1991 Chysler New Yorker possible problem with fuses

Sounds like you overlooked a fuse. All the things you mentioned have the dome light fuse in common. That circuit, which is always live, feeds the clock / station preset memory for the radio. Look for the "interior lights" fuse in the glove box.

Intermittent problems can be very frustrating to find since there is no defect to be found when the problem is not acting up. The worst thing you can do is run from shop to shop. Just like going to a doctor, sometimes it takes multiple visits to figure out the problem. Every time you go to a new place, that person has to start over from the beginning. Sometimes the most likely suspects have to be tried first, then more testing later leads to the next suspect. You have to go back to the same shop so they can continue on with the next steps.

I hope the new Engine Computer solves the intermittent no-start condition but during that time period Chrysler had extremely little trouble with them. When it didn't start, what was the symptom? Did you hear one kind of loud clunk under the hood but the engine didn't spin? Did the engine crank (spin) but didn't start and run? Did the engine ever stall while you were driving at a steady speed? Intermittent no-crank is real common and is caused by worn contacts in the starter solenoid. That's a pretty easy fix. If the engine cranks fine AND never stalls while driving, that would be typical of a high-mileage fuel pump failing to start up. Chrysler pumps rarely quit while you're driving.

The camshaft and crankshaft position sensors usually cause stalling when the engine gets warm. Unless they fail completely, they don't typically cause an intermittent no-start condition.

Caradiodoc

Happy to hear about the fuse, but don't jump the gun on the fuel pump. Too many are replaced when they aren't needed. I understand about the multiple mechanics and it is understood the camshaft sensor was not related to the current problem. I needed to state my case because that is another thing I read about a lot. People understand they might have to go to a doctor multiple times to figure out a diagnosis, but they hold their mechanic to a higher standard. He's considered incompetent when he doesn't find the answer right away.

Back to your fuel pump, each time you turn the ignition switch to "run" you should hear the hum of the fuel pump for one second. That's the proof the pump is starting up. It won't turn on again until the engine is cranking or running. If you become accustomed to listening for that you should notice you're not hearing it when the engine doesn't start. Banging on the bottom of the gas tank while a helper cranks the engine will often get it started. It is real common for GM fuel pumps to die while you're driving, but Chrysler pumps almost never do that. Once they start up they will continue running as long as the engine is running.

If you hear the pump running but the engine still doesn't start, first turn the ignition switch all the way back to "off", wait a few seconds, then try again. If that works every time after a no-start condition, fuel pressure might just be bleeding off while the car was sitting. That is not serious except for the inconvenience. During engine cranking the battery voltage is drawn down which makes the fuel pump run slower than normal. It can't build up pressure fast enough for fuel to squirt from the injectors. Cycling the ignition switch multiple times lets the pump run for a total of a few seconds before you crank the engine. That gives it time to build up enough pressure.

Normally that pressure in the system will stay there for many weeks, but it can bleed down due to a leaky injector, fuel pressure regulator, or check valve in the pump.

If you DO hear the fuel pump run yet the engine doesn't start, there are two things you can do to start the diagnostic procedure. One is to have someone show you how to check for spark. It's easiest with a helper to turn the ignition switch while you watch under the hood but there are ways to do it yourself. The second thing is to measure the voltage on the dark green / orange wire at any one of the injectors or the ignition coil. You should see 12 volts there for that same one second after you turn on the ignition switch, then again when you're cranking the engine. If it doesn't come back during cranking, the camshaft and crankshaft position sensors would be the first suspects. I don't think that's what's wrong now because it's more common for those sensors to fail after they warm up.

Caradiodoc

There is a coolant temperature sensor that affects how much fuel squirts in to start a cold engine, but those sensors give almost no trouble at all. There are more problems from people leaving them unplugged. Doing so is also a part of a test procedure. It will cause the radiator fan to run whenever the ignition switch is turned on.

Remember, the pump only runs for one second when you turn on the ignition switch. You will likely not be able to hear it again over the noise of cranking the engine. That's why I always have people measure the voltages at the ignition coil, injectors, or alternator field terminal instead.

The next time it doesn't start, immediately jump out and check for spark. Let me know if you don't know how to do that. I can also tell you how to do it yourself without a helper to turn the ignition switch. If there is no spark, measure the voltage on the dark green / orange wire at the coil or one of the injectors. There should be full battery voltage there while the engine is cranking. If there is voltage, the coil may be defective.

Caradiodoc

Which engine do you have? If you have the 3.0L you can pull the wire from the center terminal of the distributor cap. If you have either the 3.0L or the 3.3L you can pull off one of the front spark plug wires. If you're brave, hold the wire by the rubber part so the brass terminal on the end of the wire is about 1/4" away from any metal part of the engine. I prefer to stick a screwdriver into the terminal, then lay it on the engine so there is that 1/4" gap. When the engine is cranking you should see a spark jump across that gap about two times per second.

If you want to do this yourself, you won't be able to see the spark from inside the car. That means you have to crank the engine from under the hood so you can stand next to the wire and watch for spark. I only have a '92 service manual so I'm not sure which type of starter relay you have. If there is a fuse box under the hood right behind the battery, pop the cover off, look for the starter relay and remove it. In the diagram below, find terminals 30 and 87 in the socket. A stretched out paper clip works nicely to momentarily connect those two terminals, or any piece of wire will work.

If you do not have a fuse box under the hood, the starter relay will be bolted to the left inner fender behind the battery. It will have a red wire and a brown wire that are fatter than the other two or three wires. The connector can be unplugged, then those are the two wires to connect to crank the engine. When you do this test from the relay, the ignition switch must be turned on to the "run" position. Be sure the car is in "park" in case the engine starts. You'll look funny chasing it down the driveway!

A third alternative, if you have the relay that plugs into the fuse box, is to snap the cover off the relay and reinstall it that way. There is a metal "flipper" on one side that can move about 1/16". The starter will crank if you squeeze that flipper. It won't hurt anything to leave that cover off for a few weeks. That will make cranking the engine by yourself from under the hood real easy and fast.

Caradiodoc