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Blue4Ice

Overfuelling

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I ran freescan on the weekend and all seemed pretty normal apart from the BLM figure and spark advance

According to the manual, the BLM figure should be around 128. However mine sits at around 95 which means its overfuelling quite a bit. Any ideas what could be causing this?

Also the manual has a figure of spark advance 75 which I think is wrong as the on screen guage only goes to 60 lol but the screen shot of I assume Dermot's Esprit shouws around 11-12 where as I went to as low as 8 on idle. Again any ideas?

Everything else seemed fine and all other parameters within spec. I didn't manage to record any on the road data as my laptop battery is knackered an I haven't got around to getting a new one yet.

Any advice would be most appreciated :o

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iirc a blm of less than 128 is showing the self learning bit is actually swaying towards lean coz its compensating for a slightly rich mix. maybe your decatted or have a sports exhaust? compared to its base tables. this should happen with chip upgrades etc, so I'm told. 80 or 90 is ok AFAIK.

like it shows in the manual, i'm sure the spark advance shows 75 on mine too, when engine isint running.

mine goes from around 8 or ten, right round to 47-48 at full chat. as i understand, its high like this when u do a ECU reset, then the knock sensor does it stuff, and the maximums are set slowly in the volatile bit of the ecu. when i reset mine, it is a totally different car to drive, miles nicer, then things slowly get backed off to stop prevent damage. if u reset the ecu quite a few times, u may notice as i have, that the car drives differently. it seems to depend on the fuel, the weather, the baro press or my "breaking" the ecu in driving style.

get the battery/or a power supply to plug the lappy in the car and get out on the road.

take a good look at what the injectors are doing on the log file. mine are woefully inadadquate, 16 m/s duty cycle on the primaries and 99% saturated on the secondaries. this may be dreadful fuel pressure related, or just cack Rochester Injector syndrome. a better fuel pump/new regulator could be my answer.

Edited by pitstoppete

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Thanks for the info pete. I am sure tha manual states that over 128 is lean and under is rich. I replaced the spark plugs for standard NGK items just before I ran freescan but the old one were slightly black and carbonated which usually shows a slight overfuelling issue. Does anyone know what I should check?

With regard to spark advance it looks like that mine could be ok, but will see further when conducting on the road tests

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Steven,

I will check but I think the spark section may be slightly misleading or even wrong in the manual. I will correct this for the next version.

BLM values below 128 is OK, some of my cells drop as low at 70. You have long term rich condition under come engine conditions so the ECU trims the fuel tables back.

Dermot

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Thanks for clearing it up Dermot it puts my mind to rest a bit. I have had the battery disconnected a recently and the ECU is proabbly still in its learning cycle.

By the way the manual is a god send! :D

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