Engine Running Rough... need to find out the trouble

I have had the V6 for a bout 5 years now. Well it just really hasnt run right. I have changed out everything from carbs to ignition parts. Pretty much everything is new and good condition. Well i had my jeep running rich for a bit to get my edelbrock carb to work better. And when i readjusted the idle mixture before Tellico it ran OK. Billy then came to my aid and tuned the carb and it ran pretty good. Well it ran good for Tellico, actually ran all day on differnt angles and such just fine. Well i put the jeep on the traielr and brought it home. When i started it on the traielr to put it in the garage it would run very rough and not want to stay idling. Yesterday i opened up the hood and installed new accelorator cables. I then bumped up the idle speed to get it to stay idling. It did but just isnt smooth, then i richened the mixture and it ran better but still not perfect.

Bottom line is i am still frustrated that this motor just hasnt acted right.

Only thing i am pretty much for sure on is that i have valve problems. I ran the headers for a while with blown glasspacks and i didnt not have any backpressure. So I know i burned something up. And i especially know i have been running the new exhaust with a massive exhaust leak in the rear driver side bank of the motor.

So what kind of bad things will valves do?? In the equation of all things they are the last thing on the jeep that wasnt changed out. I do plan to pull the heads off it when i get the T18 in.

Do you think that the culprit could be bad valves?? Like i said Billy was there and tuned the jeep he heard it run and it ran etty nice, but after running it all day and letting it sit on the trailer and then getting back to florida and it runs like poop. I really do not think it was altitude, but i could be wrong.

 

Could it be gunk in the bottom of the fuel tank? Or
clogged fuel filter?? If you were bouncing around off
road, could have stirred up some setiment from the
bottom of the tank. Just a thought...

 

Valves don't normally go bad quickly, it is more of a gradual thing. And no, I don't think running the blown out glasspacks would do it either. Race cars run open headers all the time!

I would look into the fuel system a little further like panzer suggested, or maybe even the floats in the carb got jostled on the trailer. How about the possibility of a vacuum leak? I think the key here is that you had to richen the mixture to make it run.

Back to the valve idea; Have you run a compression check?

 

The Valves have been abused for a while. I had the coil go bad and one side of the jeep was shooting flames bout 2 feet from the glasspack (hench why one got blown)

As for Vacuum leaks I have resealed the intake manifold many many times and it should be OK. But Then again i do have some leaks. I have not done teh compression test, i have been menaing too but never got the compression tester, i have to run over to Harbor Freight one day to get the tool.

As for fuel, It is real clean, the tank is new, and the filter is very clean.

I agree with the mixture being the key. I had a PIA time getting the carb jetted and tuned. I had issues with pinging before and that is why i had the mixture so rich before, but when i put on the stock manifolds it went away, even with the massive exhaust leak i have, i have zero pinging, and this is when i first put the new exhaust on and i didnt have any problems. It was very odd, but pleasing to know the pinging is gone.

 

Ok, we may be getting somewhere here. The pinging having miraculously cleared up sounds like either the carb was jetted very lean (not likely out of the box) or a decent vacuum leak. Headers often require re-jetting the carb to make it run right. An over-lean condition will make pinging a problem. You removed the headers and the pinging went away. Hmmm.

Were the heads ever off this engine that you know of? If so, were they milled or resurfaced in any way?

Do you have a vacuum guage you could put directly onto the manifold? That might give us some key info......

 

I replaced the head gasket on the motor before, not because of a blown gasket, but rather i was just trying to fix a oil leak, and while i was there i changed it. Everything seemed normal then but that was a while ago. The carb was jetted to get it to run good with the headers. I have the jet kit and everything and i hooked up propane to diagnose a lean condition (was in contact with a guy on another board who showed me this way) so finally i got it running good. Now it was running really rich. So maybe i should go and rejet the carb again? Like i said i have the edelbrock carb (non Q-jet) i have teh other rods and jets so i guess i could just try rejetting it. And possibly i am thinknig i have the plugs really fouled because of running it so rich.
HHHHHMMMMM

 

The carb is not the Qjet. it is the Carter copy. It is realy simple. It actually has the offroad goodies to it.

I will get a compression tester to get that out of the equation.

As for vacuum leaks i do not have any. I have tried the spray around the manifold trick and it didnt change anything.

Well that is good news then about the valves. i will get the compression done, to see if they are in good shape. would be very cool to find out they are fine so i wont have to spend $$$ to rebuild them

Thanks!!!

 

I did think about fuel injection. it would be easy for me becuae of the later even fire motor. I thought bout th emegasquirt system, but never really went into ti because we do not have many hills around south florida