Weird vibration on restart

[idrthrbfishing]

I have a 2000 Cherokee with a 4.0 and 97000 miles. If I shut it off and restart it with in about five minutes like when I get gas it has a bad rumble for about 20 seconds after which it goes away and does not return. It only happens under this scenario and by the time I et the hood open it is gone. Putting it in gear does not change it. The engine must be fully warmed up for this to happen.
Any ideas?
Thanks

 

[SteelHeadz]

Rumble like a misfire?

 

[idrthrbfishing]

No misfires more of a vibration I initially thought a bad pully but everything is tight and no squeaks or squeals no check engine light if it's a misfire it would have to be at least two cylinders dropping out but engine seems to rev very smooth
Thanks

 

[SteelHeadz]

I would suggest that you try to duplicate this with the hood already up so when it does occur, you can isolate where noise is coming from. One thing that i know that causes a rumble type noise is an airpump for the emmisions. That's only if your jeep has one.

 

[idrthrbfishing]

Thanks I will try that hopefully I can duplicate it and isolate

 

[idrthrbfishing]

Ok seems to be heat related and fuel related I'm thinking the fuel is vaporizing in the rail. Does any one know if insulation would help? The jeep needs to be run at least five to ten minutes and then sit for five to ten minutes sitting for less or more and the issue does not occur.
Thanks

 

[SteelHeadz]

Ok seems to be heat related and fuel related I'm thinking the fuel is vaporizing in the rail. Does any one know if insulation would help? The jeep needs to be run at least five to ten minutes and then sit for five to ten minutes sitting for less or more and the issue does not occur.
Thanks

You can try to insulate the injectors individually with some sort of heat wrap or a hose and tie straps. Do the same with the fuel rail and retest if it still occurs.

 

[69jeepcj]

they sell exhaust header wrap at most auto stores in the performance dept. I know back in the day people used to wrap fuel lines with wrap to prevent fuel vapor lok, They put clothes pins on the fuel line as well and claimed it worked.
I havent heard of anyone having to do that with the newer cars, but its worth a try.

 

[SteelHeadz]

Actually, a few years back there was a recall issued out to certain jeep models and year that has the 4.0liter. The recall involved installing a heat shield on the intake manifold to help insulate the fuel injectors and rail from heat coming up from the exaust manifold.

they sell exhaust header wrap at most auto stores in the performance dept. I know back in the day people used to wrap fuel lines with wrap to prevent fuel vapor lok, They put clothes pins on the fuel line as well and claimed it worked.
I havent heard of anyone having to do that with the newer cars, but its worth a try.