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Cypha

Bike carbs and coil packs.

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Ok long story short. ECU/EFI gone. Bike carbs in place.

Using standalone electronic ignition.

The standard coil pack require a stable 12v at crank to fire, however when cranking the voltage at the coil is between 10-11v. It has a new bigger amp battery with a regular reading of 13v.

As the ECU did the step up to compensate for this situation, I need ideas on how to get round this issue or anyone that has already converted to carbs, how did you get round this issue?

Many thanks in advance for any help.

For reference is the lupo sport AUB engine with custom wiring loom.

Edited by Cypha
Additional information.

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No idea, but i would be looking at the engine wiring diagrams to figure out how VW does it.

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2 minutes ago, Sausage said:

No idea, but i would be looking at the engine wiring diagrams to figure out how VW does it.

I have searched online for diagrams and the lupo is so overwhelmed by polos it is hard to know if you looking at the right schematic. Got any good links you can rely on?

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Just having a rummage on the internet now:

https://docs.google.com/leaf?id=0B_V9-6xfgGlIYzMzOTI2YmYtNDQ3My00MTZhLTkwMGMtMGE1ZWU3Yjc1OTBj&sort=name&layout=list&pid=0B_V9-6xfgGlINzhhM2IyNmItOWRhZS00MzBkLTk2MTEtNGIyZDFmMDg0NWM2&cindex=124

Wrong engine though so likely not much use.

Probably someone on here has them though.

Edited by Sausage

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19 minutes ago, Sausage said:

Well that doc would be good but didn't go into much detail, so I searched the VW part number 032 904 106B and hit the jackpot!

https://r.tapatalk.com/shareLink?url=http%3A%2F%2Fwww.msextra.com%2Fforums%2Fviewtopic.php%3Ft%3D49837&share_tid=49837&share_fid=45446&share_type=t

Only issue I don't really get what they mean. I know I need a pullup on it but the instructions are so vague! Grrrr

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I would be tempted to cut out the middle men and try powering direct from the battery 

From Sausages link, page 3  - just found out you can paste Snip tool images - Very cool!

image.thumb.png.bf3288aff3f944f2c7e35df06b525d9d.png

 

Terminal 4 on the coil pack is the switched live feed, there is 3 or 4 connections in the standard loom, removing them temporarily to test 

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Just now, LR5V said:

I would be tempted to cut out the middle men and try powering direct from the battery 

From Sausages link, page 3  - just found out you can paste Snip tool images - Very cool!

image.thumb.png.bf3288aff3f944f2c7e35df06b525d9d.png

 

Terminal 4 on the coil pack is the switched live feed, there is 3 or 4 connections in the standard loom, removing them temporarily to test 

Well that's fine but I also measure across the battery during cranking and it also drops below 12v, so a pull up might be the only way.

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The 4b/2 is the +12v feed (via ign sw). You need that. 4b /1&3 are the signals to run the coil pack. Either pull down to fire or pull up (can't remember!), but not critical initially. Try just grounding with wire.

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Update: spoken to Motorsport and they have openly admitted (after checking online) that the information in their documentation is wrong and the leads need to go in a different configuration.

They have tole me the voltage drop is not a issue as if it drops below a level that the system will not support it reboots/resets. As this is not happening the voltage it good, it must be the connections.

Will update when I have some news.

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I roughed up this quick diagram for anyone interested. I have to test it out, been busy and I need some fuel parts but will report back when I have done it.

IMG_20180807_100457.jpg

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I reckon 4 is ground.

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After replacing the coil pack for a ford ka (circa 1999) and some fiddling it is all working.

This is because the bosch VW coil pack needs the voltage to be a stable 12v at startup. This is not achievable since the voltage drops at crank and without the ECU (which takes care of this for you) your pretty much screwed. The Ford coil pack only needs 5-12v to ignite and so was the logical choice.

I have drawn up the wiring diagram should this be of help to anyone in the future (see attached).

I will update this when i have accessories wired in, but for now, this is all you need to get the car up and running.

 

Nodiz VW Lupo Basic Wiring Diagram v1.0.pdf

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