QuestionHello,
I'm trying to fix a 1991 Chrysler LeBaron, 2.5L, carburetor vehicle. The car stalls out intermittently. When it runs, it will run great for 15-30 minutes, then it will stall out and not start for another 15 minutes. It isn’t guaranteed, but that is the usual symptoms. We replaced the spark plugs, wires, rotator, fuel filter, but no change. When it wouldn’t start we used starter fluid in the carburetor to see if it would kick over, but it didn’t. It doesn’t have an alarm system on it, so that shouldn't be the problem. We looked at the codes on the dash and it first showed at 32 and we found a broken vacuum line. We tried it again and it was a 35 which was the fan. We thought about replacing the EGR valve, but we were told it doesn’t have one. I am not a mechanic, but since it’s not fuel injected, I assume we can’t clean the throttle body. Any ideas what would cause the problem? I’ve looked on line and can’t seem to find anything that rivals this discrepancy.
Thanks,
Carl West
AnswerHi Carl,
There are several misunderstandings in what you wrote. First, this is a fuel injected engine, but the injector (only one) is in the throttle body. Second, it does have an egr valve unless, at least my '89 2.5L engine and most that I have seen in that time period had them. Third, the throttle body butterfly valve plate can be cleaned.
The injector is in the top of the throttle body and it sprays a fine mist downward on the throttle plate when you crank over the engine. So remove the air cleaner and take a look while a helper cranks it. Look for any dripping after you stop cranking or an uneven spray pattern while cranking that would suggest that the injector is beginning to fail.
Open the valve and clean both the back side and the side-of- body-throat air passageway which is how idle air is fed to the intake manifold.
The egr valve is located on the right side of the engine, near the firewall and toward the front of the engine. Inspect the valve stem (a rod with a circumferential slot) located between the valve body and the vacuum actuator, inside of a saddle-like flange. Make sure it moves freely against spring pressure and closes tightly. If not spray the stem with WD-40 and move the stem back and forth.
Finally, either with a screwdriver with an insulated handle or a spare spark plug, the next time the engine stalls out check for the absence of spark immediately before it cools down. Either insert the tip of the screw driver or the spark plug in one of the spark plug wire/caps, then either: hold the screwdriver by the handle and the cap with the tip of the screwdriver inserted so that the shaft of the driver is about 1/4" from the cylinder head or any engine metal surface, OR insert the spare plug in the wire/cap and hold the cap and place the threads of the spark plug against the cylinder head to ground it, then which ever way you do it have a helper on board to crank the engine and observe for spark. What you describe, dieout in 15', is consistent with the loss of spark due to breakdown of the hall effect sensor inside the distributor due to its heating, followed by recovery upon cooling. This is not guaranteed, but it sound like it if indeed when it stalls you lose your spark. You might try this when the engine is cold so that you know what it will look like when you do get spark and so you will surely no when you try it after it has stalled.
The hall effect failure will set a code 11, but in the early phase of its deterioration is may not reach the threshold to set a code. The sensor costs about $40 and is also called the "pick-up" plate.
There are other possibilities (like a degrading MAP sensor but it too should set a code 14). On the other hand if a MAP sensor begins to degrade it can cause a stall without setting a code. That would be detected with a Chrsyler DRB II readout tool which would show an inaccurate reading of the barometric pressure.
The fan code is irrelevant to this issue. We'll work on that later.
So those are enough things to keep you busy for a while.
Let me know what you learn, please.
Roland
