Adjusting Air/Fuel mix

haywes · July 12, 2010, 03:20:23 PM

Following on from my thread about my FC failing on emissions by about 0.38%, with some help we figured out my air pump has been removed, so over time I will need to source bits to replace it, but for now to get it past the MOT I need some help with adjusting the air/fuel mix. It\'s an 87 FC EGi, and I just wanted to know a few things - where is the adjuster (and is it \'tamper proof\'), is it directly the air/fuel mix or is it electronically controlled, and are there any other methods to just get it past an MOT using a temporary measure.

Like I said, I\'ll be on the lookout for airpump bits, and I\'ll have to have some work done on the exhaust to allow for it, but for now any help with this would be great, as I\'ve only got about 5-6 days left for the retest.

Cheers :driving

BlitzBoy · July 12, 2010, 03:42:14 PM

Its ECU controlled Im afraid dude. Try new plugs and airfilter

haywes · July 12, 2010, 04:25:27 PM

Quote from: BlitzBoy;704054Its ECU controlled Im afraid dude. Try new plugs and airfilter

Had a bad feeling it was - balls! Thanks for the info though man.

I\'ve only just replaced the plugs, done an oil/filter change etc, along with a full tank with some 44K put through it, and I\'ve recently replaced the foam filter in the HKS mushroom. It\'s starting to sound like I might have to take it off the road until I get the airpump system sorted!

Any other ideas that might help at all? Anything you\'ve got might be worth a shot, as it\'s only just out.

BlitzBoy · July 12, 2010, 04:34:59 PM

Hopefully some of the FC owners will chime in, if the MOT is only testing the Idle emissions, maybe adjusting the idle screw to a higher idle speed might help

haywes · July 12, 2010, 08:25:19 PM

Quote from: BlitzBoy;704075Hopefully some of the FC owners will chime in, if the MOT is only testing the Idle emissions, maybe adjusting the idle screw to a higher idle speed might help

It is just an idle test yeah. Would a slightly higher idle speed be more likely to give better results than lowering the idle speed? Also, where is the screw located on the 13B? Just to make sure I have the right one!

m1tch · July 12, 2010, 08:28:09 PM

I think Prof managed to get his FC past once when his was idling at like 500rpm lol there is an idle screw on the BAC on the UIM, there is on a turbo II, but not sure about an egi

haywes · July 12, 2010, 09:35:31 PM

There\'s a picture if it helps, not sure if it\'s big enough to see some details. 500rpm - sounds lumpy!

m1tch · July 12, 2010, 09:45:15 PM

Ah yes! I can see it, you see on the top of the engine, just to the right there is a silver tube, 2 hoses coming out of it with a brown cap, thats the BAC valve, it has a hot water feed that changes how much it vibrates to control the idle when cold and then warmed up. There should be a screw on it.

haywes · July 13, 2010, 09:59:12 PM

Quote from: m1tch;704162Ah yes! I can see it, you see on the top of the engine, just to the right there is a silver tube, 2 hoses coming out of it with a brown cap, thats the BAC valve, it has a hot water feed that changes how much it vibrates to control the idle when cold and then warmed up. There should be a screw on it.

Here\'s a picture of my BACV - after having a look for this screw I saw a picture of StavFC\'s he was selling (hope you don\'t mind Stav!):

But on mine, it appears that the screw isn\'t there!:

Any ideas?

haywes · July 14, 2010, 12:24:32 PM

Is there another way to control the Idle? I\'m taking it in for a retest today, so I need to do all I can. Like I said, it wasn\'t stupidly far out, so anything might help!

TiddlesRX7 · July 14, 2010, 12:34:50 PM

Think there is one on the throttle linkage too. You\'ll have to have a look as Im not clued up on the EGI\'s im affraid.

Prof · July 14, 2010, 01:26:26 PM

Quote from: haywes;704450Is there another way to control the Idle? I\'m taking it in for a retest today, so I need to do all I can. Like I said, it wasn\'t stupidly far out, so anything might help!

Because of the age of the car - they should be able to test the CO on \'fast idle\' which it should pass. It\'s covered in their MOT testing notes.

The usual tricks:

New Plugs
Thouroughly warmed up car before hand
Ethanol in the fuel tank (it\'s what the americans do apparently)

haywes · July 14, 2010, 01:40:16 PM

Another picture of it helps!

For the fast idle test, would that be instead of or as well as a normal idle test? Would a faster idle be more likely to produce lower emissions then?

haywes · July 14, 2010, 02:19:41 PM

Also, If the Air/Fuel mix is ECU controlled, what sensors does it use to gather the data ? And regarding the TPS - is this ECU controlled or can it be adjusted manually?

haywes · July 14, 2010, 09:30:49 PM

Quote from: Prof;704465Because of the age of the car - they should be able to test the CO on \'fast idle\' which it should pass. It\'s covered in their MOT testing notes.

The usual tricks:

New Plugs
Thouroughly warmed up car before hand
Ethanol in the fuel tank (it\'s what the americans do apparently)

The guy on the phone said they have to do it at idle or something - I know for sure he\'s not one of the testers though so I\'ll ask the tester tomorrow.

I put in new plugs very recently, and I always take it for a good drive before hand. I wonder if the ethanol thing might be worth a shot?

I managed to move the retest to tomorrow morning - does anyone have any other ideas at all on what I can do to improve my chances of a pass, or any idea on where I can control the idle other than the BACV since mine doesn\'t have a screw? Also, any ideas on what sensors the ECU uses and where to regulate the air/fuel mix?