Car dies after foot off accelerator

jsmcortina · Post by **jsmcortina** » Tue May 23, 2006 2:38 pm

Could you re-scale your rpm so it shows x100 not x1 and turn on PW on the log - the few variables you have plotted aren't enough to see what is happening.
Or better, post the actual logfile here.

James

arnold · Post by **arnold** » Wed May 24, 2006 11:59 am

sure, here it comes

jsmcortina · Post by **jsmcortina** » Wed May 24, 2006 12:36 pm

I _think_ you need to add a chunk more fuel into the low rpm medium/high map areas. As the rpms drop the pulse widths drop and the wideband goes way too weak. Increase all of the bins around say 500-1000rpm and 60-100kpa by maybe 20% ?

See around 103 seconds in the log, the revs drop and the mixture goes weak.
I still do not understand why you get so much MAP with the throttle shut - that really is not right.

Can you open the throttle stop to bring the revs up a bit? It looks really sick down around 500rpm. Maybe aim for a 1000rpm idle to start with and reduce later if you can.

James

arnold · Post by **arnold** » Wed May 24, 2006 1:58 pm

jsmcortina wrote:I _think_ you need to add a chunk more fuel into the low rpm medium/high map areas. As the rpms drop the pulse widths drop and the wideband goes way too weak. Increase all of the bins around say 500-1000rpm and 60-100kpa by maybe 20% ?
James

OK, I will

See around 103 seconds in the log, the revs drop and the mixture goes weak.

jsmcortina wrote: I still do not understand why you get so much MAP with the throttle shut - that really is not right.
James

You mean the MAP reading at idle are too high? I mentioned it is a forced induction application? Anyway I can pretty easily connect the MAP somewhere else to see if that changes any.

Also: I am pretty sure that damping the closure of the throttle will help, as I close it slowly no problem! But when I do it quicly the RPM's fall back into cranking mode and the it very hard to get it out (throttle open and close trying to rev it again)

jsmcortina wrote: Can you open the throttle stop to bring the revs up a bit? It looks really sick down around 500rpm. Maybe aim for a 1000rpm idle to start with and reduce later if you can.

James

It is idling at 1100 rpm's

jsmcortina · Post by **jsmcortina** » Wed May 24, 2006 4:08 pm

The "dropping back to cranking" is fixed in the MS1/Extra code. Once you are out of cranking mode for more than a second you always use the VE table, it never returns to cranking mode until you reset.

James

mops · Post by **mops** » Wed May 24, 2006 7:52 pm

i run into similar problem myself. allowing more idle air/less idle fuel and timing I managed to keep reasonable idle and reduct the 'dying' issue. As well some timing incerase around idle rpm and lower than idle map to make recovery 'stronger'

Mine was happening as the enigne was running slower and slower until it past idle and instead of recover to idle speed died....

arnold · Post by **arnold** » Thu May 25, 2006 12:41 pm

small update: I increased the decel enrichment to 125% and I moved the MAP connection to the manifold for sure now. The The decel enrichment helped a bit, the idle seems to recover a bit better, but not good enough yet.

I also found an vacuum leak, which I think is teh main cause, I will repair it this weekend and post a new log soon after

arnold · Post by **arnold** » Sun May 28, 2006 11:10 am

Ok, I repaired the vacuum leak, I increased the decel enrichment to 150%! Still the rpm's fall back, sometimes too far sothat the engine is back in cranking, ASE with all side effect of that. Anyway I attach the latest log file and VE table, please have a look....

jsmcortina · Post by **jsmcortina** » Sun May 28, 2006 11:14 am

arnold wrote:Still the rpm's fall back, sometimes too far sothat the engine is back in cranking, ASE with all side effect of that.

The MS1/Extra code doesn't suffer from this.

Where in the UK are you?

James

arnold · Post by **arnold** » Sun May 28, 2006 11:53 am

Hi James

I am in the Netherlands, you told me about the extra code. I am a bit afraid to change the code, never done and all the extra parameters to fill in scare me a bit.

Anyway, f there is no other way I upgrade the code