Vw Speed Shop Crank trigger problem

yakboy
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Vw Speed Shop Crank trigger problem

Post by yakboy »

I have been running EFI for a few years now ( Full Speedshop kit, DTA S40 etc), but have always struggled getting an even idle from day 1. The local EFI tuners are more used to motorbikes and never really got on top of a decent start up map . So today booked a rolling road session with someone experienced in DTA software and what we found was that the Speedshop crank trigger sensor gives loads of errors at lower revs (a huge amount on start up) and idle. Has anybody had experience of this. The tuner whilst impressed with the quality of the Speedshop crank sensor kit , thought the design flawed as any endfloat and expansion with heat would alter the sensor position, he did check the spacing to ensure it was correct. He suggested looking at alternative crank trigger sensor set ups. Has anybody got any recommendations?

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paul_f
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Re: Vw Speed Shop Crank trigger problem

Post by paul_f »

Plenty of people use them with success and the expansion with temperature is likely to be minimal.

Is it a VWSpeedshop loom? It's more likely to be noise on the wiring
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yakboy
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Re: Vw Speed Shop Crank trigger problem

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Thanks for the reply Paul, it is a VWspeedshop loom, anything I can do to shield it?

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vwJim
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Re: Vw Speed Shop Crank trigger problem

Post by vwJim »

A pro-built loom will be shielded already.

Poor earth causing issues?
CPS gap incorrect?
Simply not got the map correct?
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yakboy
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Re: Vw Speed Shop Crank trigger problem

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Jim, Can rule out map problems. I watched the laptop when he started it up...it racked up 35 errors just turning the engine over. Doesn't seem to rack errors when you have your foot on the throttle but take your foot off and again errors rack up. The van earth is definately good but may get an auto-electrician to check over the ECU earthing. The system was set up by someone who used to work for speedshop and knows what they were doing so may ring Speedshop tomorrow for any idea's. As ever though Jim, thanks for taking the time to reply

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vwJim
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Re: Vw Speed Shop Crank trigger problem

Post by vwJim »

Have you called Alex at DTA? He'll be able to say what could cause it.

They have a RR now too, so could take it there to experience the faults + solve it.
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paul_f
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Re: Vw Speed Shop Crank trigger problem

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Have you got a photo of the connector for the sensor. Normally you only shield at the ECU end, the sensor end is left floating. I am wondering whether someone has tried to help by grounding it at both ends
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yakboy
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Re: Vw Speed Shop Crank trigger problem

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Thanks Jim, Firstly, checked the sensor gap myself and it's bang on .015 thou as recommended by speedshop. Tried to ring speedshop but no answer , so rang DTA who were very helpful and think it is definately electrical interference with the crank sensor signal, so it's needle in a haystack time trying to find the cause. My local auto-electrician is a good guy and has done lots of work on the van so will go and have a chat.

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Re: Vw Speed Shop Crank trigger problem

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Paul,
Will have a dig around now and try and get some photo's

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Re: Vw Speed Shop Crank trigger problem

Post by yakboy »

A couple of shots of the crank sensor wiring. The cable goes behind the fan housing, and enters the rear NS wheel arch where the ECU is located. The 12v feed from the leisure battery goes through here too (I don't know if this can cause interference)

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paul_f
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Re: Vw Speed Shop Crank trigger problem

Post by paul_f »

Can you disconnect the leisure battery cable?

It should be fairly easy to find the interference with an oscilloscope.

Where is the ignition coil mounted and what type is it? Which leads do you have?

Edit - and which plugs. Might be worth getting some resistor plugs if yours aren't
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Re: Vw Speed Shop Crank trigger problem

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Thanks for all the suggestions Paul. Not really my area of expertise but gives my local autoelectrician something to go on. Will keep you posted

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paul_f
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Re: Vw Speed Shop Crank trigger problem

Post by paul_f »

Before you go to the auto electrician, get the part number from the plugs.

If you have non resistor spark plugs, then that is a common cause of interference
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yakboy
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Re: Vw Speed Shop Crank trigger problem

Post by yakboy »

Plugs are NGK B5HS.
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Last edited by yakboy on Thu Jul 16, 2020 9:29 pm, edited 1 time in total.

yakboy
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Re: Vw Speed Shop Crank trigger problem

Post by yakboy »

They don't have the "R" in the code so not resistor plugs, so that'll be my first port of call...wish me luck

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