Engine starting issue

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dr_jones
Posts: 162
Joined: Wed Jun 08, 2016 3:24 pm

Engine starting issue

Post by dr_jones »

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!
sicup2
Posts: 16
Joined: Thu May 29, 2014 6:58 am

Re: Engine starting issue

Post by sicup2 »

Could you revert to the old map with incorrect map sensor calibration to confirm whether the IAC valve is your problem or not?
dr_jones
Posts: 162
Joined: Wed Jun 08, 2016 3:24 pm

Re: Engine starting issue

Post by dr_jones »

Good idea - I should have a cal of the same firmware revision that I could quickly pop on there to see. Cheers.
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