Lean when entering PE

[xsesiv]

I've been on to this problem for a while but still can't get it right. It seems everytime I enter PE mode it goes lean big time (>19:1 AFR on the PLX WB) and I don't believe my VE table is that far out. Car is a Holden Commodore 5.7 stock with an intercooled Vortech S Trim kit I just installed so it's my first blower tune.

I'm logging fuel pressure from an Autometer sender in the fuel rail and it's running a BR FPR, fuel pressure seems to be working alright. Injectors are Siemens 63lb's and they're no where near their limit. Tune is a 2 bar OLSD with a 2 bar MAP sensor.

Any ideas?

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[RomansDesigns]

Your VE Table is way off. You need to datalog commanded afr vs actual to see the % error. You need to smooth your ve and spark tables.
When you have your ve table right, there will be no difference between commanded and actual afr's.
Mark

[xsesiv]

Yeah your right, my VE is way off as I returned to my original VE table. I started performing normal VE tuning as you suggested (using % error from Commanded Hi Res vs Actual) but every round of logging/correcting showed it needed more fuel when in PE, so I kept increasing the VE values until they were around 100.

Having a 100 VE around the 2400rpm 40kpa region doesn't sound right to me, that's why I thought there must be another issue somewhere other then the VE table being out? Unless this is normal for a blown LS1, the twin blow off valves close just as I enter PE so all of a sudden the engine is getting a heap more air.

I'll try what you suggested again tonight and post back the new logs and tune file.

[blownbluez06]

although this is mainly an issue with the trucks, you may want to look at this

http://www.hptuners.com/forum/showth...682#post109682

[Dozer]

What is your fuel pressure at idle and what dose it raise to?

[xsesiv]

RomansDesigns: I spent 4 hours VE tuning tonight with the PLX WB02 and it seems the more I tune the VE table, the worse it gets. After every round of logging, the AFR % histogram shows I need to pull more fuel out in the low RPM & MAP regions but add more fuel above 3000rpm in the +50kpa region. I started getting VE values of +265 in the cells above 3600rpm and 110kpa.

blownbluez06: I've tried zeroing out my PE delay values but it didn't help.

Dozer: My fuel pressure hovers around 48psi at idle (34.6kpa or -9.5psi vacuum) and it reaches 59-63psi when the lean outs hit (115kpa or 2psi boost). I do find that the fuel pressure isn't very stable, it jumps around a fair bit but that could be normal for a Turbosmart BR FPR?

I changed my min injector pulse and offset vs volts vs vac but this didn't seem to have helped. The PCM is still not trying to reference the non existant MAF is it?

Here's my updated tune and some logs from tonight:
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[Bill@HPTuners]

You might want to try failing your maf rather than keeping it active

[Dozer]

It was the first thing I checked and it is failed 0 Hz. (Edit: I just went back and looked at your DTC's and you have the p0101, p0102 and p0103 set to 3-No Error Reported. There is your problem you want it at 2-No Mil Light. When you set it to 3-No Error reported the pcm will still use the maf. So as Bill said fail the MAF.)

[xsesiv]

Thanks guys, I should have checked the MAF DTC's properly . I've now disabled SES and set to No MIL light for the MAF codes. This helped the massive lean outs I was having down low but didn't solve them all. It was still going very lean at around 4500rpm but I found this to be a disconnected IAT sensor.

So IAT plugged in and MAF DTC's set, I started tuning the VE table again. I couldn't get the VE values low enough for a 14.7:1 idle, best I could do is 12.5-13.5:1 and it was still massively leaning out at around 5200rpm. I've now changed the Offset vs Volts vs VAC and Min Injector Pulse for the Siemens 60lb's from info supplied by RWTD in post http://www.hptuners.com/forum/showpo...&postcount=120 and that has helped slightly.

I'm still having issues, a rich 13:1 idle and extreme lean outs at around 5500rpm or 7.5psi boost. I logged at a small track event today and you can see it's leaning out in PE at frames 699, 972 and 1490. Fuel pressure isn't rock solid but 66psi at 7.5psi boost should be sufficient.

What can be causing this? Does it need more injector tuning or is there something else pulling fuel out?
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[Dozer]

Only thing i saw that might pull fuel would be under Engine/ Torque Management/ ETC Limits/ ETC Injector Disable. That table might be pulling fuel for torque management.

[xsesiv]

The car is a 2000 model so it's got a cable throttle so the ETC tables shouldn't be used. Even so, I changed the ETC Injector Disable table to 255 for all 8 modes but it didn't make any difference, it still leans out big time.

Is 255 the correct value for all 8 modes to remove all injector disabling?

[Dozer]

I remember reading this post and it might be your problem. The part that caught my eye was the pcm on holdens lowering volts to the fuel pump???
http://www.hptuners.com/forum/showpo...1&postcount=14

[xsesiv]

Yeah I've played around with those transmission values but didn't seem to affect anything. The fuel pressure seems to be working fine running off the boost reference and the injectors are only reaching 70% DC and 14ms IPW so it's got to be something in the tune.

I'm running the standard in-tank pump feeding a 3 litre pot with two Bosch 044's and a Turbosmart T-Reg Pro running up two 3/8" steel lines to SpeedInc fuel rails. The fuel system should be overkill for my combo!

I'm going to replace the standard valve springs over the next few days but I don't expect this will help. Would the blower dramatically change any of the transient fueling perhaps? I've got heaps of track events coming up soon so I need to get this fixed.

[xsesiv]

I was watching some video footage of my car at the track last weekend and noticed it was blowing black smoke like unburt fuel out the exhaust at some points. Looking through my logs there's no evidence of it going pig rich anywhere.

So I was thinking, is it running too rich like 10:1 or richer and the PLX WBO2 is seeing this as a lean condition? So then I thought my VE or IFR table could be too rich, my VE table seems to be alright (I think!) so my IFR must be off.

I then lowered my IFR across the board from 8.81g/sec to 8g/sec, went out for a quick blast and the scanner was reporting the lean outs again but earlier at 4700-5000rpm. I changed the IFR across the board to 10g/sec and the lean outs had disappeared for the first time!

Tomorrow night I'll return my IFR table back to 8.81g/sec or I might try 9.125g/sec (I've seen both figures advertised for the Siemens 60lb's) and start reducing some high RPM areas of the VE table to see if that helps.

Has anyone seen a wideband report a very lean condition (19:1) when in fact it's actually very rich (10:1)?
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[blucreek]

When w/b sensors start to go bad they start reporting leaner #'s

quick check: Remove your w/b power up (plx) hold a cigarette lighter directly under the sensor, squeeze the trigger on the lighter without striking, releasing the lighter fluid into the sensor, your w/b should go from 19-20(highest reading) to 10 Rich(lowest reading) as soon as the trigger is squeezed on the lighter. If the sensor reports to "Rich" slowly or not at all, my be time for a new WBO2 sensor.

WARNING: Sensor will(should) be very HOT!! Handle Sensor w/ Care.

chris