V8 Emmisions

HELP PLEASE.

3.9efi 96 discovery with emmisions at 11% managed to get it down to 6% with new plugs air filter new Maf and new exhaust.
Any one know what else to do?
Cheers in advance

I've just come on with a similar issue, mine is at 6% and need it to be 3%, my tickover is approx 1200 so I heard to reduce the revs but the screw is already on its seating! I've got the Lucas Hotwire system and have been told it might be a problem with that but know they can be expensive parts

Check to see if there be a vacuum on the vaccum doofer on the distributor> Once I sorted that the emissions just fell away down to a couple of %

Vacuum doofer please explain more, I need to know more thank you

DaveW said:

I've just come on with a similar issue, mine is at 6% and need it to be 3%, my tickover is approx 1200 so I heard to reduce the revs but the screw is already on its seating! I've got the Lucas Hotwire system and have been told it might be a problem with that but know they can be expensive parts

Click to expand...

The screw sets the 'base idle' only, the tick over is controlled by the idle-control valve via info sent from the EFi ECU.

So start with checking the setting of your base idle then move on to checking the function of the valve.

vacuum advance. I assume you have one. It fits on the side of the distributor you need to suck on the wee hose going into it and then put your tongue in the hose to see if there is a vacuum.

It's the brass bit in the pic below

Brilliant will try these suggestions, cheers guys

Got it sorted, my local landrover garage warmington hill did a fantastic job and put a Japanese chip into the loom and got the co2 from 13% to 0.3%. Needless to say it flew through the MOT.
Can't say how chuffed I am and would recommend the garage to anyone.

Ironside said:

Got it sorted, my local landrover garage warmington hill did a fantastic job and put a Japanese chip into the loom and got the co2 from 13% to 0.3%. Needless to say it flew through the MOT.
Can't say how chuffed I am and would recommend the garage to anyone.

Click to expand...

do what??please explain

Yep got us all on that one Japanese chip?

Sounds like a cheep resistor fix on an ecu input???

Tune resistor I guess.

Although the CO is adjustable using the grub screw on the MAF.

Do you mean a tune resistor?

Bit confused as to how sticking one of these, into your wiring loom is going to reduce emissions.

LO. Yer tune resistor to select a different map in the ECU. however this should not be needed and really I would strongly recommend finding the real reason the % was high as you could e damaging your engine at the moment.

Could also be as a result of crappy fuel.

I had a similar issue with my Volvo T4 and i was going through almost everything related to emissions to get it through its MOT.
In the end, it turned out to be carbon deposit build up on the seats of one of the valves.
It wasn't found until the same valve blew and i had to get it replaced.

While the head was in the cylinder head specialists, the de-carbed the head and lapped the remaining valves for me too.
Afterwards, when the valve was replaced and the engine put back together, the emissions were as clean as new car with an engine of similar size.

I have a similar issue with my Range and now that one, or both, of the head gaskets have gone, i will ask them to do the same on them too.
The emissions test for the MOT barely scraped through but seeing the carbon build up on the valves, i can understand why.
Once i get the other head off, it'll be interesting to see the build up on that.
I expect it to be pretty uniform.

I'll get the emissions re-tested once the engines back together and i'll let you know the result.

As far as I am aware the only tune resistor for the hotwire is to tell the ECU that it has Lambda sensors or not please correct me if I'm wrong.

Mick

There are different market resistors aswell, only 4 in total though

Visual inspection of wire color codes will allow you to quickly differentiate between resistors.
White 3900 Ohms USA and European vehicles with catalytic converters
Green 470 Ohms UK and European vehicles without catalytic converters
Yellow 910 Ohms Saudi vehicles (without catalytic converters.)
Red 180 Ohms Australia and "the rest of the world."

Thanks for that mr noisey. But none of those should change the emissions enough to pass the MOT I wouldn't of thought.

Mick