[Diy_efi] Re: diy_efi Digest, Vol 17, Issue 31

[Bill Washington]

Joel,
    I can't add anything to the suggestions so far about the unloaded 
behaviour, but can ask some questions....
    What does the laptop logging tell you about the injector driver 
pulse width when it is surging?
    What does a CRO tell you about the delivered pulse width during surging?
    Does it still surge under load?
Bill

>-----------------------------
>
>Message: 6
>Date: Mon, 21 Feb 2005 20:15:35 -0700
>From: joeld <joeld at ualberta.ca>
>Subject: [Diy_efi] Can anyone diagnose this engine problem?
>To: List for general do-it-yourself EFI talk <diy_efi at diy-efi.org>
>Message-ID: <421DA9E1 at webmail.ualberta.ca>
>Content-Type: text/plain; charset="ISO-8859-1"
>
>Ok, been trying to figure this out for far too long. Maybe someone on here can 
>provide some insight.
>
>What we've got:
>-polaris 600cc 2-stroke 2 cylinder snowmobile engine bottom end
>-our own billet cylinders and head
>-injectors in the cylinder walls
>-running a motec M4
>-centrifugal supercharger
>-45psi fuel pressure
>-88pound/hour injectors
>
>What its doing:
>It will rev up and idle perfect, right to 4500rpm or so and then it surges, as 
>can be seen in this video http://www.putfile.com/media.php?n=100_0008 . When 
>it is surging, I am holding the throttle steady.
>
>We've tried timing, all sorts of fuel map changes, fuel pressure, 3 different 
>crank sensors (2 magnetic and one optical), adding fuel with a squirt bottle 
>right at the supercharger, running without the supercharger. Nothing changes 
>at all. We are totally stumped. Its not the rev limiter, we've ruled that out 
>as we have it set at 18,000 and it sounds different when it cuts in. Even the 
>motec guys have no answers yet. Does anyone here have any ideas? This is a 
>university SAE project and we have to go to competition in 2 weeks.
>
>Thanks,
>
>Joel Day
>4th Yr. B.Sc. Min Eng
>2004 C.S.C. Project Coordinator
>Home: 780-434-9294 Cell: 780-722-5376
>C.S.C Team Website: www.ualberta.ca/~uacsc
>
>
>
>  
>
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