Hi Jag Lovers
I am building a cobra replica kit car fitted with a 1979 v12 pre-he jaguar engine
I found out just last week in the UK more stringent emissions must be met for all kit cars registered after a new law comes into effect very soon regardless of engine age
I have a question regarding emissions from my pre-he 5.3 v12 engine with D Jetronic fuel injection which I am about to register for the road.
There are no catalytic converters fitted and the system runs open loop i.e. no o2 sensor feedback as in the original donor series 2 jaguar saloon.
I have never had the engine tested for emissions, so I don’t know what the values are at the moment
The new regulations for emissions will be
Fast idle at 2500 to 3000rpm CO <=0.2%
HC <=200ppm
Lambda between 0.7 and 1.03
Idle test 450 to 1500rpm
CO <=0.3%
What are the normal emissions of this engine and if higher than the new regulations to be implemented will just fitting catalytic converters to the exhausts reduce the emissions to be within the new regulations
Thanks for any input
Peter
Peter,
My car is fitted with catalytic converters. Here are the results of my last test:
15 MPH 1332 RPM
%CO2 13.6, %O2 1.0, HC 125 PPM, CO% 0.17, NO 869 PPM
25 MPH 1370 RPM
%CO2 13.7, %O2 0.5, HC 150 PPM, CO% 0.76, NO 530 PPM
I seem to recall someone, perhaps Roger Bywater, telling us the engine would likely pass California emissions tests without cats. However, they do a visual as part of the test so they have to be there. I believe some here have gutted them.
BTW, California emission law originally said cars over 25 years old did not have to be tested. A few months before my car reached that age they changed it to say cars made before 1976 didn not have to be tested… so I’m a lifer 
every 2 years I have to have it tested. I don’t mind, though, because if it doesn’t pass I know something’s wrong and I want to fix it.
Hope this helps
Ed Sowell
'76 XJ-S
Ed
The CO% has to be less than 0.2% 2500 to 3000 rpm fast idle, and less than 0.3% 450 to 1500rpm idle to pass the test
Do you think this is achievable with my Pre he fitted with cats?
Peter
Peter,
Probably. All I know for sure is what my car measures. Calif no longer does a idle speed, but if you look at my data you see CO% is 0.17 at 1332 and 0.76 at 1370. If that trend continues it would be well below 0.2 at 750-800 RPM. I’m no expert though.
Why don’t you get in touch with AJ6 Engineering. Don’t know if Roger Bywater is still running the place, but if so he would know for sure. Probably someone else there could probably help you.
Ed
Hi Ed
I have just spoken to roger Bywater and he said a pre he with D jetronic fuel injection will not pass the new emission regulations, The way forward would be to fit a fuel injection set up from the he engine and have the ECU programed to suit the pre he engine
Two more questions did the cats fitted to your pre he engine exhaust system come as a standard fitting and do you have D jetronic fuel injection?
Thanks
Peter
Glad to hear you got in touch with Bywater. AJ6 tested & adjusted my ECU several years ago and Roger has given me lots of good advice over the years.
To my knowledge, the cats and D-jet were fitted to all XJ-S preHEs in the US market, which includes mine.
Ed
I don’t think the exhaust systems are significantly different between pre-H.E. and H.E., so you could pick up a set of downpipes from an H.E. in a junkyard and bolt them on.
I suspect the reason Bywater says you need to move to the H.E. EFI is to get the feedback function, which means you’ll also need to fit oxygen sensors. Fortunately, the H.E. downpipes have those, too. I recommend you go with 3-wire sensors so they will work at idle.