[Gmecm] $58 F29/F29E VE lookup weirdness

[Rob Handley]

Test drive log with engine speed up to over 6800 RPM showed no VE blips 
either. :-) Thanks for the pointer.

BPW still zero for 98 % of the time, so shall start investigating that 
now...

Robin

----- Original Message ----- 
From: "Rob Handley" <Robin at FuryWorld.fsnet.co.uk>
To: <gmecm at diy-efi.org>
Sent: 24 August 2007 00:34
Subject: Re: [Gmecm] $58 F29/F29E VE lookup weirdness


> Had another look at this. I've just tried a chip where my enlarged F29 
> looked up VE _overwrites_ the last value of VE - rather than setting VE to 
> zero (in place of the F30 look up) and later adding on the F29 looked up 
> VE value. The idea of this was so that there would be no CPU cycles when 
> the VE byte had zero in it. Based on a quick engine off test, this seems 
> to have done the trick; I saw no VE flicking on my ALDL monitor.
>
> Robin
>
> ----- Original Message ----- 
> From: "Dig" <turbodig at yahoo.com>
> To: <gmecm at diy-efi.org>
> Sent: 23 August 2007 17:22
> Subject: Re: [Gmecm] $58 F29/F29E VE lookup weirdness
>
>
> Sort of a well-known bug... The ALDL stream is reporting erroneous data.
>
> It doesn't seem to be real; there is no corresponding fuel hit that I've 
> ever observed.
>
> I haven't as yet found the cause, but I suspect it has to do with the 
> timing of the routine involved in sending data and the fuel routine.
> It's on our "to do" list for code59.
>
> ----- Original Message ----
> From: Rob Handley <Robin at FuryWorld.fsnet.co.uk>
> To: gmecm at diy-efi.org
> Sent: Wednesday, August 22, 2007 2:35:22 PM
> Subject: Re: [Gmecm] $58 F29/F29E VE lookup weirdness
>
> Tried it with a code modification to provide a hard-wired 'MAP' value to 
> use
> in the F29 look up, and the look up routine still regularly returned zero!
>
> Robin
>
> ----- Original Message ----- 
> From: "Rob Handley" <Robin at FuryWorld.fsnet.co.uk>
> To: <gmecm at diy-efi.org>
> Sent: 22 August 2007 09:03
> Subject: [Gmecm] $58 F29/F29E VE lookup weirdness
>
>
>> I've been looking at VE for the last few days and, after putting test
>> values in F29, F29E, and F30 I spotted the VE regularly (every ~6 secs)
>> reverting to the F30 only value. Looking back at one of last year's logs
>> this was happening then too. It also happens with the ignition on and the
>> engine not running !
>>
>> Has anybody seen this or have any suggestions why the table look up (as
>> used for F29 and F29E) should be returning zero every now and then? I 
>> find
>> the table look up code hard to follow.
>>
>> Robin