Crusty burnt injector

[danno]

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 miles or so ago and you guys know I threw moose Junior and a factory turbo with all the flow upgrades at this thing and a whole new fuel system and I’ve had nothing but grey smoke issues. I was tinkering with timing and got it to idle pretty nice and the smoke went to pure black (yay!) so I figured what the hell let’s pull #7 and see what’s up. The injector was completely covered with crusty tar-like layer of goo. I put a magnet to it and there may be some steel dust in there from what I can tell. I’m going to worm a bore scope down there tomorrow to see if there is visible piston damage, if not then do a compression test. I have the numbers from a test prior to my “upgrades” so it should be pretty obvious if there’s an issue but does this even look close to normal/expected? If I had to guess that cylinder was NOT firing and this is all the gunk from blow by and no combustion ... and the spewing fuel around the return line connector was because no fuel was making it through the injectors nozzle and it was pressurized at the return port ... makes sense? more to come.....

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[NeverHave-I-Ether]

Oof, pretty nasty looking. If the cylinder is damaged you should try getting Rockauto or the company to pay for an engine rebuild for a faulty injector.

Never-Ether

 

[gnathv]

The tip looks like it was firing. What does the copper washer look like from that injector? Did you have a dead miss?

 

[danno]

The tip looks like it was firing. What does the copper washer look like from that injector? Did you have a dead miss?

So hard to tell really in the years I’ve had this truck I’ve never taken it on more than a shake down joy ride or a 20 mile round trip for a bed full of fence lumber. It’s always been a hard starter and had every possible fueling issue when I got it and I’ve just been working through things following advice on this forum. This is one of my favorite vehicles it’s just low on my project list since it’s never been that reliable.. dead miss IDK.

 

[Big Bart]

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 miles or so ago and you guys know I threw moose Junior and a factory turbo with all the flow upgrades at this thing and a whole new fuel system and I’ve had nothing but grey smoke issues. I was tinkering with timing and got it to idle pretty nice and the smoke went to pure black (yay!) so I figured what the hell let’s pull #7 and see what’s up. The injector was completely covered with crusty tar-like layer of goo. I put a magnet to it and there may be some steel dust in there from what I can tell. I’m going to worm a bore scope down there tomorrow to see if there is visible piston damage, if not then do a compression test. I have the numbers from a test prior to my “upgrades” so it should be pretty obvious if there’s an issue but does this even look close to normal/expected? If I had to guess that cylinder was NOT firing and this is all the gunk from blow by and no combustion ... and the spewing fuel around the return line connector was because no fuel was making it through the injectors nozzle and it was pressurized at the return port ... makes sense? more to come.....

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Danny,

That looks like your injector did not seal like it should. (Or that would not have happened leaky injector or not.) FYI if the cylinder was not firing I believe you would have no carbon, just diesel or diesel and oil. Your GP has carbon and other indicators of ignition.

If the truck runs or idles rough you could have a bad cylinder so do a compression test to see what comes up. But with a injector not sealing and using the glow plug hole to test, you would expect lower compression.

I would get the injector pop tested to see if it leaks and if it pops in or close to spec. But it may work fine and your seal failed.

I have seen a few of these over the years. Very common when the the injector does not seal up to the head lip and air, fuel, and exhaust go up to the next chamber which sits above the combustion cup. Then fouls the sides of the injector. Some see bubbles from the injector threads.

 

[danno]

Thanks! I don’t know anyone around here that’ll pop test an old injector. Most of the diesel shops around here are power stroke only or Cummins only and they’re backed up for months with work, most won’t even answer or return phone calls any more. Not complaining I get it, business is good and there are LOADS of power strokes and Cummins rolling coal around here so nobody wants to mess with the old stuff. I couldn’t even find somebody with a pulse timing setup within two states...

I have some extra injector copper seals, the one in it looked like it was burnt so it probably didn’t seat. I’ll bore scope it and check compression tomorrow if things look ok I’ll throw it back in with a new seal... more to come... thanks!

 

[jrollf]

Injector tip doesn't look too bad. Looks like the copper washer did not seal allowing blow buy around the injector. May have some oil getting into the cylinder past the rings ultimately making the build up worse.

If the copper washer is not sealing, there are a couple posibilities... the injector was not torqued properly, or the injector seat in the head has crud on it and/or is pitted and needs to be reamed smooth before it will seal. There are injector seat reamers made to do exactly this.

 

[Big Bart]

Thanks! I don’t know anyone around here that’ll pop test an old injector. Most of the diesel shops around here are power stroke only or Cummins only and they’re backed up for months with work, most won’t even answer or return phone calls any more. Not complaining I get it, business is good and there are LOADS of power strokes and Cummins rolling coal around here so nobody wants to mess with the old stuff. I couldn’t even find somebody with a pulse timing setup within two states...

I have some extra injector copper seals, the one in it looked like it was burnt so it probably didn’t seat. I’ll bore scope it and check compression tomorrow if things look ok I’ll throw it back in with a new seal... more to come... thanks!

Two thoughts
1) Buy one, will come in handy in the future. ~$100. Here is one, but confirm it has the fittings you need.

Amazon.com: ABN Diesel Injector Tester Kit - 6000PSI Diesel Fuel Injector Tester Fuel Pressure Gauge Kit Engine Compression Tester : Automotive

Buy ABN Diesel Injector Tester Kit - 6000PSI Diesel Fuel Injector Tester Fuel Pressure Gauge Kit Engine Compression Tester: Fuel Injector Kits - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

2) Send it to one of these guys. (Or all the injectors.).

Where to go for injectors and injection pumps.

I wanted to post this since it is a weekly question “who/where do I go for injectors and injector pumps?” I believe this has been posted by vendor but not a list. Unlike a oil filter, ignition switch, or fan belt. Buying injectors and pumps at the auto parts stores or worse yet online have...

www.oilburners.net

If you buy the tester
1) Your injectors new should all pop within say +/- 50 psi of each other. (Depending on the tester, it’s gauge, and the fact you have 5k miles on them, perhaps +/- 100psi.)
2) Then apply pressure, perhaps half of pop pressure, to see if they dribble/leak.
3) Injector should mist/spray not stream.

I am not an injector expert so others will chime in who have more experience testing rebuilding injectors.

Part of the challenge is it is hard to clean the seat on the head that the copper seal seals to. (The hole is skinny and long. I carefully use a nylon brush that looks like a riffle cleaning brush.). As stated by jrollf there are seat reamers to grind/sand the surface to clean and smooth. (Try to keep the debris and fallout to a minimum. Maybe pull the injector and glow plug, put the piston at TDC, then blow air into the glow plug hole so most of the debris comes out the injector hole. VS going in the cylinder.)

Here is what I use.

https://www.amazon.com/Industrial-Brush-Shank-Stainless-Steel/dp/B07G56BJYK/ref=sr_1_12?crid=ZWHTQ1APWK6M&keywords=Nylon+bore+brush+set&qid=1646583174&sprefix=nylon+bore+brush+set%2Caps%2C126&sr=8-12

This looks promising (The flat top one fits it would clean up the seat face.)

https://www.amazon.com/Glarks-Compatible-1994-2018-Powerstroke-Caterpillar/dp/B08RBKXW8H/ref=sr_1_3_sspa?crid=30JKQOZC0FO5Z&keywords=Engine+bore+cleaning+brush+set&qid=1646583292&sprefix=engine+bore+cleaning+brush+set%2Caps%2C130&sr=8-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzUDFQSjRDQ0lFOUo0JmVuY3J5cHRlZElkPUEwODQ3Nzg2R0JVWjNHRlRXR040JmVuY3J5cHRlZEFkSWQ9QTAyNzQ3NzIzS1ZLOVpVMTJUVU1LJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

Or better

https://www.amazon.com/gp/product/B01F78V7II/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

Check to see if this kit works on IDI injectors but this is what you are looking for if you need a reamer.

https://www.amazon.com/KUNTEC-Injector-Removal-Compatible-Mercedes-Benz/dp/B08RRP8Y2N/ref=sr_1_24?crid=2INLQ76QHLWFG&keywords=Ford+IDI+injector+seat+re-emerge&qid=1646583644&sprefix=ford+idi+injector+seat+reemer%2Caps%2C165&sr=8-24

 

[jrollf]

...Maybe pull the injector and glow plug, put the piston at TDC, then blow air into the glow plug hole so most of the debris comes out the injector hole. VS going in the cylinder...

This is what I did, ran about 25 psi air pressure through the glow plug hole. Suggest wearing eye protection as the grit/crud you clean off will blow back up at you while cleaning the injector bore.

 

[danno]

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That’s the seal that was on it... about to look down the hole.... WML

 

[IDIBRONCO]

I would say that it looks like the bottom of the washer wasn't sealing for some reason.

 

[Big Bart]

Some thoughts.

1) Interesting only one side failed on the washer/seal. But more interesting is the injector base looks as bad as the burned side of the seal. The other side looks like it sealed but perhaps to the head.
2) How close is the match between the injector tip and the seal hole? I wonder if the seal center hole is much larger than the injector tip? So it busted through the gap.
3) What did you put on the injector to hold the seal from falling off? Or did you use another method to get the seal into the hole and the injector through it?
4) I would have expected the leak would be on the head side of the seal and not the injector. The head side potentially being old, corroded, and dirty and the injector clean and ready to seal.
5) I thought maybe the injector did not thread all the way in, but if not both sides of the washer would likely be burnt.

The mystery continues.

 

[danno]

Eureka! That injector bore was a complete mess as expected... obviously there was a seal issue first time around.

 

[danno]

So I used my shop vac with a 6’ length of 3/8” fuel line wrapped in a rag to plug the vacuum hose and created myself a 3/8” shop vac hose and sucked all the big chunks out, then sprayed some blaster around the threads and then sucked that out after about 20 mins so it could to do its magic. The bore and seat cleaned up surprisingly well. Unplugged the runaway kill circuit on the IP and ran it on starter with no fuel for a few turns to purge any goop or blaster that got through. Injector is back in and seated with a new seal, return lines hooked back up and voila!! Thanks again...!

 

[jrollf]

So I used my shop vac with a 6’ length of 3/8” fuel line wrapped in a rag to plug the vacuum hose and created myself a 3/8” shop vac hose and sucked all the big chunks out, then sprayed some blaster around the threads and then sucked that out after about 20 mins so it could to do its magic. The bore and seat cleaned up surprisingly well. Unplugged the runaway kill circuit on the IP and ran it on starter with no fuel for a few turns to purge any goop or blaster that got through. Injector is back in and seated with a new seal, return lines hooked back up and voila!! Thanks again...!

Hate to say it, but IMHO the sealing surface/seat still looks not that great. Looks like some pitting in the borescope picture. This is what mine looked like when I had a leak. Carefully reaming the seat with an injector seat reamer finally fixes the problem for me. When done I had a smooth seat with not pitting or carbon buildup.

You might still have a leak, hope I'm wrong.