2006 knocks when cold

[tobaccogrower]

below 32* my 2006 knocks at idle. its so bad it sounds like the motor is running without oil. above 32* engine sounds normal. it goes away after warm up. dealer has offered no help. they put in writing " drive it till it blows"! no joke!!

runs and drives fine. above idle sounds normal.

anyone have any insight on this? i forgot about it over the summer but 29* this morning same problem. 60,000 on the od.

thanks

 

[AEdelheit]

Its probably fuel knock from an injector. Id do an oil sample on your oil to check for metals to be safe or if a shop can do a compression test but a bad enough fuel knock can sound like a rod knock. I dont know the best way to test the injectors for that through honestly.

 

[HBarlow]

With the long list of modifications in your signature what would you expect a Ram dealer to do?

 

[AEdelheit]

The only engine modifications I see are intake, injectors and turbo. None of that would affect there ability to diagnose a problem. I didint see the word "Warrenty" mentioned anywhere. The dealer is just to lazy to deal with it.

 

[Prairie Dog]

I agree it's probably an injector issue. I would find someone else who knows how to test them.
Heck, you may even be able to feel the injector lines to tell which one is bad but keep in mind that you can always feel more "knock at #1 and #6 injs on a normal eng.

 

[cerberusiam]

What spec and maker are EDM80 injectors? As a guess, you have a tip that is not spraying exactly right in the cold engine program. The ECU will change injection specs base don temp and it likely has introduced a glitch in the spray pattern. You may be better off questioning the injector builder to see what they say.

 

[tobaccogrower]

mass diesel put them in. i'll get in touch with him and check on the injectors and see if he can test them. i know the dealer wont.

the only mods on my truck are the injectors. i pulled the turbo off 2 years ago to have it inspected for what i thought was a problem. i still havnt gotten it back... ... but thats another story!

 

[AH64ID]

That's a big injector for stock programming. It's probably effecting the timing (like injectors do) and that combined with cold weather timing is knocking.

Can you bump the idle up (fast idle with cruise control) and make it go away?

 

[tobaccogrower]

when it idles up it goes away. only at idle

 

[MChrist]

That's a big injector for stock programming. It's probably effecting the timing (like injectors do) and that combined with cold weather timing is knocking.

Can you bump the idle up (fast idle with cruise control) and make it go away?

I wasn't aware that timing was different at cold temperatures. How much "bigger" are the EDM80 injectors? They must be pretty big to allow the diesel out so much quicker as to affect timing. This info is new to me and probably others, so could you please explain?
Thanks.

 

[AH64ID]

Timing is effected based on ECT and IAT, in order to have a smoother, cleaner, quieter motor at cold idle. The larger holes in the injectors get the fuel out sooner, and thus it ignites sooner. On a cold motor more advanced timing can be quite noisy.

 

[MChrist]

Timing is effected based on ECT and IAT, in order to have a smoother, cleaner, quieter motor at cold idle. The larger holes in the injectors get the fuel out sooner, and thus it ignites sooner. On a cold motor more advanced timing can be quite noisy.

So if the ECT (engine coolant temperature) is one parameter, could just employing the block heater change his results?
A whole lot cheaper than changing out injectors...

 

[Bob4x4]

So if the ECT (engine coolant temperature) is one parameter, could just employing the block heater change his results?
A whole lot cheaper than changing out injectors...

Yes the engine would not be cold if the block heater was on long enough

 

[JBallou]

I can reach 130* coolant temp with the block heater plugged in for a few hours. Give it a try

 

[LNaugle]

I would still have the injectors tested if it seems like only one or two individual knocks... all of em knocking then the block heater is fine.

 

[rscurtis]

With the Rokktech crank sensor, my truck soundl like a 12V for the first mile or so in colder weather until the ECM retards the timing. It doesn's do this in warm weather. The fuel system, other than the Fass, is completely stock with no "magic black boxes".