1994 Chrysler New Yorker Won't Start sometimes.

AXEMILLER

MEMBER
1994 CHRYSLER NEW YORKER
6 CYL
FWD
AUTOMATIC
140,000 MILES

This is very odd, and it doesn't happen all the time. If the car is allowed to sit, say on a weekend or at the airport, the car is not happy starting.

If it doesn't catch immediately fire, then it pings or chugs, and chugs and chugs, and almost fires, and if you have enough patience (and enough battery) and slam your foot to the floor long enough it will finally fire. This process takes sometimes a few seconds to several minutes. I bought a new battery and it has eventually started every time, again, eventually.

Once it fires it stays going, it is only on the start, and once I get it started it usually is good for a week of travel. The only codes it shows are "running rich or lean."

I had it at a shop for 2 weeks during Christmas and he thought it was temperature related and changed the cam sensor to no avail. I'm not sure it is temperature related or just because it has to sit for a while. What I have been doing is turning everything off before I turn the engine off and if I get a chance starting the car late at night the night before I have to use it. That seems to have helped but the problem is still occurring.

I do not think it is the fuel pump, I do think that it is electrical but I haven't found any burnt or browned wires or harnesses. It has been very frustrating to say the least.

Thank you.

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

This kind of sounds like a problem with the MAP sensor. It tells the Engine Computer barometric pressure when you turn the ignition switch on, then it reports intake manifold vacuum when the engine is running. That corresponds to load on the engine and has the biggest affect on the amount of fuel going into the engine.

There is a very specific range of signal voltage the computer will find acceptable. Anything outside that range is detected as a defect and will cause the computer to memorize a diagnostic fault code and turn on the Check engine light. The signal voltage can be wrong, but as long as it's between the acceptable limits, the computer will believe it and will command fuel metering based on those incorrect values. Your mechanic should be able to verify the sensor is working properly by connecting a hand-held computer, called a scanner, to watch the sensor readings while the engine is running.

A leaking fuel injector could cause these symptoms too. Either way, you might find a clue when this happens if you stop engine cranking and start over, BUT, you must turn the ignition switch off before trying again. If fuel pressure dropped while the car was sitting due to a leaking injector, it can't build up fast enough to spray from the injectors while the injectors are trying to fire. Each time you turn the ignition switch off and back on, the pump will run for one second. Doing that two or three times will get the pressure up enough for the engine to start. The leaking fuel will cause a temporarily flooded condition at startup that will clear up and the engine will run normally then.

If the MAP sensor is beginning to fail, and is reporting the wrong barometric pressure, the computer will command delivery of the wrong amount of fuel. If you simply stop cranking the engine, then crank it again, the same wrong barometric pressure will still be in the computer's memory. Only when you turn the ignition switch all the way off, then back on to crank the engine again will it take a new, hopefully correct barometric pressure reading.

These are just two of the many possible things your mechanic will look for. You already noticed some helpful clues. These tricks might provide some more hints.

Caradiodoc