new exhaust..now popping till warm

[ermie571]

Hiya folks,

bit of guidance required exhhere.

2.1DJ running LPG on carbs

brand new SS exhaust.....Shiney....

sounds and runs great when warm.....but warming up she's popping away back there....engine doesn't feel particularly rough, but maybe irratically losing a cylinder. Not doing this before new exhaust, but this could be coincidence

So --- am I looking at ignition fault or exhaust fault?

thanks

Em
xx

[waltraud]

If new exhaust could an air leak or I'll fitting joint slowing air in or out? But, if the stainless system is also a different design etc it could be possible that it has affected the lox tyre which- if popping back through exhaust- suggests a lean mixture so you could try. Adjusting the mixture slightly , only if no leaks etc though.

[Oldiebut goodie]

it has affected the lox tyre which-.

lox tyre???
What's one of them then?

[ermie571]

thanks all

lean on cold start.

ok....will check for leaks first....if clear, mixture it will be

Em
xx

[waltraud]

Lox tire is in fact Hackney dialect for mixture I believe.....

[ermie571]

ok folks, a little update, as I don't know what to do now

have been running it round last couple of days.

the popping is still occuring, but only when the engine is cold, and only under load. It will sit and idle fine. Is the under load bit a clue ....leads/plugs/dizzy on the way??

so, If I let it sit and idle a while, the popping is definitely less. The popping isn't so bad as to make the van jerky like a flat spot....

Where do I look for the air leak? In the exhaust itself? Why would it go away once the engine was warm?

It is running really well once warm, so could it be choke? I'm going to give it a go on petrol later....but she's a bugger on petrol anyway...so not expecting much change.

How do I change the position of the choke? Its doing what it should on the stepped cam for reducing revs, and as bove, the idle is fine.

thanks for any advice

Em
xx

[waltraud]

Have you had the mixture set? I suppose the dj must need more fuel/different mixture to the DG that your carb probably came off. Why don't you ask the people who did the LPG conversion?

[ermie571]

Hi Waltraud,

thanks for the thoughts - mixture been set as has been on there many years!

regards

Emma

[waltraud]

Ahh I see. You need my friend the cat in the hat.....or someone like steve at Gasure. Good luck. Tim

[kevtherev]

Is the piping a larger diameter Em?

[ermie571]

Hmmmm hadn't thought of that Kev.

However, if I drive it a little harder....and by this I mean keep it in gear longer before changing up, I am finding it difficult to tell between popping and the normal exhaust sound. Not had any backfiring. Its knocking slightly somewhere, so back to the fitters for adjustment next week.

Overall, very chuffed! Vwspeedshop exhaust. The only tiny weeny thing I am worried about is that I have had to change the oil filter for the polo one. I don't like changing from standard, but have searched and found no issues. (2.1 with oil cooler so exhaust doesn't fit unless you use a dumpy filter from a polo). But the website says this....so, fingers crossed I've done the right thing. More frequent oil changes??

Em
xx