This site contains car modification and auto upgrade information specifically for the turbo import Toyota JZX90 MarkII TourerV, however the principles applied here can be mostly utilised regardless of the make or model of motor vehicle.
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Walbro 700HP Fuel Pump Upgrade 5/2/2005
The standard fuel pump is a relatively high volume pump when compared to non turbo cars or four cylinder models, however has a limit of fuel flow that caps the available power output at somewhere near the 200-250 rwkW mark. In order to get more power of course it is necessary to provide more fuel. Since I am planning an injector upgrade and eventually a turbo upgrade, the stock fuel pump was just not going to cut it.
So with this in mind I purchased a Walbro 255LpH in-tank fuel pump that is almost a direct drop in replacement to the stock item. I could have purchased a high flow external pump and surge tank, but this would mean a much higher expenditure, and also a lot more noise. The hope was that the in-tank pump would be a lot quieter (since it is submerged in a liquid).
The first thing to do is to disconnect the fuse for the fuel pump, start the car and let it run til it stalls. In my car this happened very quickly. This releases the pressure from the line, so that you don't get convered in fuel when disconnecting fuel lines!
The next thing to do of course was to locate the original fuel pump. I knew that the fuel tank in the JZX90 resided between the rear seat and the boot. A quick inspection of the boot interior behind the trim revealed no sign of a fuel pump. Scanning the internet revealed to me that the MkIV Supras fuel pump was accessed after removing the rear seat. So I removed my rear seat.
The lower part of the rear seat is held in by two clips (the yellows ones) and is removed by firmly pulling the seat up near these two points.
The lower section of the rear seat can then be removed from the car. The back section of the rear seat in the JZX90 is held on by four bolts on the underside and clips at the top. The four bolts are easily removed with a 10mm socket and the whole rear section is lifted firmly to enable it to slide off its upper clip points. It can then also be removed.
What is then visible is what you see here. Not having any instructions to go on, I presumed that the lower rectangular panel would be the point of access to the fuel pump. After removing this panel I quickly realised that this was not the access point to the fuel pump. It did however seem to show the fuel lines and breather line.
The round plate above this must then have been the acces point to the fuel pump. This was held in by a butyl mastic (gooey black stuff) and was easily pried off with a screwdriver, revealing the "pot of gold", or at least the next door to it. I firstly unplugged the electrical cables that supply power to the pump, and disconnected the fuel lines. There are seven screws that hold the fuel pump assembly in and once these are removed it is a matter of gently manipulating the in-tank assembly to the correct angle to enable extraction from the tank.
Removing the pump assembly is not exactly easy as it requires getting it at just the right angle in order to be able to clear everything. The pump sits inside a baffled section inide the tank so this makes it a bit more dofficult. Be patient and gentle and it will eventually come out. It is worth mentioning here that good ventilation is of utmost importance when performing this task. The last thing you want is for your whole garage to become a combustion chamber (with you in the middle of it!).
So ensure that all doors of the car are open, and ideally perform this task outdoors, or have all windows and doors of the garage open. To further reduce fumes it is worthwhile to tape over the opening while you are swapping the new pump into the pump assembly. I just used some wide duct tape, however as soon as it is sealed over the opening, the vapour pressure of the fuel will force a gap between the tap and the tank. It is futile to fight this as it is inevitable, however at least the fumes will be reduced dramatically compared to an uncovered opening.
The instructions suggest cutting the fuel hose entering the old pump to enable easier removal, however I did not find this necessary. The kit comes with new hose, isolation rubber and clip with cable plus a cable tie and new hose clamps. I unplugged the power lead, then loosed the hose clamps and with a bit of manipulation was able to remove the pump from the assembly.
Here you can see the old and the new pumps side by side. Now earlier I said that it is almost a drop in replacement pump, and the small difference here explains why I said "almost". You will notice that the new pump has the fuel line on the opposite side of the fuel pump as the standard pump. This means that either the fuel hose has to perform a miraculous bend in a very short distance, or that the fuel pump will sit and an angle. The pump cannot be turned 180 degrees because the filter will foul with the assembly. I have heard of people cutting the assembly to accomodate this, however I think it is unnecessary to do so, and besides it would reduce the strength of the bracket.
When putting the new pump in the assembly ensure that you use all of the new parts. Do not re-use old hose, clamps or rubbers. I placed the pump as best I could in the isolation rubber at the bottom of the bracket and attempted to fit the hose at the other end. This proved impossible, so I discovered the best method was to slide the hose almost all the way up the metal pipe before placing the new pump into position. It was then a matter of sliding the hose back down over the fuel pump outlet. It is important to make sure the hose clamps are loosely in position before mounting the pump as it is a bit hard to put them on afterwards.
This anlge shows how the pump sits at an angle to the bracket. It has a gap at the top where the standard pump would not. The instructions suggest using a zip tie to ensure that the pump is sturdily located, but after tightening the hoses I discovered that it was already quite firmly held in place and was not going to go anywhere. You can see in the second picture that the pump does not sit perfectly on the isolation rubber, hoever despite how it looks it nice and firmly held.
The next step it to change over the plugs. The new pump has a different socket so the original plug needs to be removed. A pair of sidecutters do the trick, and also are used to trim down the excess cable from the new plug. The kit comes with some crimp connectors that are insulated, and the instructions stressed using only these connectors. I can't see what the problem would be with soldering and using heat shrink, but I am sure it would be foolish to try and insulate the connections with electrical tape (which would fall off when the adhesive dissolves in the fuel tank). The resulting short in a low tank would probably create quite a nice spectacle to someone standing a safe distance away (probably about 100 metres away).
The new plug is plugged in and the connectors crimped, being careful to ensure that the correct polarity is maintained, and the whole assembly is ready to be re-fitted. Re-install the tank assembly in the reverse order of extraction, connect the fuel lines and plug in the lead, replace the fuel pump fuel and crank over the engine. Again it was only a momentarily longer cranking time than normal before the car fired up and began to idle.
The fuel pump was emitting a lovely hum, reminding me that it mean't business. 700 Horespower of business. Yeah baby.
site
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RECENT MODS CHRONOLOGY
5-Jan-2007
Turbo pages and Headlights
I have recently added a new page about my single turbo conversion. There is a second page yet to come, but page one outlines some of the supporting components needed as well as the turbo itself.
Page 2 will be forthcoming where I detail the fitment of the turbo, manifold and wastegate.
I have also added a page for modifications to my headlights that should be very useful for owners of import vehicles.
25-Jan-2007
Site Revamp
Wow, it has been a very long time since I worked on the site, but now I
am in the process of redesigning it so stay tuned as I add some more content
and attempt to bring this project up to date.
18-Mar-2006
Car Changes
Lots has happened since my last update on upgrades to the car. For instance
the car is now running a 2JZ bottom end and the gearbox has been completely
rebuilt with a stage 1.5 shift kit, beefier clutches and a 2800 rpm stall convertor.
To say that this has transformed the car is an understatement. The car is now
torque heaven, and is an absolute pleasure to drive. The lag that was sadly
felt with the 2.5L motor is now completely gone with the 3L and the stally.
When I can find time to update the site with the process I went through I will
do so. I have many hundreds of pictures to add.
Whatever your vehicle is, whether it is a turbo car or NA or a Toyota or other manufacturer, I hope that the automotive information on this page is of benefit to you as you take the path of modification and upgrade on your car.
Toyota JZX90 MarkII TourerV.