Friday, June 11, 2010 - 12:37 am, by: Sagib Mehtijev(Sag)
Bought my self a soarer 2,5tt with strange problem. When I start my car cold, so revs are too low for the cold car, about 500rpm. When it gets hot enough to drive I get trouble with accelerating, it seems to me that injectors flow too much fuel in to the engine while I press throttle pedal little bit more than usually. So when engine is under load I can not drive with boost. Ecu does not show any problems, no warnings at all. Without load engine revs fine, even with full throttle, also driving backwards is fine and no trouble with boost. Have been to all local car shops, no one knows what could be wrong. All the hoses are in place, 100% stock car.
A common problem in these cars is the fuel pump ecu/controller, it switches between low voltage and high voltage to the fuel pump depending on engine load. When defective it may not switch the fuel pump to run at 12v, causing an insufficient amount of fuel delivery in order to maintain acceleration under load.
To rule out this problem, we bridge the terminals FP and +B on the diagnostic connector in the engine bay with a piece of wire, this allows the fuel pump to run constantly at 12v, bypassing the control of the fuel pump ECU.
The diagnostic connector is located to the right of the intake manifold, the terminals are labeled on the underside of the cover.
If the symptoms you are experiencing go away when +B and FP are bridged on the diagnostic connector, you have a defective fuel pump ECU and it needs to be replaced.
They can be had for about $100 second hand or $200 new from Toyota.
Some people chose to run the fuel pump at 12v constantly instead of buying a new fuel pump controller/ecu, I am not aware of any problems doing it this way.
Please try what I have suggested and post back so we can rule out this problem.
Regarding the 500RPM Idle on cold starts, this could be a defective or dirty idle speed control valve (ISCV), also called an IACV (Idle air control valve).
This valve is located on the inlet manifold, it is controlled by the ECU to allow extra air to come into the inlet manifold when the throttle body is almost closed at idle, this increases the idle speed.
If the motor in the valve is not functioning it will not be able to bypass air to regulate the idle speed when required, such as increase it on cold starts.
If the valve is dirty, the dirt and gunk buildup caused from blowby vapours over time may be impeding the flow of air through the valve into the inlet manifold, resulting in erratic idle speed or in your case low idle speed.
Remove the idle speed control valve and check for dirt on the seat and the metal part that contacts the seat, if a very heavy buildup is present, this may be the cause of your low idle and should be cleaned, however since you are experiencing very low idle speed, I suspect the valve itself may be defective and a working replacement should be installed.
Friday, June 11, 2010 - 05:23 am, by: Sagib Mehtijev(Sag)
Thanks a lot, tomorrow will try that.
Few days ago, car did not want to start at all, found that fuel pump is not working, also thought that that is the source of a problem, fuel pump is dying and does not give enough fuel pressure. Changed it to one from a supra, still same illness.
Also I have SC400 and when I bought it, previous owner give me fuel pump ecu, he told me that that thing is often goes out of work and I should be prepared for that surprise.
Friday, June 11, 2010 - 06:25 pm, by: Sagib Mehtijev(Sag)
Did that bridge FP and +B on the diagnostic connector in the engine bay, did not give any result. Still same problems. Also made a video of this trouble.
Also strange thing happend. Got battery connected, turned on the car, but digital dash did not go on, and cold engine revs were fine, about 1200rpm. Turned off the car after 1 min and back on, dash went working (only upper part) and still cold engine revs 500rpm. After few hours of running the engine, lower digital dash part still does not work, only flashes once when I turn the key.
Friday, June 11, 2010 - 10:31 pm, by: Rob Rojo(Rob_tt)
Also if you have disconnected the battery for any longer than a minute or so it will reset the ECU which I have found usually causes a low idle until its driven for a few k's.
You may also want to check the earth from the battery to the chassis, they often get quite dirty and corroded and can cause all sorts of electrical problems.
Sunday, June 13, 2010 - 09:16 pm, by: Sagib Mehtijev(Sag)
how can I check them ?
Also what could be the problem with Digital Dash, lower part does not work any more, it was blinking for a second when I turned the key on, now it does not work at all.
Monday, June 14, 2010 - 08:29 am, by: Neil Griffiths(Aussiesc)
Sounds like Plugs on Ignition Coils need replacing ( Replace spark plugs at same time ) Coil plug is generic across a lot of Toyota's , If you have the V6 Hilux / Landcruiser / Camry, then your Local Toyota place will have the plugs ( Part number is at work )
Spark Plugs - NGK - BKR6E
If this turns out to be the problem, then there is a good chance your idle will be better.
Lower part of dash sounds like a faulty capacitor on the circuit board in rear of dash.
Wednesday, June 16, 2010 - 01:42 am, by: Oki Zoubari(Oki)
sagib
In regard to the lower dash, This happened to me a few weeks ago, not sure it is the same in your case, but in my case, I shorted the cigarette lighter and that caused the fuse to blew, this has caused the cigarette lighter and lower dash to disappear, The fuse in is 15 amp and I is located in the drivers side kick panel, In short, check to see if it is only a blown fuse.
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