Out of fuel?

[Calan]

Why am I running out of fuel above 46-48lbs/min?

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(ECMLink file)

This log was on 91 pump (with a couple of gallons of E85 left in the tank at fill-up). I see an almost identical trend in the AFR with E85, which seems logical since I run a higher AFR with the E85. Either way, it still starts leaning out at roughly the same spot.

FIC Blue Max 1250's, injector IDC never goes above 70%, and I've tried two different wally 255HP pumps (rewired) with identical results. Increasing VE or adding fuel with the sliders up top makes no difference, so I'm pretty sure I'm really out of fuel.

I've also verified that the AFPR is rising 1 to 1 and it looks spot on. (37 psi base)

According to this source and others, I think the 255HP should be good up to at least 52 lbs/min or so on my setup, but I'm not seeing it.

Ideas?

If I really am out of fuel, any suggestions for how to run the two 255's I have? Run both in-tank, or convert one to be inline? I need to work cheaply here.

 

[knochgoon24]

If you're running out of fuel because of the pump, you'd notice your fuel pressure slowly start dropping up top.

I'm having a very similar issue right now on my car, but without a fuel pressure gauge, I can't confirm it.

 

[Calan]

Yeah...I've been scratching my head on this one for a while now.

It's not a pressure issue, but rather volume. The AFPR holds pressure and rises 1-to-1 like it should, but it appears that the pump(s) isn't flowing the volume it should at the higher pressures.

I know the volume drops off with pressure, but it looks like it's dropping off too fast. I should be able to get 52 lbs/min on E85 with this setup, and I can barely hit 48 lbs/min now, even on 91 frog piss + meth injection.

About the only other thing I can think of is a voltage drop, but system voltage stays good and the pump is rewired..so that doesn't seem likely.

I think tomorrow I'm going to measure the flow at the 62 psi the pump should be hitting (37 base + 25 psi boost), and see what I get. I'll need to do a little math based on RRE's numbers, but I'm guessing I should see something around 210-220 liters/hour.

 

[Chicken Patty]

I can't view the file, I suppose you need the link software to do so.

The 255 has to be good for that flow rate, not sure what your problem might be.

However, as far as dual pumps, I know this shop locally who does this. Maybe you can call them and they can give you some advise on what you might need or what not. I know I was there one day and they were telling a customer what he needed and needed to do to run one in the tank and one inline.

Give them a call on Monday, pretty sure they can head you in the right direction. Here's their contact page.

Speed Injected

 

[Calan]

I can't view the file, I suppose you need the link software to do so.

FYI - You can download the ECMlink software for free, in case you ever want to look at ECMLink logs: ECMTuning downloads

And thanks for the input.

 

[Chicken Patty]

FYI - You can download the ECMlink software for free, in case you ever want to look at ECMLink logs: ECMTuning downloads

And thanks for the input.

Why didn't I think of that Geez, can you tell it's 4am? . I'll do so tomorrow and take a look at your log. Thanks bro.

 

[rEclipserGST]

Do not want logs. Want fuel filter upgrade. The stocker has limited flow

 

[Calan]

Do not want logs. Want fuel filter upgrade. The stocker has limited flow

I run a large Golan filter and -6AN to the rail.

The Golan is capable of 900 gallons per hour...just a hair better than stock.

 

[brisvr4]

I could be wrong but your fuel flow seems to be rising nicely right through the lean area. Have you tried bumping up the area in the SD map that correlates to the lean RPM section? There isn't anything stopping you from going up over 100 on the VE.

 

[habitatguy187]

A local here is having similar problems running link and SD. He has a 255hp in-tank and a bosch in-line, along with 1600s. All fuel lines upgraded along with the filter. He's done a lot of work trying to figure out what's going on and no matter what he does he can't richen it up anymore. He's also one of the guys most of us locals go to when we have tuning problems (he's pretty knowledgeable about tuning)

 

[Calan]

I could be wrong but your fuel flow seems to be rising nicely right through the lean area.

Why do you say that? The only indication of actual fuel flow is the wideband, which is definitely going lean above 45 lbs/min.

It looks like it should be rising, but acts like it isn't.

Have you tried bumping up the area in the SD map that correlates to the lean RPM section? There isn't anything stopping you from going up over 100 on the VE.

Yeah

...Increasing VE or adding fuel with the sliders up top makes no difference, so I'm pretty sure I'm really out of fuel....

I took the values up to 105 or so in the affected areas of the VE table as a test, and AFR's didn't change.

A local here is having similar problems running link and SD.

Brad... can you PM me his name and number? I'd like to compare notes.

 

[steve]

I think tomorrow I'm going to measure the flow at the 62 psi the pump should be hitting (37 base + 25 psi boost), and see what I get. I'll need to do a little math based on RRE's numbers, but I'm guessing I should see something around 210-220 liters/hour.

Don't forget to add in the pressure drops between the pump outlet and the rail when you do the math. You may have to actually measure the pressure at the outlet from the pump assembly to find out what sort of losses you have.

 

[->PrOjEcTGS<-]

If you use the trace map feature in link you'll notice that everytime you go lean you drop to the next lower (higher load) line on your SD map. Where were you previously adding VE? Looks like to me you need to add some in the 40.4 line in the 6000 and 6500 columns.

 

[Calan]

Thanks Steve.

If my numbers are correct (feel free to check them ), I should need a fuel flow of about 41 gal/hour (155 liters/hour). This is figured on pump gas with a weight of about 6.2 lbs and a target AFR of 11.5:1, at 48 lbs/min of airflow.

According to RRE's chart, the 255hp flows 189 liter/hour at 12.5v and 73psi. So at my voltage of around 13.5v and less pressure (62 psi), I should easily be within it's capabilities. Unless I hosed the math somewhere...

If you use the trace map feature in link you'll notice that everytime you go lean you drop to the next lower (higher load) line on your SD map.

I'm guessing that is a "coincidence" due to the actual load increase. Those higher airflows are when the lean issue starts showing up. My boost curve actually looks like crap in that log due to the WGS values not being dialed in, so as the load factor (airflow) starts bouncing around and flirting with that 45-48 lbs/min area, it starts leaning out.

I have a another log somewhere with a much smoother boost/load/airflow curve that is a bit less distracting. I'll see if I can dig it up.

 

[steve]

Thanks Steve.

If my numbers are correct (feel free to check them ), I should need a fuel flow of about 41 gal/hour (155 liters/hour). This is figured on pump gas with a weight of about 6.2 lbs and a target AFR of 11.5:1, at 48 lbs/min of airflow.

According to RRE's chart, the 255hp flows 189 liter/hour at 12.5v and 73psi. So at my voltage of around 13.5v and less pressure (62 psi), I should easily be within it's capabilities. Unless I hosed the math somewhere...

I get 210 l/h just based on your DC. (1250cc/m * 0.7DC * 4 * 60) / 1000

 

[Calan]

DOH! I had a brainfart on the injectors.

How did you correct for the targeted AFR?

 

[steve]

Crap, I forgot your running 36 psi. Let me calculate the effective flow rate and run the numbers again.

1250 cc/min @ 36.3 psi = 1142 cc/min

192 l/h

I don't have to correct for target AFR, you said you couldn't get over 70% DC and this is how much fuel you need to do so. The other side of this is that the ECU will gladly ask for IPW's in excess of that you can deliver so if the ECU thinks from your maps and it's idea of air mass that you need more it will ask for it. and if you can't provide it for actual AFR will lean out from your target.

Since the flow rate for the pump depends on the pressure seen at the pump you have to include the drops in the system as well as the base + boost pressure to decide if the pump can actually do it. You also should include a fudge factor since not all pumps flow the same and you don't really want to be counting on the pump running at 100%.

 

[Calan]

Ahhh... IC.

You're coming at it from the perspective of what the injectors are doing, and I was looking at it from airflow and a target AFR. I hadn't thought of it like that.

Either way, it still looks like I should have more pump left.

 

[steve]

I question if you have any pump left since you could be exceeding 73 psi at the pump.

On the other hand if your changing the VE or enriching the target and can't get the IPW to increase something is wrong with the IAT or pressure sensor when your running SD. I haven't looked at the log so I don't know what your IPWs look like.

 

[Calan]

I question if you have any pump left since you could be exceeding 73 psi at the pump.

Why is this? At 37psi base + 28psi boost (max), I should be around 65psi at the pump outlet.

Could there be 8psi worth of restriction between the pump and the rail? (If I understand you correctly)

Thanks Steve

 

[steve]

Why is this? At 37psi base + 28psi boost (max), I should be around 65psi at the pump outlet.

Only assuming no resistance to flow between the two points. Frictionless systems only exist in school.

Could there be 8psi worth of restriction between the pump and the rail? (If I understand you correctly)

I don't know for sure since I've never measured it but there is friction between the fuel and the fuel line when it flows, inside the filter, and at every transition that add up to a pressure drop between the beginning and end of the fuel line. You have to account for this when looking at what the pump if working against.

I think this is secondary to the the question at hand. The logs show from the MAP sensor that you hit about 28psi @ 4233 rpm and it pretty much starts dropping slightly from there. The IAT sensor says the temps rise 10*F from the start to end of that pull. Changing your VE or Target AFR should change the IPW and IDC and any given point regardless of if the pump and do it or not. If it doesn't something is broken.

Now what was the question again? Is it why does the WB show the AFR hitting 12:1 at 5673 and 6356 and you start knocking?

 

[Calan]

Now what was the question again?

I believe it was...

Why do my AFR's start leaning out above 45-48 lbs/min of airflow, even if I command more fuel via the fuel sliders or by increasing the VE values at those points.

 

[knochgoon24]

Are you getting an increase in IDC when you increase the fuel sliders or VE values?

 

[steve]

And how much do you have to increase them to get it to stop knocking? Or can you?

 

[Calan]

Are you getting an increase in IDC when you increase the fuel sliders or VE values?

Yes. The ECU commands more fuel as expected (IDC's go up, AFRatioEst changes, etc), but the result doesn't change (WB still reads lean).

And how much do you have to increase them to get it to stop knocking? Or can you?

I'm severely octane limited on the 91, so I can't really get rid of the knock past a certain airflow due to the lean condition. With E85, I don't necessarily see much knock...but the AFR's climb to around 13:1 which is starting to push my comfort level.

****

I am now injecting pure meth in an attempt to compensate for the fuel falling off. It helps, but you can still see the car starting to go lean above a certain airflow. I'll try to get another good log once I get it dialed in a bit. (I'm working on removing the correct amount of fuel via the secondary global and custom FPS settings, to balance fuel flow with the meth injection for any target AFR).

I'll probably be back on E85 before I get too much further anyway. I don't really like running the WAI this way due to the chances of AFR mismatches across the cylinders, not to mention the increased danger of a WAI failure. It also complicates the whole process of observing actual fuel flow.