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1995 Explorer will not start

Help… 1995 Ford Explorer, 4 ltr. engine, pushrod. Will not start. Replaced fuel pump, fuel filter, every relay, pressure regulator, and the crank position sensor. I realize there’s a whole bunch more parts under the hood, but I am ready to give up. Before the fuel pump would not run. Reason for replacing the parts. Now it won’t stop running and you can feel the fuel by-passing at the pressure regulator. When checking the pressure at the rail I get zero !! I used a tire pressure tester for this. And, like I said no pressure. Any thoughts !! This vehicle has around 170,000 miles on it.

It turned out to be a bad computer. Surprised the replacement was less than $150

Good for you! Computer problems are often tough to diagnose.

Here’s a little story about this subject.

You’d think it would be easy to figure out why a car won’t start. It might not be easy to fix, true, but you’d think a person could at least figure out why. After all, for the engine to start you just need a few things working, like gas and air in the right mixture, compression, and somewhere near the top of the compression stroke, a spark plug firing.

But it isn’t always easy to figure out why. I had a VW Rabbit one time that wouldn’t start no matter what I could figure to do, and it seemed to me from my testing that all of the above was working fine. Good fuel pressure, good compression, good spark, and at the right time in the cycle. I even pulled the injectors and verified they were spraying fuel.

So why wouldn’t it start? Well, as part of testing the injectors I pulled them one at a time. Then verified that particular one was spraying the correct measured amount of fuel at full throttle in 15 seconds. But the other three were spraying too. Inside the engine. And as I did this test for each of the four injectors, the cylinders were filling up with gasoline. The reason it wouldn’t start is because the engine was flooded!

I gave up and had it towed to the dealership one evening, and they phoned me the next morning, they said “So what’s wrong? It started right away the first thing this morning! We didn’t even pop the hood!”

What a dope I was! The gas had time to evaporate somewhat by then I guess. And the cold temps from the car being outside (in winter) made it like the rich mixture. It started right up. What a dope I was!!!

My 95 ford also is having starting/running issues. i noticed the fuel pump replay did not have a large enough voltage drop across it to activate the pump. the “ground side” had 2v the "hot side had 12v. I believe the "ground side is connected to the PCM. for the past year i have had a jumper wire from the 2v side to the battery ground. when i turn on the key the pump runs continuously. this worked great till this past week. I drove to Atlanta from Mobile. the car randomly shut off 3 times at 65mph. i stopped (in the rain), screwed around with the wire(on or off), did a few key turns. And for no noticeable reason it starts again. My fiance wont drive the car now. i am about the replace the fuel pressure sensor. Could it be the PCM? Which should i change first.

Symptoms: with no jumper wire
I turn the key, fuel pump sometimes runs till pressure is built up. sometimes the car does not start.
the car shakes a little at idle (1000rpm). does not feel like missing. power is smooth. no smoking.
exhaust does not smell like fuel.

I have replaced the spark plugs and wires 15,000mi ago. the car has 200,000mi

2 volts between the loaded relay ground and the battery ground seems excessive. I’d guess anything over 0.3 volts indicates a wiring problem somewherre. This sounds like there’s a missing or loose ground wire somewhere. Or a faulty connector, one that has corroded or come loose. Has this car been in an accident? Is there a rust problem? Has there been major mechanic work or other electrical work done prior to this happening? If any of those are the case, look for a loose or corroded ground wire or connection.

I don’t think it is a problem w/the PCM. Especially since you don’t mention the CEL.