Some Trigger Errors

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Some Trigger Errors

Postby Grillage » Sat Oct 24, 2015 4:16 pm

Hey all,
I have a thread on my V8 coupe but I thought I'd put this here instead.

I'm having some trigger errors only when I rev. Here's a screenshot...
Image

The car doesn't really seem to miss or anything when I do this but obviously, I'd like to have no errors.

I'll attach my config and a triggerlog too...

config:
v3.3_u009476-A-2015.10.18-12.41.48.vemscfg
(13.28 KiB) Downloaded 102 times


triggerlog:
v3.3_u009476-2015-10-24-12.29.57.triggerlog
(14 KiB) Downloaded 109 times
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Re: Some Trigger Errors

Postby Marc » Sun Oct 25, 2015 4:55 pm

looks like your secondary trigger is going away as you rev.

you're running auditrigger, so your ecu relies on the combination of the reference pin and distributor to produce the pulse. that means one of two things (more likely the 1st)

1) your reference pin to distributor aligment isn't dead centered, so as you rev the distributor goes out-of-window relative to the reference pin. this happens as the t-belt flexes.

2) either your reference pin or cps signal physically goes away under revs. unlikely because the pin signal (VR) gets stronger the faster the engine revs and the hall sensor in the distributor is usually a pretty reliable signal. revs shouldn't really affect the relaibility of the signal. if its marginal it should be marginal everywhere.

The engine still runs because it already knows what TDC cylinder #1 is from seeing the cam pulse earlier at lower revs so it notes the problem but keeps going.
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Re: Some Trigger Errors

Postby Grillage » Sun Oct 25, 2015 6:24 pm

How would #1 be possible? The cam sensor only goes in one place and same for the flywheel.

And what's the way to fix this? Widen the window somehow?
CURRENT
1995 90 Quattro
1994 Cabriolet - 5 speed
1986 Maserati Biturbo Spyder
2011 A4 Avant


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1993 Audi 90 CS Quattro - 1990 CQ - V8 - 1995.5 Audi S6 - 1993 Audi V8 - 2013 A5 Prestige
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Re: Some Trigger Errors

Postby Marc » Sun Oct 25, 2015 6:40 pm

Grillage wrote:How would #1 be possible? The cam sensor only goes in one place and same for the flywheel.


I mentioned it in the post. timing belt flex. As the engine revs the belt stretches and dynamically moves the position of the pin relative to the shutter wheel in the distributor. that and slop in the distributor rotor itself.

it should remain in-window as long as the two are perfectly aligned and there is minimal slop in the dizzy.
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Re: Some Trigger Errors

Postby Grillage » Sun Oct 25, 2015 6:56 pm

Sorry, missed that the first time

So what's the remedy? Should I find a sonsor setup with a larger window? The belt isn't overly loose or anything. I just did the timing belt service a couple months ago. If everything runs okay should I just ignore it?
CURRENT
1995 90 Quattro
1994 Cabriolet - 5 speed
1986 Maserati Biturbo Spyder
2011 A4 Avant


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1993 Audi 90 CS Quattro - 1990 CQ - V8 - 1995.5 Audi S6 - 1993 Audi V8 - 2013 A5 Prestige
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Re: Some Trigger Errors

Postby Marc » Mon Oct 26, 2015 6:19 pm

remedy wise, first triple check that alignment is perfect. window in the distributor has to line up with the pin on the flywheel. perfectly. centered.

next, check slop in the distributor. if there is a lot of flop you can try replacing or rebuilding it, or simply widening the window.

its not the window that sets the timing, its the position of the reference pin anyway.
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Re: Some Trigger Errors

Postby Grillage » Mon Oct 26, 2015 8:32 pm

Thanks for the reply.

I know it was perfect once but now re-checking it would be a major undertaking. The only factor that could change the relationship between the two is the timing belt tensioner. I did do the TB job but I used the proper tools and was careful to tension the tensioner thing to the right length. Looking back at pics it appears to be the same length as the old one too.

ill try another distributor/cam sensor first. Happen to have one?
CURRENT
1995 90 Quattro
1994 Cabriolet - 5 speed
1986 Maserati Biturbo Spyder
2011 A4 Avant


PAST
1993 Audi 90 CS Quattro - 1990 CQ - V8 - 1995.5 Audi S6 - 1993 Audi V8 - 2013 A5 Prestige
User avatar
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Posts: 676
Joined: Feb 28, 2013
Location: Cincinnati, OH


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