[Diy_efi] Can anyone diagnose this engine problem?
Bret Levandowski
skishop69 at yahoo.com
Wed Feb 23 01:59:36 GMT 2005
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One other thing... Hook up a fuel pressure guage and watch what happens when it cuts out. If it is the injectors, you will see the gauge pulse. Does it matter if it's hot or cold? Ski
Rick McLeod <dunvegan at sbcglobal.net> wrote:I have herd a very similar 'audio' from one of my
cars, it has a park/neutral rev limiter that modulates
the injectors anytime it sees RPM in park/neutral
exceed about 3000 RPM.
Therefore, my question: is your injection computer rev
limited? Could it be it came from an application that
is 4stroke low rev?
Just a thought, based on the audio clip, it actually
sounds like everything is working as prgrammed, and
hitting a rev limiter?
--- Bret Levandowski wrote:
> We do a few mods with our sleds as well. Though, we
> use Arctic Cats because they're already injected.
> Injectors in the cylinders instead of at the crank
> base aren't as efiicient and generally suffer form
> heat soak. That's why 'Cat moved them to the base.
> I'd hook your injectors up to a good scope and check
> the readings. Also, make sure you've got good ground
> and driver connections. In the video, it sounds like
> the injectors or ignition is cutting out. Since you
> say you've eliminated the ignition, that only leaves
> the injectors. If you're not running an O2 sensor,
> you should consider hooking one up. A wideband would
> be your best bet to monitor if it's going lean
> enough to cause you're problem. Unfourtunately, the
> reason they don't use them on two strokes is the oil
> doesn't react well with them. It should be useful
> long enough to see what's going on. My best guess
> (all though not that great) is that you've got an
> ECM hardware problem or you're injector windings are
> cooking. Ski
>
> joeld wrote:
> 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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<DIV>One other thing... Hook up a fuel pressure guage and watch what happens when it cuts out. If it is the injectors, you will see the gauge pulse. Does it matter if it's hot or cold? Ski<BR><BR><B><I>Rick McLeod <dunvegan at sbcglobal.net></I></B> wrote:
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">I have herd a very similar 'audio' from one of my<BR>cars, it has a park/neutral rev limiter that modulates<BR>the injectors anytime it sees RPM in park/neutral<BR>exceed about 3000 RPM.<BR><BR>Therefore, my question: is your injection computer rev<BR>limited? Could it be it came from an application that<BR>is 4stroke low rev?<BR><BR>Just a thought, based on the audio clip, it actually<BR>sounds like everything is working as prgrammed, and<BR>hitting a rev limiter?<BR><BR><BR><BR>--- Bret Levandowski <SKISHOP69 at YAHOO.COM>wrote:<BR><BR>> We do a few mods with our sleds as well. Though, we<BR>> use Arctic Cats because they're already injected.<BR>> Injectors in the cylinders instead of at the crank<BR>> base aren't as efiicient and generally suffer form<BR>> heat soak. That's why 'Cat moved them to the base.<BR>> I'd hook your injectors up to a good scope and
check<BR>> the readings. Also, make sure you've got good ground<BR>> and driver connections. In the video, it sounds like<BR>> the injectors or ignition is cutting out. Since you<BR>> say you've eliminated the ignition, that only leaves<BR>> the injectors. If you're not running an O2 sensor,<BR>> you should consider hooking one up. A wideband would<BR>> be your best bet to monitor if it's going lean<BR>> enough to cause you're problem. Unfourtunately, the<BR>> reason they don't use them on two strokes is the oil<BR>> doesn't react well with them. It should be useful<BR>> long enough to see what's going on. My best guess<BR>> (all though not that great) is that you've got an<BR>> ECM hardware problem or you're injector windings are<BR>> cooking. Ski<BR>> <BR>> joeld <JOELD at UALBERTA.CA>wrote:<BR>> Ok, been trying to figure this out for far too long.<BR>> Maybe someone on here can <BR>> provide some insight.<BR>> <BR>> What
we've got:<BR>> -polaris 600cc 2-stroke 2 cylinder snowmobile engine<BR>> bottom end<BR>> -our own billet cylinders and head<BR>> -injectors in the cylinder walls<BR>> -running a motec M4<BR>> -centrifugal supercharger<BR>> -45psi fuel pressure<BR>> -88pound/hour injectors<BR>> <BR>> What its doing:<BR>> It will rev up and idle perfect, right to 4500rpm or<BR>> so and then it surges, as <BR>> can be seen in this video<BR>> http://www.putfile.com/media.php?n=100_0008 . When <BR>> it is surging, I am holding the throttle steady.<BR>> <BR>> We've tried timing, all sorts of fuel map changes,<BR>> fuel pressure, 3 different <BR>> crank sensors (2 magnetic and one optical), adding<BR>> fuel with a squirt bottle <BR>> right at the supercharger, running without the<BR>> supercharger. Nothing changes <BR>> at all. We are totally stumped. Its not the rev<BR>> limiter, we've ruled that out <BR>> as we have it set at
18,000 and it sounds different<BR>> when it cuts in. Even the <BR>> motec guys have no answers yet. Does anyone here<BR>> have any ideas? This is a <BR>> university SAE project and we have to go to<BR>> competition in 2 weeks.<BR>> <BR>> Thanks,<BR>> <BR>> Joel Day<BR>> 4th Yr. B.Sc. Min Eng<BR>> 2004 C.S.C. Project Coordinator<BR>> Home: 780-434-9294 Cell: 780-722-5376<BR>> C.S.C Team Website: www.ualberta.ca/~uacsc<BR>> <BR>> _______________________________________________<BR>> diy_efi mailing list<BR>> diy_efi at diy-efi.org<BR>> http://lists.diy-efi.org/mailman/listinfo/diy_efi<BR>> <BR>> __________________________________________________<BR>> Do You Yahoo!?<BR>> Tired of spam? Yahoo! Mail has the best spam<BR>> protection around <BR>> http://mail.yahoo.com ><BR>_______________________________________________<BR>> diy_efi mailing list<BR>> diy_efi at diy-efi.org<BR>>
http://lists.diy-efi.org/mailman/listinfo/diy_efi<BR>> <BR><BR>_______________________________________________<BR>diy_efi mailing list<BR>diy_efi at diy-efi.org<BR>http://lists.diy-efi.org/mailman/listinfo/diy_efi<BR></BLOCKQUOTE></DIV><p>__________________________________________________<br>Do You Yahoo!?<br>Tired of spam? Yahoo! Mail has the best spam protection around <br>http://mail.yahoo.com
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