Crank Shaft Position Sensor 1993 Ford Explorer. 4.0 , push rod type. | Ford Explorer - Ford Ranger Forums - Serious Explorations

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Crank Shaft Position Sensor 1993 Ford Explorer. 4.0 , push rod type.

mange1234

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Virginia Beach, Virginia
Year, Model & Trim Level
1993 Ford Exployer
My fuel pump keeps running before starting. It should cut off with in two or thee seconds and then stop until the engine starts. However, when I turn the key to the run position, the fuel pump keeps running and the engine will not start. If the pump stops the engine will start.

I am trouble shooting the electronic system to find the problem, and started with the crank shaft sensor. So, here is my questions:

The book says there should be 1.5 volt on one of the wires on the two contact which plug into the sensor. But, I tested these and there is 1.5 volts on both leads. I cant see how that would be normal.

I also checked the sensor with a volt meter and did get an slight pulse when my wife cranked over the engine. So, I assume that the sensor is ok. But, not getting a strong pulse, but several pulses of different strengths on the meter, not sure about that either.


I would appreciate any help please. Lead me in the right direction.

Also, I cleaned all the connectors with alcohol.

Thanks,

Mike in Virginia Beach
 


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bovine

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1994 ford explorer 4x4
It could be one of several possible things it could be a bad fuel pump, a hole in the line somewhere a bad fuel filter or a bad fuel pressure regulator. I would check out those things before I went into the electrical side of things.
 




mange1234

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1993 Ford Exployer
It could be one of several possible things it could be a bad fuel pump, a hole in the line somewhere a bad fuel filter or a bad fuel pressure regulator. I would check out those things before I went into the electrical side of things.

Thanks for the info. I checked all those things and all was good. Today I tested all the relays and they proved good.

So, took out the PCM and found a burnt/corroded condenser. I just posted a blog on the forum a few minutes ago. I got excited and wanted to share with the forum, so, took pics and rushed to the computer to send. Only to discover I could not post pics. May have to come off the $20.00. May be a good investment. As I have learned a lots on here in the few weeks as a member.

I was very happy to finally find a problem. Hate mystries.

I am going to try to make repairs myself. If that does not work, will have to go buy new PCM. Or go to pick and pull and get an old one. But, not sure how smart it is to take out a 19 year old computer and then turn around and put in another old one.

Thanks for response. I appreciate it.

Mike in Virginia Beach
 








jasondelane

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1997 Explorer Limited 5.0
Did it work, I have the same problem with 1.5 volts on both pins
 




mange1234

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Crankshaft Sensor on 1993 Ford Explorer 4 WD

Did it work, I have the same problem with 1.5 volts on both pins

Hey,

I tested the voltage and got a voltage on both pins. But, apparently, that is normal, because my old hoop has been running fine everysince I put the sensor back together.

Seems, I need to read up on the "Hall Effect"

Buy the way, I checked out my PCM (comouter) and right away saw that one of the capacitor leads was corroded and disconnected. I went to Radio shack, bought another capacitor and installed same on the computer circuit board. A very easy task.

Every since then, My old hoop is running great. Before, the fuel pump would keep running and car would not start.

How happy I was when I soldered in the new capacitor, put PMC back together, turned the key on and the fuel pump ran a couple of seconds and then stopped. (Which is what it is suspose to do) the the old hoop started right up. And has been running fine for months.

I learned a lots about this and the PCM from this forum. One important thing is: there are no new PCMs on the market, and the ones you buy will be rebuilt. So, unless your PCM is fried, change out the capacitor or capacitors yourself.

It is common for these capacitors to leak and corrode the leads.

Since it is so each to open and just have a look at the PCM solid state circuit board, I would say, open it and look, anytime you have a problem that is not obvious.

4.jpg


1-1.jpg
 




jasondelane

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So the 1.5 volts on both leads was present even after your fixed the capacitor? I'm confused now. The Haynes manual said it was supposed to have 1.5 volts on 1 of the wires, not both. I even cut the wires on pins 21 and 22 at the PCM and still got 1.5 volts on both.

I was going to buy a junkyard computer today but now I'm thinking there may be a different problem. I guess I'll just repair the connector at the crank sensor and try it.
 




jasondelane

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Found this while doing research today. Guess I dont need a PCM...just need to repair the connector.

2) Check For CKP+ Voltage Fault

Reconnect PCM connector. Turn ignition on. Measure voltage between CKP+ terminal at CKP sensor wiring harness connector and negative battery terminal. If voltage is more than one volt, but less than 2 volts, go to next step. If voltage is not as specified, go to step 19).
3) Check For CKP- Voltage Fault

Ensure ignition is on. Measure voltage between CKP- terminal at CKP sensor wiring harness connector and negative battery terminal. If voltage is 1-2 volts, go to step 10). If voltage is not 1-2 volts, go to next step.
 




mange1234

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1993 Ford Exployer
So the 1.5 volts on both leads was present even after your fixed the capacitor? I'm confused now. The Haynes manual said it was supposed to have 1.5 volts on 1 of the wires, not both. I even cut the wires on pins 21 and 22 at the PCM and still got 1.5 volts on both.

I was going to buy a junkyard computer today but now I'm thinking there may be a different problem. I guess I'll just repair the connector at the crank sensor and try it.

If you buy a PCM at the junk yard for a 1993 Ford Explorer, be sure to open it and inspect. Make sure the board is not fried and the components look good.

It is a common problem for the capacitors in this model to leak our a corrosive fluid and corrode the leads. (see my pic posted0

I will do my homework and find out why both leads have a voltage.

My truck drives good. knock on wood.

Good luck.

Mike


2-1.jpg
 




jasondelane

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Try backprobing it with the connector hooked up to te crank sensor. I only got 1.5 volts on one wire with it hooked up, both wires with it unhooked.
 




mange1234

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1993 Ford Exployer
So the 1.5 volts on both leads was present even after your fixed the capacitor? I'm confused now. The Haynes manual said it was supposed to have 1.5 volts on 1 of the wires, not both. I even cut the wires on pins 21 and 22 at the PCM and still got 1.5 volts on both.

I was going to buy a junkyard computer today but now I'm thinking there may be a different problem. I guess I'll just repair the connector at the crank sensor and try it.

Hello,

Upon reflecting on what I told you about getting 1.5 volts on each lead of the Crankshaft Sensor, I realized, that I did not test the voltage after I installed the repaired PCM. So, can not say if there is still voltage on both leads or not.

Sorry about the confusion. I will get under the car when I get time and check the voltage again while the truck is running well.

Good luck,


Mike in Virginia Beach
 




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