Injectors in a 99 7.3

[Kayakn]

A friend of mine "pinged" the injectors. He said the number seven sounded very hard to hear all others sounded great. Does that mean the number seven is bad?

[dray8165]

Did he ping them or buzz test them? If he buzzed them, and #7 was hard to hear, it means either the solenoid is going out (rare) or it is worn and binding inside - either way, it should be replaced. A confirmation of this would be to do a cylinder contribution test (using the same scanner he did the buzz test with) - if the PERDEL reading is over 5% then, the injector is likely bad

Note - over 5% doesn't always apply to #8 or #3 depending on what CPS you are running...

[Kayakn]

Well the injector has been replaced. Back in the truck today, now it's blowing white/blue smoke when you gas on it. It never done that before. The real test will be tomorrow in the morning to see if the truck cranks smooth.

[dray8165]

When you swap an injector, quite a bit of oil and fuel get dumped into the cylinder. You are supposed to suction it out, or blow it out through the glow plug hole, but some will remain and have to be burned off. Also, you get air into the fuel rails and high pressure oil rails - that sometimes takes 20-30 miles of aggressive driving to get all of that out.

[Kayakn]

Ok, thanks so much!!!!

[Kayakn]

Well the new injector didnt take care of the rough idle in the morning. Is it common to have one or more injectors go out at the same time or when you install a new one? Should the injectors all be replaced at the same time?? Thanks for all your help!!! I would love to have my truck back to normal

[dray8165]

The injectors "wear" out together, but don't fail as a unit. I would want another cylinder contribution test to see which one is at fault. Also, there are other causes of a rough idle when cold - such as an IPR o-ring leaking, ICP failure, exhaust back pressure valve engaged, etc...