QuestionI have a problem with my 1997 3.0L Plymouth Grand Voyager, which has defeated my local Chrysler dealer. Any suggestions would be very welcome!
The car has the following symptoms:
* The engine can be lumpy when it is first started in the morning, and it occasionally cuts out. This lumpiness usually clears after a few seconds.
* The acceleration is intermittently weak for the first ten minutes or so – it can be so bad that the car will not accelerate above 20mph.
* The weak periods cut in and out suddenly. They usually occur when the engine is under load, such as when pulling away from a stationary start.
* The warning lights on the dashboard do not indicate any fault.
* During the weak periods, the engine sounds a bit muffled. At really bad times (such as when the accelerator is fully down but the engine is hardly responding), the exhaust sometimes makes a spluttering noise.
* The engine will usually idle properly. Accelerating in neutral gear, to rev the engine, does not usually show up the problem – it only seems to occur under load.
* The car seems to run well after the first ten or fifteen minutes, once the engine is really warm.
* The problem shows up on 60-80% of mornings. It shows up much less often in the evening.
The following work has already been done:
* The Chrysler dealers have attached their computers but found no fault.
* The spark plugs, ignition leads, distributor cap, rotor arm and temperature sensor have been replaced, but this did not resolve the problem.
* The dealer advised me that their next steps would involve trying lots of things, in the hope that they manage to replace the right component by accident. This will be expensive and may not resolve the problems.
So I would gratefully receive any ideas about what could be causing my car to run so badly!
Thank-you!
AnswerHi Alister,
My first thought is to look over the exhaust gas recirculation (egr) valve and associated control and vacuum hoses. This system connects the rear (side of the engine next to the firewall) exhaust manifold to the intake manifold and the pipe that connects the two runs between the two manifolds. The valve is bolted into that pipe and controls the exhaust gas amounts that return to the intake. The valve has to open and close firmly and quickly or the engine will not operate well due to a mixture of fuel and air that will not allow the engine to accelerate or idle well, if the valve is not where it is supposed to be. Often it will get sticky and fail to close all the way, for example which it has to do at idle and when stepping on the gas toward full open throttle. It is controlled by a vacuum operated and electrical control solenoid mounted near by, and those vacuum hoses should be examined to make sure there is no cracked, leaking, or disconnected hose fittings. 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, insert it in the slot, and then use the driver to lever the valve up (against spring pressure) and let it return to see if it is dropping back all the way down due to spring's action and closing positively to a firm closed position. Spray WD-40 or other penetrating lubricant on the valve stem to loosen it up in that in and out motion. 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.
Let me know if that doesn't help and we'll consider some other possibilities. But the egr function can be a big detriment if it isn't in the correct position for the conditions that are needed for a good mixture.
Roland
