Initial tune woes with new manifold and TB on my 355

[vlad01]

Search it, it is a scalar. If you can't find it I will have a look on my PC next time I am at it.

[Mr DOHC]

Search it, it is a scalar. If you can't find it I will have a look on my PC next time I am at it.

I can find Run A/F Param - Minimum BPW for Async fuel delivery, and its set to 0.20 Msec already

[vlad01]

I don't think that's it. I will have a look next time.

[Mr DOHC]

I seem to be making some headway, save for 2 small issues.

when i back off the throttle, it goes into decelerative enleanment, and a lot of it, its leaning the car right out to 19.x:1 and it takes a while to come back to normal, or a throttle blip to bring it back to normal values.
I cant find a map or table that might be doing this.

attached is the latest log that show it

[vlad01]

Going lean on decel is normal, this is decel fuel cut. When calculating the new VE table just ignore the areas of quick throttle movement. I do this by playing the log only in the gentle/steady areas to avoid AE and DE getting into the data.

Only when your tune is mostly done can you adjust things like AE/DE settings if it's still not right.

[Mr DOHC]

But it’s doing it while it’s just sitting there at idle in my shed. Not even after it’s been under load

EDIT, have a squiz at the log above, i pull it into gear while stopped at 1:33 and 1:56, both times it goes into enleanment

[vlad01]

Yeah it will do it even when revving the engine. There is no need for fuel if the engine is slowing down, otherwise it will crackle and backfire/smoke?

[Mr DOHC]

But I haven’t touched the throttle. It just randomly goes really lean while sitting there and nearly stalls the engine.

[vlad01]

VE table prob not right. Idle areas can be a pain if you are using calcVE as the slight delay from wideband to logging causes a feedback loop making a bad VE cell/s worse which makes the engine hunt which makes the VE cells even worse and so on. Sometime you need to manually adjust them and judge what is good value by looking at ones near by and interpolating from that. Also have you checked your idle and main spark tables? Closed loop idle uses the idle table and open loop idle uses the main table, they need to be correct for the engine's need and the same or close to each other. These can also cause the idle to be crap and hunt.


Anyway I found the setting. It's actually the min allowed pulse for cranking. Default was 7.9ms. I just changed mine to 2ms so it was less than the smallest value from either stage 1 or 2 crank tables. This is what I missed when going to bigger injectors and flooded the engine often when starting, fowling the plugs which then made it run even worse.

Min crank BPW.PNG (7.37 KiB) Viewed 1717 times

[Mr DOHC]

How do I calculate what BPW I need for the cranking? If stock is 19lb injectors, I have 45lb, so I simply change them all by 0.4 (or whatever the correct is) across the cells?
Also, what’s the difference between the first and second crank?