7.3 Bad #8 Injector
 

sooo... my 2000 F250 was down to getting about 6 MPG. I took it to the dealer and then ran it through the "tests". They told me #8 injector was bad and they replaced it. Heres my question.. will 1 bad injector cause a drop in fuel economy of 70 percent or more? SHould I believe they have found the problem or dig deeper?:-huh

Thanks ahead of time!

Does the truck seem to run better now than before they changed the injector?

I would personally be skeptical of the idea that one injector could dump enough fuel to cause that big of a drop in fuel economy? Was it smoking excessively? maybe it had a cracked injector tip...?

On my way to pick it up now... Ill post back and let you know. Something just doesnt sound right to me.... we'll see.

Ask them how they came to the conclusion that the #8 was bad. When I do a CCT test with the AE, #8 always comes out bad, but I know there is nothing wrong with it.

According to my fuel records...one bad injector yields a 20% reduction in mpg.

EDIT: "bad"= Not firing (loose armature plate).

My #8 injector went bad at 25K..(sounded loud and noisey) and Ford replaced it with a long lead under warranty.. been good ever since. Woodnthings just did a buzz test on all of them yesterday and they checked good..

I have replaced two injectors that did not need replacing. A buzz test was done and #6 and #8 did not buzz sooooooooooo I replaced them when all that needed done was replace the solenoid, if that is what they are called, on top of the injectors.

Don't rely on a buzz test.

OK... back from the dealer and here is what the work order says: "PERFORM POWER BALANCE TEST CYLINDER 8 LOW PERFORM MANUAL COMPRESSION TEST 390 PSI REMOVE AND REPLACE #8 INJECTOR ROAD TEST OK"

Other than a bit smoother idle, I cant really tell a difference. I filled her upo to the top, added 16 ounces of Power Service Cetane booster and will run it to find the MPG now.

BTW, I have a Bank's tuner chip in it now... im getting the vibe I should rip it out and go DP... any feedback?

#8 is last to fire and checks bad on a scan most of the time, and most of the time it is fine.

Thanks for all the replies!! But here is the million dollar question... if I cant rely on th dealer for a proper diagnostic or repair then whom can I turn to?
As I posted earlier, I just purchased this 2000 F250 with 142k miles on the PSD. The truck was taken care of and seems Ultra Clean in terms of the interior, paint, etc.
We are getting ready to go on a family vacation that will entail 3500 miles of mixed driving in CA, NV, AZ,UT, WY, SD, NM all the while towing 26' and 8500 pounds of travel trailer.
I know we cant always plan for everything, but the last thing I want it to have this truck take a crap on me in the middle of nowhere.

So bottom line... where do I go thave this tuck ran through a COMPETENT diagnostic?

Oh yeah, 1 other thing... does anyone recommend I pull an oil sample and send it in for analysis? and if I do, how many miles should be on the oil before doing so?

Thanks!!!!!!

Right here! These guys will step you through the trouble shooting themselves. There is little you can't do with the help of this forum and a scangauge or scan tool. Keep asking the questions and these guys will steer you in the right direction.

what city/st you live in

What part of calif are you located in..? Maybe someone here with a AE analyzer can drop by and check your engine for problems.. Maybe start a new thread with the subject "Anyone near "......." with a AE.

His profile says, CA.

His profile, not showing up on my screen...i meant "avatar" profile, just found it.