Running lean. PL review

[LeeRoy]

I'm looking for some Powerlogger review help.
See attached. There are 3 highway wot runs on there with incrementally more boost added.
I have a TT chip and PLX wideband. Fuel is being logged. Running 100 octane.


Why are my BLMs climbing on the 2nd and 3rd run? It's trying to add fuel but my pressure is falling. It's a new Walbro FP and I tried 2 FP regulators.
Are my injectors maxing out? Is the pump being maxed out? Am I flowing to much?
Any comments?
Thanks!!

[Steve Wood]

Okay, I have more questions than answers.

What size of injectors are in the car?

The voltage reported by the scantool is way low.  This may be affecting the injector duty cycle but I don't think it is quite that low yet.

What voltage are you reading at the back of the alternator  (terminal to case) and what voltage do you read with your meter across the two battery posts?  If the battery going to the pump is low, that can affect the pressure.  I assume the pump is hot wired?

Looks like you are reading fuel pressure with a transducer into PL, that is not always completely accurate.  In this case, your stock O2s are dropping along with the pressure so it may be.

Which Walbro did you buy and whom did you buy it from?   Are you sure you completely tightened both ends of the hose when installing the pump?

[Steve Wood]

Oh, yeah, adjust your tps on the high end so it reads over 4.2 volts (or whatever Eric says it should be so you can adjust your chip properly)


Something like .38-.44 on the low end, and above 4.2 on the top end should do it.

[Steve Wood]

and this looks like a 6.0 v chip?

Appears to me that the fuel pressure is dropping and the chip is running up the duty cycle trying to obtain your 10.8 requested a/f

The pump needs to be hotwired and seeing at least 13.5 volts to do its job.  Your low scantool voltage bothers me, but sometimes the scantool reads a little lower than the alternator.... but not that low

[LeeRoy]

Steve thanks for helping out.


I have 55lb injectors and I read 14.5volts across the battery terminals. Same for alternator bolt to chassis.
I got this pump last year-  [size=78%]http://www.gbodyparts.com/product_info.php?cPath=46_21_49&products_id=544&osCsid=20d15bf56dbd5903659f7471ee67918a[/size]


The FP is hot wired and I measured 13.8V at the connector back by the fuel tank.
And yes I'm running a 6.0 V chip.


Could I just be out flowing the FP? I really don't have a feel for this so any help is greatly appreciated.
Thanks!

[Steve Wood]

those injectors are good for upper tens without a problem.

You were running at a pretty rich A/F and the pump does not seem to be able to flow enuf as the pressure was falling and the chip was opening up the duty cycle trying to get to the 10.8 you asked for.

That does not tell us which pump it actually is.  The pump that began with an F in the number has failed on most of us that bought one.  Sometimes in the first five miles and sometimes a 1000 miles later.

Not sure why PL is reading so low on the voltage.  Got some high resistance somewhere between the battery and the ecm, it appears.  But at that voltage you seem to have at the pump, you should have plenty of power and plenty of fuel.

Looks like one of three/four things to me.  Bad pump.  Hose not tight on the hanger-pump, obstructed hose, plugged up fuel filter

[LeeRoy]

I found a pretty bad kink in the rubber part of the supply line- maybe 50% restriction.
This has got to be it.

[Steve Wood]

hope so!  Otherwise the pump is the next stop.  That ad reads just like the ones that were failing, but they claim they fixed the problem a couple of years ago

[LeeRoy]

Still has problems at WOT. This is really frustrating...
Please see attached PL dat file.
Thanks

[LeeRoy]

What I don't understand is why it's trying to add fuel when it looks like it is running around the programmed AFR.

[Steve Wood]

I saw no problem this time other than you are running way too rich for 17 psi of boost.  11.5 would probably be closer for that boost level

It kept up the fuel supply and there was no drop off on the A/F nor the o2s

the fuel pressure reported by the transducer seems steady.

On this run, you did not show any problems with the pump.

[LeeRoy]

So if I understand it is closed loop just running on the high side. It's erratic because I'm running way too rich?
And it does look like the kinked fuel line fixed the BLM pegged problem.
Maybe I should rename thread to help me tune.

I could also increase boost, correct?
Is there some sort of chart of what the proper AFR is for boost?
And given my combo what would I need to adjust my boost, AFR, and timing to be low 11.0s (or not break the motor) running on 100 octane.
I have ported M&A heads, FMC, TE-63 turbo with 55lb injectors.
Thanks!

[Steve Wood]

I don't look at the blms in this case.  I have not read Eric's instructions for the 6.0 chip so I won't comment.

I looked at your A/F's and they were steady.  I looked at your fuel pressure and it was steady.

I looked at your O2s and they were steady.

Hence my statement that the fuel pump was keeping up with your current demands.

A/F requirements have too much to do with total combination to put out a table.  You have programmed 10.8-1 which should be enuf to run 26-27 psi on a strong engine.  A/F will depend on air flow, timing, octane,  ambient conditions, etc.  That means tuning is an interative process that takes work to fine tune it.

Not know why Eric put in for timing, I would say just work on the boost at this point.

It takes quite a bit of hp to go low elevens and the more hp you make, the greater the stress on the engine so there is no free lunch, and not necessarily a safe lunch

Bump the boost a couple of pounds and see what the fuel pressure, a/f, and O2s do.  If the fuel pressure drops, or the the o2s get below 760-780, or you see timing retard, stop.

If things look stable, add some more.  I don't know how much you can run on 100 octane because timing, and combustion temps will be the limiting factor. I would guess at least 22 psi of boost, but, ymmv as above.

I would like to be assured the fuel pressure problem has been fixed but we don't have enuf data to say it will hold as the boost comes up as of yet.

[motorhead]

I agree completely with Steve here. It should be noted that your heads will flow more than stockers and that should be taken into consideration while tuning; ie. less boost will produce the same power.

[Steve Wood]

and I meant to say I don't know what Eric put in your chip for timing