what are the symptoms of a failing injector ??when i am in tow haul mode going up a long hill up to where i live i have the truck running up the hill at about 30-35 mph and at about 2000rpm .. and ever so often it will have a slight miss .. nothing to bad but i don't think that is right .. and if i HIT IT wot it seems to clear up .. i am sure if i brought it into the ******* they would say it is fine .. but i don't think it is .. happen also when entering the freeway .. thanks for any info

Gary

 

Usually white smoke at start-up will give you the signs of leaking injector.

 

thanks for the fast reply .. well i have no white smoke at start up .. i have tried additves etc. but they don't seem to clear the problem either .. like i said it is very subtle but it is there .. almost like a gas engine missing when under load .... hmmmm

 

Injector pump?

 

geesh i don't know !! even when i started it up this morning it ran kinda rough at idle ... man !! i don't wanna take it to the ******* !! i really hate going there .. i would rather go to the dentist for a root canal !!!

 

Have you checked to see if your mileage has decreased? That's usually one of the first signs that something is wrong.

You said you tried some type of fuel additive - have you tried both Howes and Power Service? If so, you may want to try adding a much larger dose.

It's interesting since it seems to work fine under certain conditions - so I would think an injector is fouled up, vs failing. But that's just my best guess.

Before bringing it in, maybe wait till the next time you take a long trip towing something - if you really make the engine work, higher rpms under load, it might clean itself up - assuming it's fouled up.

 

I had a '94 GMC 6.5. It started doing that once in a while. The first time was up a hill. It was the injector pump. (I've used a conditioner with the diesels since then.)

 

Probably one of the first signs of injector failure is your dealer service department telling you "there is nothing wrong, that is normal".

 

well that is what i am afraid of !!!! .. injector pump ?? really ??? yikes !!!!

 

A leaky injector will give you a longer than normal crank time .....then eventually the truck just wont start up. Water in the fuel is a major factor to failing injectors.

 

Change that fuel filter & hit another dose of fuel conditioner, I use what NAPA sell behind the counter & it is cummings approved. The name slips my mind, sorry.

 

well , i change my fuel filter , every oil change (every 6500 km 4030 miles ) and i have been running howes and power service these 3 things dont seem to help it ... ... it seems to start fine .. but runs rough when i first start it in the morning . but once it is warm it idles nicely ...well i have to take it to the ******* again to get the weather stripping replaced AGAIN !!! so maybe i'll tell them about it ... i know they'll say it's fine !! anyway thanks for all your you guys !!

Gary

 

Mine is doing this too,runs great then all of a sudden it will knock then smooth out again,it is steadily getting worse.

 

I'd throw in my .02, but I'm a dealer tech so you obviously don't want hear anything from me.....and you're common rail setup doesn't have an injector pump, but rather a high psi pump to keep the rail charge at spec.

 

now why would you say that ??? your just the guy all of fus would love to hear from ???!!! if you have some info please do tel ??? then it gives us some info that might be able to send our dealers in the right direction ??!! thanks for any info !!!