Author Topic: Please help: Trigger Errors on Audi I5 (3B)  (Read 19917 times)

Offline amd is the best

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Please help: Trigger Errors on Audi I5 (3B)
« on: July 07, 2011, 10:34:38 am »
Hey Guys,

Some background:
1991 Audi 200 20v (3B)
VEMS Plug and Play system from EFI Express
LS2 Coil packs
Stock VR sensors and distributor (AudiTrigger div3 135 tooth flywheel, TDC pin and TDC cam sync)
Firmware currently 1.1.94 (07/07/11)

Overall I am loving my VEMS system however I am constantly getting a trigger error around ~6,500rpm which causes the car to stumble almost like a misfire.  I have tried a wide range on firmware versions which has not helped at all.  In newer firmware versions I set "Event at bad trigger position" to "Just show (default)" and Ignore sectrig pulses above 0kpa (always) and this doesn't help any.

The car doesn't do it every time, but more often then not.

Any ideas as to what could be wrong or what I can do to try and resolve this issue?

You can see the car misfire in this video right in 1st gear: http://www.youtube.com/watch?v=TxEm9TFcWls

Thanks in advance,
Nick
« Last Edit: July 07, 2011, 11:02:28 am by amd is the best »
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Offline boostd audi

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #1 on: July 22, 2011, 10:30:46 pm »
may sound dumb but intermittent problems scream sensor to me.. is the wire to the crank sensor good shape.. how old is the trig sensor itself?
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Offline amd is the best

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #2 on: July 26, 2011, 02:11:17 am »
may sound dumb but intermittent problems scream sensor to me.. is the wire to the crank sensor good shape.. how old is the trig sensor itself?

Sensors are not new but look to be in great shape.  On top of that, another 200 20v owner with the same kit gets exactly the same issue on his car.
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Offline mattias

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #3 on: July 26, 2011, 09:05:19 am »
Vemslog or it didn't happen.

I would make sure that the sensors at the flywheel are properly aligned to the home tooth and starter ring gear, it's been a problem on many non-AAN installs I've done and caused similar problems.

Offline Erikk

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #4 on: August 01, 2011, 02:31:27 pm »
I´ve also seen a few Audis with problems around 6-6500rpm's

Here´s a large log with several missfires, sometimes it revs with no problems at all.
I made a quick clickthrough and theres misfires at 04.45, 07.10 and 37.15

http://vems.hu/files/ErikEnglund/Logs/audi_missfire.vemslog


Looks like the Sectrigg-position is very jumpy.
« Last Edit: August 01, 2011, 02:37:03 pm by Erikk »

Offline jrussell

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #5 on: August 02, 2011, 02:27:12 am »
By all means contact Marc, he'll help you out properly. When I see a stumble around 6k on an Auditrigger application, it's generally that the home pin is a bit too far into the flywheel. You can grind out the sensor mount a bit to move it closer to the flywheel (counterclockwise looking from above) or try to move the pin out further. It's really too bad Audi didn't make the pin just the right length to bottom out in the hole... if you drop the flywheel on it's face it'll push the pin it and you wouldn't even notice.
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Offline amd is the best

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #6 on: August 07, 2011, 03:14:09 am »
By all means contact Marc, he'll help you out properly. When I see a stumble around 6k on an Auditrigger application, it's generally that the home pin is a bit too far into the flywheel. You can grind out the sensor mount a bit to move it closer to the flywheel (counterclockwise looking from above) or try to move the pin out further. It's really too bad Audi didn't make the pin just the right length to bottom out in the hole... if you drop the flywheel on it's face it'll push the pin it and you wouldn't even notice.

I'll have to give that a try.  Thank you!
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Offline amd is the best

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #7 on: October 24, 2011, 07:37:46 am »
By all means contact Marc, he'll help you out properly. When I see a stumble around 6k on an Auditrigger application, it's generally that the home pin is a bit too far into the flywheel. You can grind out the sensor mount a bit to move it closer to the flywheel (counterclockwise looking from above) or try to move the pin out further. It's really too bad Audi didn't make the pin just the right length to bottom out in the hole... if you drop the flywheel on it's face it'll push the pin it and you wouldn't even notice.

Would you happen to have any pics to explain what you mean when you mentioned grinding down the sensor mount bracket?  This is still occurring and its killing me!
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Offline billman

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #8 on: October 24, 2011, 11:11:03 am »
I took the sonsor bracket out and started grindint the whole surface in the block direction. I took 0.3mm off every time till i got it right. When I see the errors you get i believe that it is very minor and simply need just a tad. Try no more than 0.2mm for the beginning. Check while turning the engine with the hand (Gear in and one wheel only in the air) that it doesn't hit.

Offline amd is the best

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #9 on: October 24, 2011, 12:19:14 pm »
I took the sonsor bracket out and started grindint the whole surface in the block direction. I took 0.3mm off every time till i got it right. When I see the errors you get i believe that it is very minor and simply need just a tad. Try no more than 0.2mm for the beginning. Check while turning the engine with the hand (Gear in and one wheel only in the air) that it doesn't hit.

So I will need to machine down the bracket in the image below so that the sensor closest to the engine (tdc pin) will end up closer to the pin, correct?

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Offline billman

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #10 on: October 25, 2011, 05:41:21 pm »
That is what i did. I ended up grinding too much and then i used a washer between the bracket and the sensor so that the sensor doesn't hit the pin. So be careful and try to measure the distance if it is possible. If the error persists then maybe you need to check that the Hall and the pin coincide.

Did you managed to get a log with the trigger error? What kind of trigger error exactly do you get? Less Sec.Trig. or Less Prim. Trig?
« Last Edit: October 25, 2011, 05:43:57 pm by billman »

Offline Reidar

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #11 on: October 31, 2011, 03:55:39 pm »

The most common problem i see on these cars with a singlemass flywheel, is that the sensor is to far away from the trigger pin. I usually just grind up the upper bolt hole, or drill it bigger to move the sensor closer to the flywheel. I made a little picture to explain the problem:



Another common problem, is that the HALL is not masking the trigger pin correctly. If the distrebutor is not timed correctly, this would cause problems. The best thing to do here in my opinion is to use a dual channel scope, to meassure both the Hall signal and Trigger pin signal at the same time, and then adjust the distrebutor so that the TriggerPin signal aligns up in the center of the hall-window. This is uasually not a big problem if you got an ABY, ADU or late AAN engine with a stock-camgear. An adjusteble aftermarket cam-gear could cause problems if the cams are advanced or retarded. Usualy the trigger wheel on these camgears are adjusteble allso, so they will have to be moved back in position if you get any troubble.



Offline amd is the best

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #12 on: October 31, 2011, 05:42:12 pm »
Thank you very much Reidar!  Just for clarification, you grind/drill the upper hole (mount to transmission) of the bracket and rotate the whole barracked inward?

Also, how do I go about logging the hall cam and trigger pin so I can see if mine are off?
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Offline Reidar

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #13 on: November 01, 2011, 03:36:21 am »
Yes, I move the whole bracket closer to the gearbox. I usually use a drill and make the hole in the bracket oval. I then move the bracket so the sensor touches the flywheel, and then move it littlebit back, so it`s not scrubbing all the time to the flywheel wall.

To "logg" your signal, you will need an Ocillioscope with a dual channel input. you can find cheap USB ones that you connect to your laptop that will do the job. And meassure both signals at once. Then you can twist your distrebutor untill the signal match up nice. By scoping your signals and posting them here would allso probably help, so we could see the signal-strength and so on.

I dont got an dual channel ocillioscope anymore, so this is what I to know that I`m at the right track of things:

Remove the sensor bracket. Hook up your DVM to the hallsensor signal output (pin in the middle i think).
put the car i 5th gear or so, an slowly push it untill you get the 5v reading on the DVM. Try too find the exact spot where it switches from 0v to 5v. Now if you want you can take a white color marker, and make a little dot at your pulley and engineblock/timingcover as referance. Keep pushing the car untill you see the trigger pin aligne in the sensor hole, and make a new mark at your pulley. push the car again to see when the hall-signal goes from 5v to 0v, and make a new mark at the pulley. You should now have 3 white dots on your pulley. the one in the middle is the trigger pin, and the two at the sides show rising and falling signal. If two of these dots are close to eachother, you will know your hallsensor timing might be a little off if you did it the correct way.

Note! The signal will change by rpm a little when running, so this is not the best way to do it. It`s only something i came up with one day I was strugling with this issue.

As you probably allready know. The secondary trigger in vemstune is the trigger-pin, and not the hall-sensor. The hall-sensor masks the trigger pin every-other crank rotation, so the ecu is only allowed to see the signal each 720 crank deg. This is why it`s important that it actually mask the pin. When I search for errors, I somtimes just ground the hall-signal on the hall-inverted boxes. this will help you roule out the errors, but will give you a 50% chanche that the engine will start in the right cycle.

I got an 3B engine my self, and had exactly this problem after adjusting my cam timing. the only thing was that it happened at around 1400rpm, and not 6500rpm like you.





Offline loxxrider

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Re: Please help: Trigger Errors on Audi I5 (3B)
« Reply #14 on: November 04, 2011, 04:50:20 pm »
I've been having the exact same issue. I have modified the sensor housing and have moved the sensor closer with no effect. Maybe I'll try and move it closer.