logalinipoo

Could you move your presser sensor to the pump outlet and see how much pressure you have there before the drop from the fuel lines?

TeamRX8

iTrader: (25)

did you just look at fuel pressure, or did the same lag issue persist?

RotaryMachineRx

iTrader: (1)

^ same lag issue persists, I will attempt to load a video up from my phone of the fuel pressure gauge.

Edit: This is WOT with fuel speed control relay jumped. Used 14AWG wire for what it's worth. What I see typically with the relays installed is a fuel pressure drop to about 52psi then after about a 1 second lag I see pressure rise to about 53 or 54 psi after turbo is fully spooled and I get the full effects of the engine pulling. In that 1 second delay there seems to be no power and it all comes on at once when AFR's drop and turbo is completely spooled. No exponential power growth as turbo is spooling as you'd expect.

TeamRX8

iTrader: (25)

out of curiosity, how did you replace an internal fuel filter on an S1 pump?

RotaryMachineRx

iTrader: (1)

Replaced the "sock" filter at the bottom of the assembly sump, new one came with the new assembly.

TeamRX8

iTrader: (25)

That's a pre-filter, betting the actual filter is the issue ...

PhillipM

It's not something silly like acceleration enrichment having been turned off for dyno tuning and then forgetting to switch it back on is it?
Maybe showing up more given the new mods?

RotaryMachineRx

iTrader: (1)

Now I was doing a little bit of research... I can't find much on a fuel filter other than the sock filter, or diagrams showing the filter as part of the pump??




I'm not sure.... I didn't do the tuning so I'll let Brettus comment on that.

RotaryMachineRx

iTrader: (1)

When I look at the diagram above 2 different scenario's come to mind.

1) Either something in the PCM is not triggering the pump to go from Low to Hi causing the pump to lose pressure when floored. Problem with this is that even with that relay jumped I was seeing pressure drop dramatically.

2) The PCM will not switch to Hi voltage mode with the car in neutral and something mechanical is causing fuel pressure to drop (ie. Pop off valve, clogged fuel filter, ...???) and this lack of pressure is causing the fuel delivery lag for that 1 sec when I push the accelerator.

Am I aimed in the right direction here? How do the injectors know when to open and close; does the signal come directly from the PCM or is it related to the fuel pressure as well?

dannobre

iTrader: (3)

Wire the stupid resister out of the equation altogether

Then check to see what it is doing......

Brettus

iTrader: (2)

It's enclosed in the center part of the pump assembly . It's even in that diagram you posted (fuel filter , high pressure)

As far as turning off fuel enrichment ........... there is no such "switch" .

Also : Don't get sidetracked by the fact the hi/lo system isn't working . You have already proven that isn't the issue .

RotaryMachineRx

iTrader: (1)

I think I will just do this yeah.

Hmm, so a new high pressure filter would have come with the new assembly I installed then. I can't imagine the filter being plugged that much already but I will have a look as soon as my fuel pump ring tool shows up in the mail.

TeamRX8

iTrader: (25)

There is a throttle tip-in fuel enrichment map. Pretty sure thats what he was referring too.

RotaryMachineRx

iTrader: (1)

Here's a better video of a more typical experience when I tip in to WOT. I just took this this afternoon, it is in 3rd at about a 28mph roll approx 3500rpm up to about 40mph and approx 6000rpm. You can see a distinct 1ish second dip in fuel pressure once I go WOT. Once you hear the turbo get fully spooled up you can hear the engine start revving up.

Fuel pressure seems to dip for about 1 second, then pop back up then slowly decline as RPMS increase.

PhillipM

This. I don't know specifically on that setup but most standalones let you switch it off for steady state dyno mapping, was just a thought.

Brettus

iTrader: (2)

It's has 3 x 2D maps that don't function that way.

JimmyBlack

Come on man, replace the damn fuel pump already!

TeamRX8

iTrader: (25)

I think it has to be either that or the filter, assumes there isn't some kind of blockage in the fuel line system

would suggest an S2 pump assembly, but it would requiring a different new pump too since it uses a different body size than the S1. The advantage is the fuel filter, PRV, and sock are all replaceable and the PRV design doesn't require heat-gluing the cap like on the S1. And the whole assembly is better for fuel pickup with a low tank etc. Gotta admit that Denny/Olddragger got that one right.

RotaryMachineRx

iTrader: (1)

Better update this thread...


Replaced the fuel pump a few weeks ago.... seems to have solved the lean throttle tip-in issue. AFR's are sitting pretty solid now but I do still see the same pressure dip on my fuel pressure gauge (who knows could be the gauge itself...). I have come across a new issue now, under larger loads I believe I am experiencing some misfires (pretty much only happens in 1st gear WOT). I will be testing the coils and wires when I get home from this shift at work in a week using Team's handy dandy coil testing DIY thread.

Hoping this has the car running trouble free again and I can resume with the final stages of tuning.

Attached a log showing the issue which I believe to be misfiring.... let me know what you guys think.

9krpmrx8

iTrader: (46)

Are you sure your gauge is accurate? Did it ever read 60psi?

9krpmrx8

iTrader: (46)

What AFR's are you seeing on your aftermarket wideband when your AFR's bottom out on the graph?

Brettus

iTrader: (2)

Mine had that dip as well before i mucked around with the siphon. I'm pretty sure its just the pressure relief opening up . I wouldn't be too concerned about it if it's not affecting afrs.

As far as the lean spike goes , that's why we need to test the coils . Misfiring coils do cause it to go lean ............ have never figured out why this is , seems counter intuitive.

RotaryMachineRx

iTrader: (1)

My wideband reads +or- .2 of the Cobb readings normally. Typically I see bottomed out AFR's of 11.0 on the wideband.

Yes, my fuel pressure gauge has never read greater than 59psi (always reads this when car is initally fired up after being completely cooled down). The hotter the weather/car/engine the lower Fuel pressure I read at idle. When the ECT temps are in the high 190f's idle fuel pressure is approx 56-57psi.

As Brett mentioned above, the fuel pressure is not affecting my AFR's. I am getting the lean spike (thank's for graphing it for me 9K!) only when I go WOT in 1st gear at the moment. All other gears seems to pull normally again with AFR's staying in that 11.0-11.5 range

9krpmrx8

iTrader: (46)

Your aftermarket wide band bottoms out at 11.0? How do you know if you are crazy rich or not? What are your target AFR's under full boost/load?

RotaryMachineRx

iTrader: (1)

I am using an AEM UEGO afr gauge.... I believe it reads below 11.0 but what I'm saying is that it reads consistently with the Cobb data. When I am in full boost the graph shows 11.02 and my UEGO shows 11.0-11.2 AFR.

Edit: quick google search tells me AEM UEGO bottoms out at 10.0 AFR.