Aspire ignition timing questions

[TominMO]

In my Haynes Festy/Aspire manual, the process for adjusting ignition timing in my Aspire involves grounding the TEN (PCM STI) pin in the Data Link Connector. No prob, I know how to do that and have done it several times to adjust idle speed.

But in my Chilton Aspire manual (for US and Canadian Aspire models), it does not mention grounding the pin for ignition timing, only for adjusting the idle speed.

Q1. So how necessary is it to adjust the "base timing", i.e. with the STI pin grounded?

Also, since installing the Dickmeyer B3 head with larger valves, more cam lift and port work, I notice that on my permanently-installed Innovate digital AFR meter it seems about one point leaner than usual, both at idle and while driving. I'm thinking this gen1 FI computer can't figure out how to compensate for the increased airflow, and so it just runs leaner. BTW, no codes are being thrown. Intake system is functional and completely stock, other than lower airbox breathing-improvement holes.

Q2. Can I compensate for this by adjusting ignition timing a bit, since this would affect burn efficiency?

I think my timing is set at 10 BTDC right now, or close to that anyway. I had it more advanced with a stock head, but backed it off yesterday because I was getting pinging I didn't have before sticking this head on--no doubt due to the head's airflow improvement. Luckily, since I have the AFR meter, I can visually check it as I go. But will it help?

[FestYboy]

By grounding the STI pin, you remove the ecu from the equation and are then able to set true base timing without any compensation.

As for the a/f issue, you should have an adjustable FPR on your rail. The aspire already runs lean to begin with, which according to Jim is a big reason why aspires don't feel as peppy as a Festiva, and I have to agree.

[TominMO]

By grounding the STI pin, you remove the ecu from the equation and are then able to set true base timing without any compensation.

As for the a/f issue, you should have an adjustable FPR on your rail. The aspire already runs lean to begin with, which according to Jim is a big reason why aspires don't feel as peppy as a Festiva, and I have to agree.

I understand why I ground the STI pin. But I was wondering if it mattered for my situation; if I can just move the disty forward and back without grounding the pin, to try to get the best (i.e. richer) AFR readings.

Yes I do have an adjustable FPR, as a matter of fact. It is set at 37 PSI, which is stock. So I can try to play with that too.

I'm thinking it would be best to get the ignition timing optimal, either with or without grounding the pin, then set the FP. Sound right to you? Do you think grounding the pin when timing the ignition matters in my situation?

[FestYboy]

Timing should not have any affect on a/f... if you see a change to the rich, you're seeing incomplete combustion which is not what you want. Ground out and find what the head likes and leave it there.

Matt sent me an FPR and it started at 40 and he said I would likely have to go higher to make things happy... I have Skippy at 42psi and when I set it there, I saw a gain in MPG if you can believe it. With your mods, you might be at 44-45 psi to find your sweet spot.

[TominMO]

Timing should not have any affect on a/f... if you see a change to the rich, you're seeing incomplete combustion which is not what you want. Ground out and find what the head likes and leave it there.

Matt sent me an FPR and it started at 40 and he said I would likely have to go higher to make things happy... I have Skippy at 42psi and when I set it there, I saw a gain in MPG if you can believe it. With your mods, you might be at 44-45 psi to find your sweet spot.

OK, thanx!

[TominMO]

Took the FP up to 42 PSI; seems to have taken care of the leanness. Might fiddle with it a little more--the readout stlll seems just slightly lean. I know my gas mileage will suffer a bit tho. Definitely runs strong(er) now, according to the butt dyno.

Also, the idle was pretty stumbly before, but seems to have stabilized, and not wanting to die when I shift from a gear to neutral, like when coming to a stop sign. It's still a little stumbly, but I think that's the more aggressive cam grind, and I can live with that.