Injector Change How To???

kino_fab

kino_fab

KTPA Tech Official
Joined
Aug 19, 2007
Messages
2,244
Got a friend that has a bad injector on his D-max. Not sure what year or engine series it has. I'm thinking its an LB7 or LLY. He is wanting me to swap the injector out on the truck because he has no clue how to go about it and doesn't want to pay the high dealer prices to have it done. I've changed many in the Cummins engines, but never really messed with a D-max. What all is involved in changing an injector on these trucks? Thanks
 
you need to find out which engine it is. 8th digit of VIN is a 1 = LB7. If it's a 2 = LLY. It's a LOT more involved on the LB7 than any other series.

Once you find that out, I'll get ya some material to thumb through to get an idea of what you are up against.

FWIW, on an LB7, the shop rate calls for 8-10hrs of bill time for swapping all 8. Doing one won't be any different than changing all 4 on one side so still looking at 4-5hrs if only changing the one.


C-ya
 
if it's an LB7, let me know as I've written a DIY article thats published on another site that i can send over to you. LLYs are easy and straight forward.
 
Crap. Its an LB7 early 04. Number 7 injector. I found a how to over on Diesel Place. How is the injector order listed on these? I know I need the return line seal kit for all 4 injectors and the vavle cover gaskets. Any thing else?

Also does any one know about the 200K mile LB7 injector policy? The truck is still under warranty and only has 71K miles on it, but the dealer will not replace it because they said something like the injector is leaking at the top and not the bottom? Yet the reason why he wants it changed is because is white haises and you can smell the raw fuel in the exhaust. I told him to try another dealer cuz that one may be yanking his chain on it. Who knows.
 
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Kino...some info for you. I bought a set of 8 from JakeGMCHD on dieselplace for $1200 shipped, no core charge. Not sure about the policy on the injectors. If its your first time, you can expect about 2 days worth of work. You can get creative on how to get the injectors out of the cylinder head. I heated up a pry bar past 90 degrees and pryed up on them. Sometimes the injector cup that has coolant around it will come out with the injector and can be a pain to get off. Get new orange o-ring seals for the injector tubes for the ones that come out and tap in straight with a rubber mallet. The most difficult thing is getting all the crap out of the way to get the valve covers off. They are a 2 piece design. Also, copper o-rings for injectors. Give me a call if you have any other questions...I have all 5 books for the lb7 that tells torque values, etc. 317-847-4092
The most important thing is to make sure you have all the coolant out of the cylinder before re-installation. I had coolant left over in the cylinder wall that wouldn't allow the engine to turn over. You can pull the glow plugs out and bar engine over this way if I remember right. Luckily I caught it before attempting to fire the truck and bending a rod! Also, don't forget to take the yellow caps off of the injector before installing the upper valve cover. (I don't know who did that???????) Hope this helps.
 
ok thanks. Was that for new injectors or remans. The guy is wanting a brand new one instead of a reman.
 
Don't think you can get a brand new one. All remans.

If it were my truck, I'd pour a little fuel in oil n go to different dealer. Fuel in oil is a valid reason to change injectors n his is still under warranty. Worst case, they still say no n he has to do em himself anyways.

If end up doing himself (you) let me know n I can get you in touch with a good place local to get quality stuff.


Cya
 
The lower valve cover gasket can be reused if in good shape. The upper valve cover gasket is a form-in-place deal with the gray GM engine sealant.

The grey stuff is fantastic, I use it for tons of things.

One of the PITA you may run into is corrosion of the valve cover screws. You strip one of the 5mm hex heads out and it can be a real pain. Make sure you are square on and fully inserted (allen heads sometimes fill up with chit). Sometimes tapping the head of the ratchet with a hammer can help loosen tough ones. I replaced all of mine with stainless replacements from McMaster Carr. But we're in a salt-laden area up here in winter.

Blow out the injection line connections before you start, a lot of crap can collect in them and it comes out during disassembly. I use a blow nozzle with a very fine tube and go around each line. Then I run some WD-40 around each one to kinda tie up whatever schmutz is left. Clean the crap out of all your lines with Brakleen before reassembly.

Sometimes you need the injector removal tool, sometimes not. My injectors pulled right out, but I have had ones that you would think you'd need a jackhammer.

Injector cup seals....if the cup comes out make sure you have everything super clean and dry, then daub the tip of the new cup (don't re-use old ones) with red loctite and insert it and gently tap in home. Install the injector immediately since it's what holds the cup down. You want pressure on the cup while it is curing so you don't get coolant leaks (and the whole mess has to come back apart!).

Injector policy is 7 years / 200k mi. Get it to a dealer who will work with you.
 
I just caught that in that post as well. I've reused them MANY times before w/o failure. I've only replaced 2 out of probably 40-50 injector sleeves I've removed.
 
Couple reasons:

1) GM says if there is any sign of scoring or other damage, replace it. The ones I have pulled out didn't look absolutely perfect, so I tossed them.

2) They're not that expensive and a leak will kill every bit of profit in doing the job, if you have to go back in. What a nightmare that would be.

3) On competition trucks running 50+ psi boost and a lot of fuel, again not worth the risk... Might be fine for street trucks.

The tip of the cup is thin, and every one I've looked at seemed like it was deformed or "mooshed," even if only very slightly (they're a light press fit for a reason). I just thought it was best to have them as tight as new to avoid any chance of a leak.

I take risks with other stuff but not with anything in that deep. JMHO.

Y'all are free to do as ye wish though. If the old ones fit tight and it's not an extreme application then I might consider it.
 
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