conig

iTrader: (1)

can anyone point me to were the fuel pressure sensor is located? Thanks I can't seem to find it.

DuckDodgers

The fuel pressure regulator is connected to the fuel pump and sender. First step to replacing is "Remove the fuel tank unit"...seems pretty clear it's IN the tank.

nbtx

There is no fuel pressure sensor.

conig

iTrader: (1)

http://www.rockauto.com/catalog/x,ca...,parttype,6376

heres the part i didn't see at the pump. anyone have a parts fiche with pics?

DuckDodgers

I don't see the part you are talking about on the TSX fuel system in the service manual. What is it you are trying to do? Airtex mainly sells pumps and regulators...

conig

iTrader: (1)

diagnose a poor start condition, I found an rsx thread that led me to this sensor. Its a basic bosch system thing, which i thought we used.

its almost like starting a carb car takes a couple rotaions. I know its not spark related so leaves only one thing.

nbtx

OK, that's a new one on me - maybe this part monitors vapor pressure and senses when you don't tighten the gas cap ?

Trouble shooting hard starting - begin by checking fuel pressure at the injector rail when the engine is cranking. You might have a weak fuel pump or any number of other things. There's probably a fuel pump relay which runs the pump for a second when you turn the ignition on. Then the pump shuts off until you crank the engine. If this isn't happening ... well, you need to run the complete FSM diagnostic tree for hard starting.

Sal's Type S

iTrader: (1)

Ding Ding Ding Ding...

Trouble shooting hard starting - begin by checking fuel pressure at the injector rail when the engine is cranking. You might have a weak fuel pump or any number of other things. There's probably a fuel pump relay which runs the pump for a second when you turn the ignition on. Then the pump shuts off until you crank the engine. If this isn't happening ... well, you need to run the complete FSM diagnostic tree for hard starting.[/quote] Could also be caused a bad fuel press reg.

conig

iTrader: (1)

i beleive the vapor sensor is a seperate sensor then what I am looking for.

something has to be telling the pump to increase or decrease the pressure, I assume thats the pcm, but the pcm cannot just make that up it has to have a reference somewere.

heres the vent pressure for the cap. ACURA TSX VENT PRESSURE SENSOR
Part# 37940-SNA-A01

another. ACURA TSX PRESSURE SENSOR ASSY.
Part# 80450-SFE-003


This caught my eye, the car uses a map sensor so why does it have this sensor as well?

ACURA TSX AIR FUEL RATIO SENSOR
Part# 36531-R40-A01
ACURA TSX MAP SENSOR ASSY.
Part# 37830-RNA-A01

thanks guys this probable wouldn;t bother most people but its driving me nuts.

DuckDodgers

Actually, most systems use dumb measures to regulate fuel pressure in dual line systems. Restrictors or valves limit returned fuel to maintain pressure in delivered fuel lines...the system returns excess fuel to the tank/pump.

Itchytoe

The TSX normally takes a couple of rotations to start. It's part of the emissions control system. A longer start time actually reduces emissions during start up. At least that's what I've read by other members here, so I assume it to be true.

Is yours taking longer to start than it used to, or has it always had a slightly longer than normal start time?

poltergeist

There is no "fuel pressure sensor" in the TSX. It's a single line "returnless" system where the regulator is mounted on the fuel pump in the tank. PCM commands the pump on, regulator regulates max pressure by bleeding fuel directly back into the tank. If you have measured that the fuel pressure is low at cold start, it's most likely either a bad/or dislodged regulator (I've seen them pop out on Accords) or a bad check valve in the pump itself.

There is a "fuel tank pressure sensor" which is used exclusively for EVAP emissions monitoring.

DuckDodgers

You sure it's single line, the system diagram seems to indicate otherwise, but I'm not an expert on reading this thing.

As a side note, the part "conig" initially referred to seems to be the "Fuel Tank Pressure (FTP) Sensor", part of the "Evaporative Emission (EVAP) Control System".

poltergeist

There's a vapor line that runs back to the EVAP canister under the car. There is no return line back to the tank because the TSX uses an in tank regulator. Cars with a fuel-rail mounted regulator have a dedicated return line to send liquid fuel back to the tank.

DuckDodgers

Got it, so the EVAP canister is the retangular (with cylinders) box located in front of the fuel tank...I'm used to the old school underhood purge canister. It seems clear the "regulator" we talk about above is part of the EVAP system then.

conig

iTrader: (1)

ok getting off track. I understand return and returnless. If this was return it would have been adjusted how I want by now. I'm experienced and even build small racing motors (drag quads, dirtbikes).

I still have the same wonder, what is the pcm using to make the determination? bleading off seems better. O2 sensors? OBDII turns them off wide open seems risky.

poltergeist

What "determination"? From what I've seen, the PCM energizes the Fuel pump relay when the key is turned to "On" for a few seconds. If the engine starts, it energizes the relay until the key is turned off or the engine stalls. The pump does not cycle as the engine runs.

conig

iTrader: (1)

so it's a set mechanical pressure at the pump then?

poltergeist

Yes