Accel enrichment clarification

[Philip Lochner]

On the MT 2.25 Acceleration enrichment page is a value titled "End Pulsewidth (ms)".  Does anyone know what this does?
 
I find* no explanation of this value, not in http://www.megasquirt.info/megatune.htm#index and not in http://www.megasquirt.info/ms2/tune.htm
 
*I am blond...
 
Kind regards
Philip Lochner  
MS-2/V3/2.35/MT 2.25/Innovate LC-1/LSU4.2
Land Rover 4.6 V8i std, 4-2-1 exhaust headers, IAC
 
PS: I posted this on the " Injectors, Fuel & Air Supply" forum but no answers were forthcoming. I hope this warrants what I think is defined as cross-posting.  Apologies if it still is undesirable.

Posted by email.

[grippo]

The end pulsewidth, in conjunction with the starting pulsewidth, defines the slope of the acceleration enrichment, you start with a long pw and ramp down to the end pw over x ms, then turn off. It allows a gentler slope than just going from start pw to 0.

[2WHEELENGR]

I'm using 100% TPS on Accel Wizard. Does the "Accel Time(s)", "Accel Taper Time(s)" & "End Pulswidth(ms)" concern me? Are these only for MAP use?

Thanks.

[69 1/2 Six Pack Bee]

Phillip,

Any resolve to your IAC issue?

Thanx,

Bud

[Philip Lochner]

Any resolve to your IAC issue? 
PL: Thanks for asking Bud. Can't use the word "resolve" yet.  At best "limited progress"...
At this time I am convinced that my IAC is opened to the fully open position when I switch the ignition on in the morning.  It makes that "krrrr" sound it does when fully open.  Trouble is that it seems to me that either my IAC then gets stuck in that opening position (when cold) until the whole thing warms up, or MS-2 simply does not have enough "grunt" to close it when it is still cold, or both.  It did the same thing on the bench BUT if I reversed the wires to the IAC it would happily close - explain that to me....  (This was before I shorted out R4 and R5)
 
I've now got it on "15 Min IAC" and on first start she will "idle" at 2500rpm, but just about 2minutes later if I switch off and start again, things will be nicely under control at around 900rpm.  Also, when the engine runs, if I move the points immediately before or after the green dot way up or down, nothing seems to happen.
 
What it boild down to is that other than the initial opening and then closing for cranking (when warm), the IAC does not seem to behave anywhere close to what I think it should.  Bit of a nuicance actually...  I'm rather close to giving up on it.  Just want to tray an IAC from a friend of mine to see if that behaves the same.  I also have other MS-2/V3 ECUs which I want to give a try just to see if I still get the same results (assuming they work).
 
Kind regards
Philip
MS-2/V3/2.35/MT 2.25/Innovate LC-1/LSU4.2
Land Rover 4.6 std, 4-2-1 exhaust headers, IAC  
'80 Jaguar XJS V12 5.3 (10:1 CR) is waiting for its turn

Posted by email.

[Philip Lochner]

Thanks for the clarification Bruce! This has made ALL the difference. The default setting of 2ms was WAY to high for my engine. My starting pw's at lower values is 0.5 and 0.8 so the 2ms was orders of magnitude too high causing the "late" bucking. Assuming this 2ms setting was resulting in pw's INCREASING and not tapering.

In the short time I've been participating on the forums, a wealth of valuable info has been forthcoming which really ought to be in the manuals in my humble opinion. I do hope someone is working this into the relevant manuals (to improve what is already very good)?

The end pulsewidth, in conjunction with the starting pulsewidth, defines the slope of the acceleration enrichment, you start with a long pw and ramp down to the end pw over x ms, then turn off. It allows a gentler slope than just going from start pw to 0.

[Philip Lochner]

I'm using 100% TPS on Accel Wizard. Does the "Accel Time(s)", "Accel Taper Time(s)" & "End Pulswidth(ms)" concern me? Are these only for MAP use?

I (very green newby) do believe so. It is my conclusion that ALL the parameters below the blending line impact the BLENDED result of the parameters above the blending line. Don't write off MAP. I realise your bike is very different from my V8 but a combination of the two may just be the optimum. Happy hunting!