Hoot, Mackin, NutnbutGMC, SoCalDMAX

[01_Duramax_Dually]

I know you guys have earlier 01's like me, I have recently noticed when I come to a stop light that the motor is making a lot more noise(like a Cummins) When I put it in neutral and the RPM's go up slightly the noise goes down significantly, then I drop it into gear and the noise comes back loud. The truck runs fine, MPG is steady at 16, no SES codes, just run of the mill type driver however this noise is getting loud. Any of you guys experienced this now......? I have about 42K on it now.

Before you guys start in on me :D :D , I know...IT'S A DIESEL but it always ran quieter. Even my Pops noticed it and I did not tell him.

Could this be an injector problem?

Could the idle be to low (around 600 in gear) for consistent fuel management?

Any thoughts?

Thanks Fellow DMaxers

[mdrag]

01_Duramax_Doolie,

Mine is a late '01. A few weeks ago, the Dmax was acting wierd and I THOUGHT it sounded louder at idle, along with a pronounced idle surge...Then it would not start, and when it did - VERY loud, uneven idle speed all over the place - I shut down immediately. Fortunately when the no start occured - I was getting ready to leave the shop and was not stranded... :eek:

Long story short - the fuel filter was clogged with just over 3K miles on that filter. I must have got a bad tank of fuel. All back to normal with a new fuel filter...

From sounding louder to no start was almost 2 weeks for me. FWIW.

[SoCalDMAX]

I bought my '02 in Nov '01, built Oct '01.

I noticed mine seems quieter at times, a little louder at times. I chalked it up to whether the engine was hot or cold or maybe a little more or less fuel additive in that tank. I don't think mine has ever been as loud as a PSD or CTD though.

There may be a number of possible reasons, fuel filter being the most likely, cheapest?

Regards, Steve

[hoot]

I also have noticed more of the diesel sound recently. Not loud but more like a diesel than when new. I think it's a combination of cold weather and the winter fuel mix.

[mackin]

I can experience the same symptoms.....At idle you get a distinctive diesel knock....Just raise the IDLE a hair,gone....Summer or winter....I feel it is dirty or possible failing injector(s)....I's waiting for some JK additive in hopes it will quiet down,or to see if it changes,if it does I'll chalk it up to cleanliness.....Still not as loud as a Ford or Cummins tho....Well have to wait for Nuttin he had injectors replaced but never told us why....

MAC
:D

[ 12-11-2002: Message edited by: mackin ]</p>

[01_Duramax_Dually]

Thanks All(sorry Mittie, Forgot about you having the same set up as me). Been so long since I posted...

I listened again on my way home tonight....I might have stretched the "Cummins" a little far. The only reason why I say that is I was at a stop light and a Cummins rolled up...Still way louder and I could not here my truck....I think I am experiencing what Mackin explained. However it just started about a month or so ago....I have 6 Fuel filters here so I will replace one this weekend. I have 8K miles on the current filter.

It is weird that a "Scoosh" more RPM makes the noise go away.....then drop it back in gear moments later it starts up again...The "Knock" is very consistent like a firing order. Could be a plugged injector. What do you guys recommend for fuel treatment that is a good cleaner. I will add that when I change the fuel filter.

Come On Nutn, whatchya got for us..... :D

[D-max Man]

I have seen a Fuel Injection Control Module go bad causing the pilot injection to stop working in certian RPM ranges yet work well in others.

[mackin]

D-max Man

Pilot injection what is that????

You know I can no longer tell the difference in other words I haven't heard mine shut off in 6-7 months at any rpm....I think it's on permanent vacation .....So that could be a maybe,in addition to dirty injectors which I truely believe I have.....Any ill affects D-man????

MAC

[ 12-12-2002: Message edited by: mackin ]</p>

[sdaver]

hey mac hope you can wait jk is sending me your additives........split case right......just kidding...got some coming too. :D dave

[Maverick]

01_Duramax_Dually,
I had one injector replaced because it was bad and mine never had increased noise of any kind. Just blue smoke. I think what D-max Man is more the case. My truck seems to be loud up to 2600 then gets quiet. I thought it used to be the other way around?

[01_Duramax_Dually]

Well, like I said this is a strange deal. Only occurs at stop lights. It takes a few seconds for it to start making the noise, but it will. Like I said kick it in to neutral and the sounds goes away instantly. Drop back in gear and it comes back.
I am listening carefully now to see a pattern. I will change the fuel filter this weekend and see what it looks like. I will check on some injector cleaner/ additive.
As I said in an earlier post, what you all recommend for additives?

Thanks

[Maverick]

Stanadyne Performance Formula. It did clean up my exhaust. I could see it at idle before usage. Can't now after usage.....and for you smarties out there....yes, while the engine is running.

[mackin]

01_Duramax_Dually

I went with the FPPF total power ...Got it from JK if he's running it I got to figure it works..... ;) ....As there has been a additive go around here before as to what is better,so I took the easy way out....I took the mixed case option as I run extra cetane boost do to lousy fuel quality around me.....I have the same condition your experiencing,if you need a filter change do it,but I'll bet it doesn't improve,didn't with mine any way....

MAC

[ 12-13-2002: Message edited by: mackin ]</p>

[D-max Man]

Mackin,

No ill effects, just noisy.

The one I an talking about went as far as GM buying the truck back before the problem was found and fixed.

Too bad that they had to do a Buy back and the customer had to get a new truck (Another d-max) before it was found.

If I recall, this truck was quiet at idle and up tp 1350 RPM's then it rattled like heck to around 1425 RPM's and then it was quiet above that to 2500 RPM's (Normal Pilot injection shut off point). Other than that, the truck ran great.

[mackin]

First tank of fuel with Total Power in .....All ready noticeably quieter at idle.....Wonder why so soon???? How much detergent or cleaning agents are present??Seems like I had a little extra foam while refueling,could of been the fuel.....What was on my mind??My injectors are in for a bubble bath !!!!!!! He HEEE !!!!!

Or is it a lube thing?? Just came off the highway idling NO knock present....To quick.....? Wishfull thinking??

MAC

[ 12-18-2002: Message edited by: mackin ]</p>

[hoot]

I'm using it now too Mac and have noticed smoother running.

[BOOMERHD]

Hey guys,

Long time........, running FPPF for 5 months, and it is surely smoother. Took the top tech service guy for a spin the other day(steering box adj.), he was very impressed. We got talking about noise. The d-max gets louder with time was his statement. "broker" would know probably. I have noticed a small increase in DIESEL noise now at 34k miles. Also an early '01.

Hey Mackin, I'll be running through Hartford Feb. 9th. You going to be around?

Boomer :D :D :D :D :D :D :D :D

[Rebel_Horseman]

I too have an early '01 (05/01 date on the door patch). I've noticed a bit of a diesel sound at idle but nothing unusual. When I shift o neutral it gets a bit quieter. A co-worker's Cummins is noticably (sp?) louder when it's at idle in gear vs when it's in neutral or park. I've ran a few bottles of Red Line Synthetic additive through my truck (usually about ever 2 or 3 tanks) and have noticed better MPG. Of course I've only owned my truck for a month now so I don't have any real long term results. BTW the fuel filter was changed about 2K miles ago right after I bought it.

Reb [&gt;&lt;]

[mackin]

BOOMERHD


Hartford??? Hell I'm in the route 8 corridor and or exit 17 off of 84....I'll flag ya down on the way by !!!!!

Coming across the cesspool to route 8???Or no paddle boat and 84??? Any rate all be around as of right now,long ways off.....When it gets closer shot me an E-mail.....We'll hook up some where,here or there.....I'm 30 mins or so from Hartford.....

MAC :D :D

[BOOMERHD]

Yeah Mackin,

I'll be float'n over. Less hassle, kids dig it, and I can sleep. I come from the east end of Long Island. It's really 3 ferry rides to New London for me. I'll be going up through Chesterfield and Colchester. We couldn't hook up over the summer, so let's try. I'm in no rush, headed to stratton a couple of days later. Staying at my brothers pad in Avon first.

We'll e-mail later.

Boomer :D :D :D :D :D :D :D :D

[01_Duramax_Dually]

Well changed the fuel filter this weekend. Water in bottom was present but nothing to trip the SES about the fuel filter. I want to take it to the dealer but I know what they will say" Has it thrown any codes"..Answer...NO....Then will come the "Well it is supposed to make noise, it is a diesel", I agree. However it is a change from what it has been. It is one of those weird deals. You have a vehicle cruising along and then it starts to make a different noise, just want to be proactive and nip it in the bud before it becomes a SERIOUS problem and the truck is down. I see both sides of the debate, Dealer cannot do anything and I am saying there is a difference.....Final arguement from dealer will be "Wait until it breaks then we will know".

The truck runs GREAT...matter of fact excellent. It crusies around town and GREAT at 75- 80mph on freeway at 2200-2300 RPM. It is just a weird deal at stop lights when you come to a stop. Takes a few seconds and then starts making a very rythmic "Diesel Knock" noise.(like 1 cylinder) Then take off and it is gone. Truck does not idle rough or smoke....I have 46K miles now..Just wondering if this is just the motor settling in and doing what it is supposed to do....As with anything, as it wears, things change...
I will try some diesel fuel additive like Standyne and see if maybe it is a plugged injector.

Any further comments are appreciated.

Happy Holidays