Leaning out on change
Turbo Mini Forums

Been doing some running in/tuning of the van. We are finding that on changing up at med/high revs that jumping back on the throttle the wideband jumps lean and we get a brief missfire.

Could this be too strong a spring? we have a standard turbo one in there and an additional red spring as we thought it was too light to start with. however it may have been down to the lack of oil.

Any thoughts? I'm reckoning whip the second spring out and give it a try.

If something is worth doing, it's worth doing half of.

i would start off by removing the spring then if its no better start experimenting with some different weight oils.

what oil are you using in the dashpot atm?

Is adding another spring a common thing? or is that how Turbo HIF's are?

Lack of oil?

If you mean in the dashpot, this would be the first thing to do.

In the 13's at last!.. Just

adding another spring will keep the mixture richer for longer when planting you foot down, much the same as a thinker oil will.. until the needle catches up

but really i guess its just a fine tune once you have the needle where you want it.

Will have another sesh on saturday then.

Second spring out first, experiment with oil. got some 15/40 in there at the moment. I have some SU oil at home and some 20/50 so can try all these.

Edited by John on 25th May, 2010.

If something is worth doing, it's worth doing half of.

Still goes bloody well though for 6psi

Do you have the part throttle lean off pipe connected? I know a lot of people are keeping this on for fuel economy, but I could never get my fueling right on transition from part to full throttle whilst it was connected.

Just an idea.

Edited by theoneeyedlizard on 25th May, 2010.

In the 13's at last!.. Just

It is connected. Fuelling etc was pretty good before the engine swap and on Sat after the new engine went in.

I'm putting my money on the extra spring being at fault.

i think the needle is either rising too fast or falling too slow, if the fuel is ok on a 2nd gear pull from say 1.5-2krpm up to redline, id say its not falling fast enough

had another think over this, is the piston sticking?

Edited by Brett on 26th May, 2010.

Yes i moved to the darkside

Instagram @jdm_brett

Which would indicate sprint too weak or oil too thick?
So removing the second spring would make things worse?

Just keep your foot to the floor, problem solved :)

no, keep your foot to the floor when you change up :)