CO Readings and venturis - again

[Dan6457]

Hi there,

I'm starting to think there should be a separate forum section for venturi problems :roll:

Right then, today I took my car for its Mot. The emissions came out as 4% but should be 2%. No problem I thought, just lean it off with the screw. A little tweak and it wont idle properly, it keeps going up and down, up and down, so set it back to where it runs nicely, but of course with CO too high.

I then dug out the MOT from last year and looked at the readings, 1.6% CO.... pretty much perfect. Since last year the venturi was changed over (at eurotec actually) to a volvo one with the correct partnumber to match up to the volvo fuel distributor already on there. I'm tempted to put the old one back on, but technically that would be the wrong one :?

Anyone have any ideas?

Thanks.

[Dan6457]

I have just noticed something else. If you give it full throttle from idle, it hesitates slightly for a second. If you bring the revs up slowly its fine. Is this related or something else?

At eurotec, NickT pressure tested it, and the primary pressure was correct for a Delorean, but could it need to be increased to 'volvo spec' now its got the larger venturi?

If no one has any ideas I think I'll put the standard venturi back on it, but the standard one is technically the wrong one for the fuel dizzy.

[NickT]

I have put my K-Jetronic Info here:

viewtopic.php?f=22&t=2472

NickT

[Chris Williams]

If it helps sometime we can compare part numbers and set up as ours should be pretty much identical. I tested mine with the aid of Nick's meter and it was spot on 2%
perhaps its got something to do with the way the vacume pipes were set up? I remember Nick telling me how to do this as it's different from a D set up.
Chris

[Dan6457]

Nick checked my vacuum pipes at eurotec and they were fine.

[Guinney1971]

since RichH sorted out my vacuum plumbing ( ) and gave the car a tweak,
Flopsy has been a revelation and is now averaging 25mpg, which is fantastic compared
to the usual 17mpg.

Might want the timing doing though, as she does backfire a bit now coming off the throttle -
have checked the 'bung' is in the adjustment hole ok - so can only think the timing might be
out slightly, but will have to wait until RichH is free one day as he's got a timing light.

I'm even using Flopsy for work today!

[Dan6457]

Thats great Glad to here its running well now.

[NickT]

Claire Usher Wrote:since RichH sorted out my vacuum plumbing ( ) and gave the car a tweak,
Flopsy has been a revelation and is now averaging 25mpg, which is fantastic compared
to the usual 17mpg.

Might want the timing doing though, as she does backfire a bit now coming off the throttle -
have checked the 'bung' is in the adjustment hole ok - so can only think the timing might be
out slightly, but will have to wait until RichH is free one day as he's got a timing light.

I'm even using Flopsy for work today!

If your throttle plates don't have the poppet valves in then you will get this anyway !

NickT

[Guinney1971]

the throttle body has been changed on the car - is this the bit you're referring too?

[NickT]

Yes. I will dig out a diagram for you.

NickT

[Guinney1971]

ah right - perhaps a squirt of carb cleaner is in order?

[NickT]

If your throttle plates do not have the poppet valves on then they would probably need to be opened slightly to prevent too high a vacuum on the overrun.

NickT.

[Guinney1971]

okey dokey If I get time, I'll have a look at it this weekend.

Cheers dude!