[M35] Deatschwerks Fuel Pump Install

[scotty nm35]

If you can't use the FCon to change the line pressure that the ECU tells the Trans to run (there is a table for it)- Get some injectors that you'll run somewhere between 75-90% duty cycle where you reach your goal.

To test what It would be like if you stuff it up, use really light throttle and change up a gear in manual, and see how long it takes to change.

It doesn't quite work like that, although the Fcon allows it but I don't know which output map it is. You would need full line pressure at anything above a gentle acceleration imo. You can run whatever injectors you want with the Fcon.

but depending on the pump it can still out put more than enough at a higher pressure. Wont you run into injector flow problems if you lower it? The Bosch 1000cc is rated 1015cc at 43.5psi and a bit more at higher pressures, with a higher pressure of 7ba allowable, so you can run a stock base of 43.5 and still bang in up to 70psi of boost assuming your turbo can do that. if you lower your base pressure id imagine your also dropping the flow rate of the injector, why do that. I'm going to use the walbro 400+lph E85 approved pump and that will still flow 355lph at 70psi, more than enough supply.

I did consider 2000cc but if I decide to go back to 98 pump fuel it will need more work to get the afrs spot on as the injector will run at a really low duty cycle. I think my 1000s will get me to 300-320rwkw and seeing as the injector can run with more base pressure to a total of 7bar, I still have a little up my sleeve if needed. The SR block doesn't like too much more than low 300rwkw without starting to distort.

It's a completely different setup on your SR, you can run the Walbro as it fits in your tank and it would give you good overhead if you plan to wind up the pressure, but you will hit a point where that won't help. From 45 base to 70 peak only gives you a 25psi boost margin and what happens if your controller or wastegate fail causing unlimited boost? I like leaving a buffer with my car like larger injectors and pumping ability as when things go bad the ecu can control temps with extra fuel flow. Running 90% on injectors is just asking for trouble I believe, especially now there are suitably large ones to choose from that idle perfectly. (bosch ev14's)

[PN-Mad]

It doesn't quite work like that, although the Fcon allows it but I don't know which output map it is. You would need full line pressure at anything above a gentle acceleration imo. You can run whatever injectors you want with the Fcon.

I know we've covered this before, but tell me how you think it works.

The line pressure map is actually quite complicated, and factors n a few different drivability scenarios.

The example I used above isn't perfect, and does not take not account k value, and how the ecu scales load, but it's the simplest way to explain it and get a good drivable result.

[scotty nm35]

I know we've covered this before, but tell me how you think it works.

The line pressure map is actually quite complicated, and factors n a few different drivability scenarios.

The example I used above isn't perfect, and does not take not account k value, and how the ecu scales load, but it's the simplest way to explain it and get a good drivable result.

Add to that the fcon runs as a plggyback which complicates it even further.

I don't pretend to know exactly how it works, just that HKS have managed to seamlessly control gear change timing and line pressures by tricking the stock ecu, through an unused input (pin) I have no information on. I would love to know what's happening with those 4 programmable fcon outputs and what they control but I would need HKS support or a portable scope and plenty of road. If those can be cracked we could run any standalone ecu setup with the same copied set of output voltage maps.

Once I have got it tuned (If we have time) I will look at adjusting some of those maps and see what the outcome is.

[slippylotion]

Hang on. The fpr can set base pressure between 30 and 70psi, not a max of 70psi and then adjust at 1:1, so you don't have a 25psi window for boost. Now I'll admit I don't what max pressure it can support but it obviously wouldn't let you set the base pressure to 70psi and that's the max it can do. I don't see how an SR is different as its still an air pump effectively just like the vq.

I think they also suggest limiting duty cycle to a general point as the inner workings of the injector can hear up when operating at near maximum and cause it to stick shut or open. Again that's my interpretation behind the idea.

All set ups should be left with a bit of headroom but if boost spikes badly it's generally for a very short time as you would back off unless you don't watch and listen to your engine and keep the boot in for some strange reason.

[bigkevracer]

So anybody know which wire is which going into the pump before I start poking around?

[scotty nm35]

I did mention it yesterday in my post. Did you miss that with all the non pump related banter?

[scotty nm35]

Hang on. The fpr can set base pressure between 30 and 70psi, not a max of 70psi and then adjust at 1:1, so you don't have a 25psi window for boost. Now I'll admit I don't what max pressure it can support but it obviously wouldn't let you set the base pressure to 70psi and that's the max it can do. I don't see how an SR is different as its still an air pump effectively just like the vq.

I think they also suggest limiting duty cycle to a general point as the inner workings of the injector can hear up when operating at near maximum and cause it to stick shut or open. Again that's my interpretation behind the idea.

All set ups should be left with a bit of headroom but if boost spikes badly it's generally for a very short time as you would back off unless you don't watch and listen to your engine and keep the boot in for some strange reason.

Sorry, I barely understood what you were trying to get across. With the last part though, how long do you think a piston takes to melt at 1400 degrees combustion temps? Perhaps a few seconds, even warnings wont save you in extreme cases.

Base fuel pressure + boost pressure = max fuel pressure at regulator and pump.

Base pressure = fuel pressure at injector tip all the time due to boost pressure acting against it.

If you run a standard Walbro at 80psi it will not flow very much fuel at all, and it is working very hard to do it. The higher pressure you go the less fuel flow you get out. Perhaps the new Walbro pump is much better but its a brand new design that was released because the last 400lph kept failing, I would be wary, re-read my first sentence. As this pump won't fit into an M35 you should probably ask about it in the FI section, we are stuck with the Deatschworks.

High boost isn't the answer anyway, it is just a measure of your engine's restriction to the airflow.

[bigkevracer]

I did mention it yesterday in my post. Did you miss that with all the non pump related banter?

Yep. OT much?

Thanks mate...

Wiring:

Black with a yellow line is Positive (black with a red line inside the tank)

Green with a red line is Negative (black inside the tank)

[bigkevracer]

All done. Piss easy in the end, can't believe its taken me this long to do!

What do you use as a ground Scott? I've just used a seat belt bolt for now. Taking it for a test drive, then I'll put it all back together (well, put the back seat back in, anyway).

[scotty nm35]

I used the battery terminal I ran two thick wires and two thin ones back to the battery compartment, through the relay and fused the positive. I don't like relying on the chassis earth.

[bigkevracer]

So you earthed the chassis side of the negative wire as well as the relay side?

Makes sense. Probably a better solution, no decent earths under there. Have to run a wire somewhere, may as well be back to the battery.

[scotty nm35]

Exactly, and the 25 or more amps the pumps require will cause lower voltage at the pump fairly easily with a dodgy earth. I use speaker wire to energise the pump off the old pump power wires and a pair of heavy gauge audio power cables for the feed through a 60amp relay. The only hassle is getting it all through the rubber grommet into the battery compartment.

[bigkevracer]

Went to fill up today for the first time since doing the pump. Hadn't driven the car too much since really.

As soon as I'd finished filling up fuel started pissing out of the bottom of the car. Since I hadn't finished the ground wires yet, the back seat wasn't in, so I opened up the tank cover to have a look at what was going on. Both fuel lines looked like they'd blown off, or at least half off, and fuel fuel was running down the side of the tank. Not heaps, but enough to create a decent sized puddle underneath the car.

Pushed the fuel lines back on and good as new. The fuel gauge is still reading full, so I'm guessing it didn't loose much.

My uneducated, non-mechanic suggestion is that the higher fuel pressure from the new pump is responsible, so I'll throw a couple of hose clamps on for good measure.

Next weekend I'm going to try and install the adjustable FPR and adjust the fuel pressure back down to stock until I get it tuned. It's running really rich, and economy is up about 1-2L/100 (Normally get 12-13L/100, now sitting at 14+L/100).

Also keen to try and get the wideband on now and see what the AFRs are at before and after adjusting the FPR.

[scotty nm35]

Hose clamps on what? They are clip lock fittings, perhaps you didn't push them right in?

[bigkevracer]

The plastic clip lock fittings don't appear to hold the hose properly. There's a clip to hold the two plastic parts together, but doesn't appear to be anything to hold the hose onto the plastic fitting?

[scotty nm35]

How did you disconnect them? The clips need to be sideways and as you slide them in you will hear them click into the fitting. They shouldn't pull back off without pushing the clips back in. A hose clamp wont help you.

[PN-Mad]

Did you turn the car on, before it pissed out? Or without pressurising the system. Just thinking the o ring if fuel out and no pressure.

[bigkevracer]

I'll have another look and see how I go.

Alex, didn't turn the car on. Went in and paid, came back and saw the pool. Disconnected the fuel pump power, cranked the motor, then reconnected the hoses with no fuel pressure.

Reconnected the power, started no worries. Car is running fine. Just the fuel lines.

[PN-Mad]

I just don't know how you would get to the servo without the lines properly connected, and fuel not going everywhere. But weird stuff happens.

I would just have a check that the o ring seated ok, can be a bit of a pain. Hopefully it's nothing too hard. I just did my filter so had it all apart and back together.

[bigkevracer]

Problem diagnosed!

While a couple of the hoses looked dodgy, pushed them back on and they were fine.

Worked out it only happened when I filled it up, no problems after that.

Then, when I filled up last night realised it repeated, and I didn't get that nice sound when you remove your fuel cap and hear the pressure release...

So mucking around this morning I've realised that 2-3 of the bolts that hold the fuel pump assembly top in have become stripped/damaged. They hold the top in, but not strong enough to seal it.

I'll see if I can get some more bolts from somewhere today and hope that fixes it, otherwise I'll get dad to rethread the assembly next weekend.