MOT fail on emissions

[SuperRedMR2]

Car failed this morning on emissions only.

3.5% is allowable but mine is 3.661% - idle screw turned right down and it won't go any lower than that.

Suggestions?

[charlie]

Have you changed the oil?.that makes a difference.

[SuperRedMR2]

I've just rebuilt the engine.

It's a mixture of ignition timing and the fact the engine has only 10miles on it since the build.

Kwik fit said "if you can drive it around to put some miles on the clock that might help it" - very helpful, as I haven't got an MOT!

[BIGBOBO]

Adjust the screw next to the MAP sensor. This controls the idle mixture.

It's either broken or set way to rich.

Check page 4-26 of this manual.

http://files.aeu86.org/manuals/4age-dia ... parrot.pdf

[elbon50]

Interesting manual that Bobo

Don't recall ever seeing that one before

[BIGBOBO]

Don't recall where I got it but it saved me after months of troubleshooting why my NA would always stall at a red light. It's for a Celica/AE86 but it should be the same for an AW11.

This screw (just a variable resistor) was busted and the mixture was too lean/rich to idle properly. This setting is gradually ignored by the ECU as the rpm rise so there were no symptoms while driving the car.

All the BGBs are US spec and use an AFM instead of a MAP sensor so this bit of information is left out.

[SuperRedMR2]

It's not that, its the timing.

Its spot on now so will take it back during the week for my free retest.

But 0.661% over was a bit of a p1$$ take but hey ho. The PPM was 290 as well.