Hi everyone,

I have a 89 f250 with a 351w EFI and c6 trans and 4:10 gears. I have replaced everything possible, brought it to an old school ford mechanic, and can't seem to get it to stop running rich. I followed the truck home one day and it about chokes you out it's so bad. I get about 4 mpg.

I was wondering what options I had for engines and trans to put in this truck. I wouldn't mind a 4 speed to help out with the longer distances traveled. A straight 6 would be perfect. Is a donor truck the best option? What years? Could it be an F150?

I thought about just selling it and starting over, but it's rust free for the north east and perfect for what I use it for.

Thanks

 

Did you pull the codes yourself?

Sounds like you have a bad fuel press regulator or injectors that are stuck open. Pull the vacuum line off the fuel press regulator and see if it's squirting fuel out, if it does then it's bad.

Check fuel pressure and do leak down test....check while running, then when the engine is off the rail should hold pressure. If you can watch the fuel press drop, you have bad injector(s).

 

I have changed fuel pressure regulator. I suppose that doesn't mean it works, I will test it today.

Every other sensor on truck I have changed as well. The mechanic said he checked injectors but I may go out and buy a guage and check it myself. If it doesn't hold pressure should I replace all injectors or figure out which one is bad? When I come to a stop in drive, the engine likes to lope kind of, wanting to stall. Pop it in neutral and give it a little throttle and it evens out.

I have a obd1 code reader, I tried decoding the check engine light but had little sucess.

Thanks

 

Yes check everything yourself.

If it doesn't pass the leak down test, definitely pull all of them to clean at the very least. If you replace, replace them all.

 

Sounds good thanks a lot.

 

Try checking the codes yourself manually if your code reader doesn't work.

Ford ? OBD Trouble Codes

 

Lots of possibilities for en extreme rich condition. Check the FPR for leaks and also measure fuel pressure and check that it holds pressure after the pumps stop. Also check the carbon canister for raw fuel, if it is full of fuel then it's being drawn in from an overfilled fuel tank. And speaking of tanks.. is this a dual tank truck? If so there is a very common fuel transfer problem that will fill and overflow the unused tank. Also check the oil for the smell of fuel, if one or more injectors is stuck open because of either dirt or an electrical short then the EFI system won't be able to compensate. Finally if all that checks out OK then you could have a bad MAP or O2 sensor, there should be a code if one of these is fubar but sometimes there isn't, and if you can't seem to pull codes as in no response from the PCM at all then it may be toasted, so you'll need a new or reman PCM.

 

Thanks for all the help. I found this too.

http://www.therangerstation.com/forums/showthread.php?t=149506

They said turn the key to on, put the throttle to the floor and try starting the engine. If it starts, there is a leak into cylinders and if it doesn't then injectors check good.

How true is that?

Is it possible to post a video on here that I make and you guys could help me decode my check engine light?

 

the computer shuts off the injectors with the throttle position at WOT, so if it starts then

a)you have an outside source of fuel (or a stuck open injector)

or

b) your tps isn't capable (out of range) to actually get a reading high enough to cut them off.

for the purposes of your testing, I wouldn't rely on that procedure as a concrete piece of evidence pointing toward injectors, but its certainly worth a try. if it starts @ wot or sputters then it is more info pointing toward stuck open injectors.

 

Brining this thread back.

I went to my local mechanic and asked him to check the fuel pressure at the rail. It tested good and after I shut the engine off it held pressure for a good 5 minutes until we finally disconnected it. I checked my fuel pressure regulator and that tested good as well.

This truck only has 1 o2 sensor. Is that correct?

The truck also has only one fuel tank.

Someone mentioned a new PCM. Where can I buy one?

Also sometimes when I go to stop from driving I need to bump it in neutral otherwise the engine lopes and sometimes stall. Is that a engine issue or transmission issue? I have the C6 tranny.

And lastly, I have access to a carbed ford straight 6 out of an 85. If the PCM doesn't fix my extremely rich condition that may be my last option? What are my 4 speed auto options to match that engine?

Thank you!

 

Did you ever do any of the other things we asked? Like check for codes?

 

Yes I did check codes. On my code reader....

Key on engine off. Code 11 - No codes.

Key on engine running. Code 41 - System lean
Code 77 - Goose test fail

What is the goose test? WOT test?

Here is a video of the truck engine light test. Can someone please help me decode it?
I think I may have a small leak in my EGR tube. Could that cause my extremely rich condition as well?

I have check everything else everyone has mentioned.. I appreciate the help.

 

Code 41 system lea means the oxygen sensor is telling the computer the engine is stuck lean, and in response, the computer is enriching the fuel mixture.

 

That makes sense. So bad o2 sensor? Auto parts said I should have two, but my truck only has one. Are they right?

 

Parts store guys are clueless they only know what their system says and that is almost always wrong for these trucks.. better plan on at least 2 trips back there to get the correct O2 sensor. LOL.