EZ EFI New Tune every time engine is started.

[lim34]

Oh Dear !!!!! Spoke too soon.

Took the car out today for a 100 mile round trip.

Started fine but rough running till warmed up. Motorway running at 70-80mph all ok.

Stopped for about 1hr after 50 miles. Car started, but would not idle and stalled if tried to drive. Checked fuel pressure as set.

I reset ECU to base tune again. Car started and will idle staight away. Checked fuel pressure ( 40psi ) and IAC ( 18-20 ).

Drove back home another 50 miles at same speeds. Pulled into garage, all ok on idle and settings. This is a strange problem which keeps reoccuring.

Tomorrow i'm going to check the wiring throughly for and default connections.

Any advice again will be helpfull.

Cheers Ian

[Webby]

Now this is similar to what I am getting.
New tune no problem. Then as distance goes by things change. Engine still idles but hunts badly and will not rev cleanly from idle.
It is possible that something in the set targets is wrong and as the unit tunes into that idle target things go wrong. Ie it is possible that the target is wrong. or that the o2 sensor is picking up false info due to air leaks in exhaust manifold maybe and then tuning to that.
It is difficult to believe that something else is causing it when it runs good with new tune.
When it runs good what is actual afr at idle with warm engine? Is it any different when running bad?
Will check this on my engine when it is running again in a few days.

[FAST Tech Maxwell]

Maybe you should try to note what the A/F ratio is when the engine is "happy", and then make that your AF Target at idle.

It sounds like the engine is not happy once it actually learns the programmed target. The base tune usually starts out on the rich side, so maybe the engine wants a richer A/F ratio at idle.

[lim34]

Ok, checked the wiring...all ok. No loss of Ohms between battery connections in boot to ECU under dash.

Have throughly checked for no exhaust leaks, or air leaks.

AF was 13.3 at 850rpm when warmed up and 'Happy'.

AF when running bad was between 11.5 and 12.5.

I have programmed the AF to 13.3 on the handheld unit.

When resetting to base tune it runs well. What would be the AF target be at that stage, and if i did make it to run richer at idle whats the best to Up or Down the setting.

Ian

[Webby]

I think idle A/f target after reset is 13.5. but what does it actually run at? this is on another page.
From what you say the engine is running bad when the mixture is richer. When you see these rich mixtures what is the target A/F mixture?
If it runs richer than target when it has done some learning then why?
According to Matt and I would agree the mixture would tend to be richer than target straight after a reset and nearer to target after some learning has been done.
You seem to have the opposite. I will have mine running again in a couple of days so can do similar observations.

[lim34]

Thanks Webby.

Ian

[lim34]

Matt, should i try takeing the idle AF down to 12.0 to make it run richer.

Ian

[FAST Tech Maxwell]

Try not to get too hung on the number. Just get it to where it runs the best.

I would move in increments of .2 then let the engine run for several minutes or take a short drive and see how it does.

When cold, the air/fuel target changes based on coolant temp and your commanded idle AF target.
You will have to actually look at the AF number in Live Data, not just the bar graphs that go side to side. Just jot the numbers down. You should be able to watch the AF and see when the engine starts to surge or "run bad" or whatever it does.

[lim34]

Cheers Matt.

I'll do that tomorrow with a run, adjusting and taking note of readings.

Ian

[Webby]

I should be able to do the same as car now back on road.
I started her up tonight and tried a/f from 12.0 to 14.5 at idle and got no change.
Idling ok but hunting up and down from 800 to 1000 all the time.