1998 Plymouth Breeze 2.4 Wont Start

Gotta catch it when it's not starting, then check for spark. If it's missing, you don't have a pump problem. Also, if that's the case, the pump should run for one second right after turning on the ignition switch. It will not run again until the Engine Computer sees engine rotation, (cranking or running). If there is no spark, suspect the camshaft position sensor. It's his pulses that tell the computer it's time to turn on the automatic shutdown (ASD) relay which sends current to the ignition coils, injectors, alternator field, oxygen sensor heaters, and fuel pump or pump relay. None of those things will work if the camshaft position sensor isn't working. He's on the driver's side of the cylinder head. There's a crankshaft position sensor too on the back of the engine but he causes a lot less trouble.

Caradiodoc

You're confusing the term "crank". Not cranking means the starter isn't spinning the engine so it won't even try to start or run. That is a very common problem with a fairly easy fix. It causes one clunk from the starter each time the ignition switch is turned to "crank", but it won't turn the engine. There won't be spark or a reason to check for it unless the engine is cranking and not starting. I think that's what you mean.

If the engine is cranking (spinning) but it won't start or run, there are three circuits to check. The ignition system (coil and spark plugs causes the least trouble. The fuel pump acts up a little more often, but the trigger circuit affects both of them and causes about 90 percent of the no-start problems. That trigger circuit is the crankshaft position sensor and camshaft position sensor. It's the pulses from these two sensors during engine rotation, (cranking or running) that tells the Engine Computer to turn on the automatic shutdown (ASD) relay. That relay sends voltage to the ignition coil, fuel injectors, alternator field, and fuel pump or pump relay.

If the Check Engine light came on, there will be a diagnostic fault code stored in the Engine Computer. Cycle the ignition switch from "off" to "run" three times within five seconds, then read the code(s). If the engine cranks, even for a fraction of a second, stop, wait for a few seconds, then start the procedure again.

Caradiodoc

The only thing the pump and gauge have in common is the ground wire at the tank. If that ground connection is intermittent, it could cause a no-stat condition and it would have no affect on spark. Since you do have spark, the cam and crank sensors are working. I described how that trigger circuit works in the second paragraph of my second reply but I didn't do a real thorough job.

There are two ways to tell when these two sensors are working. Mechanics can use a scanner to view live sensor data. The scanner will display when the pulses are coming from the sensors. There's a much easier way you can do this yourself. Grab a test light or an inexpensive digital voltmeter and measure the voltage on the dark green wire with orange stripe in the coil pack, one of the injectors, or either of the two wires or small terminal nuts on the back of the alternator. First, you should see 12 volts on all of those points for just one second after turning on the ignition switch to the "run" position. That proves the Engine Computer is working. Next, that voltage must come back when you crank the engine. When the engine is rotating, the cam and crank sensors develop pulses that tell the computer the engine is turning and it should turn the automatic shutdown (ASD) relay back on. That's the relay that sends the 12 volts to the coil, injectors, and alternator.

Your car model uses a separate fuel pump relay but it is turned on at the same time as the ASD relay. Because there are two different relays, it IS possible to have a dead fuel pump when you do have the voltage at the coil, injectors, and alternator. It is rare for a relay to fail, but a fast way to check is to replace a suspect one with a different identical one. Good choices are the starter relay because you know it's working, or the AC compressor relay.

To boil this all down, based on your dandy observations, I am fairly confident we can narrow the search down real quick. First of all, you have spark. That proves the cam and crank sensors, Engine Computer, and automatic shutdown relay are working. That leaves just the fuel supply system. That circuit includes the fuel pump relay, Engine Computer, fuel pump motor, and the wires. Everything in that circuit has nothing to do with the fuel gauge except the common ground wire at the tank. That's where I believe you will find the problem. (Gee; I feel like a psychic)!

Your original post, second sentence, where you found no fuel, is the clue when you do still have spark. The entire fuel supply system is not monitored by the Engine Computer so there will be no related diagnostic fault codes set in memory as there would have been if a sensor had failed.

Caradiodoc

I KNEW you were going to ask that as soon as I closed up the service manual! :)

They don't show a picture, just a wiring diagram. There should be four wires in the electrical connector. Dark green / white is the 12 volt feed for the pump motor, dark blue is the fuel level sender and goes to the Body Computer, (which sends the information to the instrument cluster), the black wire is the ground for the pump, and the black / light green is the ground for the sending unit.

If the break was in the black wire, only the pump would not work; the gauge would be unaffected. If the black / light green wire had the break, the pump would run, the engine would run, and only the gauge would not work. HOWEVER, ... Those two ground wires share a common connection somewhere nearby on the body. When the break is there, both items will have a problem. Current will go through the pump motor but since it can't get to ground, it looks for a different path, and that's through the level sending unit on to the Body Computer. They don't indicate which way the sender moves to read "full", so the symptom would be the gauge, I believe, will read either maximum full or maximum empty.

Now, here's an interesting point I just found. When the pump doesn't run, check the operation of the rear tail lights and brake lights. The diagram shows both rear light assemblies are grounded in the same connection as the pump and sending unit. That connection is way at the rear of the trunk, slightly left of center. Look there for a loose terminal or corrosion on the wires.

Another way to find this is to measure the voltage on the black wires right at the pump connector in the front of the trunk. Normally you will have next to 0 volts, (engine cranking or running), but when the ground connection is broken you will find close to 12 volts there. Grounding those wires with a jumper wire will get the pump running when you crank the engine.

Caradiodoc

The diagram doesn't show if there are two different terminal ends bolted on in the trunk or if all four wires go to a single terminal. If there is just a single terminal, adding the jumper that you did will make the lights work properly too. It doesn't matter where the wires are grounded, just that they are. If the lights have their own ground terminal and the bolt is loose, you may still have intermittent lights but your jumper wire will keep the fuel pump humming right along.

Happy to read you are able to sail off into the sunset.

Caradiodoc