RB25DET coughs/splutters/misfires/stalls when idling, fine otherwise, any ideas?

[BryanB]

hey simo, how much does this tony guy charge to fix?

[druzilla32]

It seems that all of us have a similar problem, just some worse than others:

http://www.skylinesaustralia.com/forums/sh...&threadid=28398

http://www.skylinesaustralia.com/forums/sh...&threadid=28133

http://www.skylinesaustralia.com/forums/sh...&threadid=28270

[rustya]

Check your firing amplifier and all your coils sound like one of it is bad. If nor check TVP sensor it could be bad..

[rustya]

ECU diagnostics

The ECU is found in the passenger footwell, behind the plastic kickplate to the left of your feet when sitting. Usually you have to remove the computer from the mounts in the footwell, as the LED(s) you need to see is pointing away from you.

Switch on the ignition, but don't start. The LED on the ECU will be glowing.

Turn the selector screw clockwise all the way (gently!) If your ECU doesn't have a diagnostic mode screw, use the diagnostic connector to enter the diagnostics mode.

________________________________________________________________

There are three different types of factory ECU available in Skylines.

One type has two LEDs and five modes

The second type has no LED's. The error codes are flashed with the engine check light in the instrument cluster.

The other type has one LED and two modes

________________________________________________________________

For two LED EDU's: the LED will flash once, pause, flash twice, pause... all the way up to five. This is the diagnostic mode. Mode 1 = one flash, mode 5 = five flashes. When you reach the right mode, turn the screw back counter-clockwise. Mode 3 is what most people use.

For one LED ECU's: wait a couple of seconds, and turn the screw back counter-clockwise, the ECU is now in mode 2.

Note - the engine check light on the dash will mirror the LED on the computer.

The LED will flash out a code (or series of codes if there is more than one fault) More recent ECU's have two LED's (red = first digit, green = second digit, eg red 2x flash, green 1x flash = code 21) The ECU's on most R32's have one LED, long flash = first digit, short flash = second digit, eg long, long, short = code 21.

Codes:

11 Crankshaft position sensor

12 MAF sensor circuit

13 Coolent temperature circuit

14 Vehicle speed sensor circuit

21 Ignition circuit

31 ECU (ouch!)

34 Knock sensor

43 Throttle position circuit

45 Injector leak

51 Ignition circuit

54 Auto signal to ECU

55 All OK

Turn the ignition off to put the ECU back to normal.

There is also a O2 sensor test in real time available - do the above to get the ECU into mode 2 (single LED ECU) or mode 1 (2 LED ECU's) Start the engine. Warm the engine, and then run under no load at 2000 rpm for the test.

Single LEDs: on = lean, off = rich

Dual LED's: green LED on = lean, green LED off = rich

Go by the trend shown, eg mostly on = lean, mostly off = rich. The LED should be flashing between 5-10 times per 10 seconds under normal conditions.

[druzilla32]

Ok did the test.

34 - Knock Sensor

This would be the reason for my missfiring problem i guess...

How do i fix this problem?

O2 sensor test -

Flashed on and off, so this is fine i take it.

[druzilla32]

sh1t Bozz, didnt mean to take over your thread like that!

Il start another on my knocking problem..

You can have your thread back now

[Bozz]

No worries, I'll just go back two years and re-earth the fuel pump, after I replaced the cams with stock ones (which fixed the problem)

I'm sure it'll make it work better.

Thanks champ! Couldn't have done it otherwise