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ECU / PCM Not Responding (Dead?) - '96 Contour

B

Bayley

New CEG'er
Joined
Apr 19, 2008
Messages
17
Location
Jiveonia, MI
Well, I'm about ready to start hurting small animals. :mad:

Last week while trying to get the radiator to take coolant (much more difficult than it sounds... because it's a Furd ya know...) I had the engine idling in the driveway. Suddenly, out of knowhere, the engine just dies.

I checked the fuel pressure and it was zilch. However, I was able to jumper the relay and run the fuel pump up to 42psi. Next, I tried to read the fault codes using my OBD scanner. No luck! The ECU was not responding. :cry:

I checked all the fuses and they were fine. What now? Does anybody have the pinouts for a '96 2.5L V6 ATX Contour? I'd rather beep out the harness and verify that I'm getting power to the ECU before I swap in a new one.

Please, I need help. Nobody wants to see me hurt small animals!!! :shocked:

-Andy
 
start checking your wiring harnesses, particularly at the fuel injectors, if there are wires exposed, I am willing to believe your harness is the culprit, we had the same issue when doing a 3L build, car was running for a minute or two, then it died and we stopped getting PATS and the Computer.

and you did check the fuses under the driver side of the interior and the engine compartment right?
 
AliasJerk said:
and you did check the fuses under the driver side of the interior and the engine compartment right?
Click to expand...

Yeah, I checked the fuses inside and the fuses / relay outside. They all beeped out just fine.

I agree with your hypothesis that something has shorted out in the engine harness, but I wanted to verify the connectors first. I suppose I"m just making more work for me in the long wrong. I've seen worse harni (plural for harness?) but not by much. I wonder if the FOUR trans swaps I've recently performed pulled something loose under the hood.
 
projectSHO89 said:
See if your CEL comes on during bulb prove-out. If so, the PCM is getting power. If not, you've lost primary power.

Steve
Click to expand...

what he said.

Also check the harness under the fusebox when this happened to me on my 96 I had a wire corroded clean in two under there.
 
The Engine Light is NOT coming on when I turn on the ignition. All other igntion related items (radio, HVAC, windows, etc...) come on with the ignition, but the PCM remains dead.

I'll have to start checking fuses and probing wires tonight... assuming it stops raining sometime this week. :eek:

Might have to trade the Contour for an Ark pretty soon.
 
UPDATE:

I learned that the 20A main fuse under the hood that powers the PCM is blown. Thank you Tony2005 for pointing that fuse out. There was no mention of that fuse ANYWHERE in the Furd owners manual. :mad:

I put a new fuse in last night, but it imediately popped once I turned the ignition switch on. The last time this piece actually drove, the speedometer was cutting out. I then noticed that the wires on the speed sensor are frayed and exposed at the base of the sensor. I'm going to disconnect the sensor tonight (when I Get home from the rat race) and see if that stops the immediate fuse popping.

Wish me luck!
 
Bayley said:
UPDATE:

... The last time this piece actually drove, the speedometer was cutting out. I then noticed that the wires on the speed sensor are frayed and exposed at the base of the sensor....!
Click to expand...
Frayed wires at the VSS is very common with the Contours. I had that too! :blackeye:
 
Well, I have a speed sensor that came off a '95 Contour (I think). It looks identical to my '96 sensor except that it has a physical old-fashoined cable coming out the top of the sensor. I'm thinking about removing (read: hacksaw!) the cable, dabbling a bit or blue RTV over the cable hole and installing the '95 sensor. The wires are in beautiful condition.

I tried to fix the '96 sensor once already, but the quality of the wires are so "Fordtastic" that they have already deteriorated away to the same point that it was in before I made the repair. I didn't half a55 it either. I cut the sensor wires in half, heat shrank (is that a word?) some new insulation around the original wires at the base of the sensor and re attached the hardness connector. By the time I had reinstalled the transmission back into the car, the wire insulation had already slid up the wire a good 1/4 of an inch... including the heat shrink.

So... I'm going to try the '95 sensor and see if that works. If not, I guess I'll take another crack at repairing my '96. For a quick "one-week-flip" (that I started in late March), this Contour has proven to be quite the headache. :cry:
 
Bayley said:
Well, I have a speed sensor that came off a '95 Contour (I think). It looks identical to my '96 sensor except that it has a physical old-fashoined cable coming out the top of the sensor. I'm thinking about removing (read: hacksaw!) the cable, dabbling a bit or blue RTV over the cable hole and installing the '95 sensor. The wires are in beautiful condition.

I tried to fix the '96 sensor once already, but the quality of the wires are so "Fordtastic" that they have already deteriorated away to the same point that it was in before I made the repair. I didn't half a55 it either. I cut the sensor wires in half, heat shrank (is that a word?) some new insulation around the original wires at the base of the sensor and re attached the hardness connector. By the time I had reinstalled the transmission back into the car, the wire insulation had already slid up the wire a good 1/4 of an inch... including the heat shrink.

So... I'm going to try the '95 sensor and see if that works. If not, I guess I'll take another crack at repairing my '96. For a quick "one-week-flip" (that I started in late March), this Contour has proven to be quite the headache. :cry:
Click to expand...
Don't waste time with the 1995 sensor. It won't work.
 
UPDATE:

With the ignition switch ON, there was a short circuit from the fused supply to ground. When I disconnected the speed sensor, the short circuit went away and I was measuring ~650 ohms between the fuse and ground. :cool:

Unfortunately, I ripped a wire out of the knock sensor harness while trying to disconnect the VSS. :mad:

I'm going to take both of my sensors (the 95 and 96) into work tomorrow and hook them up to a scope. While both sensors have three of the same colored wires, they are not layed out the same between the two sensors. I'm going to hook up 5VDC to the sensor and make sure I'm getting a speed pulse out of the same wire.

Of course, I'll need to re-wire the knock sensor while I'm at it... not looking forward to that one. :nonono:
 
Bayley said:
Is it because of the mismatched wires, or something else?
Click to expand...
The early 1995 used a cable driven speedometer. Not knowing what period of 1995 the VSS came from, it could be a cable driven one (or the wires would not be mismatched).
 
Tony2005 said:
The early 1995 used a cable driven speedometer. Not knowing what period of 1995 the VSS came from, it could be a cable driven one (or the wires would not be mismatched).
Click to expand...

Then here's a wierd twist for you... my '95 sensor has both! :eek:

Yes sir, there is both a cable that runs out of the top AND an electrical pickup signal. I ran both sensors on a scope at work and they both generate the same electrical signal. The catch, is the the wires are layed out different. If one were to cut the '95 wires and color match the wires to a +96 VSS, then there wouldn't be any problems. Also, the cable simply threads onto the top of the sensor. It was very easy to remove. Of course, there is a small hole that will need to be blocked (i.e. glob of RTV) but it should work in theory.

Personally, I went ahead and reused the old '96 sensor. I re-did the wires again... this time making damn sure they weren't going to pull loose this time. I probably used 1/2 a stick of hot glue at the point where the wires meet the sensor. :laugh:

I was hoping to drop in the new sensor today after work, but it has been raining since I've gotten home. Hopefully by tomorrow night I'll have good news.

-B
 
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