Engine/Transmission (1994 - 1998) Is it time for new injectors?

[CRobbins]

Is it time for new injectors?



I just rolled past 317k miles and the engine just doesnt have the "crack" in the sound as it used to.

Its really lame/lazy sounding compaired to my boss's 03.

But what is strange is that I just got the highest fuel mileage that the trucks ever got, 19. 5 mpg. The average/max was 17 mpg.



CR



97 C&C, 215, 5spd, 15. 75*, afc/plate full forward, wg plugged, guages...

 

[CRobbins]

Gee, thanks for the info guys!

55 reads and no info...



All I'm asking is how many miles is too many miles on a set of injectors.



Thanks...



CR

 

[McCRam]

I'm not an expert on this. I had two bad injectors at 190k. He said the rest were weak, so i ordered a new set. It is not hard to pull them and take them to a diesel shop to have them tested. They didn't even charge me since I had just bought some parts from them.

 

[fortunate1]

How clean are they? Have you pulled them (or even 1) for inspection? Could be build-up (take them out & clean them). A few inj. holes could be plugged (same cure). I have over 330K now, but I upgraded to 215 at about 50K. You probably have the same 215's stock in your truck. They're still working great in mine. One last thought: have you checked your timing. It can slip a few degrees, and the truck still runs "fine" but not screaming. Mine stock is 12. 5; when checked it was actually 10. 5. Advanced it to 15. 5. Lots of improvement there.

 

[CRobbins]

With bad injectors there would be a miss I'd think, which I dont have. Its a little "cranky" when cold, but I've heard worse.

Timing was upped to 15. 75 deg 3 years ago, a major improvment.

I've played with the pump some, plate full forward, same with afc.

Checked the gov arm hitting the plate, its ok.

What is involved in cleaning the injectors? And if I take them out, I'd just rather replace them. I had found some 315 hp injectors with the correct spray pattern but haven't seen them in a while. They were from some place in Utah.

Oh, and I've replace the overflow valve a few times, that makes a big difference.



Any ideas are appreciated...



CR

 

[Joseph Donnelly]

I suggest that you didn't get a definitive yes or no answer becasue there isn't one. Over time the injectors wear. More problems can occur with dirtier fuel and with habitually too low or high egts. The pop off springs lose tension gradually, lowering pop off pressure and making it uneven cylinder-to-cylinder. Unless one or two malfunction, you just change them wehn you feel it is a good idea. Like how long between oil changes--do I "have to change it" at 4000 miles, or is 4500 OK? Well, what about 5000 miles. Gee, it depends on your level of concern and how you use the truck.

 

[JFaughn]

It seems these trucks are runnig way below the peak efishency , the injector hole grow with age , fuel cuts them , now your getting more fuel , also getting closer to peak eff. , so better millage , Thats my plan and I'm sticking to it .
Unless you have a better idea .

 

[tgordon]

Like john siad there is no definative answer, some people overhaul at a set number of miles/hours, others wait until the engine has lost power. All depends on what you want out of it and how you run it. If you want to upgrade your injectors it sounds like a good reason as long as you are getting new ones anyways go a little bit bigger.

 

[Vaughn MacKenzie]

A friend who has worked at a diesel injection shop for many years says injectors could use at least a pop check and quite likely a little work by 150,000 miles, and rebuild or replacement around 200,000. But like mentioned it all depends on how the truck was serviced, maintained, and how efficiently one wants it to run.



When I pulled the stock injectors out of my '96 at 353,000 miles they were horrible!!! Had HUGE globs of crud and buildup on the tips. The original owner never used diesel fuel additives.



Vaughn