My 1989 V12 only just passed the MOT emissions test here in the UK for CO content.

I think I remember reading somewhere that there is an adjustment on the ECU that you can make to tweak the idle emissions - does anyone have any details/whether it's possible on a 1989 Marelli UK car without cats?
I cleaned out my injectors, replaced all coils/leads etc etc whilst the car was off the road so it's occurred to me that whatever historical tweaks that might have been done over the years might no longer be relevant.

The exhaust doesn't emit any smoke, but is quite smelly/petrol fumey if that makes sense - my clothes always smell just being near the car whilst it's running.

 

I'm really not sure if this applies to your car specifically but i remember reading about a fuel map "jumper wire" on these cars. I think with the jumper it adjusts for high octane fuel, and without it it sets it to low octane mode. Also is your timing ok? Car runs good? Having no catalytic converters puts you a little behind in the exhaust smell department.

 

Probably read this.

REMEMBER it only adjusts mixture AT operating Temp, and Idle. Outside that, the various sensors, internal mapping, etc all do their thing.

 

Sounds as if some of the injectors are not closing properly. I realise you have done them, but I would check them again. What were your CO numbers?

 

For what it's worth my '89 had similar symptoms and the reason was a broken full throttle enrichment microswitch mounted on the throttle capstan and the engine was running rich all the time.

 

A band aide that will help is if you use 10 Ethanol next time you are tested.
Ethanol “cleans” the exhaust by running slightly lean( not dangerously ). If you’d like I’ll explain the whole chemistry. We’ve ( here in America) been using 10% Ethanol for over 30+ years and it has no ill effects.
What might happen though is ethanol is a wonderful cleaner. Gasoline is horribly dirty, leaving deposits on the back sides of the intake valves. Accordingly ethanol will clean your gas tank and the results will go into your fuel filter. IOn occasion depending on how dirty the tank is plug up your fuel filter. So run a tank or two and then replace the fuel filter.
Do this before your next MOT.

One final question. Does one side of the exhaust smell worse than the other? If so the cap or rotor is your issue. Replace them.

 

Only the very early system had an adjustment. The Bosch system. Once Jaguar went to Lucas that adjustment went away.
What you are attempting to do will make the engine look great but power gains will be really marginal.
Ask I’ll walk you through it. But I have more than 30 years of racing that engine under my belt.
I’ve made all those mistakes.
Two things will gain you a lot of power for not a whole lot of money.
First all cylinder heads from 1981 on are terrible at making power. They limit you to a max of 450 hp. If( and only if) you do everything right.
The best heads are 1971-1980 much greater potential. Yes they will bolt right on *
(* you will need to change pistons ).
Second the Jaguar camshafts leave a lot of power in n the table. The valve only opens 3/8 of an inch and have very little duration.
Camshafts are easy to change. It takes less than 1/2 the time it takes with a V8.
You’ll want something approach 1/2 inch of opening. And a lot more duration
Remarkably. The wildest race cams I was ever able to buy still idled smoothly and at factory idle speed.

The easiest way for a lot of power is a pair of
E BAY T2 turbochargers. ( $160 each).
Nope! You won’t need to open the engine at all.
And you can hide them under your front fenders.