The engine I have is at 150k and I am replacing the injectors. Should I go ahead and replace the cups while I am at it? Or should I just leave them be? I'll be replacing the cups in a truck with over 350k for sure so ill have the tool kit on hand.

 

I'd replace them when they fail (unless you have an early model engine and switched to ELC coolant, then I'd get out in front of it)

I replaced my factory injectors back around 300,000 miles. Left the factory cups in place. Now sitting over 515,000 miles and the factory cups are still doing just fine.

 

Well, that all depends on your level of boredom and length of the Honey-Do List.

From your post, you're going in to do the Sticks. So "what I would do" is:

Compression Test
New Cups (depending on compression test)
New Glow Plugs
Updated UVCH's

and, be done with it.

And here is the $1m Question? Stock, New, or otherwise.

I say this because, depending on the route, and manufacturer process, you could well be seeing the under side of a Valve Cover more than you ever wanted to.

I've done them all for all kinds of people.

Mine....... Stock Motorcraft OEM's ONLY!

 

Thanks! Are you inquiring about cups or injectors? You can give me your input on injectors in this other thread of mine: https://www.ford-trucks.com/forums/1...r-size-qs.html

 

And what updated UVCHs are you speaking of?
Thanks!

 

The cups are not under any real strain, unless the copper washer on the injector tip gives way, or a failed fuel O-ring on the injector has allowed the fuel pressure to whittle at the seal. Doing cups has the potential to introduce a redo, so I wouldn't want to do it - unless I saw signs of strain or it failed a leak test.

 

Thanks Rich. How do I perform a leak test?

 

Additionally, should I just order cups in case one is bad? I don't want to get the injectors out of that truck with 350k+ and then find out that I need cups and then have to wait for the tool to come available from Clay? And if I buy them, I feel like it would be a waste of money to not replace them.

 

If they are not leaking, leave them the hell alone. It's a big job fraught with complications when done in frame.

 

If it aint broke, don't mess with it.

 

I couldn't agree more with that.

 

So what if I open up the truck with 350k on it and find out they are bad? Then I am just stuck until clay can send me the tool...

 

Rental cup tools are always ready to ship, we have over 20 rental sets now so if you need them they would leave same day.

 

Exactly what I needed to know! Thanks, you guys are awesome!

 

One other thing then, Tom mentioned a doing a compression test for the cups. What is the best way to facilitate this, and how do I know its the cups that are the culprit? Are there any other signs besides visible cracks to be looking for?