Aeb auto tune just going rich

[minimutly]

Yes I understand now how the gas map is a multiplier for the petrol map. The reason for the 23ms is that the petrol numbers are up there. The reason the map numbers climb is that the lambda display shows weak - I have a barograph display hooked onto the lambda sensor. It's a reasonable way to keep an eye on the mixture, one thing the aeb map page doesn't have.
It was difficult to watch the gas pressure on all loads, and it may be that the pressure is dropping off at the top end - I noticed the liquid feed pipe is 6mm coated copper, which feels a bit small for 180bhp.
I'm also trying to get my head around the relative/linear/percentage options, and if I change these, can I globally change this setting without altering the map, just the map display.
Huw

[classicswede]

The map and leaning out at the top end sounds and looks like the MAP referance pipe has not been connected to the reducer.

[minimutly]

Yes agree, it looks that way, or the reducer isn't holding pressure.
I've had a play with the map corrections, and now understand the absolute/linear/%age thing.
I have some new checks to run on the pressure side of things, then if I still can't get enough gas in on full power I'll look at new injectors.
Oh, the petrol ecu is std as far as I know.
Thanks,
Huw

[minimutly]

I've not had hold of this car to do anything with, was in Cardiff for the rugby at the weekend..
I've had a chance to think about the pressure thing. with petrol if the pressure is lower, the injection volume is reduced because the flow rate is lower. With gas, I guess the flow and hence the volume will be reduced but since it's a gas and compressible this has added effect.
So, I will recheck the pressure, ensure the ecu is set to the idle pressure, and that it holds on full throttle and boost. If pressure is not stable, how much variation should be allowed? Bearing in mind it should actually go up on boost?
Anyone have an opinion on the 6mm liquid pipe?
I feel almost there with this, if it was mine I'd put a tankful or two of petrol through it to see what the lambda says on part load, but apparently it's driving quite well on gas.
Will report back again.
Huw

[classicswede]

The displayed pressure should read close to constant regardless of manifold pressure as the reading is differential rather than absolute

[LPGC]

What do the gas pressure reading and map reading show under load / boost conditions? The reducer is connected to manifold vacuum? Is the reducer vac reference T'd to the map sensor vac reference?

[minimutly]

If the reducer is referenced to the manifold (I'll check, but would expect it is), then how can ithe pressure be constant, it will vary according to vacuum and boost surely? The gas system map sensor should be teed in to this signal, also need to check if this is the right one for boost applications I guess? There is a selection to make aeb025 rings a bell.
Will check,
Huw

[Gilbertd]

If the reducer is referenced to the manifold (I'll check, but would expect it is), then how can ithe pressure be constant, it will vary according to vacuum and boost surely?

No it shouldn't vary at all. It is referenced to the manifold pressure so if it is set at 1.2 bar say, it will, or should, always be 1.2 bar above whatever pressure is in the manifold. Think about it, if you had the reducer pressure set at 1.2 bar absolute (with reference to atmospheric) but under boost you had 3 bar in the manifold, no gas would come out of the injectors, it would get blown back towards the reducer as soon as the injectors opened.

[minimutly]

Oohkay, so the pressure varies, but will be constant wrt manifold pressure. So the aeb display reads relative to this pressure?
So as I open the throttle, the manifold pressure display shows an increase, but the gas pressure shouldn't change at all?
I seem to recall it does move around, not sure how much though.
I'm expecting to be getting close to the original problem with this, that is rich on gas, well at light loads anyway, I never checked full load. The map I sucked out of the ecu was 255 all over it - probably to try to fix the weak on boost issue, but considering it had done 70k on gas, it wouldn't have been like this from new.
Huw