Knocking after injector change

[IDIBRONCO]

I've never seen one, but I talked to a guy who had one and he explained it to me. It actually sounds like a wonderful tool to have.

 

[Rupert8]

Great.

I see there are versions of the Engine Ears on Amazon but a lot don't use contact microphones so pick up a lot of ambient wind noise when driving (probably pretty good when stationary but that doesn't help me here....). If I can't figure things out I may invest in one.

Think I'm going to do an injector swap as soon as I get time (I'm away with my cub scout den this weekend so likely early next week) - I'll post results either way just as soon as I have them and go from there. Thanks again.

 

[Old Goat]

When you are swapping Injectors around, or even when you are replacing all of them.
Remove the Hard Line Clamps, or at leas the first one. This way you have less chance of bending the Hard Line.
Be sure to reinstall the Clamps as this keeps the lines from vibrating, and cracking.

Also when swapping around the Injectors, the Copper Washer needs to be replaced. They are really a one time use, they are a crush washer, and this is what keeps the pressure from the compression stroke from blowing past the Injector seat.

Crusty burnt injector

So... Number 7 cylinder had bubbles coming out around the injector, and no matter what I tried I just couldn’t get the return line fitting to stop leaking. I thought it was a bad copper seat/seal so I pulled the injector and it was UGLY. These were “new” injectors from rockauto about 5000...

www.oilburners.net

Some guys say you can heat up the Copper Washer to anneal it and reuse it. I personally would replace with new.
You can get by when swapping around to solve the knocking problem. But when you finally figure it out, replace it with a new Washer.

I did a search this past year to find where to buy just the Copper Washers. seems like only place is when buying a new Return Line Kit. That makes for some expensive Washers......
Here is a thread about the washers I forgot about, searched in my Folders and here it is.

Where to get injector copper washers in-store?

Did a compression test today and everything was going great until I got to #7, suddenly I had 10PSI. Looking closer, the injector was spurting diesel out of the injector threads so I took it out and there’s no copper washer. Hopefully that’s the issue and I can get compression back (fingers...

www.oilburners.net

Goat

 

[typ4]

I need to be quick here, its not timing, different injectors wont make much of a difference in timing, IF the pop is in spec.
Yes an injector can stick, at any time.
Pensacola,,,, Shudder.
Ive been to their place for perkins injectors in an emergency, suffice it to say, never ever would I use or recommend .
Its a good thing IDI's are forgiving , thats the only reason they get ANY positive reviews.

 

[The_Josh_Bear]

Pensacola,,,, Shudder.
Ive been to their place for perkins injectors in an emergency, suffice it to say, never ever would I use or recommend .
Its a good thing IDI's are forgiving , thats the only reason they get ANY positive reviews.

Amen to that, as soon as I read Pensacola and injectors I figured that would be the problem. And the fact that it worked great at the start then poorly later suggests a loose bit of something got into the system from the poor rebuild they did or maybe even while you were doing the swap. It only takes one grain of sand, after all.

I went through 3 IP's of theirs under warranty before I got one that was "good enough" and it wasn't good in any way. That was 16+ years ago and before I knew about quality rebuilders. Of course they act like everything they've ever shipped is pure gold and couldn't possibly be bad...

Sorry to hear about your troubles, I hope you get it sorted out soon. If you end up getting different injectors, @typ4 sells rebuilds that he pop-matches to within 50psi minimum. Very sweet. https://russrepair.com/

Did you happen to get a new IP as well?

 

[Rupert8]

Once again, thanks to all in this community. Things are a lot more in focus now.

I'm seeing a pattern here regarding thoughts on Pensacola injectors.... I'll reserve judgement until I get to the bottom of this but well-noted.

Just got back from Scout camp with my den! I'll be working on the problem this week before it gets rainy and will report back.

The_Josh_Bear: No, I don't have the expertise or space (or time...) to change out the IP. My thinking here is that since the injectors worked just fine when I went on the test drive, the injection pump is not the issue. Or do you have another reason to ask....... (gulp)?

Copper washers: Noted - thanks.

Hard lines: Absolutely. I was super careful with them and will be again.

And, believe me, I wish I had known the russrepair link before - and will be keeping it handy in case needed. That contact keeps being mentioned, which tells me a lot.

Thanks again.

 

[IDIBRONCO]

Look at it this way. If it does turn out to be the injectors, you're not the first. Most of us on here have made that same mistake (maybe not from Pensacola, but from others) before we knew better. I know that I sure did.

 

[Rupert8]

So! I had time to do some work yesterday. I took out the Pensacola injectors and installed some I got from Accurate Diesel (I took a $250 gamble and figured I'd have a spare set of injectors if one went south - I like having spares). I checked copper washers etc, vacuumed out the whole area, torqued them right.

The result: Smooth idle - but knocking over 2000ish rpm when stationary in park, knocking when the truck is moving and I'm on the gas, even a bit.

So no difference.

Some questions:
*Is it possible that the timing being off won't create a knock when idling - but create a loud knock when under load or at higher revs?
*What else could produce this knock since the injectors were changed?
*If it's something mechanical that has gone out, wouldn't I hear a knock at idle/lower RPMs?
*I know I should replace the IP but I don't really have space, money or time to do so. Is it honestly critical that injectors and pump are done together?

Oh boy, could use this truck running right now...... Still puzzled why the first test drive was fine but later drives were not. That's got me stumped.

Pending any input from folks here, my next steps are to crack the fuel lines to make sure that each one is delivering fuel to its injector (per onetonjohn's suggestion) and if that doesn't show up anything, put the original injectors back in to see if I get a knock. And go from there, whatever that means.

Again, any help here would be much appreciated to get this truck back on the road.

 

[Brian VT]

I can't speak to the knocking, sorry.
But as far as the IP...I replaced my injectors with ones from Russ. Big improvement over what was in there from the previous owner. I didn't do the pump at that time as it was starting and running great and I didn't have the cash. Within a couple months the pump started to act up. The truck didn't want to restart when warm. If I cooled the pump down with (room temp.) water the truck would start. So you may have some time before needing a new pump.

 

[KansasIDI]

So! I had time to do some work yesterday. I took out the Pensacola injectors and installed some I got from Accurate Diesel (I took a $250 gamble and figured I'd have a spare set of injectors if one went south - I like having spares). I checked copper washers etc, vacuumed out the whole area, torqued them right.

The result: Smooth idle - but knocking over 2000ish rpm when stationary in park, knocking when the truck is moving and I'm on the gas, even a bit.

So no difference.

Some questions:
*Is it possible that the timing being off won't create a knock when idling - but create a loud knock when under load or at higher revs?
*What else could produce this knock since the injectors were changed?
*If it's something mechanical that has gone out, wouldn't I hear a knock at idle/lower RPMs?
*I know I should replace the IP but I don't really have space, money or time to do so. Is it honestly critical that injectors and pump are done together?

Oh boy, could use this truck running right now...... Still puzzled why the first test drive was fine but later drives were not. That's got me stumped.

Pending any input from folks here, my next steps are to crack the fuel lines to make sure that each one is delivering fuel to its injector (per onetonjohn's suggestion) and if that doesn't show up anything, put the original injectors back in to see if I get a knock. And go from there, whatever that means.

Again, any help here would be much appreciated to get this truck back on the road.

Not sure that was $250 well spent…

The recommended rebuilders for injectors and injection pumps are,

RussRepair
R&D IDI
Classic Diesel Design
Moose Diesel

Probably not a good idea to buy from anyone else. Also make damn sure not to get dirt or gunk or any kind of crap in the injectors when installing. They must stay clean.

 

[KansasIDI]

Also, all my injectors leaked at the torque spec, with clean holes. Has to be tighter, in my experience.

 

[Rupert8]

Possibly right on the $250 - but learning curves are sometimes spendy, unfortunately. Wish I hadn't spent it right now but, as I say - sometimes learn the hard way.... I'll keep that list, I just learned of RussRepair (see above).

What does "with clean holes" mean? The thread and inside the chamber, or on the injectors themselves? I vacuumed out the chamber and surrounding area, and made sure the injector was inserted very carefully. I added a small amount of Vaseline to keep the copper washer in place. Used some anti-seize but a small amount and made sure none was below the thread area.

The injectors were pretty darn snug when I had them torqued to 35 or so. Do you recommend I get them as tight as I can, within reason? Probably could have taken them a little further.

Is there an argument for driving until everything is good and hot to see if anything gets 'cleaned out'? If I take it in to a shop, I'll have to drive for half an hour or so. Any risk of damaging anything, presuming it is a fuel-related problem, and not mechanical?

Thanks.

 

[KansasIDI]

Possibly right on the $250 - but learning curves are sometimes spendy, unfortunately. Wish I hadn't spent it right now but, as I say - sometimes learn the hard way.... I'll keep that list, I just learned of RussRepair (see above).

Didn’t mean to be offensive when I said this, but from what I’ve seen, you need to be careful where you buy injectors for these trucks.

What does "with clean holes" mean? The thread and inside the chamber, or on the injectors themselves? I vacuumed out the chamber and surrounding area, and made sure the injector was inserted very carefully. I added a small amount of Vaseline to keep the copper washer in place. Used some anti-seize but a small amount and made sure none was below the thread area.

The holes the injectors go in, is what I meant by clean holes. That may have seemed unclear. Sorry about that.

Sounds like you did it the same way I did it, pretty much.

The injectors were pretty darn snug when I had them torqued to 35 or so. Do you recommend I get them as tight as I can, within reason? Probably could have taken them a little further.

I torqued mine initially, but they leaked before too long. I have returned rails instead of return lines, though… so I just tightened them down with a wrench until they stopped leaking, it is a pain to mess with those return rails.

Is there an argument for driving until everything is good and hot to see if anything gets 'cleaned out'? If I take it in to a shop, I'll have to drive for half an hour or so. Any risk of damaging anything, presuming it is a fuel-related problem, and not mechanical?

Half an hour is a little longer than I would drive it with a knock, If it doesn’t clear up in a few seconds, then somethings off…

Might be best to try and isolate where the sound is coming from. Could also try ATF. Maybe you already did that, I don’t really remember what you put in your thread as to what you did so far

Thanks.

You’re welcome, happy to help.

 

[Rupert8]

No offense taken, thank you for the detailed reply. I self-righteously lecture my kids about 'learning from mistakes' and then forget that myself when the dollars are spent and I'm cursing my decisions......

ATF? No, not tried. Do you mean added to the fuel filter and left to soak overnight in the IP etc? More than willing to give that a go, if so.

I've tried isolating where the sound is coming from but just can't locate it, even with a stethoscope. When it's working I love the sounds of these IDIs. When they aren't, maybe not quite so much...

 

[Rdnck84_03]

ATF? No, not tried. Do you mean added to the fuel filter and left to soak overnight in the IP etc? More than willing to give that a go, if so.

Yes that is usually a good starting point for anything that is though to be fuel related.

James