New to HPtuners and could use some help. I have a LS2 with turbo and seem to be limited by the installed 42lb injectors to 6 lbs of boost. When I try much over six lbs and reach approx 5200 RPM's the injectors reach 78% and then start dropping off. The car then hesitates. I have plenty of fuel pressure-stays at 58 throughout the run. I live at altitude-5800ft. I know of another LS2 turbo in the area that is having the same issue. Any thoughts would be appreciated.
Mike
42s are not enough. the fact that your injectors are showing only 78% most probably means they're misconfigured. regardless of their configuration, you can't go past their natural limits.
post your tune and logs, we'll take a look at them.
My 03 Radixed SS truck as a boost referenced fuel pressure regulator. I run about 65psi at WOT. Maybe you should look into a FMU to up the pressure. Eventhough the injectors are rated at 42lbs they'll flow more at 65 psi than 58. Just a thought. Later
Dave
Thanks for taking a look at my tune. It is below. I have not saved a log (as I noted I am new at this) but will get one up as soon as it stops raining.42s are not enough. the fact that your injectors are showing only 78% most probably means they're misconfigured. regardless of their configuration, you can't go past their natural limits.
post your tune and logs, we'll take a look at them.
I now have both a tune and a log to share with the experts. The tune is the same as listed above. As you scroll through the brief log you will see two second gear runs. The first at 5 lbs of boost. Even this run shows some inconsistances once 78% injector cycle is reached. The second is at 7 lbs of boost and as you will see things go bad very quickly. I think with the cool crisp weather we are having today I am making more power at lower RPM's and boost levels thus having even more issues.
Would certainly appreciate any thoughts and, btw, what do you mean by misconfigured injectors?
Thanks again
Mike
oh man, where do i even start with this one....
1. it's a 1 bar maf tune for a boosted setup. this simply wont work (well, it obvieously works, i mean work WELL). maf has a limit of about 56lb/min of airflow, and that's nothing for an LS2, especially boosted. 1 bar map is gonna be missing about 40kPa of pressure, and therefore 40% of airflow. wanna guess what that does to the fueling?
2. because it's a MAF tune, VE looks stock. trust me, you put a turbo on anything, and the VE table should look nothing like stock.
3. injectors setup looks strangely low. how did you arrive at it? what kind of fuel setup is it? fuel regulators? pump?
i can write an epic here, but let's concentrate on basics here, i dont wanna drown you in detail.
the sad part this is 3rd crappy boosted setup this week, let's develop this cleanly so we can make a sticky/tutorial in the end, i dont feel like typing this stuff up 3 times a week.
[QUOTE=michaelmmoore]I now have both a tune and a log to share with the experts. The tune is the same as listed above. As you scroll through the brief log you will see two second gear runs. The first at 5 lbs of boost. Even this run shows some inconsistances once 78% injector cycle is reached. The second is at 7 lbs of boost and as you will see things go bad very quickly. I think with the cool crisp weather we are having today I am making more power at lower RPM's and boost levels thus having even more issues.
Would certainly appreciate any thoughts and, btw, what do you mean by misconfigured injectors?
Thanks again
You need to apply the Maf Freq Patch under the operating system. Then you have to perform a write entire. This will allow the maf to report up to 15000 HZ, your's is limited to 11500 HZ.
Log maf freq and commanded afr. Also set the pe delay to 0 rpm and the enable rpm to 0. You must get a wide band to set the afr.
Russ Kemp
Why not do the 2-bar LS2 VCM enhancement?
Just takes a 2-bar sensor (search for AC Delco and 2-bar on the HPT site)
EC
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Thanks everyone for your input. Sorry for the lack of response and this short reply at this point but other stuff is keeping me snowed. I do think I have a lot to work with when I can get back to it-having some minor surgery tomorrow (except it is on right wrist so shifting out for a while). When I get it worked out or if have more questions will get back to you guys-a promise.
BTW-EC_Tune, utimately will go to 2-bar, but was not able to find a part number through the HPT search. Any other ideas how to find.
Thanks again
AC Delco 213-1631 GM 12580698
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Your IFR table looks to be a little low for 42 lb-ers @58PSI. This would explain why the injectors stall at 78% instead of 100% or greater.
Also, what size MAF are you running? Like RHS said, it looks like your VE hasn't been touched, along with your PE enable settings. I wonder if all that has happened is the MAF re-cal and IFR change....
muncie: i just fixed a very similar situation (boost+bad tuner) with similar bad ideas in the tune. the idea behind setting IFR lower than proper, according to the 'tuner' was "if you dont have enough injectors, you just make them seem smaller so you make them work harder" and now Bernoulli's rolling over in his grave...
There's a limit on injector size for LS2/LS7 vehicles of 63.95 lbs/hr. That's not his case with the 42's but when you are limited by the PCM you have to take other measures.
BTW: 42's *should* be enough for just 6 lbs boost... And I think Russ is correct, you are banging the MAF limit. You MUST apply that MAF patch and do a Write Entire for it to work correctly.
BTWx2: The LS2/LS7 PCM's are hard coded so you can't "kill" them like an LS1 PCM. If a write entire fails, check battery voltage, charge for 10 minutes if necessary & re-try. Don't disconnect the battery under any circumstances. If you keep having problems with a write entire, contact support. There is a fix in the beta software for this *rare* issue. I personally ran into it with a very early production 05 C6.
HTH
EC
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EC: how do you figure 42s shoudl be enough for 6lbs? how do you calculate these things?
Since he's at 78% at 5200 with only about 1400 RPM to go, should be OK at 6 lbs. The 42's should take him to ~630 flywheel HP or about 550 RWHP. If it's a stock LS2 I wouldn't push past 9 lbs anyway or the pistons will be short lived.
Now if this is a forged motor capable of higher boost (10-12 lb range or higher) or higher RPM capable then the 42's are a waste of time.
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Had the wrist surgery and it has taken more time then I thought to be back up and running. I patched the MAF, changed the PE enable and disable, and reduced the EQ tables (running too rich-Apparently LS2-edit, used by the tuner, does not allow a MAF patch and he was trying to overcome with more fuel. He has switched to HpTuners). It now runs great up to redline at 7-7.5lbs of boost (also have meth injection-for safety).
The negatives: the MAF is maxing at 5300 RPMs at a little over 60 and the 42 lb injectors are reaching 96-98%. Also, the O2 sensor (B1) will correlate with B2 in the low 900's mVs, then after a few runs to redline B1 starts climbing and can get over 1000. B2 stays constant. I have not seen any KR.
So, I am installing 60 lb injectors and replacing B1S1 later this week and then will retune. Will let you guys know the results.
Thanks for your help and if you have any other thoughts let me know.
Mike
Did you check the AFR with a wideband? Being too rich will increase the injector duty cycle. Did you apply the maf patch? I agree with EC_Tune that 42 lb injectors are fine for your set up.
Russ Kemp
Yes, I applied the MAF patch and it stopped the MAF shutting off. I will be checking the AFR (I don't have a wideband at this point but will be upgrading) later this week (on a dyno) after changing the O2 sensor and before putting in the 60's. However, I am now running 7.5 lbs of boost so I think the 42's may be maxed out.
Mike M
Last edited by michaelmmoore; 08-28-2006 at 04:56 PM.
*Sounds* like you are running rich (safe) currently. Thus the 96-98% D/C. You'll probably pick up injector duty cycle by leaning out a bit but *not* until you get a wideband in the pipe.
Most FI LS series run best at ~12.0. You can only bandaid them with a little fuel and then the power starts dropping. (Generally anyway hehehe)
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