View Full Version : D-Max Knock
My 2002 D-Max has what sounds like a slight fuel knock under light acceleration, and cruise, with or without trailer. It sounds like one cylinder, and around 2700 RPM, all others make the same sound and it all blends. Something doesn't add up because pilot injection goes away at 2400 RPM's. My local Chevy house has reflashed and run injector balance test with no help from either. The Svc Mgr told me to run it till it blows up! I don't think it will ever "blow up". It is very annoying to drive like this. This all started around 20,000 miles last October while we were running from Hurricane Lili. I dumped some Stanadyne Fuel Conditioner in the fuel which seemed to help and got us back home. The noise seemed to go away till now, 28,000 miles. I have made an appointment with another, larger, probably more advanced, dealership for Wednesday morning. I know they will run a fuel flow check, but should I suggest anything else or let them take it from there. Any help will be appreciated. :confused:
Go to Best Buy and buy some CD's of your favourite artists and turn the volume up!
Great Idea ! but.... I already have XM and do jam it up. But between songs, the underhood beat goes on. I really don't want to take out a piston with this thing. :cool:
Billy T
Same problem here. Started around 25,000 miles - But the knock was at 1,700 RPM. I could make the engine knock on command by hitting the throttle at 1700 RPM. At first I was told the knocking was "normal" - that because these engines are so quiet people are hearing engine noises never before heard in a diesel engine. I was then told the engine is under a 100,000 mile warranty and that I should drive it till it blows.... (sound familiar?). I told them to drive another dmax and listen to it - see if it made a knocking noise. The other truck had no knock. They called GM Service for help. Their response - I was asked me to return when the dealer could keep it a few days. They wanted to put the computer on the truck for several days and drive it - shutting down one cylinder at a time to isolate the knock.
Anyway, I took it back, left it for a few days. They ran a balance test, test drove it with the computer shutting down each cylinder and no problems showed up. I believe they reflashed the computer prior to the tests to do away with the lopey idle problem. Now, most of the time the knock is gone and I can no longer make the engine knock on command. I guess I will have to drive it till it blows.... Or someone finds another answer to the knock. Short of it is I was told it was just like the "tick" - it is a normal characteristic of the some dmax engines. I don't believe them. Let me know what the next dealer finds.
Steve, the Tech at Service Chevrolet of Lafayette, LA took less than 15 minutes to find #2 Injector bad. Tey are going to pull it and if it is of the early design, yhey may change them all. Kudos to those guys! There is No Substitute for Experience!
Well Steve, the Tech at Service Chevrolet in Lafayette, LA took less than 15 minutes to find #2 Injector bad. They are going to pull it and if it is of the early design, they may change them all. Kudos to those guys! There is No Substitute for Experience!
Diesel Brad
06-19-2003, 16:06
Originally posted by Billy T:
Well Steve, the Tech at Service Chevrolet in Lafayette, LA took less than 15 minutes to find #2 Injector bad. They are going to pull it and if it is of the early design, they may change them all. Kudos to those guys! There is No Substitute for Experience! Billy,
It would probably be best to change all eight injectors. From what I've read on the forums, the chance of another injector going bad later is pretty great. Not sure why, but it seems to be a trend.
FYI, pilot injection shuts off at approximately 2700 RPM. Don't be alarmed that all of the injectors sounded like the faulty one at that RPM.
Just out of curiousity, are the Techs at Service knowledgeable and helpful? Some of the other dealerships in the area act is if they are paying for warranty work out of their pockets...it's very annoying.
Good luck...hopefully you'll be back in the truck soon!
OFF TOPIC: How much are the Bilstein HD shocks going for?
[ 06-19-2003, 04:14 PM: Message edited by: Diesel Brad ]
I HAVE GOT MY BABY BACK! Picked up my truck Friday afternoon after Service Chevrolet replaced all eight injectors. She is Back! Quiet and smooth running again. After putting up with this cackling for almost 9 months it feels and sounds great.
Brad the Shop Foreman at Service Chevy, John Boudreaux nd I go back a few years. While this is my first service experience with them, I was very pleased from write-up to pick-up. The service writer, Caroll, called me periodically to let me know how the job was progressing. Very Pleased I am! I told my Wife that whoever took the trouble to find my problem and fix the truck would sell me my next truck. I just find the techs in Lafayette are more willing to troubleshoot problems than in New Iberia. This is from both Ford and Chevy dealers in the past.
The folks at Service Chevy did not make me feel as though they were doing me a favor to fix my truck under warranty. I felt I was treated very fair and based on this experience, would recommend them highly.
As far as the Bilsteins, I need to follow up on them. Last time I priced them from my distributer, I was floored by the cost. I will check again to see if they have come down at all.
Billy T :D
Diesel Brad
06-23-2003, 18:47
Originally posted by Billy T:
I HAVE GOT MY BABY BACK! Picked up my truck Friday afternoon after Service Chevrolet replaced all eight injectors. She is Back! Quiet and smooth running again. After putting up with this cackling for almost 9 months it feels and sounds great.
Brad the Shop Foreman at Service Chevy, John Boudreaux nd I go back a few years. While this is my first service experience with them, I was very pleased from write-up to pick-up. The service writer, Caroll, called me periodically to let me know how the job was progressing. Very Pleased I am! I told my Wife that whoever took the trouble to find my problem and fix the truck would sell me my next truck. I just find the techs in Lafayette are more willing to troubleshoot problems than in New Iberia. This is from both Ford and Chevy dealers in the past.
The folks at Service Chevy did not make me feel as though they were doing me a favor to fix my truck under warranty. I felt I was treated very fair and based on this experience, would recommend them highly.
As far as the Bilsteins, I need to follow up on them. Last time I priced them from my distributer, I was floored by the cost. I will check again to see if they have come down at all.
Billy T :D Billy,
Glad to hear that the truck is back and all is well! Thanks for sharing the good experience with the Techs at Service Chevrolet...I'll definitely keep them in mind if any problems surface.
Brad
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