I have a 1993 F250 with a 5.8L 5spd, 4x4. The cat has suposedly been punched out by a previous owner, whatever that means - since the GVRW was raised so it doesn't need any emission testing. I've only had the truck for a few weeks and the check engine light comes on and off, mostly comes on when gear down and goes off after 30-60 seconds usually. but comes on during any drive.

any ideas?? Would the cat being punched out have something to do with this? Will the cat like this give me more power and fuel milage, or the opposite??

thanks

 

Pull the codes, something will show up if the check engine light is coming on.......Then tell us the code number/s.

 

sorry to be ignorant, but how do I pull the codes???
this is my newest vehicle, My last truck was a 1980 f250 and my other car is a 1970 Torino, so never dealt with computers, codes, etc..

thanks
mat

 

Connect a length of wire(I use single strand doorbell wire) from the sig-rtn to the STI. Get in your truck. Move the key to run but dont start the truck. The check engine light will blink. It will blink once to tell you it's starting the Key Off Engine Off test. It will then flash a number of times, say 5, then have a slight pause, flash again, say 6 times. That's code 56. It will have a longer pause, then go into another code if there are any, or blink once to tell you it's going into the memory to tell you codes that occured recently while driving. All this information is available at fordfuelinjection.com. Check what the codes are here
http://fordfuelinjection.com/index.php?p=14 for 2 digit codes
http://fordfuelinjection.com/index.php?p=45 for 3 digit codes(you should have these)

 

One more stupid question, where do I find the sig- ret and the sti, thanks
mat

 

Great info from Nep. You should find both connectors bundled on the drivers side inner fender near the washer bottle under the hood.

 

Those connectors would likely be near the hood spring mounting point on the driver side fender. Here's another site that may help you count the blinks: http://www.thorssell.net/hbook/eectest.html

 

thanks everyone, I'll post how it goes

mat

 

Ok, I think I got the codes right. Put in wire, turned key to run
the check engine light faintly flickered. Pause. 111 pause 111 long pause 1 long pause 327 pause 328 pause 327 pause 328
pretty sure that's what happened, does that sound right?- I got the 111 code twice, than long pause and 1 blink to say going onto recent driving check codes????
111 on web decode says" system pass" - guess good
327 "DPFE or EVP circuit below min voltage of 0.2V "- Is this serious - remedey??????
328" EVP circuit below min volt of 0.24"????? So guessi g EVP circuit is below th 0.2 - 0.24 volts, what's this mean, what does this effect of cause, how do I go about fixing this?
Thanks again for all the help and handholding, very much appreciated
mat

 

EVP is the EGR Solenoid. It has 2 names. It's on the right side of your engine if you're looking at it from the front. If you can't find it look at your vac diagram on the hood(might wanna grab a magnifying glass the print is small). My guess is it's bad since it's not putting out the right voltage. The CEL is intermittent because the EVP is only activated in certain conditions, so it won't realize the problem until it's activated. I had the same problem but I had Code 332 which was EGR valve failing to open. My problem was the vacuum canister having a hole in it, so there was no vacuum to open the valve with. Your best bet is to check all the wiring going to the EVP. It also has vac lines connected to it, so check those too just for safe measure, even though they aren't throwing your code. If the wiring looks sound, which it should, replace the EVP. They run about 50 bucks on rockauto, or you can take the gamble and pull one off of a donor truck, which I wouldn't recommend. You can also just live with it, as it won't affect how the truck runs, except for the mpg very slightly at highway cruising speed. I fixed mine just so I didn't get into the bad and common habit of ignoring the check engine light. Now it's actually a usable warning sign instead of just "that annoying thing that's always on." Sorry for the rant, I hope I didn't confuse anyone lol

 

Don't worry about the rant, thanks very much for the info. I think I'll replace the EGR, since I do a lot of highway driving and was already thinking of pulling the Anoying flashing "check engine" light. Thanks a lot for the help, these modern computer controlled vehicles are pretty handy at time.
Mat

 

dont replace the egr valve. replace the EGR solenoid. A new valve won't fix a broken solenoid, and why replace the old one if it isn't broken? Lol

 

copy that, egr valve only

thanks again mat

 

sorry meant EGR solenoid

 

haha it's cool. EGR valve also costs just a tad more than the solenoid lol