Knock - Knock,,,UPDATE !!

I'll try posting this here.....

My 07 5.9 is louder at idle all of a sudden.

I cranked it up one afternoon and it had a dead cylinder,,it took about 1 minute for it to clear up and then seemed to be OK...I figured no big deal.

Several day's ( and a tank or two different fuel ) I noticed the engine was louder at idle and has a noticeable fuel knock (injector ??)
while accelerating up thru the gears,

The fuel knock is pretty consistant under light throttle, but when I shift to 5-6 gear or step down hard on the throttle,, the knock goes away and the engine pulls hard like normal...

It feels and sounds like the computer changes something at about half throttle or when the turbo begins to produce boost...the change is that noticeable..under light throttle while driving highway speed it rattles bad,,
but as I step on the throttle (just a little ) it quits just as the turbo starts to whine...

Took it to the stealership,,they claim they "can't reproduce customers complaint" and said there is nothing wrong...no fuel in the oil,,,,blah blah,blah...wanted to sell me an injector cleaning for $99.99..

any ideas or thoughts ???

another question...
Under light or no throttle is the wastegate open or closed ?

 

my truck does it too, 82000 miles makes all kinds of strange noises lately thought it was injector problems and dealer told me no its fine....i have noticed with different fuels(diesel) can make it more loud or quite...same sa my engine oil after 5000 miles starts to run rough and louder as well...i guess these diesels have a mind of their own....

 

Ah, the classic "we can't find it" and then try to sell you the work they should do under warranty anyway. Try another dealership. Or keep using the same one and start telling them you're going to lemon law the sucker if they can't fix it. This is a warranty issue and you shouldn't have to pay a dime for the repair. Make them fix it. I think 3 strikes and you can lemon law it. Just threatening to do that will often make them magically "find" the problem and fix it.

Many dealerships like to find ways to either not warranty something or at least get you to pay out of pocket for it.

-Chuck

 

wasted wages....have you had any luck. my 07 with 18k miles does the same thing. this is my first cummins, didn't know if it was normal. thought about taking it in and seeing what the dealer has to say.

 

Update 12/09/07

No codes,

Took it to the dealer again...
This time they did not write it up,,they sent the tech out to ride with me.

Tech claims that cummins changed the number of holes in the injector tip from 8 to 5 and they can carbon up easier...still think it's a bunch of bull.

They suggested a flush again ( some kind of valvoline product ) to which I declined...( 34K miles,,,, come on.......)

He also stated that the injectors fire 3 times per stroke. 2 small injections to prechamber the main injection. True ?

I do know that the oil pressure is not affected,,no fuel in the oil,,the truck pulls hard and the engine does not miss a beat,,,just this damn rattle on light to part throttle as I row through the gears...then at highway speed if I start to roll onto the throttle there is a .5 second rattle before the boost comes up and then it goes away.

It seem like a fuel delivery / timing problem more than anything else...

I may take it back again and tell them to do the flush and if that fixes the problem I will pay for it..if not they change the injectors.

Cummins Southern Plains is not far from where I work,,,I may swing by there also and see if they will give me any info...

 

Have you done anything with the computer as far as programers? Also from what they are suggesting from Valvoline is the Synpower Fuel Cleaner, recomended every 3K, it works well. I'm also wondering if a Finch catalist wouldnt hurt that issue either.

 

Bone stock---no programmers.



Well it finally bit the dust,,,it's running on 5 cylinders and 1's going along for the ride...:doah:

It's at the dealership now ...will update what they find....

Stay tuned.....opcorn:



EDIT 12/18/07

spoke with the service dept today,,,only thing they could tell me so far is,, the tech has 1 injector and 6 terminal plugs on his work order.....

 

Well,,,I have my truck back and it runs smoother than the day I drove it off the lot. This is the best it has ever run,,,quiet,,smooth,,pulls hard and the mystery rattle at light throttle is gone.

Mileage went up 2.2 mpg.

The dealer did the following:

Ran flow test on the CP3 pump ( ? ) and the lift pump ( both OK )
Ran flow test on injector return flow ( was high )
Reflashed the computer,,,replaced all 6 injectors and crossover tubes,,replaced 6 connectors ( ? )
adjusted the valves,,
and replaced a frozen u-joint on the rear drive shaft.

All done under warranty N/C. waytogo

 

Called dealer. Take it in on the 27th. See what happens.

 

BLK07 -- you leavin' your Banks programmer hooked up when you take it in ?

 

don't know yet....i talked to banks and they told me to disconnect the ODBII plug and pull the fuse feeding the 6-gun. when i talked to the dealer, i was up front with them and he said it was ok. the only difficult part to remove is the connections to the cam sensor and crank sensor. not looking forward to messing with them. i did ask banks if they flashed the computer, am i ok?....they said i was.

 

I'm suprised that dodge would honor any warrenty after a power adder had been installed on the truck.

I was basically told that if I installed anything other than a chrome tip on the tailpipe,,I could kiss my warrenty goodbye,,,I haven't even thought about a chip until the clock hits 100K...

Let me know how your issue goes when you take it in...

 

So do we think it is an injector????

I talked to my dealer today. He said he would unplug my box to flash the computer.waytogo He said my warranty could be voided but he didnt mind the box. I have an appointment tomorrow. So is this an injector causing all of this. It sounds like all of the trucks are acting the same. My truck has a rattle that comes in and out when pulling my boat. And the knock at idle. I will let you know what I find out.

 

Not to hijack your post but…..I may have the same issue. Mine’s got an off idle rattle or clacking sound. It’s worse when it’s cold (pretty sure that’s normal though) but after it warms up it does it sometimes and then other times it sounds fine. Seems to be most prominent when I’m cruising around 2000rpms, let off the throttle and let it get down to about 1700 and then get back on the throttle lightly…then it rattles/clacks fairly loud. There’s no power or boost loss, EGT’s are ok it drives perfectly….just makes a noise that doesn’t seem right to me. But, it could be fine. This is my first diesel and I’ve only had it about 10k miles (it’s got about 85K on it now) and I don’t really recall hearing this rattle/clacking sound until about 5-8 weeks ago. Any ideas?

 

Got it back

Got my truck back today Got the usual answer couldnt duplicate. But we flashed the computer. Found out my service manager is a cummins guy and is very interested in this problem though. The flash was for long start problems. Truck fires off a lot faster and seems smoother but rattle at light throttle is still there. Just wanted to update everyone. Hope someone finds a definite reason for this

 

took to dealer and left the banks system installed. disconnected power to it and also the odbII connection. louder noise wasn't there when i took it in, but the quieter knocking/crackling sound was. tech couldn't here what i was hearing and asked me to drive him and point it out. he told me all injectors were working within specs. one was down to 90% but cummins says replace at 87%. drove for him and pointed out the noise (like a knocking gas motor on bad gas)....he said that is normal. blameded it on carbon build-up. when he went to show me the results of the injector test, #1 was down to 88-89%. at that time, he made the call to replace it. watched him change it and when he pulled it out, there was a large amount of carbon on it. he said this is what i hear knocking/crackling.

i talked to the tech a little about power adders, and he said they know power adders don't cause this problem, so they work with the customers to keep them happy....what a concept.

on the 30th, went to another dealer (bought my wife a nitro) and they asked if i wanted a new truck. said if the deal was right..... picked the new 6.7 with a 6-speed manual up new years eve. see how this one works out.

 

My 03 never sounded like this 07 does.

Why would carbon build up on the injectors be happening so much with the 07's ?

The dealer told me the injectors in the 07's are different ( less # of holes ) and that the injection pulses 3 times for each firing of the cylinder.They claim this is what causes the carbon build up.

It's more of an annoyance ( the crackling sound ) than anything else.
The engine performs great,,It just doesn't "sound " right.

Since I had mine worked on, It is much quieter,,but I can still detect the rattle at times,,

I was just wondering if the rattle is more noticeable on the manual trucks or does anyone have the same issue with an automatic ?

 

my truck is an automatic

 

Tranny shouldnt matter if its an issue like carbon build up I'm just wondering what it is????

 

I have heard rumors that the 07 dodge with a manual trans has a half second
delay built into the computer that defuels the motor while shifting to
help with clutch life.

At highway speed when you lightly roll into the throttle the rattle lasts about a half second...and quits just as the turbo starts to spool up...if you feather the throttle at cruising speed you can hear it come and go...come and go...

I was just wondering if this rattle issue was being heard on trucks with auto
trans also...