Injector o-rings in the kit

[erikv11]

But if we pay attention to history, we won't be doomed to repeat it!

Seriously though, read some tuning threads, look for the posts by people who know what they are doing. I'm not tuner, but I have read them enough to know that ... there is no gain with larger injectors without changing the ECU map and/other making hardware modifications. Here is one example post because it is easy to find, but there is a ton of information out there: https://www.matthewsvolvosite.com/forums ... hp?t=50558

I also agree that the best way to spruce up old injectors is to send them to someone for cleaning and all new parts. If you're just wanting to change the o-rings, because the old ones are dry and cracked and/or shrunk and not sealing well, then yeah spare parts from the junkyard the way I have gone. But rather than changing baskets etc. myself, I would send them to http://cruzinperformance.com/ for a refresh.

[kcodyjr]

Let me see how much I can ham this up with $5 words.

I concur unreservedly that uprated fuel injectors are contraindicated for this application.

In English, dear readers:

1st of all, uprated means higher-flow, because our stock injectors aren't physically flimsy in the first place. Higher flow means wider bore, because fuel pressure hasn't changed. This means that a greater amount of fuel will get injected for the same open time driven by the ECU. Without immediate reprogramming that specifically addresses that (a custom hardware tune), it's going to run way rich, and have to adapt, which it possibly won't have the range to.

Thus, a bigger injector on a stock ECU is asking for trouble.

2nd, our injectors not being flimsy, the only reason to uprate them is to get that increased flow, and fuel flow doesn't become an issue until you're running big turbos at high boost. There's nothing a 13G turbo is going to push that these stock injectors can't keep up with at any RPM, even at WOT, even if I went to higher-than-stock boost pressures.

Thus, a bigger injector is just not useful in an LPT engine until it's so modded it's not really an LPT anymore.

I have no specific indication of any injector fault. I also haven't really looked for one.

My desire is simply to do whatever long term maintenance refurbishment is practical and useful while I've got it apart.

Doing o-rings whether they need it or not sounds like a good idea. The lower will be easily accessible, and I only have to take the injector off the rail to get to the upper.

Unless someone tells me that, at 200K, I can expect to have to refurbish injectors at 220K, I don't see that it's worth adding that to the work list at this time, whether DIY or sent out. Maybe next year when it's due for timing.

When the time comes, I can see the wisdom and convenience of sending them out, but I don't think that DIY can't do the job just as well. I don't think ultrasound is the only way to remove the varnish inside the nozzle and inside the casing. My dad had a severe varnish buildup problem in a 1979 MGB's carburetor after sitting for 15 years. He couldn't dislodge it by chemical or reasonable mechanical means, and at my suggestion, because I knew it was chemically designed to prevent varnish, and it was worth trying to see if it was soluble, he soaked the parts in straight fuel stabilizer. It did wonders. He did have to rub out the bowl and body with a cloth soaked in the stuff because the buildup was so thick, but the small parts cleared right up.

I don't think it was the mechanical action of the cloth, though; otherwise, any decent cleaner on the cloth would have done it. It was the constant replacing of the chemical in contact with the varnish that got it done. So, my proposal would be to obtain a small pump and appropriate tubing, and continuously force straight fuel stabilizer through the nozzle. A submersible pump would be nice so you can just dunk it and the injector into a can of the stuff.

[j-dawg]

If the pintle caps are so prone to breaking, I'd rather just plan on replacing them.

I don't see 'em on FCP. Got a source? Tell me I don't have to go crawling through a junkyard...

I got them from eBay. That is the actual item I ordered a little over two years ago. I recall considering a 6-cylinder kit so I'd have the extra parts in case I needed them, and I didn't because I was in grad school and had no money. It worked out fine.

If you want to clean your injectors at home, I would add to your list of supplies a means of opening the injector. Not sure if it's as simple as feeding it 12v or if there's more to it.

[erikv11]

No, the injectors don't have a record of crapping out at 200k or any other mileage. Occasionally one does and burns a valve (according to my indy - I have never seen that), but I think that is mighty rare. Any cleaning service will also check the flow rate as part of the service.

You can help preserve the pintle caps by heating them up first before you pry them off or put them back on. Heat gun or blow dryer. Still I have broken a few.

[rguzz]

This place has a good reputation per Audi forums. None of these places are dirt cheap but if for some reason your injector cannot be rebuilt they will let you know at no charge. http://www.mrinjector.us. Looks like they provide all new seals, caps, etc.