LBZ: New nozzle now sounds like powerstroke

05chevy

05chevy

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I just helped my buddy install 75% II nozzles and twins in his Lbz. At idle till 1500rpm it sounds like a power stroke. Almost lime bad fuel knock. But does not haze or smoke at all. Once you get above 1500rpm everything smooths out quiets up and sounds good. Like a duramax again. Lol. I tried checking the rail pressure with efi live but the scan function is not working right with the new update. Any help will be appreciated. Thank you
 
05chevy

05chevy

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OK I'll take a look at the tunes when I get home. But even if I switch from tune to tune it still sounds the same. What would a ideal idle timing be?
 
05chevy

05chevy

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PACougar said:
Don't be surprised if it turns out to be the nozzles. Hopefully it's something easy like a tuning problem.
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What would be wrong with the nozzle to cause this issue? And what in the tune could I change to try and fix this threw tuning?
 
PACougar

PACougar

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Jun 27, 2012
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El Dorado Hills, Ca
05chevy said:
What would be wrong with the nozzle to cause this issue? And what in the tune could I change to try and fix this threw tuning?
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I've had personal experience with II's nozzles and in both cases they weren't good experiences. I know have had a great time with them, but I think they have the worst QC in the business. Were the nozzles brand new before they were modified? Has the tune been updated for the big injectors?
 
WVRigrat05

WVRigrat05

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Jan 1, 2011
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French Creek, West Virginia
My 20% over II's are fairly noisy too. I get a nice knock but mine is steady all the way from idle to 4200 rpm. Changed tuning on mine 3 times, the last time the rattle almost is gone til 2450 rpms but the knock is still there an an LLY is nosier anyhow. Probly gonna have to play with the tuning or send the injectors back to get balanced.
 
05chevy

05chevy

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PACougar said:
I've had personal experience with II's nozzles and in both cases they weren't good experiences. I know have had a great time with them, but I think they have the worst QC in the business. Were the nozzles brand new before they were modified? Has the tune been updated for the big injectors?
Click to expand...

He bought the nozzles used off a member on here. I have modified the tune myself for the larger nozzles. Like I said before the thing is awesome after 1500rpm. Noise is gone and sounds and runs great.
 
PACougar

PACougar

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05chevy said:
He bought the nozzles used off a member on here. I have modified the tune myself for the larger nozzles. Like I said before the thing is awesome after 1500rpm. Noise is gone and sounds and runs great.
Click to expand...

To me it sounds like the nozzles are possibly dripping fuel in under lower rail pressure and then the higher rail pressure clears it up. There are plenty of trustworthy people on this site, but I would be very leary of buying used injector nozzles. I had some 60 over on my injectors I sent in to have cleaned and tested, they told me 5 of the injectors were bad so I payed to have them replaced and the nozzles of course swapped and "calibrated on the new injectors. Turns out the nozzles were had worn out and who knows how they "tested and calibrated" them. With those injectors I had some decent idle smoke and they too were really loud until higher rpm's. Do you guys notice in smoking at idle?
 
05chevy

05chevy

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Doesn't smoke at idle at all. It will haze a little going down the road. And some times it will puff a little white.

The truck also has a weird start issue too. Cold start it sounds like only 2 or 3 cylinders are running then slowly runs on all 8. Guessing that could be the nozzles also? Where is a good place to send them to be tested?
 
PACougar

PACougar

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05chevy said:
Doesn't smoke at idle at all. It will haze a little going down the road. And some times it will puff a little white.

The truck also has a weird start issue too. Cold start it sounds like only 2 or 3 cylinders are running then slowly runs on all 8. Guessing that could be the nozzles also? Where is a good place to send them to be tested?
Click to expand...

Have you noticed any extra pressure in the cooling system, it could be a blown head gasket as well.
 
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