tegwin
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| posted on 27/7/10 at 10:13 PM |
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Checking injector signal locost?
Is there a locost way of checking that the injectors are recieving the correct voltage?
I tried sticking a multimeter on each injector in turn... I only get around 6.5V at each injector... but this might be because the pulse is so
small...
What I am trying to do is workout why I have a misfire at idle... injectors or engine management system are the only options left following an engine
rebuild which has not fixed the issue..
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blakep82
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| posted on 27/7/10 at 10:14 PM |
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think an osciloscope would show the peak voltage. multimeter would only show an average i think
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RazMan
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| posted on 27/7/10 at 10:24 PM |
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Yep, only a scope will tell you the true voltage.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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jambojeef
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| posted on 27/7/10 at 10:52 PM |
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Iirc the injectors on my honda VFR had permanent 12v to one pin and were switched to ground by the ECU on the other.
Might be worth checking how they are switched to make sure you measuring the right thing - sorry if Im a step behind you here.
Geoff
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Dusty
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| posted on 28/7/10 at 12:46 AM |
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quote:
Iirc the injectors on my honda VFR had permanent 12v to one pin and were switched to ground by the ECU on the other.
Yup. That's
how they work. Ignition live 12v to one side, ecu earths the other to fire them.
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britishtrident
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| posted on 28/7/10 at 08:01 AM |
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Needs a scope, some DMMs will give you the duty cycle.
Quick simple check is to use a Noid light --- with experience it can tell you a lot.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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tegwin
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| posted on 28/7/10 at 08:48 AM |
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The fact that all of them appear to be giving the same average voltage with a multimeter suggests that they are all getting some sort of feed..
I assume an injector is a logic device in that it only fires if there is enough voltage, it wont "half fire" if the voltage is too low?
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Would the last person who leaves the country please switch off the lights and close the door!
www.verticalhorizonsmedia.tv
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britishtrident
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| posted on 28/7/10 at 12:54 PM |
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Most injector problems are due the injector getting gunged up, this would show up more at wide open throttle.
If the engine passes a compression test (or better a leak down test) then the most likely cause of an idle speed single cylinder misfire is a coil
pack/plug/plug lead.
However first check the inlet and exhaust manifolds for leaks.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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tegwin
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| posted on 28/7/10 at 05:32 PM |
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so far I have:
replaced coilpack
replaced HT leads
Replaced plugs
Remove the head, reground valves, replaced camshaft and rockers
Installed with new inlet/exhaust gasket and head gasket..
And the misfire still persists...
Its very noticeable at idle, but at around 3000 RPM it becomes les noticeable for the most part...
Its almost like the timiing advance at idle is out...
I really have no idea where to look next...
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Would the last person who leaves the country please switch off the lights and close the door!
www.verticalhorizonsmedia.tv
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