94 F-250 5.8L 4x4 auto trans, non air.
It burnt a poston, so I put in a low mileage replacement, a jasper motor with less then 2K on it out of a smashed truck.
I get a check engine light, its not on when I start out and it might take some time for it to come on, sonetimes it turns back off again while driving. It always turns off turning the ignition off and then restarting it.
Seem to come on under moderate/heavy acceleration and go off when cruising at highway speed.
Sometimes the ABS kight comes on with it or shortly after the check engine light,not always, just sometimes.
The truck runs fine with or without the light on, the check engine light was not on before the engine swap.

Ford dealer told me if the light is not on when they try to retrieve the code, the code wouldn't be there. They won't connect the code reader and take it for a ride. All I have is an OBD 2 code reader for 96 or newer.


Anyone know what is causing this?

Thanks, Dan

 

Hi Dan, and Welcome to FTE! Please take a moment to check out the Guidelines as they contain important information you'll need when posting on the site:

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Without a code I can only guess at what's triggering the CEL, but I'd say it could be caused by the EGR. It could be the EGR control valve, or the EGR itself.

But the person you talked to at the Ford dealer doesn't know what he's talking about. The CEL doesn't have to be on to check for a code, codes are stored in memory and don't just dissappear the instant the light goes out. My guess is that you'll get a code 33 (EGR). And that's a code that shows up without even starting the engine.

You can check the codes yourself without a code reader, here's how:

http://fordfuelinjection.com/?p=13

 

Hi TigerDan,

Hey great, I really thought it was odd the code goes away with the light and my manual shows how to get the code. So when I was told at the dealer the code would only be there if the light is on when the key is turned on I didn't try it. I should have just tried it anyway.

I'll post back after I try it.

Thank you, Dan

 

No problem, Dan.

 

Ok I retreived the codes and this is what it had.

key on engine off- 626

Continuous memory- 172 and 334

KOEO. test results
626= Coast clutch solenoid circurit failure.

CM. test results
172= there is not a "X" in the box for the CM test so why or what does it mean.
334= DPFE or EVP circurit above the closed limit of 0.67 volts.

Could you tell me anything you can about the results and briefly tell me what to do and or check if you can.
Also do these results look like something that could trigger a Check engine light after a engine swap. Is all this associated with sensors on the intake area that would have been on the other motor and came over with it when I did the swap. (is it something I need to get off the original intake, I still have it) Ie. eegr vale, throttle position sensor. and others that would be on the intake area.

I really appreciate your help, I'd just take it in but every time I do they charge me 75 bucks to look at it to tell me they can't find anything wrong with it!

Thank you, Dan