Greetings,

I'm a brand new member (Welcome thread)

I've obtained the codes from the KOEO test on the '94 F250, and they are as follows:

12- Idle control fault
25- Knock not sensed during dynamic response test
65- Check intermittent HO2S (signal or ground) Fuel control

I've read from a different couple places that the 25 can be ignored if the motor is not knocking.

The reason that I got the codes in the first place is that the motor, when accelerating, will lurch and act like water in fuel or like it could be running out of fuel. I have not tested this using both fuel tanks, only the forward tank. From past experience, it makes me think of a vacuum problem or a fuel delivery problem? It doesn't happen 100% of the time, but a majority. Sometimes if the truck comes to operating temp. and is cut off for a period of time, then started again, the problem is no longer present.

I have an bit of understanding of what the codes are saying, but my question is where if any, is a resource that may point towards the next step in addressing the problem that the codes are representing?

Thank you in advance for any information!!!

Jeff

 

https://repairpal.com/gm-obd-code-12

https://repairpal.com/gm-obd-code-65

I wouldn't worry about the knock sensor for now. Sandy

 

25 is not a KOEO code and also it is not even a 1994 Ford code at all.
The last year Ford trucks had a code 25 was 1993.
What did you use to get theses codes with?
I would think you would have three digit codes not two.
What engine and transmission do you have?

 

I just googled those codes for him since he is new and didn't really check further. They are for a GM Now I don't even see a code 65 for the 94 F250. Thanks Subford for catching that.

 

12 Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) - ISC

25 Knock sensor not tested (ignore if not pinging) - KS

65 Check intermittent HO2S (signal or ground) - Fuel Control

From OBD-I Diagnostic Trouble Code (DTC) Applications - 2-Digit Ford Codes and a couple other places online.

Got codes by performing the test outlined here. https://www.2carpros.com/articles/fo...-and-retrieval

5.8/351 EFI Gas
5 speed manual 0-D HD Trans

 

You can clean the idle air control by taking it off and using throttle body cleaner. I think some use brake cleaner but you might search just to make sure. Just don't let it get into the motor area of the part. Keep the motor side up as it is soaking. Use a new gasket and while you are at it pull the throttle body and replace that gasket also. They deteriorate rapidly. Put them on dry. Most people say the cleaning of the IAC MIGHT help, some say it does help but short term. If you get positive results when you do the above just buy a new MOTORCRAFT IAC. Don't cheap out on that part, and be done with it. With your symptoms, I would do this first and then address the others. Sandy..... If you plan on sticking around (hope you do) go to your user CP and put your truck info in there so others will know what you need help on without having to put it in every time.

 

Thank you Sandymane, I'll do this.

 

What is your build date ?
Assuming he has a stock system, it would not surprise me if a 94 has 2 digit codes.
He might have an early build date as well.

Code # 12 – Cannot control rpm during high rpm test
This could be many things; Air Bypass, TPS….. Vacuum leaks…
Never hurts to clean up the Air Bypass like Sandy describes

Code # 25 –(KOER code) Did you perform the WOT procedure after the Code # 10 appeared?

Code # 65 was used for a multitude of applications.
Do you have an E4OD? Overdrive Cancel Switch?
((R) E4OD truck - cycle OD cancel switch after engine ID is received – Transmissions)
Do this switch toggle immediately after the Cyl Code “8” appears.

Seems he ran a KOER Test (was your engine running?)

Can be a 2 or 3 digit code depending on model, build date & configuration
2 Digit – Thru 93’
3 Digit - Starting at 90’

Engines are easier to diagnose over the internet when all the codes are listed, and in order of test. Thanks.

KOEO - (O) Self-Test Codes =
KOEO - (C) Continuous Codes =
KOER - (R) Self-Test Codes =

 

You are welcome. VJ that just posted helped me with some similar issues. He can give you much better knowledge and help. I strongly suggest you follow his advice and suggestions. Good luck Cowboy and keep er in tune.

 

I still think you would have three digit codes not two.
I think those codes are all wrong.
There were no engine left that had a Knock sensor and two digit codes in 1994.
The one in 1994 that had the Knock sensor were three digit and the code was 225 for the Knock sensor.
Also the 5.8L engine like he has did not have a Knock sensor for any year..

 

I agree with Bill.

 

I think this is what happened. He actually has two three digit codes both of which are real obd 1 codes and one for sure is for his 94 250 5.8. So, I think he had legit codes 122 and 565 ....... He wrote down 12-25-65........ 122 TPS low voltage... 565 canister purge circuit. Yes, I did run Scotland Yards in the 70's

 

I don't see a Knock Sensor in the 94' 5.8L schematic. Only the 4.9L & 5.0L

Ahhh, Sherlock, aka Sandy is on the job.......

 

VJ see above

 

FYI -




Looks like the 7.3 was the only configuration still using 2 digit codes in 94'.