch. It is not running in the red, only slightly above 210. Average temp on road is just below. Temp rises to about 215 or 220 when shut down during route. Would check cap rotor and wires if this model had them. It has a coil pack for each cyl.


HI, DO YOU HAVE A/C IF YOU DO TRY SWICHING THE THE A/C ON IT, IT SHOULD KICK THE ELECTRIC FAN ON. THE RELAY SWITCH DOESN'T KICK FAN ON TILL IT'S REALLY,UP IN RED DALE [email protected]

I have same model vehicle and also #4 misfire code. How did you solve problem. Please reply. Thankyou