When the LNF enters 'closed-loop' operation, a 'cricket' type of sound can be heard under the hood ??
During the 1st few minutes after startup, in 'open-loop', this sound can't be heard...
'Closed-loop', causes something that rapidly cycles ??
What is it....
Last edited by 2000Firehawk; 10-12-2015 at 05:29 PM.
2009 HHR SS automatic--- 350 HP - 450' LBS TORQUE,http://www.youtube.com/watch?v=mDZgoSN8Gk0
Mostly stock - K&N air intake, TTech engine mount, 2nd cat 'cored', E47.5 tune, Lighter - wheels/tires/rotors.
13.0's @ 110MPH, street tires, 12.28 @ 112.67 best on slicks, 1.7s 60' ETs
purge solenoid? or cam phazer noise?
Can you describe this cricket noise a little better?
If you are referring to a little tick that has a frequency of about 1 Hz or maybe a little less, that is only noticeable during the warm idle, then that is linked to the high pressure fuel pump (probably some regulator). If you record the high pressure fuel pump measured signal with HPTuners, you'll notice the tick falls in line with the small sawtooth pattern the high pressure signal makes. it seems normal, or at least it seems that all LNF's do it.
Last edited by TurboCobalt; 10-13-2015 at 08:45 AM.
I'm betting it's the hpfp, there is defentially a change in it's sound when going from open to closed loop. There is the ticking of the injectors and then cycling of the pump, the injector tick is much faster and the cycling of the pump is slower.
Its most likely the throttle body squeaking, it will cycle at start up to control the idle until the cam switch to the warm (open loop) mode.
--Christian
cam phase changes and fuel pressure changes. The HPFP noise is what you're hearing.
The most hated, make the most power.
93 Ranger. 5.3 D1X. 1069hp.
Yes, it is the HPFPOriginally Posted by Area47
I've got to keep up with the simple things.
During cold start up, pressure is 370-380psi, in open-loop, such a tight range.
After 3-5 minutes, when changing into closed-loop, pressure rapidly changes from 360 to 560psi, a 200 psi change, making a sound, like 'crickets'.
My idle in drive timing is 10 degrees, swings from 9.5 to 10.5 degrees, while the HPFP is changing from 360 to 560 at idle in gear.
After changing my tune, I wait until I hear the 'crickets' , before driving, as I know it's then in closed-loop.
2009 HHR SS automatic--- 350 HP - 450' LBS TORQUE,http://www.youtube.com/watch?v=mDZgoSN8Gk0
Mostly stock - K&N air intake, TTech engine mount, 2nd cat 'cored', E47.5 tune, Lighter - wheels/tires/rotors.
13.0's @ 110MPH, street tires, 12.28 @ 112.67 best on slicks, 1.7s 60' ETs
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