Getting a Decatt Rover v8 through emissions test

[Graham]

IS it possible.

The car only fails on the co. we managed to get that down to 1.4% holding the idle at 3k.

The car runs an emerald programmable ecu, so do you think it would be possible to tune a special map so around 2750-3k rpm it runs leaner ?

i have access to an analyser and the lap dog to reprogram. obviously the old map would go straight back on after the test.




any ideas

G

[GreenV8S]

Would have thought you could just lean it off at that load/rev range?

Alternatively, putting a restriction on the exhaust significantly increases EGR at low revs/part throttle and improves emissions no end. Got any Supertraps, or tailpipe inserts that you can almost block up?

[Graham]

mmmi Think we'll have a go on sat then

G

[joospeed]

if you've got an emerald why don't you just have the laptop plugged in and adjust the mixture during the test until it passes? If you've still got lambda sensors you can run in closed loop mode anyway so why not enable that function? If that's not weak enough just keep trimming on the live mapping screen during the test, it adjusts in real time.

[stevieturbo]

IS it some wild spec of an engine ???

If its a fairly mild build, it should be capable of idling closed loop at stioch ( 14.7:1 ) which is 0.1%CO

Either way, with the emerald, you should be able to map it to give pretty much whatever readings you want.

[350matt]

What year is the engine? so what limits apply? I'm running a lairy cam, no cat and the emerald on my Rover and mine idles happily at 0.3-0.5% CO (approx 13.5:1 AFR) but I've only got to pass 1986 limits of 1.5% at idle I can get it to run on a leaner mix but it does give the occasional misfire then, which knackers you on the hydrocarbons

Matt

[chuntington101]

running water injection may let you run it a little leaner before you get det. any chance you could just rig up some cats just for the test?????

thanks Chris.

[Graham]

joospeed said:

if you've got an emerald why don't you just have the laptop plugged in and adjust the mixture during the test until it passes? If you've still got lambda sensors you can run in closed loop mode anyway so why not enable that function? If that's not weak enough just keep trimming on the live mapping screen during the test, it adjusts in real time.

I didnt think you got it to work with the lamba? i'll have a fiddle there is still 1 lamda plugged in.

( after testing the sensor first)

The motor is a 96 so has to pass the latest test.

i'll try and fiddle this weekend

G

[eliot]

Graham said:

The motor is a 96 so has to pass the latest test.

So doesn't it *need* to have a CAT then? - Or just pass emissions at that level?

[350matt]

Correct, I think the limit is 0.3% CO at idle which might be do-able depending on what cam is fitted

[thesilverfox]

Any motor after 1992 needs a cat test. the BET new limit is 0.20 it was 0.30 at idle
what you will find is that any cat cars with a fully working lamdba sensor will nearly go through a cat test. but with a faulty or missing cat not quite ,to get it down that extra bit you need the cat to pass. best of luck

[Graham]

managed to get the co down fine but struggling to balance the hc and co arghh

G

[350matt]

a dodge the manufacturers use is the engine driven air pump which dilutes the exhaust mix? alternativly disconnect a cylinder? As this will reduce the volume flow and the number of hydrocarbons produced, getting below 0.3% CO without it misfiring is the pretty tricky, one way is to bung is a load of retard with a large idle /throttle opening this will increase the CO but really lean out the hydrocarbons

Matt

[chuntington101]

why not just run it as a V4???? this would maintain the balance of the engine (i think???) and only running half the cylinders would only make have the emisions no??? just depends if the ecu will let you do it.

thanks Chris.

[ultra violent]

...your first clue was the use of %

[GreenV8S]

ultra violent said:

...your first clue was the use of %

Clue to what?