QuestionQUESTION: 96 voyager starts fine when engine is cold-(first start of the day) but once engine has warmed up-(20-30 min.s of driving) then shu-off and restarted 20-30 min. later it cranks for a long time-(8-10 seconds) tried crank sensor and temp sensor. they did not change the problem. any ideas. Thank you the tech working on it is stumped. there are no codes, have spark and fuel pressure.
ANSWER: Hi Patrick,
You didn't mention which engine is in the minivan but if it is a 2.4L then there is an air intake sensor on the manifold that you might check to see if it is changing its resistance between cold and hot conditions. It is at the rear end of the intake manifold.
That and the coolant sensor are the most responsible for adjusting the mixture to temperature of the engine.
Other than that, I can suggest that you check the egr valve to make sure it is not stuck slightly ajar when it is hot. It has a valve stem with slot into which you can insert a screwdriver and move the stem back and forth and it should close to a dead stop via the internal spring-action.
Roland
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QUESTION: It is a 3.0L if that helps
AnswerHi Patrick,
Well that leaves me to suggest that you check the egr, and one final possibility after that. The egr system is in a pipe that 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.
One other possibility, but I don't know of any fix other than opening the hood and leaving it ajar when you stop, is that the fuel in the gas lines of the fuel rail is vaporized and so it needs to be cooled down. If it is really not under the hood that may explain this problem.
Roland
