Hello,

I'm hoping something maybe able reinforce what I suspect it to be (Fuel Pump) Hope this is the right place for it.

Right over the last few months I've been added more and more fuel to the WOT VE table area. 2-4 points at a time.

I good example was last night.

Drove to my parents to get the bonnet sprayed AFR 10.9 - 11.2 during WOT. lovely spot on for what it was tuned for.

After sorting the bonnet I drove home. during WOT It was 11.8 - 12.2 of course I snapped off the power when I saw this.


Had to add 6 points of fuel to the WOT VE table area to bring it back down.

The air temperture had not changed give or take a few degrees difference.

IAT correction was @100 across the table.

during idle & general driving the AFR are spot on.

So I belive it to be a fuel pump playing funny games. Voltage drops = less fuel pressure. or just the pump playing up.

I want to say that if I fill the tank up it runs much richer. But It's something I need to do and test now that I really do have a problem somewhere. Which would also lead to the fuel pump if it does run richer. I've also been reading the sock on the fuel pump can collapse on itself causing restrction. which would causing WOT to not have enough fuel and require the injectors to be open for longer to make up for less pressure.

It's driving me mad as im chasing my ****. with the fuel map. Adding / removing fuel.

Just hope someone can shed some light or reinsurance myself on what I think it is. Even better if something else had had the problem.

SPEC (in regards to fueling):

OEM fuel rail
OEM FPR
DW200 Fuel pump kit
EV14 850CC injectors
MS2e (mslabs)


** EDIT **

I had my main injector relay go latly. so It's possible the fuel pump relay is playing buggers. So I will look at swapping this out to test. not sure if it has any effect but worth a shot?

 

Do you have any logs of this? Could it be IAT heatsoak?

You should be able to spot some differences. Pulse width and duty cycle going up without AFR going down, or GAIR correction.

 

WIll get some logs. It's random that's the problem. But seems to happen mostly at night. Which leads me to belive voltage. As when all lights are on etc. It possible it's pulling enough volts to effect something.

It's not IAT Heatsoak as I have a Dash2 setup so can view IAT all the time.

The IAT / MAT correction has been set to 100 across the tempertures so wouldn't be effecting it.


I used to run around 118-121 VE TABLE around the WOT area at high RPM. I'm now at the 135-140 values.

 

850cc/min, running at spec pressure differential, open 100% of the time, comes out to 204l/min for four injectors. That would be getting close or maybe even above the rated limit for the DW200, depending what PSI you have at the rail. But that would probably be more than 400bhp. What are your pulsewidths?

 

The DW200 is meant to outflow the the Walbro 225.

Just looking at a older log. I'm hitting 82% duty. Which is getting near the limit to be honest.

So it's possible if the fuel pressure is dropping off slightly it's going to almost put the injectors at 100% on.


** EDIT **

It could be the reason also why my duty is quite high due to low fuel pressure less than the OEM 43.5psi.

I'm currently running 304WHP / 364HP

 

Just to make sure we got the basics right: You are running intake referenced fuel pressure at 3.0bar (43.5psi) and not an NB return-less system- correct?
What is your max boost?

 

Correct.

it's a mk1 1.6 so 43.5psi with a standard FPR.

MAX boost at the moment is around 19/20psi it hits.

 

43.5psi of fuel trying to inject into a cylinder pressurized at 20psi.
I would definitely be considering a boost referenced FPR with 20 psi of boost.

 

Reckon it's worth getting a AFPR and setting a static 60psi?

I have also ordered a DW fuel pump mod. To run the fuel pump direction off the battery.

 

The OEM is a boost ref FPR 1:1 so for every 1psi of boost it adds 1psi of pressure.

From what I've been reading. or am I wrong?

Possible the FPR is playing up. Can these fail?

 

You are correct.

You should get a fuel pressure sensor in and see whats happeniing with fuel pressure.

 

Right.. I've done a little bit of reading and I reckon the fuel pump isn't getting a proper voltage plus with me adding a Dash2 & CAN to serial adaptors all taking power etc it's no doubt having a impact.

I've seen quite a few posts regarding having to add alot of fuel in the WOT map area and the outcome with low voltage at fuel pump.

I should be having 60+ PSI at the rail at high RPM 43.5psi plus 20psi boost. (Will find out once I have a gauge fitted)

So tonights task is to wire fuel pump directing to battery using the DW kit. ​Accessories : Fuel Pump Hardwire Installation Kit | DeatschWerks

This will then at least give my fuel pump 14v all the time. What I'm hoping will happen is make the WOT area's extreme rich and allow me to bring back the VE table value back to when it was on the dyno. Knowing my luck **** all will change.

 

Could you be getting some spark blow out? I know mine leans out up top when the coils get hot. Never had issues in the winter but this super hot summer has brought out some demons with the car.

 

Fuel pump sound most likely (I ASSume you changed the fuel filter and all that).

I was having a similar thing on my naturally aspirated 1.6. It would run 12.8:1 and then the next time I drove it be at 13.8:1 and all over in general. Turned out to be a ground loop. I cut the black and green wire Deezums had found abd that fixed that. But I was having issues elsewhere than WOT as well. Basically had to run EGO all the time to be anywhere close to the numbers I wanted.

Just another idea to check out.

 

Little update.

My voltage was 12.9-13.1 but I swear the begining of the year is was 13.6-13.8.

The car died well jumped around bascailly the power going on / off / on / off then it died totally.

I popped the bonnet and pulled the main relay that I had replaced a few months ago anyway. It looked burnt. on one pin and melted the pastic slightly.

So I rammed it back in hard and wiggled it and pushed even harder.


It fired up and I had 13.9v.

Drove the car got into WOT and guess what.. 10.2 AFR

I removed around 15 points of fuel form the VE table just to bring it to 11.0 even then it went down to 10.8 right at the peak of RPM.

So I reckon the fuel pump wasn't getting enough power to flow enough to keep up in WOT.

Tonight I'm installing the fuel pump mod rewire. so It doesn't run off the main relay.

Fingers crossed this was the problem. Will update if the fuelling is effected even more once pump as a full 14v