Author Topic: Hi Rev Misfire as in past 6k  (Read 22625 times)

Offline Tony C

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Hi Rev Misfire as in past 6k
« on: August 27, 2008, 04:49:56 pm »
Just after some help,
as you know was on the rollers with the v8 the weekend and we hit max revs of about 6.5k
came home and played with the .msq turned one of the values over in the h2 table etc and loaded the .msq up,
took for run today and it wont rev past 6.3k it sits and missfires just like it has got a rev limiter,
if you sit stationary and floor it it does the same thing with foot to the floor and it wont go past 6.3k just sits there bouncing on the rev counter if its got a limiter.
i have taken a datalog and the present .msq, i tried it with als on and off and made no difference, also uploaded an old .msq that had the h2 value blank as per the weekend which also makes no difference, other wise the car revs to this point no problem.

http://www.v8forum.co.uk/zip/latest.zip
« Last Edit: August 27, 2008, 04:51:57 pm by Tony C »

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Offline rob@vems.co.uk

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Re: Hi Rev Misfire as in past 6k
« Reply #1 on: August 27, 2008, 08:42:58 pm »
Looking at 3350.428s It looks like the throttle is coming up and consequently the fuel cuts, can you hold it at 6300 for a while so we can see what's happening?

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #2 on: August 27, 2008, 08:58:02 pm »
i'll try tomorrow mate,
not to keen holding it at them revs with it bouncing on the revs.
how long you need it sat there for a reading?
thanks for the help, as its got me puzzled.

Vems Ecu, Twin Plenum efi and N2o
13.314 @ 104.39 mph (10/06/07 3.9 v8)
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Offline Denmark

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Re: Hi Rev Misfire as in past 6k
« Reply #3 on: August 27, 2008, 09:03:02 pm »
It´s not the same problem as i had?

The launch control rpm limit was the fault, even though it was disabled, so try to raise that limit!

I just wrote 25500rpm, then the rpm limit was gone :)


/Skassa
working on the boxer

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #4 on: August 27, 2008, 09:10:09 pm »
could something i changed be upsetting the fuel pump?
as thats on a different channel,
one of the ignition outputs if im correct,
just seems a bit suspect i changed a h2 setting now this is happening, the one that was blank was 2 bit 0-2 others all said Ign in drop down, and from 0 bit 7 to 7 bit 7 were all set at 0
couls this be something causing it?

Vems Ecu, Twin Plenum efi and N2o
13.314 @ 104.39 mph (10/06/07 3.9 v8)
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Vems Firmware: V1.1.74

Offline rob@vems.co.uk

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Re: Hi Rev Misfire as in past 6k
« Reply #5 on: August 27, 2008, 10:20:01 pm »
If the fuel pump was switching off you'd get a leaning out of the lambda, the lambda is pretty flat, all be it rich.

Rob

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #6 on: August 27, 2008, 10:25:32 pm »
cool so can rule that out :D

Vems Ecu, Twin Plenum efi and N2o
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Offline MWfire

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Re: Hi Rev Misfire as in past 6k
« Reply #7 on: August 28, 2008, 01:24:08 pm »
Check anti lag system(als) if is disabled.

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #8 on: August 28, 2008, 01:29:13 pm »
well did another datalog and held it to the floor for a while so you could get a reading, but at a cost,
the fan belt snapped and she overheated big time and split a rad hose,
so fingers crossed we can find the problem now as need to order a top hose, you can see on the log where it broke battery voltage drops to 11.

http://www.v8forum.co.uk/zip/newdatalog.zip

Vems Ecu, Twin Plenum efi and N2o
13.314 @ 104.39 mph (10/06/07 3.9 v8)
Sponsored by: www.caprisport.com & www.interpart.biz
Web site: http://www.capriracing.co.uk

Vems Firmware: V1.1.74

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #9 on: August 28, 2008, 09:40:46 pm »
im going away in the morning for 4 days,
so if any one needs me regarding this problem, stuball and Rob have my number,

I also bought new plugs, rotor arm and cap today, to try and help eliminate things,
along with the radiator, fanbelt and radiator hose :(

not had chance to test yet as the radiator is on order with the hose,
« Last Edit: August 28, 2008, 09:42:17 pm by Tony C »

Vems Ecu, Twin Plenum efi and N2o
13.314 @ 104.39 mph (10/06/07 3.9 v8)
Sponsored by: www.caprisport.com & www.interpart.biz
Web site: http://www.capriracing.co.uk

Vems Firmware: V1.1.74

Offline rob@vems.co.uk

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Re: Hi Rev Misfire as in past 6k
« Reply #10 on: August 28, 2008, 10:07:33 pm »


Can you pull some of that fuel out? Its extremely rich: 0.7 is possibly on the verge of rich missfire - if the sensor is reading it correctly, it might be a little richer than that...

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #11 on: August 28, 2008, 10:13:30 pm »
i'll take some out when i come back off my hols mate,
I gather the log showed nowt else then other than rich at that point?

Vems Ecu, Twin Plenum efi and N2o
13.314 @ 104.39 mph (10/06/07 3.9 v8)
Sponsored by: www.caprisport.com & www.interpart.biz
Web site: http://www.capriracing.co.uk

Vems Firmware: V1.1.74

Offline MWfire

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Re: Hi Rev Misfire as in past 6k
« Reply #12 on: August 28, 2008, 10:51:19 pm »
Your map readings are strange(unstable). Try to add 2-3m of hose between map sensor and plenum.
And when you have missfires lamda doesn't read(it's frozen).

Offline Tony C

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Re: Hi Rev Misfire as in past 6k
« Reply #13 on: August 28, 2008, 11:23:52 pm »
Your map readings are strange(unstable). Try to add 2-3m of hose between map sensor and plenum.
And when you have missfires lamda doesn't read(it's frozen).


in total? or add an extra 2-3m of hose to whats already there ???

Vems Ecu, Twin Plenum efi and N2o
13.314 @ 104.39 mph (10/06/07 3.9 v8)
Sponsored by: www.caprisport.com & www.interpart.biz
Web site: http://www.capriracing.co.uk

Vems Firmware: V1.1.74

Offline MWfire

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Re: Hi Rev Misfire as in past 6k
« Reply #14 on: August 28, 2008, 11:25:49 pm »
add extra 2-3m hose.