94 Explorer cranks but no start, details inside Thanks for any help

Sounds very much like the fuel pump relay. Open the relay box on the passenger side, under the hood. Swap the A/C relay with the fuel pump relay- each has an unused pair of contacts, and they are opposites so they will be good as new.

If that doesn't do it, another common problem is the crank position sensor.

-Paul

Thanks Paul

Where is the crank position sensor? Is there a way to test if its bad?

Does it start if you push down the gas pedal? If so, you have a bad idle air control valve.

I don't have personal experience with the crank position sensor, but if you search this newsgroup you'll find info like this:

Here's some good info from Dr. Bob on the crank position sensor:

"The crank position sensor is the hall effect sensor pointing to the front of the crankshaft. The hub behind the front pulley has grooves machined in it, with one groove missing. the sensor reads each of the pulses from the grooves to know exactly how far the crankshaft has turned, and reads the missing groove to re-identify a known position to reference from.

This allows the ignition and fuel injection systems to make sparks and fuel at the right time.

There is a 'limp home' mode, as you have discovered, that allows the engine minimum operating ability so you aren't stranded.

A failed sensor generates an error code, so the diagnosis is fairly straightforward. If you weren't at a Ford dealer, the $200 is the result of not having the right code reader. The sensor takes mere minutes to change."

Here's a description of the problems it causes:

"The crank sensor went out last fall on our '92 XL, too. The car would suddenly die and wouldn't start again. After about 10 minutes, it would start up fine and run like there was nothing wrong (until it would die again, usually days later). Finally, it would run only poorly (the "limp home" mode, I guess)."

I held the gas pedal down and tried to start with no luck. However, a couple of weeks ago I remember I did that and it started, but not this time.

Thanks Paul,

Located the sensor, bottom center front (under). I ran the code reader and nothing came up. I think I interpreted what you wrote correctly.

Swapped the relays and still no start

OK, down to basics. To start you need:

1. spark
2. proper fuel/air mixture
3. timing
4. compression

At least one of those is missing.

1. Have someone crank it while you check for a spark. Create an 1/8" gap to ground somehow- old spark plug, nail, screwdriver, whatever. However, you should have an error code if the ignition system is not working.

1. Listen near the gas tank while someone turns the key to run. You should hear the fuel pump run briefly. Next check the fuel rail for pressure. It runs along the top of both heads, connecting to each fuel injector. Look for a schraeder valve, like on a tire. Have someone turn the key to run for a few seconds, then off, and see if there is pressure in the rail. Needless to say, there is some danger involved here. Don't be spraying gas all over, smoking, etc. The spec is 35-45 psi, key on, engine off. It is supposed to drop 10 psi when the engine starts. If you don't hear the fuel pump run and there is no fuel pressure, you have narrowed it down to the fuel pump or the fuse and wiring to the pump. There is also a fuel pressure regulator which can fail, in which case the fuel pressure will be wrong.

2. You should have an error code if you have a crank sensor or other timing related problem.

1. I'm sure you'd know if you had no compression in all 6 cylinders.

-Paul

I checked for spark. Pulled plug, attached plug wire, laid on alternator, cranked. No spark. Used different plug wire, no spark.

Also, for some reason the code reader doesn't seem to be working.

I had disconnected the battery and reconnected. The alarm kept going off.

Should I be able to smell gas once I removed a plug?

Well, if you have no spark I think you've narrowed it down considerably. It ain't gonna start without a spark. The alarm going off may have something to do with it, I think that also kills the ignition. You need a working code reader now, it sounds like it's not something simple and easy to diagnose, like a fuel pump problem.

-Paul

I don't have a problem with the alarm anymore, I think.

I just used the code reader a month ago and it worked fine, that how I replaced the EG sensor.

I hooked a fuel pressure gauge, but that doesn't register (fuel did come out of the valve). Does the engine need to be running?

.45 round thru the block :-)

Jim

Another thought!!! What would cause the reader to not work, no fuel pressure, and no spark???

The link indicator on the reader comes on , but nothing else.

Jim

Apparently I was impatient with the code reader. I went back out and it had cycled thru and came back 111-system pass.

Additionally, the fuel pressure gauge had a reading of 38PSI.

Guess that leaves just the spark issue!

Jim

Hmmnnnn... well, a problem with the ignition ought to set a code.

Are you sure? This is EECIV, not OBDII. Doubt if those can self-diagnose ignition.

Now it gets really bizarre. When I finally got the reader to cycle thru the test I heard the fuel pump run and then the fuel pressure gauge shot up to 40psi then dropped to 37/38psi and the pressure held.

Then I was able to start the engine. I then shut the engine and disconnected the fuel pressure gauge.

I tried to start the engine again with no luck.

I reconnected the code reader and ran it thru the test cycle, at least until I heard the fuel pump run. Then the engine started.

What the #$%& would cause the fuel pump run when the code reader is connected, but not when I turn the ignition on.

By the way, I still had no spark, therefore I must not have had it set up correctly and spark all along...I guess.

Any Thoughts?

Thanks

Jim

OBD I Code Reader Ford 1983 - 1995

Inside the owners manual though it stated the computer system is EEC-IV

I'm not POSITIVE, but I'm pretty sure it will give a code for things like the crank position sensor failing. This is a gross failure, not something like one cylinder miss firing.

But I'm too lazy to look it up, and if anyone knows for sure I'll defer to their greater knowledge.

-Paul

My code reader resets the fail codes after 3 cycles of reading them. So if the computer is sensing a code that tells it to cut off the spark or fuel, that is a possible explanation.

But this is getting beyond troubleshooting by text messages.

-Paul