Used PD injectors

I'm at 308k and considering replacing injectors for the next 100k. At about 1000 bucks to have dbw rebuild my injectors I don't see that happening.
If I come across used injectors of a suitable mileage that have been involved in a runaway, timing belt break or a run dry of oil are they subject to damage from those events?

Generally those events shouldn't hurt PD injectors.

If there's loose debris from something else, like a broken valve, it may smash against the injector nozzle.

If the engine is run out of oil, I think the engine would seize before anything happened to the injectors. The injectors are only splashed with oil that is flying around under the valve cover. They probably benefit from some oil residue on them, for the moving plunger. The part that the injector rocker presses on is replaceable and comes with the seal kit. Normally you'd be installing a new seal kit when installing the injectors, so that part would be new anyway.

Why are you thinking you need to replace them? Smoking? Power loss? Preventative maintenance?

Some smoke sometimes. Boost hoses have been gone through. Dog collar, replace connectors at intercooler, another seal on the pancake pipe all have been done. No codes but mpgs and power are off a little. Its been more than a year since balance in injectors has been looked into. At that time one injector was too far out of balance.
I understand that these injectors last longer than the ALH ones but they aren't going to get any better with age.

Do you still have a functioning EGR system? By now your intake manifold and intake ports on the head may be clogged with soot, if they have never been cleaned.

There could be cam wear at that mileage too. With correct oil they will last a long time, but if you've used 5W30, or an incorrect oil, that increases the chance of cam wear.

What about your turbo? Is it still the original?

Any chance your parking brake mechanism is sticking on, on the rear calipers? That's a very common problem with these cars, and wouldn't be good for MPG or power. An easy way to check is just park on a very slight hill, put the car in neutral, and then release the parking brake. The car should start to roll. If it doesn't, something is dragging.

Cam was done 267k. Parking brake cables replaced last year. Turbo original. As far as I know intakes don't clog like the alh. Cam was done by a guru. He would of mentioned if things were clogged. I have a screw in the intercooler to monitor oil bypassing. Nothing to get excited about.

The worst thing we know that can be done to PD injectors is to take them out and not protect them. We suggest storing them, covered with diesel in a coffee can.

We have seen injectors removed and laid on the bench in a hot Texas shop that cooked the diesel out of the injectors in two weeks. That caused the solenoid to freeze solid. The engine would start, but no power, as the only fuel the nozzle was getting was from the pilot pop.

So, somebody's used injectors that have not been cared for is just another problem. Injectors that are running correctly should be left to do their job. You know what they say, "If it ain't broke, don't fix it.", that applies here.

We have seen perfectly good injectors with 500k on them. They really do last if taken care of. Once is a while, we have been known to use Moly Diesel Purge. Directly into the pump, return to can, with a inline filter for the suction line. It's snake oil that seems to work.

On the other hand, we have seen the nozzles that were 'rebuilt' that the fuel economy tanked. If you are intending to keep the car as a fuel sipper, install a good cam (like our modified hydraulic profile cam) and lifters, set the torsion value correctly, get really good 5-40wt Ch-4+ diesel oil with the 505.01 rating, EXCEPT Castrol(sludging), and in our opinion, because of the problems we have seen with Mobile 1, we choose to not warranty with that oil on our builds. Too many heat related failures with pistons...

Now that's some good information. Seems many folks are in the dark when it comes to the PD fuel system.

So if soot is getting past the seals and being deposited in the fuel tank should it just be left or reinstall with new seals? Then there's the one that's not performing like it should.

The diesel in the coffee can sounds reasonable but how would they be shipped that way?

We don't ship them in diesel. We store them that way.

The hold down bolts have as much to do with how well the injectors seal as anything. The bottom seal on the injector is brass; not copper. The brass seal does not deform like the previous 2-stage injector copper crush washers. In my opinion, unless the brass seal is damaged, they don't need replaced. The cylinder head seal area should be clean and flat. The red/orange bottom seal needs to be in good shape. If you get a lot of black soot on your fuel filter or blackened fuel, that bottom seal is usually the problem along with the correctly tightened injector hold down bolt.

The hold down bolt is an aggravation. If you reuse a OEM bolt, you risk breaking it off flush with the head. If you use an aftermarket bolt, which are non-stretch, they end up pulling the threads out. We feel it's an imperative to use the OEM bolts. There are many with experience that agree with us that 78 INCH lbs, + 1/2 turn is appropriate. By the book, the bolt should be tightened to the preload + 3/4 turn, but that makes me pucker. From my own experience in my own vehicle, one-by-one the injectors pulled the threads out and the injectors popped loose. I installed double-depth recoil kits in the cylinder head to repair them. With that install, we think you can safely load 3/4 turn. I might also mention, when testing injectors, we install with preload and 1/4 turn. The bolt will hold the injector well enough to test for balance, yet the bolt has not been stretched. It can be reinstalled to a finish torque and still be good.

Otherwise, what we have found is that the seals generally aren't damaged except for the bottom seal, which either melts or leaves a scab in the hole. The two black seals are often in good shape, however, we find the injector bore will often have a burr near each of the top two seals, which can ruin the seals on reinstall.

The hold down bolt and block tend to push the injector so it leans against the opposite side of the injector bore from the bolt hole. The steel of the injector will vibrate against the bore causing an aluminum burr to rise up. The burr is sharp enough to cut the two top black seals on reinstall. We polish that burr out with a small 240 grit flapper wheel on a die grinder. You can use fine emery cloth. If the burr is not removed and any of the black seals are cut, all the pressure from the tandem pump is lost to the return fuel galley. You will suffer fuel starvation under hard acceleration. A cut top seal will lose fuel into the engine oil, although that is not as common an issue.

Great knowledge there frank

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So I guess I'm going to open up the fuel tank and see what's going on sootwise.

drucifer said:

So I guess I'm going to open up the fuel tank and see what's going on sootwise.

Click to expand...

Next time you change the FF, just inspect it for soot.