Questionhi ronald
i mail you about the rough idle and u recomended to check the vaccume leaks . fortunately there is no vaccume leak . is there any other means i can check this problem chrysler cirrus 95 V6.
thank you
Raj
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hi ronald
the ideling all calms down after driving for some 30 to 0 miles do you still think the problem is with the air intake just curios
raj
raja
Answer -
Hi Raja,
A similar question (high idling speed, not variable) came in a couple of days ago, and I believe the answer is identical:
"The most likely reason for fast idle is that you have an air leak into the intake manifold from one of the vacuum hoses connected to it or one of the sensors or actuators that are bolted to it. When air leaks into the intake manifold it dilutes the mixture which is sensed and compensated for by increasing the gas input, the result is just as if you opened the throttle via the gas pedal, a faster idle.
So what you need to do is look at the sticker on the underside of the hood which shows you all the hoses and items related to the intake manifold. Use the sticker as a road map and look at all those devices and and both ends of all the hoses and check along the length of the hoses for any cracks where air could leak in. You might get a can of spray starter fluid, and put a very tiny spray (if you can change the spray nozzle to one that would allow you to use a straw to better localize the spray) at each joint or object connected to the intake manifold while the engine is idling; and when you do that and the idle goes even higher for just a few seconds you have located such a leak. But don't spray any more than for a fraction of a second and don't spray it on the exhaust manifold because you can start a fire with anything more than a tiny squirt. It is a very sensitive way to find a leak. But be very careful.
On the battery, remove the - post first and clean it and then the + post. Then put the + post clamp back on. Then finish by putting the - post back on. There is a wire brush and some battery compound in a tube you can buy at the auto parts store to clean the terminals and the clamps. Be careful not to short the + post of the battery to any metal object so as not to be burned."
The attempts by the engine controller to deal with the leak is what is causing the variability, I believe. So look for a "vacuum" leak and finding it and repairing will cure the problem. There are some other possibilities but they are much less likely. So try the leak search and it that doesn't solve it I can tell you some other things to try.
Roland
Answer -
Hi Raj,
It still could be a vacuum leak that is temperature dependent so I would look over all the hoses and any other fittings attached to the intake manifold to see if you can find a leak. The other item that might be involved and also has a hose from the manifold is the egr valve. It is located on the 2.5L V-6 in pipe on the side of the engine that faces the front of the car and that runs below the air intake hose. The pipe connects the front exhaust manifold to the air intake. Look for the egr mounted horizontally in that pipe. The egr which has a pipe coming from the exhaust manifold to its underside and a pipe from it going to the intake. There is a vacuum operated round fitting on its top, and also a vacuum line going to an electrically operated valve closer to the engine, nearer the throttle body. Look under the round fitting (which is mounted on a saddle with openings for access to view) on the top of the valve where you will see a rod with a slot in it which is the valve stem. Take a straight blade screwdriver and use the slot to lever the valve up against spring pressure and see if it is dropping back down due to spring's action and closing positively. Put WD-40 on the stem to loosen it up in that motion if necessary. Check to make sure the vacuum lines are all attached and not cracked. Then warm up the engine and observe the slot to see if it goes up when you rev the engine to 2500 rpm and then drops back down fully, closing the valve, when you let the engine go back to idle rpm. Make sure that the fully down position is really down because if it is not fully closing when you let go of the accelerator and coast that will cause the engine to stall. It may be that to get it to close you'll have to unbolt it and clean out the gas flow passage past the valve due to buildup of exhaust fumes in the valve as sticky crud deposit around the internal valve.
Those vacuum and egr tests are the most likely explanations of your idling problem, Raj. So give it a go and see what happens.
Roland
AnswerHi Raj,
Assuming that there is no vacuum leak, then the second possibility is an exhuast recirculation valve that is sticking ajar until the engine warms up. So you need to try and get it freed up and moving again so that it will be closed when the engine is idling, otherwise it will be difficult to idle and will stumble when accelerating.
The first thing I would do is check the mechanical function of the egr valve which is located along a pipe that runs from the left exhaust manifold (on the side of the engine facing the front of the car) to the intake manifold area (where the incoming air in the large rubber tube enters the throttle). That valve is metal and has a round fitting with a vacuum hose attached, mounted on the top of the valve, and the round part is attached to the main body of the valve by a sort of saddle. Inside the open saddle you will see a metal rod (with a slot) that connects the round top fitting to to the valve body. That rod is a stem on the valve and it is supposed to go in and out in response to the engine vacuum which varies with RPM and throttle opening (gas pedal position). Take a spray can of WD-40 or other penetrating lubricant and spray the stem where it enters the valve body and then use a regular screwdriver blade tip inserted in the slot to lever the valve in and out to try and free up its motion. Also check all the rubber vacuum hoses associated with the valve and a nearby vacuum solenoid valve. If the valve seems to open (against the action of a spring) and close firmly by the spring action when using the screwdriver blade to facilitate the motion, then you should be able to now start the engineand get a smooth idle. You can, once it is idling, check that the valve stem moves when you rev the engine from idle to 2500 rpm and back to idle.
Roland
