Author Topic: So sparks in the right place but wont run.  (Read 24823 times)

Offline Agriv8

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Re: So sparks in the right place but wont run.
« Reply #15 on: April 22, 2007, 03:29:33 pm »
couldnt work out how to post a file so emailed my log to ROb and dnb

thanks

Agriv8
'The older I get the faster I was'

Offline rob@vems.co.uk

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Re: So sparks in the right place but wont run.
« Reply #16 on: April 22, 2007, 07:32:12 pm »
Looks frightenigly lean to me 1.1 to 1.2 all the time!

Richen it up by increasing Req_fuel but a milisecond or so.

Offline dnb

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Re: So sparks in the right place but wont run.
« Reply #17 on: April 22, 2007, 10:29:55 pm »
Agree - It's very lean.  Increase the reqfuel with the aim of making it rich.  Then set the lambda correction to allow it to lean the mixture out to the target.  (Lambda control in VEMS works best this way)

Offline Agriv8

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Re: So sparks in the right place but wont run.
« Reply #18 on: April 22, 2007, 11:50:09 pm »
thanks chaps, will double check lambda calibrations agian ( as I have been swapping maps and generally pratting about ) if Lambda still calibrated Ill richener her up a little. and then let vems lean her up from watching the Lambda

My only worry is that if I richen her up that will mean more backfiring ? ( possibly running so lean that there isnt enough fuel for the spark to get hold maybe ) it already sounds like a rally car where they dump fuel down the exhausts to keep the tubo spooled up.

will try and play more tomorow but having further laptop trouble.

Thanks once again

Agriv8

'The older I get the faster I was'

Offline rob@vems.co.uk

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Re: So sparks in the right place but wont run.
« Reply #19 on: April 23, 2007, 08:14:56 am »
You have perfect lambda on idle, it just seems that your fuel map is too lean everywhere else.

Do you have the 30v transient voltage suppression diode in your flyback line?  If you haven't then you'll find that doing so will really help flatten out your VE table with the Speed Density fueling.

Don't forget, lean mixtures burn slowly, when you are too lean on start-up you get back fires as the mix is still burning when the inlet valve opens and ignites the incoming charge.

Rob

Offline Agriv8

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Re: So sparks in the right place but wont run.
« Reply #20 on: April 23, 2007, 09:10:19 am »
No Diode fitted ( maplin dont appear to sell them unless they call them somthing diferent ).

regards

Agriv8
'The older I get the faster I was'

Offline dnb

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Re: So sparks in the right place but wont run.
« Reply #21 on: April 23, 2007, 09:23:10 am »
You're right - I couldn't find them on Maplin's website either.

The transient diode was the best tuning I did to the TVR.  Suddenly the fuelling became sensible.

Offline rob@vems.co.uk

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Re: So sparks in the right place but wont run.
« Reply #22 on: April 23, 2007, 10:12:22 am »
I have a few knocking about at home.  Fire me an email and I'll dig one out.
No email = me not remembering :)

Offline cliffb75

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Re: So sparks in the right place but wont run.
« Reply #23 on: April 23, 2007, 12:47:22 pm »

My only worry is that if I richen her up that will mean more backfiring ? ( possibly running so lean that there isnt enough fuel for the spark to get hold maybe ) it already sounds like a rally car where they dump fuel down the exhausts to keep the tubo spooled up.

Agriv8


By the sound of it, in your case its being lean thats causing the backfiring - as you say its not igniting properly in the chamber, so it ends up getting burned in the exhasut.

Anti-lag is not the same at all, plus there is the influence of rev limiters in the sounds you see on TV.

Have you got the closed loop turned on eveywhere? if it is on, and you are still 20% lean you need to ad A LOT of fuel to the base value...........

Offline dnb

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Re: So sparks in the right place but wont run.
« Reply #24 on: April 23, 2007, 02:16:06 pm »
If you're using anything based on my base map, then it will never richen the mixture by more than 5% or 10% (IIRC) this is to stop run-away richening the mixture on misfires.  Again, if the map is based on mine then lambda correction operates all the time except beyond 90% throttle.

As Cliff says - add a LOT of fuel, as my settings will let the correction lean things out by at least 20%   

Offline Agriv8

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Re: So sparks in the right place but wont run.
« Reply #25 on: April 23, 2007, 02:53:45 pm »
Was half way typing a response when you posted that up ( it would explain why the fuelling is so far out ).

suspect that My settings are not allowing the lambda to lean thing off ( or not lean it off enough anway  ) where do i start looking for these setting then.

Regards

Agriv8

'The older I get the faster I was'

Offline rob@vems.co.uk

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Re: So sparks in the right place but wont run.
« Reply #26 on: April 23, 2007, 03:28:11 pm »
You want to richen it up, lean it off any more and you'll be running on fresh air!

before you use the EGO sticking plaster get more fuel in.

Offline dnb

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Re: So sparks in the right place but wont run.
« Reply #27 on: April 23, 2007, 03:30:44 pm »
suspect that My settings are not allowing the lambda to lean thing off ( or not lean it off enough anway  ) where do i start looking for these setting then

You're already running VERY lean, so there's probably nothing wrong with the EGO (wideband) settings at all.  You just have Req_fuel far too small. 

As Rob says, any leaner and there won't be any petrol in there!