AutoVE ?

[DrX]

What causes the coasting portion (25-30 kPa) of the VE table to always be lean according to the BEN Maps. These cells always have the highest cell counts in the Map. You could increase the VE values for these cells to 200% and it would still go lean. (The other lean values in this particular BEN Map are just the result of a smoothing experiment.) DFCO is disabled.
Does something else cut off fuel?

http://i114.photobucket.com/albums/n241/TDOC2004/BenMap.jpg

[Tordne]

What is the Min/Max values for those low cells?

[DrX]

What is the Min/Max values for those low cells?

About .9/1.2 for the cells in the 25 kPa column. My WBC gauge is usually showing something like 17 AFR under these conditions.

[Tordne]

I see you are running COS3... Are you running Open or Closed Loop fuelling (or Semi-Open Loop)?

What is the value in the B3647 table?

I'm just surprised that increasing the VE massively doesn't help :eek:. Couple of other thing I'll ask... How many samples do you see in the lean area (is it like a few samples or heaps)? Could it be that your injector pulse width is too narrow to allow fuel flow - what is your min injector pulse width?

[DrX]

I see you are running COS3... Are you running Open or Closed Loop fuelling (or Semi-Open Loop)?

What is the value in the B3647 table?

I'm just surprised that increasing the VE massively doesn't help :eek:. Couple of other thing I'll ask... How many samples do you see in the lean area (is it like a few samples or heaps)? Could it be that your injector pulse width is too narrow to allow fuel flow - what is your min injector pulse width?

OL/SD. Well, I actually haven't tried 200%. But I have had this area higher than even the 105 column. Doesn't seem right to me. Heaps of samples in these columns. Min IPW is still stock at .7579 ms but I now have the Mototron 60lb/hr(8.89 g/s) injectors.

[Tordne]

OK... So are you seeing AFR's say 19+ in those areas?

I'm going to take a stab at your problem, based on my recent experience with some SVO 42lb injectors.

I think it may be that your injector pulse width is too low, and that the resultant pulse width isn't actually long enough (time wise) to actually allow the injector to open and flow fuel. If this is the case what will end up happening (more than likely) is that you will raise the pulse width till they flow fuel and then you will be pig rich ;). Basically this will be because the minimum flow of those injectors are likely to be too much for the those areas :frown:

[DrX]

Here is a snapshot of a typical instance. IBPW does not appear to be at the minimum but is less than the IBPW at idle even though TP is greater at 11% vs 2.75%.

As you stated, some with 60s on returnless systems have had issues with too much fuel at idle. Fortunately, my conversion to return style allows for a lower FP at idle.

Coast:
http://i114.photobucket.com/albums/n241/TDOC2004/Coast.jpg

Idle:
http://i114.photobucket.com/albums/n241/TDOC2004/Idle.jpg

Here is a typical starting MainVE table that yields this type of BEN results.
http://i114.photobucket.com/albums/n241/TDOC2004/MainVE.jpg

[Tordne]

Are those injectors plate or pintal style? In you coast shot the IPW is ~1.3ms. I found with the SVO 42's that are pintle style anything below ~1.8ms would see me have no fuel.

How have you accounted for the differing fuel pressures you mentioned as a result of running the return system?

[DrX]

Are those injectors plate or pintal style? In you coast shot the IPW is ~1.3ms. I found with the SVO 42's that are pintle style anything below ~1.8ms would see me have no fuel.

How have you accounted for the differing fuel pressures you mentioned as a result of running the return system?

These are the specifications on these injectors:

Static Flow Rate: 60 lb/hr @ 43.5PSI (300kPa) = 630cc/hr (sold as 65lb/hr by some vendors)
Coil Resistance: 12 Ohms / High Impedance / High-Z (No ECM driver modifications required)
Gain: 0.11ms/mg, Offset: 0.055ms, Turn on time: 1.14ms @ 14VDC, Turn off time: 0.85ms @ 600KPa
Wide angle spray pattern

They seem to idle OK in P/N. I have a flat IFR slope although the PCM wants to extrapolate with a slope when I go off the table into boost, so the Boost VE table is compensating for that. Shouldn't my IPW be greater coasting than at idle? Does the PCM determine throttle position during coast(11% in the above example)?

[Tordne]

Do you mean your IFR table is flat in that it has the same number in all cells - like all stock trucks I've seen? If you actually have variable pressure (which you indicate you do) I'd expect your IFR table would need to reflect that (like stock cars).

[DrX]

My Vac/Boost-referenced FPR maintains a constant IFR by varying the FP to compensate for the effect of vacuum or boost on IFR. So the table is flat. 04 and newer trucks with non-referenced returnless systems will have a sloped IFR table because IFR will vary with vac/boost.

My current IFR table:
http://i114.photobucket.com/albums/n241/TDOC2004/IFR.jpg

Table from my stock tune:
http://i114.photobucket.com/albums/n241/TDOC2004/StockIFR.jpg

[joecar]

DrX,

Can you post some values of the following (read during non-idle steady-state conditions):

Fuel Rail Pressure (psi)
Manifold Absolute Pressure (kPa)

Joe

[dc_justin]

I see the same issue with my radix'd truck, but only on the second bank, and largely just between 2400 and 2800rpms. My guess is a minor vac leak on the manifold there. I can add in fuel to account for it in SD mode, but it will end up being inconsistent and when the MAF is re-enabled, the lean spot re-appears. I've gone so far as to pull the supercharger off 3 times to re-check the gaskets and make sure it gets a proper seat. No change.

The way I look at it, the mishaps occur in closed throttle operation, at a point where DFCO will be active and no fuel will be commanded, so I no longer worry about it. :cheers:

[DrX]

DrX,

Can you post some values of the following (read during non-idle steady-state conditions):

Fuel Rail Pressure (psi)
Manifold Absolute Pressure (kPa)

Joe

Here's a few just from eyeballing the gauges and doing the conversions(could be slightly off):

MAP kPa/FP psi- 44/52.5, 65/55, 100/60, 121/63, 135/65

I also have some old logs with FP in psi but you have to do averages because it jumps around a lot as opposed to reading off of the gauge.

[DrX]

I've gone so far as to pull the supercharger off 3 times to re-check the gaskets and make sure it gets a proper seat. No change.

The way I look at it, the mishaps occur in closed throttle operation, at a point where DFCO will be active and no fuel will be commanded, so I no longer worry about it. :cheers:

This all sounds familiar. 3 times, even tried new gaskets, no difference to anything. Water test didn't find anything. I don't think I have any significant leaks. No misfires. Seems to be a little leakage around the shaft for the bypass valve. Would be nice to have a smoke machine.

I think I saw the same thing even when I had the 42s on there and I also wasn't too concerned because of the similarity to DFCO. But I still consider it unfinished business.

Speaking of "closed throttle," is 11-15% TP normal while coasting(the AP is completely released) at these speeds.

[joecar]

Here's a few just from eyeballing the gauges and doing the conversions(could be slightly off):

MAP kPa/FP psi- 44/52.5, 65/55, 100/60, 121/63, 135/65

I also have some old logs with FP in psi but you have to do averages because it jumps around a lot as opposed to reading off of the gauge.Sanity check: from those numbers I calculated 8.9 g/s flat as you have shown above.

[DrX]

Sanity check: from those numbers I calculated 8.9 g/s flat as you have shown above.

Looks like the FPR is doing its job.:)

[rabidbandit]

I've had the same issues with our blown car. Except that we have a slight hesitation around 1900rpm when under light throttle the AFR drops to 19 or so. We've adjusted out VE to try and compensate...but the problem returned later and worse. We're running the 60's as well. Ofcoarse we are still running the original OS. I'm thinking I'll try to flash an '01 OS and then swap to the Custom OS. We have a few more additions to the car before that happens.

[joecar]

RabidBandit, welcome to the forum. :cheers:

[DrX]

Kept my eye on the BEN map while logging today and noticed that for lower speed coasts(say 60 KMH) the BENS were all very close to 1. It was only at higher speeds(100 KMH) that I noticed BEN values in the 1.1-1.2 range being recorded. All values in the 25 kPa column were high but this column was only hit during the higher speed coasts.