With hard starts, white smoke and black fuel filter I'm heading under vc's tomorrow to do o ring swap (if they show up today). Question, is their any physical signs obvious to a newbie of worn-out injectors?

 

Also does it make sense to evacuate hpop before pulling injectors?

 

Evacuating the HPOP reservoir won't do any good before pulling the injectors. You can pull the back two injectors first and let most of the oil and fuel drain in them, but you're still going to get fluid in every hole. Just be sure to evacuate the cylinders before it's all buttoned back up. And don't leave an extra copper washer in the bottom of an injector cup.

 

One visual sign of bad injectors is to watch the oil discharge with it running and that will not tell the whole story but give a good idea. You have to do that when you can make it run either before or after doing the o-rings.

 

Just a fair warning:

If your current injectors have 200,000+ or are approaching that mileage within a few ten thousand, don't waste your time just changing the o-rings or you'll be back in there again soon just doing an entire injector job due to worn poppets.

If you don't know the symptoms of worn poppets, they include:

• Missing on cold starts
• White (fuel) smoke until warm
• Rough running and no power until warm
• Hard starts (even when plugged in and with functioning glow plugs)

 

This might help you...

7.3L Power Stroke Injector Replacement | Ford Diesel Performance Parts Blog

 

My opinion is this is just a rule of thumb, and there are always exceptions to every rule. I've seen a 500k truck that still had it's stock injectors. I swapped mine at 350k just for peace of mind. I had no issues with smoke, cold starts, rough running, and saw no improvements, including MPG's when I installed new injectors.

I do believe tuning has a lot to do with injector life. The trucks with tuning seem to need injectors closer to the 200k mark than the stock trucks do.

Then again, I've seen stock injectors fail in less than 100k, so sometimes it's just a roll of the dice.

 

Put new injector hold-down bolts in there. Sorry... milehi_350 is in on my adventures and I had to throw that in there.

 

170K on mine and I just replaced the o-rings. I used a shop vac and small hoses to suck the oil and fuel out of the rear two cylinders.

 

Stinky was running good at 260Kwith no problems other than a shakey idle... but I had lost two injectors a year ago. I replaced them more for a precaution than a search for a power-up.