Sunday, October 15, 2006 - 06:24 pm, by: Jason Storey(Buttocks)
Heres the problem I own a sc400 1991 model imported for Japan to Australia When i picked it up it was hitting a rev limiter at 3750 Now the car is absolutely stock i've taken it to the local toyota dealer who have fault check the car with the australia 1uz diagnostic tool (only shows about half of what it should as nobody here has a proper *** one) they found nothing We have changed over these parts ECU Fuel Computer igniters AFM
Its a real horrible problem that no-one here can answer and its driving me mad, its 100 percent like the rev limited that should be around 7000rpm i've been told to check the fuel pump now, but if the fuel pump wasn't supplying enough pressure it would hestitate but the car drives perfect except for the rev cut. I also found today if i get to 90 kph and knock it back into 2nd it will go above 4000 but cuts out until the revs go below 3750 again and off it goes as normal, but a fault code comes up in Japanese which i translated to engine electrical system (kind of a broad statement) Any help would be life saving
I"VE ALSO HAD A THOUGHT< WOULD A FCD (fuel cut defencer) stop the rev cut from coming in????
Wednesday, October 25, 2006 - 01:01 am, by: Peter Nitschke(Pen)
Jason, "blocked" doesn't have to mean completely blocked. If they are partially blocked, things would be OK up to a point - which could fit the problem's job description.
Thursday, October 26, 2006 - 01:38 pm, by: Harry Lemmens(Wombat)
Okay ... Not so much as a rev limit as the engine cannot breath the gas out.
This problem has been seen before ... Its not the ECU going into rev limit!
Easiest test is to drop the exhaust at the engine end of the cats. Start it up and see if it EASILY revs past your current limit.
You havent said your getting "engine electrical" up on the dash ... assume you are not ...
An FCD will not help ... FCD's are installed on the (turbo) TT2.5's to prevent the fuel cut when "excessive" boost is detected.
The fuel pump ECU may well be cactus ... They do not fail totally, but they drop back to the low power/fuel setting, and will not deliver full output.(Or, 9 volts (or less) if you put a multimeter across the output.) NB: After the car is warm, at idle the ECU will drop to this voltage ... Only at High engine loads will it attempt to step up to the higher output power setting (12 volts or more.) To sus this out, put in the diagnostic bypass jumper, which effectively bypasses the fuel pump ECU, and delivers battery straight to the fuel pump. (There should be heaps of posts on this, just do a search)
... Bad performance? You mean you dont consider 3750 RPM as being a sign of bad performance?
RE: Diags. You dont need a diagnostic tester for the Soarer OBD system. Most of the diags can be read from the "clock" on the dash. Or, you can read them from the EMV if your vehicle has one. Or, count the flashing lights.
There are several doc's on this forum that detail diags. I know, I compiled them! RTFM
Thursday, October 26, 2006 - 10:43 pm, by: Jason Storey(Buttocks)
Bad performance has nothing to do with a 3800rpm cut, as in the car is perfect upto that point, has good power etc. Fuel pump computer has been changed and the fuel pump is working perfectly as its been checked 3 times now, it switch's between 9 volt and 12 volt like it should. Its has only had engine electrical up on the dash when i've hit 90 kph in 3rd and drop it back into second which makes it go over the 3800rpm barrier, but it doesn't go anywhere until its back under the 3800rpm limit again
Friday, October 27, 2006 - 09:45 am, by: Harry Lemmens(Wombat)
Okay ... It sounds like your might be getting twice as many pulses being feed back from the ignition coil as there should be ... Easy to check with an oscilloscope ... Both coils have the feedback tap, so a quick swap might help. (Also, check for arcing on the coils)
Feedback should only come from one coil. Make sure that each coil has a seperate power feed. (Someone may have joined the two together in the past ... especially if an aftermarket ECU was tried . Many aftermarket ECU's only provide for one coil - wasted spark configuration.)
(Thinking about the above, I am not sure that joining the two power feeds together would let the car run at all ...)
...
H'mm ... I am at work, and don't have access to the wiring diagrams I need ... But ... the RPM signal goes to the dash as well...(I think) ... Wondering if its actually not getting the RPM to the Engine ECU? Never tried to see what happens to a stock ECU if the RPM signal ISN'T connected. ECU could be in a "Limp Home" mode. Not all "Limp Home" modes bring up "Eng Elec".
anyway ... keep looking.
Kim Hunt TryHard NSW Supercharged & Intercooled SC400\Soarer GT-L UZZ31