AcuraJan

Is it safe for the stock fuel-pump to run higher fuel pressure?
Do I need a AFPR, Adjustable Fuel Pressure Regulator? Or is there any mod to make the pressure higher without it?
If I get a AFPR, do I connect it where they pinch in this picture?


I also would like to get a pressure gauge to see what I'm playing with... any suggestions on a easy way to get it fixed?

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Cees-Jan

The stock fuel pump can deliver more presure , no problem, the flow amount is restricted, with the comptech SC kit a electronic device is used to diliver higher voltage to the pump, resulting in more flow.

If you want to connect an AFPR loose the original one and connect it there.

Why do you want increased FP ?????

AcuraJan

Ok good thing with the fuel-pump, I geuss I'll start with making sure it has highest possible battery-power and then change the fuel-filter, maybe it is enough.

Like I have written about in another thread, I would like to run on this E85 fuel that we have, it contains 85% ethanol and 15% gasoline. Its a lot cheaper and has higher octane, and its better for the environment.
Now im running aprox 50% of that mixed to regular gas. The engine runs smooth like normal perfect idle and feels as quick as it used to, but the "check" light has start to lighten up when I half throttle accelerate. Probably because of the O2-sensors senses wrong air/fuel ratio.
To run on ethanol/gasoline mix?

Many who converts their cars just buy a universal AFPR and leave the original in place, it will stay open since the other one makes higher pressure.

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Cees-Jan

You are right about letting the original FPR sit in place, it is open

Did you check for codes (code 1 or 2 oxygen sensor) ?

If you want to create a higher Air to Fuel ratio you can use the original injectors, in an FI NSX engine used, 360 Wheel hp (stock 270 flywheel),6 PSI boost 60 psi FP ,AFR 12:1

I am completely without knowledge of the mixture you are talking about, so no tips on that ...

AcuraJan

I haven't checked the codes... maybe it's a good idea.
But i checked the fuel pressure today it's about 225kPa (~34psi i believe), pretty normal, but it could be a little higher without problems.

Is it normal for the pressure to go away for it self when the car haven't been used for a couple of hours?
Today when I opened the bleed-screw no fuel came out, but after checking the pressure it stayed at 200kPa (~30psi) and leeked some when I removed the gauge.

Cees-Jan

It is normal for the pressure to drop in hours, this is why the main relay starts the fuel pump for 2 seconds when you turn on the ignition.

Are you shure the fuel filter is not clogged, 30psi is to low, I suggest to measure when idling, do you have the manual (downloaded), read in fuel and emmisions :fuel pressure, ther are some hints on how to test (and diagnose)

AcuraJan

Ok, sorry about that... I ment that when I first checked the car was idling. And that 34psi is normal but in the lower tolerance according to the manual, (yes I have it).
That's why I wrote that it could (or maybe should) be a little higher.
It was i little higher before starting the engine, only the ignintion on.

The 30 psi is after I had turned the ignition off and was about to take away the gauge.

I will start with checking the voltage to the pump, maybe a relay will speed it up a bit.. :p
I will also order a new fuel-filter, I dont believe it ever have been changed in my car. (Only 50k miles)

AcuraJan

Checked the codes today... one and two blinks, so it's like I thouhgt. O2-sensors....
This is because of lean fuel/air-ratio when I have ~50% ethanolmix...
Filled up the tank with gas only, ended at ~12% ethanol left, and the check light didn't come up after that.

AcuraJan

A couple more questions.
Does anyone know how much pressure the stock fuelpump can handle?
Will it wear out with time if I run to high pressure?

Today I adjusted it to aprox 60psi with the vacum connected, now the car runs great on pure E85... it's quicker then before.
I drove around for a while...

AND, on my way home i tried a full throttle acc on second gear, beginning on 1200 revs. And the engine did a hesitate on 3000 revs and the "check" light came up again.

Is it the pump that looses pressure??

AcuraJan

I have found the answer myself, the pump can not handle to high pressure.
The service manual sad it has some sort of security valve.

So for the perfect result I will need a new pump or another solution. (injectors or electronics)

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legend4life

Walbro 255 HP (high pressure) fuel pump, less than $100 with install kit, shipped.

Marshalls liquid filled fuel pressure gauge, $39, shipped, attaches to stock regulator.

For running crazy fuels like that, get a wideband o2 sensor/controller/datalogger or else you will not know what the hell is going on inside of your engine. You may be running way too rich or lean and would never know and could likely damage your engine.

Do the calculations to figure out the ideal air/fuel ratios to be run with the new fuel mixture. Different fuels have different stoichiometric values and need to be run at different air/fuel ratios to have the same effect/run the engine like normal.

Then you need something to tune the air/fuel ratios with. At minimum, get an SAFC II for a cheap solution. If you want something crazy and want to spend a couple grand, step up to a standalone.

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AcuraJan

The stock O2-sensors tells the ECU how much fuel to inject for correct air/fuel ratio...

If it get wrong the check-engine light comes up, if it get way too rich or lean it's telled by the cars performance. (smoke or poor gas response)

The fuel is not "crazy", its good for the environment and smells really good.
And at least over here it's a lot cheaper, the gasprice rises and rises all the time.

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