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Engine only runs on cranking
Posted: Sat Jan 29, 2011 5:00 am
by julian
Hi, i've recently installed microsquirt to my mk2 scirocco 2L 16v, all wired up ok me and a friend managed to get it to splutter and try and fire up when cranking it over but as soon as it goes above its 300rpm cranking speed its not fireing fuel, asif its not using the fuel map.
We altered the cranking speed to 3000rpm so that it would start up using the priming/starting fuel pulses and it runs, bit rough though!
Im completely baffled on why it doesn't seem to want to enter the fuel map.
hope i've explained this alright, my friend knows more than i do.
cheers
Julian
Re: Engine only runs on cranking
Posted: Sat Jan 29, 2011 12:20 pm
by Bernard Fife
julian,
Lots of things could cause this. You need to post a datalog (see:
http://www.megamanual.com/mt28.htm#f for how to do this) of a starting attempt and you settings (an MSQ file) before we can comment.
Lance.
Re: Engine only runs on cranking
Posted: Mon Jan 31, 2011 1:46 pm
by julian
Here's a datalog of an attempted start.
Re: Engine only runs on cranking
Posted: Tue Feb 01, 2011 12:00 pm
by Bernard Fife
julian,
It looks like your MAP sensor might not be connected. I say this because the MAP value is very high in the datalog (200+) and steadily climbing. These are the classic symptoms of an ADC channel left open.
Lance.
Re: Engine only runs on cranking
Posted: Tue Feb 01, 2011 3:00 pm
by julian
Cheers, we'll try this, any ideas on how to sort the MAP sensor issue, when i'm only running TPS?
Also any other ideas if that doesn't solve the issue.
Re: Engine only runs on cranking
Posted: Tue Feb 01, 2011 6:48 pm
by dontz125
If you have no MAP sensor, then make sure you have no 'Barometric Correction' or any other such factors selected. You're not doing anything mad like running Speed / Density with no MAP sensor, are you?
If you post your .msq file, we could have a look...
Re: Engine only runs on cranking
Posted: Wed Feb 02, 2011 2:09 pm
by julian
I don't run a map sensor, just a throttle position pot, could you confirm which settings I should be running for ALPHA N please?
Attached is the .msq file of the current map/set up.
EDIT: just noticed there are values in the barometric correction.
Re: Engine only runs on cranking
Posted: Sat Feb 05, 2011 6:13 am
by julian
Anyone had the chance to view the files i've posted up?
cheers
J
Re: Engine only runs on cranking
Posted: Sun Feb 06, 2011 8:55 am
by grippo
Your msq shows you have selected Pure AlphaN mode, which is correct for no MAP sensor.
Your engine dies after cranking for probably one of 2 reasons - it is losing ignition synch or the fuel mix is off. From your datalog, it looks like ignition synch is ok. But you are never getting over 100 rpm. It stays at 100 rpm but won't go higher, so it seems like either it's flooded or there is no spark. It doesn't enter the fuel table because it's in cranking mode, and the fuel PW in cranking is a fixed number depending on the coolant temperature - which is pretty cold. Your PW of 9.4 looks reasonable.
Are you sure you are getting spark while cranking ? Are the plugs gas soaked ? If you have a datalog of when it gets past cranking and starts firing and dies, show us that.
Re: Engine only runs on cranking
Posted: Sat Mar 12, 2011 10:45 am
by julian
Here's an attempted start, it did fire up, but then cut out after it goes past the 300rpm in "fuel set-up", "other fuel settings".
I changed the 300rpm to 3000rpm and it starts and runs, ish. But this datalog file is when its set to 300rpm as it should
I also changed the barometric settings to zero and this made no difference.
So any ideas where i'm going wrong!?
cheers