Page 1 of 2
Not sure where to put this post LOL!!
Posted: Sun May 04, 2014 8:09 pm
by Coops
Need a bit of advice,
standing start acceleration perfect up through the gears without missing a beat,
BUT if you cruise then go WOT the car takes off then holds back a bit then goes again as if it has a power band,
tried it at different fuel pressures etc and makes no difference,
and at different RPM's going Wot and does the same every time,
any ideas,
took my daughters boyfriend out today and he said its like when the VTEC cuts in on a Honda etc,
Posted: Sun May 04, 2014 9:38 pm
by mgbv8
What do your afr and boost logs say when this happens??
Sounds like it may be a timing issue??
Posted: Sun May 04, 2014 10:20 pm
by Coops
will get her out tomorrow and do another run,
didn't have the lappy with me today,
Posted: Mon May 05, 2014 6:56 am
by Quagmire
Acceleration enrichment? Too much/ too little?
Posted: Mon May 05, 2014 8:31 am
by DaveEFI
Assuming you have a wideband O2 sensor, a log should show what is happening.
Posted: Mon May 05, 2014 10:32 am
by Coops
I'm off. Out in the car in a bit so will get a log
Posted: Mon May 05, 2014 12:59 pm
by stevieturbo
More than likely a fuelling issue.
it' as easy to give them too much accel enrichment as it is too little.
If you can turn accel enrichment off, or all to zero you should be able to get it fairly decent via the main mapping alone, other than for very sudden changes.
( will be worst at lower rpm's )
After that feels decent, then you can start adding fuel via accel enrichment to smooth things out.
Ignore AFR's for the most part as you can end up chasing your tail. Start from zero, then work up.
Above 3-4000rpm very very little should be needed
Posted: Mon May 05, 2014 1:18 pm
by Coops
Didn't get a log done today as laptop said no
Will try later this week
Posted: Mon May 05, 2014 3:53 pm
by Coops
just did a run up the road,
and looking at the log when on WOT the spark advance climbs then drops off to 7 then rises again,
any ideas?
Posted: Mon May 05, 2014 4:06 pm
by stevieturbo
upload the log
Posted: Mon May 05, 2014 5:25 pm
by Coops
whats the best site to store files on
Posted: Mon May 05, 2014 5:28 pm
by stevieturbo
havent a clue, email it then lol
think i used this one before
https://www.sendspace.com/
Posted: Mon May 05, 2014 6:01 pm
by Coops
Posted: Mon May 05, 2014 7:03 pm
by Coops
mmm its detecting knock I think if im reading the datalog correctly,
never done it before it then clears and goes ok
ignition goes from 15.3 then drops off to 7 for a bit then goes back to 15.3
Posted: Mon May 05, 2014 9:15 pm
by stevieturbo
It's not a case of detecting knock.
It may be knock, it maybe noise. You'll need to manually calibrate the knock sensor input/thresholds so that it it's operation is correct
But yes it does look like knock control is pulling timing.
The fact it's relatively low boost, and only around 15deg of timing.
I really doubt there is any detonation at all. Even if you were very high compression, I'd say it would still be safe with such low timing.
Havent looked at the actual map as dont have any MS software on my computer. But you could be running a lot more timing there, and it will perform a lot better for it.
Mixtures probably ok for low boost, but I'd maybe like a little more fuel in there.
if you have a means of logging every time you drive, it really is worth doing. Logging is such a valuable tool !