Engine starting issue
Posted: Thu Jan 04, 2018 3:21 pm
Bit of a head scratcher this one - and probably more a general ecu calibration thing than syvecs specific:
Some time back I re calibrated the linearization of my map sensor - I had an old an incorrect linearization the syvecs was reading slightly out.
That meant I needed to re-work a fair bit of my fuelling map which is where this particular issue started:
On first key turn the engine fires up - overshoots slightly target rpm (1400) then dies.
Immediately after and so on second key start it fires up perfectly and drops straight into a stable high idle (1400) tapering down to target 1100 rpm exactly as it should.
Does anyone have any ideas why I get that initial overshoot and then engine stop which I then don't see again immediately after?
I'm actually starting to wonder if my IAC valve is sticking/misbehaving) rather that this being a calibration issue but it seems mighty fishy the issue began at the point I corrected the map sensor linearization,
Whats making this hard/slow to troubleshoot is the issue only happens once and then vanishes until some time (hours) later - I'd really appreciate any thoughts anyone has on this!
Some time back I re calibrated the linearization of my map sensor - I had an old an incorrect linearization the syvecs was reading slightly out.
That meant I needed to re-work a fair bit of my fuelling map which is where this particular issue started:
On first key turn the engine fires up - overshoots slightly target rpm (1400) then dies.
Immediately after and so on second key start it fires up perfectly and drops straight into a stable high idle (1400) tapering down to target 1100 rpm exactly as it should.
Does anyone have any ideas why I get that initial overshoot and then engine stop which I then don't see again immediately after?
I'm actually starting to wonder if my IAC valve is sticking/misbehaving) rather that this being a calibration issue but it seems mighty fishy the issue began at the point I corrected the map sensor linearization,
Whats making this hard/slow to troubleshoot is the issue only happens once and then vanishes until some time (hours) later - I'd really appreciate any thoughts anyone has on this!