Inabj2

Here is my problem.

Symptoms:
Lately I been having trouble starting my car, ussually when its warm. For example last time it did it, it was when I went to the store to buy some grocerys straight to work. The SC300 did not want to start. IT cranked fine but Id have to keep cranking it till it finally caught on. I could hear the fuel pump whirring but the car did not fire up. When it fire up it would run very roughly, then it shut down. I fire it up again it started up, normally reved it no problems. When I drive it, there is no problems at all, car has plenty of power, its very responsive when im driving it. (for somewhat stockish SC300, in fact its more powerful now then when this car was new or at least then it has ever been before.)

When I get home, I put it in neutral the car's idle goes way up, to around 1,500 rpms, about 500 rpms higher then its drive idle. When at this rpm I can hear a slight ticking noise, odd thing is I only hear it around when its either park or in neutral. I cannot hear it at all at any rpms in drive or any gears where it has a load. To me it sounds like the noise its coming from somewhere in the valve train.

Notes.
I have the following done to the car.
Walbro 255lph fuel pump (cheaper then a stock fuel pump when it died on me.)
BFI intake mods done. (messed with my maf before it got used to it.)
EGR stuff has be removed. (Don't like the carbon build up, it creates.)


I changed the timing belt about 10,000-12,000 miles back. When I did this, before the change, it had 2 notches to the left, from the mark when placed at TDC. (if im facing the car, or to the right if im inside the car. Or if the car is heading North the notches would be facing west.)
The manual I had told me to line everything to the mark, so I moved it so that everything would line up. (Car has responded much better since then but, slight ticking noise occurs at neutral or park. I conteplated on going trough all the nightmare of doing the timing belt all over again and change thigns back to what it was, but the car runs so much more responsive since then.....)

replaced to a colder Tstat and have TM spark plugs but that should be irrevalant.

Question:
Doing a quick research revealed that our cars for some odd strange reason has a Fuel Pump ECU, (why? stupid! more **** to break!) For a low voltage and high voltage setup. Reading other users symptoms of warm cars failing to start easily because of this, they suggest that I replace this 300 dollar piece of useless junk so that my car can start again, at any temp.

If this turns out to be the culprit rather then me replace this, would it be possible to by pass this ECU altogether? So that the car runs on the "high" 12 volt setting just like every other car in the road, at all times?

I really dont want to spend 300 bucks on such a stupid gizmo.. any ideas? (Saving up here for sr20det swap for my other car which blew its motor.)

Inabj2

Unless anyone here can give me one for like dirt cheap, then..


Aliga?

Update: I Started the car while it was still warm, and once again I had a hell of a time getting it started. Cranked it 3 times prolonged noting.

I took a paper clip, and jammed it in the connection port at the PF and B+ it took 3 cranks but when it started the car started strong no fuss no muss unlike before. Im 80% sure its the Fuel Pump ECU.

Inabj2

Sorry double post.

Tammy

The fuel pump ECU is designed to shut down the pump in the event of an accident. A different fuel pump may have caused it's failure.

It's a safety and attorney thing, since people have burned up in collisions (our DPS officers in Ford's crown victoria)

Has the vehicle passed emissions without the EGR ?

aliga

iTrader: (147)

i have a fuel puimp ecu, 50 shipped to your door. i wouldnt bypass it, it has a safety feature built into it.

Vlion007

I have had the same problem with my car. Do I need to change the fuel pump? What is the best way for me to solve this problem? I have maintained the car in similar ways, what could the problem be?

SCoupe

The SC's fuel pump's output is greatly variable by the amount of voltage applied and it should last for freaking ever. At low rpms, the ecu applies low voltage and the fuel supply is fine, it bumps it up at various increments as rpm rise.

The fuel pump ecu by-pass is more often done by 2jz-gte bpu+ owners on a swapped in SupraTT fuel pump to avoid starving the engine's demand for fuel; running a 2j lean and blowing the engine. The SC fuel ecu has no idea that it is running a Supra TT. Apparently the 12v mod jumps the output of the eom supraTT fuel pump to equivelent or more of the Walbro. After the mod, the pump is always at max output and the excess fuel is routed back to the tank. Many stock SC owners would rather not run that way.

Worth a read: http://www.supraforums.com/forum/showthread.php?t=254203&highlight=12v+mod (remember, MKIV Supra and SC3 near mechanical twins)