I was driving my 92 F-250 351 yesterday and had to make a semi-long trip. I drove about 80 miles one way and did a little driving around in the town, then I proceeded home. Everything with the truck seemed normal. Then on my way home (about 10 miles from my hometown) the truck all of a sudden started to slow down. The check engine light came on. I pressed on the gas pedal and it did nothing so I pulled over on the side of the road. Before shutting it down I tried to go again and nothing happened. Then I turned off the truck. Ten minutes later I turned the truck back on and everything seemed normal again (no check engine light). I was able to drive it home with no unusual symptoms.

I'm completely clueless about what happened. I was running on a full front tank (empty back tank). My oil pressure and temp gages don't work. I check the oil and tranny fluid, they were ok. radiator fluid seemed ok, no weird smells or noises. I notice the ABS light stays on for a second when I start the truck, don't know if this is normal operation. I know my brake shoes are worn pretty badly and I have an exhaust leak.

I want to check the codes but am unsure how. I've seen the website listed in the forums and don't quite get it. All I need to do is wire the STI to the body ground? Then count the flashes? Also, if I pull the codes will the computer store them so that I can pull them again or will it reset the computer? I know this is probably very simple, but I know nothing about this.

Sorry for the book.... just wanted to supply any information that might be helpful. If anyone has any suggestions of what to check and how to check it, that would be greatly appreciated.

 

This is probably the best article on the subject (if you didn't happen to find it before):

http://fordfuelinjection.com/files/self_test.pdf

There are 3 sets of codes: KOEO (Key On, Engine Off), CM (Continuous Memory), and KOER (Key On, Engine Running).

When you do the KOEO test, you get the KOEO and CM codes, separated by a single flash of the CEL with a 6 second or so pause both before and after.

KOEO codes show sensors that are giving out of spec readings in a static state when only the ignition is on. You should have the engine fully warmed before you do this test.

CM codes show errors that have occurred in previous drive cycles. These codes are lost when the battery is disconnected for a time (5 minutes will usually do it), or when the STI-to-ground connection is broken during the self-test.

KOER codes show real-time out-of-range readings on sensors. This should only be done on a fully warmed-up engine or there will be several false codes that show up.

All codes can be cleared by breaking the STI-to-ground connection during the self test.

Hope that helps. I would suggest reading the codes several times until you get the hang of counting the flashes and knowing what it is telling you before/between codes. It can also be helpful to have an assistant to write the codes down for you so that you don't have to take your eyes off counting the flashes.

With a '92, I think you have 3-digit codes.

Jason

 

jroehl,
using the website you mentioned I attempted a self-test. I connected the self-test input to ground and started the engine. No CEL. Keeping the connection, I turned the engine off and just turned the key on. the CEL just stayed lit as it normally does when the key is on but the engin is off. any suggestions? when the truck is warmed up, the CEL is not on, it just happened the one time the truck stopped.
Bryan

btw, where is mulberry, IN, i'm from bloomington, IN

 

Something's not right in your self-test connection, then. With the STI grounded, and then the ignition on, the CEL should go off almost immediately.

Mulberry's about 20 min SE of Boiler country...

Jason

 

i'll try to pull the codes again tomorrow, but it seemed simple enough, couldn't see how i'd f it up. the website you mentioned has a "no codes" trouble shooting section, but its like a foreign language to me, sounded like i'd have to rewire the whole truck to get it to work...

 

Even our fearless Moderator, Justin (mustanggt221), who has much knowledge and skill, had problems recently trying to pull codes on his truck--it ended up being a poor ground or connection.

Whether or not there are codes, you should get a blinking CEL. In the KOEO, the light will flicker first (after your fuel pumps run twice). The fast flicker is blinking out the codes for a code reader in about 1/4 second. Then, even if there are no codes, it should blink out: 111, pause, 111, long pause, 1, long pause, 111, pause, 111. That's the KOEO code 111 (system pass) twice, separator flash, then the CM code 111 (system pass) twice.

I actually have a length of Romex ground wire under one of the hood spring bolts (paint scraped off under the bolt head first), with a spade terminal on the other end so I can easily plug it into the STI terminal anytime, anywhere.

Jason