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View Full Version : Critique my tune please - 3 issues:



Mr. P.
December 24th, 2009, 11:27 AM
OK starting a new thread here to not clutter-up the thread on data logging -

I haven't strayed very far from VE tuning yet (learning as I go). I will have to ask you guys for some insight, I've got three issues -

Attach are the latest logs, as well as the current tune. I am not asking for outright "answers" or tune fixes (although they are appreciated!) but any quick experience or insight so I can continue to learn and figure it out on my own I'm eternally grateful for.

The vehicle is 2003 Silverado SS with LQ9 - spark plugs are TR6's gapped at .33" The OS is COS3, I am running OLSD with PE & DFCO disabled (I think?) I have been driving and mapping VE up to 4000-RPM, there has never been any smoothing applied to the VE table. The High-octane spark table is based off my NA one with high-load cells set to 17-degrees advance. I have not been able to VE tune into the A0009 Boost VE table very far yet. At the high-demand end of the commanded AFR table I ramp AFR up to 11.8:1 for safety during the VE mapping process. In the log file external input #1 is a PLX wideband; I work in EQR units, so I log ERQ and have custom pids that calculate AFR & EQR both and display them on my dashpage.

1) on decel (overrun) the RPM wanders and hits the stall-saver, when the vehicle is stopped the managed idle takes over and it idles fine, I think I read somewhere this is just not enough running airflow. ???

2) the motor spits and cuts apart at 4000-rpm if the MAP > 100 kpa, I thought this was the A0009 Boost VE table being too rich, but logs suggest that it's not the issue. Also there is no KR and spark is 17-degrees so I don't think this is the issue either, I am not sure how to troublshoot from here.

3) I get a single spike of KR on trans kickdown; I don't know where to go to address this as I'm just learning...

But so far the tune is IMO coming along well, the truck is AWD and will rip all 4 tires loose from a stop before boost comes in, and it's very strong for 4-psi, I haven't been able to spin the motor higher than this without breaking up.

Mr. P. :)

Tre-Cool
December 24th, 2009, 04:58 PM
What injectors & fuel system (if any) are you running?

Are you running a 2 bar map sensor?

Mr. P.
December 24th, 2009, 06:56 PM
What injectors & fuel system (if any) are you running?

Are you running a 2 bar map sensor?
Injectors are 70#/hr modified Multecs, pump is single Walbro 255 at stock pressure (58-psi) running through stock fuel rails, stock FPR, and stock return line back to tank.

Mr. P. :)

joecar
December 25th, 2009, 09:16 AM
Are your injectors rated 70#/hr at 43.5 psi or at 58 psi...?

Mr. P.
December 25th, 2009, 12:23 PM
Are your injectors rated 70#/hr at 43.5 psi or at 58 psi...?

640cc @ 43.5 psi = 72 pph @ 58psi. The injector duty cycle so far is really low.

Mr. P. :)