Hey guys, I am busy stripping down and making sense of my new (old) 4A-GZE motor. I was wondering if someone could help me identify the vaccum and water pipes I have labelled A-F in my pics below.







Also looking into the air intake and S/C outlet I am finding oil residue (see pic below), is this a fatal sign? where could this oil have come from, the S/C?




Thanks for your help!

X

Can't tell you much about the vac and water hoses at the moment because it must be a jdm setup and some of the stuff is backwards from the MR2 SC setup. As for the oil, however, don't worry as that is quite common. It comes mostly from the pcv hose that runs from the inlet cam cover to the throttle intake pipe, along with a little bit from oil leaking through the sc seals. It would be more odd if you hadn't found any oil in there.

Does anyone else know what these vaccum and water pipes are for?
I think the two water pipes could be cold start?
One of the vac's has to be for the break booster, but which...

Thanks

A is either ABV or FPR, from the 4agzes I've seen there are 2 steel pipes there for both ABV and FPR
B on mine I have this for the booster
C I have blanked with a plug like the one below and to the left in the picture
D P/S idle up
E P/S idle up
F I have plugged

Thanks for the reply, would you mind telling me what teh abbvreviations ABV FPR and P/S are?
The Idle-up pipes would be water pipes correct?
I've managed to find and order a workshop manual, so I should be able to find where they connect.

ABV = Air Bypass Valve
FPR = Fuel Pressure Regulator
P/S = Power Steering

Cheers... jondee86

Thanks, ok my AE92 didnt come with P/S so i'll just blank those off. I also see there is a mod to blank off the ABV if the psi goes too high, I'm sure most people have done that?
Why would the FPR have a pipe coming out, isnt the regulator sitting at the end of the fuel rail which regulates the pressure?

Thanks!

xarion wrote:Thanks, ok my AE92 didnt come with P/S so i'll just blank those off. I also see there is a mod to blank off the ABV if the psi goes too high, I'm sure most people have done that?
Why would the FPR have a pipe coming out, isnt the regulator sitting at the end of the fuel rail which regulates the pressure?

Thanks!

You want the ABV operational. Most people think it's role is much like a BOV but the most important job for the ABV is to remain open when the SC clutch is disengaged. Otherwise the motor will have to pull all it's air through the non powered supercharger lobes which will make it work much harder.

The FPR needs a vacuum reference to the mani so it can change the fuel pressure in order to keep it the same relative to the plenum pressure.
Think of it like this. If the base pressure is 40 PSI then when the car is idling at say -10 PSI the fuel injectors would be injecting at 50 PSI relative to the manifold pressure.
Even worse if you were boosting at 10 PSI then the injectors would only be injecting at 30 PSI relative to manifold pressure.
To really show the true severity of the issue if you were to run 40 PSI boost the fuel flow would stop altogether because the pressure in the mani and pressure in the fuel rail would be equalized.
The vacuum refrence allows the FPR to keep the fuel pressure the same in reference to that mani pressure.

The P/S idle up hoses go to a valve on either the P/S rack or P/S pump and are air hoses.
You can blank both of them but you cannot just loop them together as this will cause a high idle.

Thanks for the great explanation, I have managed to locate teh VSVs for the ABV and the FPR using the following diagram:



1) The pipe that I marked A i think runs to the BVSV in the picture and then to the canister, what is a BVSV and canister?

2) I have not managed to find anything to do with the EGR valve as the system diagram shows. What is this?

3) Why would the 2 VSVs have wires connected to the ECU, would this be for mesurement or for the ECU to override mechanical functionality?

Why would the 2 VSVs have wires connected to the ECU, would this be for mesurement or for the ECU to override mechanical functionality?

The ecu can control fuel pressure and boost pressure via those 2 VSVs.