When to replace Fuel Injectors?

[kurtjanson]

I have a leak in I think the fuel injector return lines and need to relace the o rings, return lines, etc to hopefully stop the leaks. I plan on getting the kit for this. Should I also relace the injectors while I am at it? It is a 1994 F350 7.3 Non turbo with 137k on it with original fuel injectors. How do you know when it is time to replace the fuel injectors?

[LMJD]

There's really no set mileage. I've replaced mine twice in 240,000 miles. My original Ford factory ones were CAV (Engilish pieces of crap) that needed replacing at 74,000 miles with Stanadynes. The Stanadynes lasted until 206,000. I replaced them a few years ago to eliminate a rough idle. It's a good idea to have new ones pop and spray tested before installing. I did not and had a worse idle than before so I had to pull them, have them tested, all 8 were out of specs, sent them back, the new set checked out, been good ever since.

[kurtjanson]

so I guess you are saying that it depends on how the truck is running? Running rough then try to replace the injectors? How about the injector Pump? Did you have to replace that yet? Thanks for you response!

[LMJD]

so I guess you are saying that it depends on how the truck is running?

To a certain extent. There sure can be other causes but in my case I was pretty sure it was injectors which it was.

How about the injector Pump? Did you have to replace that yet?

I would never replace mine, I'd get my existing one overhauled at an authorized Stanadyne pump shop which I did. Mine gave me trouble prematurely at fairly low mileage. In fact the pump shop owner asked me if maybe somebody had set the speedo back, which they hadn't, I bought the truck brand new right from the dealer. I'm convinced mine went out early at less than 100,000 because I fueled up once on a trip and the fuel was the color of diesel, but smelled more like gasoline. I questioned the station owner but the most he'd admit to was that that diesel tank had once been use for gas. I've got 165,000+ on the pump since he overhauled and calibrated it and hopefully I don't have to touch it for years from now. He said clean fuel, no water and they about last forever.

[3/4tonman]

As far as I know the CAV injectors in my truck are original, but starting to show their age. Where would you guys recommend getting injectors from?

[LMJD]

I've always got anything fuel related, fuel filters, injectors, drainback lines, from Diesel Injection Service in Lubbock, Texas. They've been a sponsor here for years, guess they still are. Good service, good prices, nice to deal with. They're the ones I got the bad Stanadynes from (not their fault) and they exchanged them no questions asked after I told them they were way out of specs.

[3/4tonman]

Pensecola Diesel has new Delphi injectors for $152 for all 8 of em. Anyone had any trouble out of these?