Diesel Place banner

61 - 78 of 78 Posts

·
Administrator
Joined
·
18,124 Posts
I have a 2017 Z71 I'm original owner . Truck just went into limp mode giving code P0-2004
I'm at 73,000 miles and its the first injector issue I've have had. Waiting for local service manager to get back to me . I wonder if they resolved this in the 2020 models ??
Welcome to DieselPlace

Check your injector connectors. There have been many issues with the harness and connectors
 

·
Registered
Joined
·
2 Posts
Thanks. Will do I would hate to get hit with a bill as ejector are covered but not connectors .
 

·
Registered
Joined
·
1 Posts
There is an L5P on another site that is over 100,000 miles.

It had to change an injector very close to the 100,000 mile mark.
Just went in today because of a weird slip/shaking. Check engine light came on while I was on the phone with the service department. Went to the dealer and code was 4 injectors (2 on each side), but unclear what would need to be done until they look at it Monday. Truck is a 2018 Z71 LTZ with 114k miles.
Hoping for the best, but thinking about trading it pending the results. They’re saying it’s $4k😳😳😑☹
 

·
Administrator
Joined
·
18,124 Posts
Just went in today because of a weird slip/shaking. Check engine light came on while I was on the phone with the service department. Went to the dealer and code was 4 injectors (2 on each side), but unclear what would need to be done until they look at it Monday. Truck is a 2018 Z71 LTZ with 114k miles.
Hoping for the best, but thinking about trading it pending the results. They’re saying it’s $4k😳😳😑☹
Welcome to DieselPlace

My bet is the issue is in the connectors or harness
 

·
Registered
Joined
·
10 Posts
Just went in today because of a weird slip/shaking. Check engine light came on while I was on the phone with the service department. Went to the dealer and code was 4 injectors (2 on each side), but unclear what would need to be done until they look at it Monday. Truck is a 2018 Z71 LTZ with 114k miles.
Hoping for the best, but thinking about trading it pending the results. They’re saying it’s $4k😳😳😑☹
Seems a might odd that 4 injectors would go at once.
 

·
Registered
Joined
·
2 Posts
32k miles on 2017 Denali 2500
Cruising along and dash lights up with SEL and traction control light. Went into low power mode but would still run but..... any throttle would result in MASSIVE shaking. The motor mounts on these engines are incredible. Made it back to the dealer and they said it’s a six hour job. Glad I was near home as this would have been even more of a pain. This injector going out without any warning has me seriously thinking about the other 7 when on long trips.....
I just lost my #4 injector also on my 2018.
Exact same result and violent shaking. 92k and dealer says not part of warranty.
 

·
Registered
Joined
·
147 Posts
Why not part of warranty? Your under 100k miles.


Sent from my iPhone using Tapatalk Pro
 

·
Registered
Joined
·
8 Posts
Good thread, I've read a lot about possible bad injectors, bad connectors, etc.

I put 333k miles on an LML with no injector issues. Just traded for a 2018 and it seems to be possessed, injector wise.

I got stranded 500 miles from home right before Christmas. I don't recall all the codes when it went into limp, but I can't forget the fuel knock that sounded like the engine was coming apart and all the white smoke from the exhaust. I had it hauled home and put it in the shop.

My mechanic said it had a bad injector on #4 as he shut it off and the knock went away. He replaced it then it had a knock at road speed only so he did some more checking and said #8 was bad as well. Replaced #8 and said he drove it a few miles and all was good.

I went to pick it up and got out on the highway and still had an intermittent fuel knock and white smoke at road speed. It would take off from a stop cleanly but up at 50-55mph, it would start knocking and smoking. When I let off the throttle, it would all calm down so I finished driving home about 50mph.

Does this sound anything at all like bad connectors? Or definitely bad injectors? I don't think anyone else here mentioned fuel knock, just codes and limping and shaking.

Edit: Truck has 126k miles on it
 

·
Administrator
Joined
·
18,124 Posts
Good thread, I've read a lot about possible bad injectors, bad connectors, etc.

I put 333k miles on an LML with no injector issues. Just traded for a 2018 and it seems to be possessed, injector wise.

I got stranded 500 miles from home right before Christmas. I don't recall all the codes when it went into limp, but I can't forget the fuel knock that sounded like the engine was coming apart and all the white smoke from the exhaust. I had it hauled home and put it in the shop.

My mechanic said it had a bad injector on #4 as he shut it off and the knock went away. He replaced it then it had a knock at road speed only so he did some more checking and said #8 was bad as well. Replaced #8 and said he drove it a few miles and all was good.

I went to pick it up and got out on the highway and still had an intermittent fuel knock and white smoke at road speed. It would take off from a stop cleanly but up at 50-55mph, it would start knocking and smoking. When I let off the throttle, it would all calm down so I finished driving home about 50mph.

Does this sound anything at all like bad connectors? Or definitely bad injectors? I don't think anyone else here mentioned fuel knock, just codes and limping and shaking.

Edit: Truck has 126k miles on it
I would inspect your injector harness and pigtails. They are known for issues
 

·
Registered
Joined
·
8 Posts
Yeah I agree they're known for issues but is fuel knock one of them? Or when you have a bad connection, does it usually present as a miss?
 

·
Administrator
Joined
·
18,124 Posts
Yeah I agree they're known for issues but is fuel knock one of them? Or when you have a bad connection, does it usually present as a miss?
I would say yes..
An example. Wire issues have caused "Tractor mode" where the engine lopes or sounds like a tractor in other Duramax engines..
Any electrical gremlin can cause many symptoms
 

·
Registered
Joined
·
147 Posts
So how many L5p’s are effected with this issue? Just Curtis it’s wide spread or a fairly uncommon problem?


Sent from my iPhone using Tapatalk Pro
 

·
Registered
Joined
·
1 Posts
So how many L5p’s are effected with this issue? Just Curtis it’s wide spread or a fairly uncommon problem?
I have a 2018 GMC Denali 3500 and at 110,000 mi. I had to replace the connector on #4. Then at 118,000 again the injector connector on #7. The mechanic was able to get the pig tail to replace it but evidently since GM knows they have a problem with the connectors, but they don't know what to do about it, they will not sell just the connector. They want to sell the connector and injector together.
The dealer wanted 1800.00 + to fix #7 and a local mechanic was 2000.00. I found another diesel shop and he replaced just the connector for less than 400.00. My experience is that this is an ongoing problem with the L5P, so hopefully GM will come up with a new harness that will fix it. Until then, I think I'll just buy the whole new harness and the next time one goes bad I'm going to have them replace the whole harness.
 

·
Registered
Joined
·
8 Posts
I have a 2018 GMC Denali 3500 and at 110,000 mi. I had to replace the connector on #4. Then at 118,000 again the injector connector on #7. The mechanic was able to get the pig tail to replace it but evidently since GM knows they have a problem with the connectors, but they don't know what to do about it, they will not sell just the connector. They want to sell the connector and injector together.
The dealer wanted 1800.00 + to fix #7 and a local mechanic was 2000.00. I found another diesel shop and he replaced just the connector for less than 400.00. My experience is that this is an ongoing problem with the L5P, so hopefully GM will come up with a new harness that will fix it. Until then, I think I'll just buy the whole new harness and the next time one goes bad I'm going to have them replace the whole harness.
My local dealer priced me L5P injector pigtails for $72 each. Since I was looking for 8, I said no thanks. I bought a kit online with gold plated contacts. I've also read that some guys buy pigtails from GM for older models, like LMM maybe, and they too are supposedly gold plated. I asked a mechanic and was told that the old connectors don't fit the Denso injectors on the L5Ps but that's not accurate. I had both Bosch and Denso injectors on the bench a couple weeks ago and the same connector plugs into both of them.
 

·
Registered
Joined
·
10 Posts
My local dealer priced me L5P injector pigtails for $72 each. Since I was looking for 8, I said no thanks. I bought a kit online with gold plated contacts. I've also read that some guys buy pigtails from GM for older models, like LMM maybe, and they too are supposedly gold plated. I asked a mechanic and was told that the old connectors don't fit the Denso injectors on the L5Ps but that's not accurate. I had both Bosch and Denso injectors on the bench a couple weeks ago and the same connector plugs into both of them.
Link for that?
 

·
Registered
Joined
·
8 Posts

I'm not going to highly recommend this kit. It seemed ok for the most part but the metal part of the plugs seemed a bit lighter than the OEM plugs. It did appear to be gold plated, at least it's gold colored. I have no way of checking the plating to ensure it's actually gold. At the price of new pigtails, I figured this kit was worth a try. It's fairly tedious work to crimp the new terminals on the injector wires. I replaced the one that I actually needed for now and I'm trying it for a while then I may do the other 7.

Edit: I do like the molded plastic replacement plug better than the bastard plugs that GM used. They're easier to snap on and feel like they're securely connected.
 

·
Registered
Joined
·
1 Posts
2019 6.6 with 70,000 Just made a trip to the keys from Atlanta area. Got home Saturday night. Symptoms started in south Florida early Saturday afternoon. I thought it was ignition failure or transmission to begin with with a slight jerk. Got worse within an hour. I then thought I had purchased bad fuel, and went to auto parts store to get fuel and injector cleaner. Seemed to help but jerking symptoms would come and go (still no CEL). Another tank of fuel and it symptoms continued worsening gradually. Luckily I made it home! Sunday I drained the fuel filter hoping to find water but it seemed to be clean so I decided to take it for another drive to check out some progress on a couple jobs. 35 miles later the abs, cel, and emissions warning came up with a limited speed message. Headed home in limp mode with violent shaking that was throttle induced. I called my mechanic buddy, we ran the code, and came up as number 4 injector. Dealership confirmed this morning and replaced under drivetrain warranty! The didn’t mention anything about connectors/pigtails, which I did inspect Sunday afternoon. #4 connector was secured fastened. Anyway, Hope this helps the next person with the same symptoms!
 
61 - 78 of 78 Posts
Top