Rough Idle
Pro
Joined: Mar 1999
Posts: 678
Likes: 0
From: Oslo, Norway
Re: Rough Idle (TRWSD90)
Hi.
To start with the simplest.
Clean the throttlebody of carbon deposits.
Clen the Check the IAC motor and clean the IAC air channels.
Do the minimum idle air adjustment:
Short circuit the ALDL terminal A&B. Switch on the ignition and do not start. Wait about 30 secs.The IAC will be seated. Then take off the the IAC connector. Start the car and adjust the idle to about 400rpm for an auto and about 450 for a manual. stop the car. Reconnect the IAC connector and start up. The idle shall now be adjusted properly
Check the PCV valve and feel for sucktion when taking it off the valve cover at the drivers side. ( with the engine off the valve shall give a clicking noise when shutteling it as the ball iside shall be able to move freely. If not change the valve). If no sucktion then take the valve off the hose and check for sucktion there. If no sucktion then the tube leading the vacuum from the manifold can be blocked.
Then check for false air by:
Checking the vacuum hoses.
False air in the connection between the manifold and the tube to the PCV valve. There is a rubber hose 3" long anbot mid of the intake manifold on the driver side. I had a lek there. Test it with some start gas or propane . If the engine changes the rpm when it sucks the gas you have a leak.
Do the same over the runner inlets on the manifold and the plenum.
If it is running rough still then check the EGR valve.
First put vacuum to the EGR valve and check that it keep the vacuum for at least 20 secs. If it dont. Change the valve. (The valve can even be all right with the vacuum but there can be deposits on the valve seat in the valve so that you get EGR when supposed to be closed).
Check the EGR solenoid after the book. Think it is like this. Apply vacuum at the plenum side of the solenoid when having the ALDL terminals A and B short circuited. The solenoid shall hold the vacuum. Then take away the connection between the ALDL terminal A&B and the vacuum shall disapair.
Hope this will help
Jan-Erik
To start with the simplest.
Clean the throttlebody of carbon deposits.
Clen the Check the IAC motor and clean the IAC air channels.
Do the minimum idle air adjustment:
Short circuit the ALDL terminal A&B. Switch on the ignition and do not start. Wait about 30 secs.The IAC will be seated. Then take off the the IAC connector. Start the car and adjust the idle to about 400rpm for an auto and about 450 for a manual. stop the car. Reconnect the IAC connector and start up. The idle shall now be adjusted properly
Check the PCV valve and feel for sucktion when taking it off the valve cover at the drivers side. ( with the engine off the valve shall give a clicking noise when shutteling it as the ball iside shall be able to move freely. If not change the valve). If no sucktion then take the valve off the hose and check for sucktion there. If no sucktion then the tube leading the vacuum from the manifold can be blocked.
Then check for false air by:
Checking the vacuum hoses.
False air in the connection between the manifold and the tube to the PCV valve. There is a rubber hose 3" long anbot mid of the intake manifold on the driver side. I had a lek there. Test it with some start gas or propane . If the engine changes the rpm when it sucks the gas you have a leak.
Do the same over the runner inlets on the manifold and the plenum.
If it is running rough still then check the EGR valve.
First put vacuum to the EGR valve and check that it keep the vacuum for at least 20 secs. If it dont. Change the valve. (The valve can even be all right with the vacuum but there can be deposits on the valve seat in the valve so that you get EGR when supposed to be closed).
Check the EGR solenoid after the book. Think it is like this. Apply vacuum at the plenum side of the solenoid when having the ALDL terminals A and B short circuited. The solenoid shall hold the vacuum. Then take away the connection between the ALDL terminal A&B and the vacuum shall disapair.
Hope this will help
Jan-Erik
