Have replaced the IAC, MAP, and TPS and still the same thing. The throttle body was taken off and completely cleaned and it will not idle. If I remove the PCV valve and let the intake breath by itself it runs like a champ with a little miss. Any help here? Would this be a plenum issue? Thank you all. (198 k miles)
1995 zj gc 5.2 will not idle
- Thread starter derffred
- Start date
Bounty__Hunter
Super Moderator
Have you checked all the CCV lines for a clogged hose? Find the CCV hose from the valve cover to the air intake and pull it from the air intake side, make sure it has strong vacuum into the engine.
1badcj82
New member
derffred said:GO ARMY..
The passenger side (no pcv) has great vacuum, the drivers side has the breather valve pushing
out air. I assume that that is correct. I sprayed starting fluid all along the intake and the hoses
and no change. Anything else? Thanks for the reply.
I think usually if the is a vacuum leak the engine will not idle down it will rev. How about fuel supply or pressure. Also on the throttle body at the butterfly there is a small hole or slot to flow air for the idle circuit make sure it is clean and the is no carbon ring on the edge of the butterfly or in the throat of the body. Not sure if that is the right direction just a idea to ponder
Don't know about fuel pressure, but if I remove the pcv hose and leave it connected to the throttle body, I can drive, back up etc. When I connect the pcv valve to the hose it dies. Would the fuel pump cause an issue? The gas tank when
you went down to fumes would have pressure when you released the gas cap, I have not had that happen recently? I did replace the fuel filter.
you went down to fumes would have pressure when you released the gas cap, I have not had that happen recently? I did replace the fuel filter.
1badcj82
New member
derffred said:
The tank does need to vent. The pcv just reburns crankcase pressure and fumes by sending it through the motor again. So it is really strange that it does that. The pvc valve should rattle when you shake it and i think it should only let air pass from the engine to the body and act like a check valve by not letting air go from body to the engine.
1badcj82
New member
By disconnecting the hose to pcv you are allowing more air to the engine by creating a vacuum leak. I still think even tho the throttle body has been cleaned there still may be a problem there.
Got that, but what would cause the blockage? If you leave the pvc line unconnected, the car will run with issues but MUCH better then with the pvc connected. When I did connect the pvc it rattled which it should but it stalled out. I don't know what else to look for? Would the egr also cause an issue like this?
I'm at a loss but no PCV car works....
I'm at a loss but no PCV car works....
Bounty__Hunter
Super Moderator
The '95 2.5L and 4.0L engines both have a CCV system (no PCV valve), wouldn't the 5.2L be similar? CCV= Closed Crankcase Ventilation.
The valve cover hoses shouldn't be pushing out any air unless it's being pulled into the intake manifold to be burned.
The valve cover hoses shouldn't be pushing out any air unless it's being pulled into the intake manifold to be burned.
5.2 has a pcv and that side goes from the passenger valve cover gasket and plugs into the intake. By disconnecting
the hose from the valve the car runs but is a little rough but you can drive it forward and in reverse, if you connect
it then it dies. I think I will get the new plenum fix (aluminum plate) and do the whole top part of the motor since
it is at 198k and I can then do new injectors and clean up everything else. Thanks.
the hose from the valve the car runs but is a little rough but you can drive it forward and in reverse, if you connect
it then it dies. I think I will get the new plenum fix (aluminum plate) and do the whole top part of the motor since
it is at 198k and I can then do new injectors and clean up everything else. Thanks.
