cheers fella

Sp are the hall senders all the same then? some people say they are others say they are not, anyone know for sure or have use a spi hall sender in a gt dizzy and how did it proform?

This is how I "think" it works (I could easily be wrong, but it makes sense.)

My understanding is The hall sender unit itself is the same, (the plug with the 3 wires that go to the other bit at the bottom) but the trigger wheel spacing is different. Which affects the signal the ECU receives. The SPI dizzy has narrower gaps than the GT, which means the ECU recieves a signal for slightly longer than it should. This screws up the advance, as the advance is (probably) applied based on the leading edge of the signal. And because the signal arrives earlier in the cycle, it adds too much advance.

Not many people have tried switching a hall sender over from another dizzy as it's quite difficult. Mk4 MPI dizzys use the same trigger wheel spacing, which means they are a potential source of GT dizzys. One good thing about the mk4 dizzy is the hall sender is an enclosed unit, ie the plug is the hall sender, whereas before the plug was connected to the hall sender via three wires which can get damaged easily. So the mk4 dizzys should be more reliable.

well i swapped over a hall sender from a spi dizzy to a gt one but something must have got broken as it wouldnt start the car, and another spare spi one did. I think ill be using a mk4 one on the g40 for a while but will try and replace the hall sender again on the original gt dizzy and report back.

my hall sender commited suicide, dismantled both dizzys, stuck 1litre hall sender on the gt/g40 shaft. works as it did before it died.

works exactly the same

okay so the hall sender detects the shaft at the opposite side (as the sender is under the plug at the top of the dizzy, not at the bottom)

but the shafts on the GT dizzy are symetrical so it is effectively detecting the same thing as the old one.

Edited 29 May, 200719 yr by rae

I had a feeling that might work.

I fear my blue one may have had the wrong dizzy on then but on the positive side it looks like if my current one needs a new dizzy then there're several option for repair or replacement. Ta muchly, just wish I still had the flowed head :(

Whereabouts is the part number on the dizzy have I got to take the cap and everything off?

I rang my local VW garage and they can get refurbished dizzys in for £124 in exchange for my old one

I think I might have the wrong dizzy as it keeps kangaroo jumping quite badly at low speed/low gears and I have changed my AFM so someone said to check the dizzy aswell then I found this thread so it maybe why it keeps doing it well I'm hoping.

its on the metal part of the dizzy, more or less face down.

I didnt expect a big improvement here, but I've got GT running gear on my 1 litre at the moment until i put the 1.3 in, and it was idling poorly and was about as fast as the SPI was. I put an AB dizzy on yesterday and it idles perfectly and is SO fast for a 1 litre now, you wouldnt believe how well it accelerates compared to before.

It appears my dizzy model number ends with AB which obviousley isn't correct what is this from?

Does anyone know where the cheapest/best place to buy a replacement (apart from vw)

Nah AB is good, its from the newer mpis and works fine, thats what mine is

Nah AB is good, its from the newer mpis and works fine, thats what mine is

Yeah but is it right for a GT?

Its the same yes.

AB is a mk4 version of the GT dizzy and seems to work on a gt without problems. It has a better hall sender on it as well. (all one part rather than plug + 3 wires + sensor.

Gay it isn't the dizzy thats causing the problems then :(

cheers guys

Whereabouts is the part number on the dizzy have I got to take the cap and everything off?

I rang my local VW garage and they can get refurbished dizzys in for £124 in exchange for my old one

I think I might have the wrong dizzy as it keeps kangaroo jumping quite badly at low speed/low gears and I have changed my AFM so someone said to check the dizzy aswell then I found this thread so it maybe why it keeps doing it well I'm hoping.

Timing definately set up alright?

Whereabouts is the part number on the dizzy have I got to take the cap and everything off?

I rang my local VW garage and they can get refurbished dizzys in for £124 in exchange for my old one

I think I might have the wrong dizzy as it keeps kangaroo jumping quite badly at low speed/low gears and I have changed my AFM so someone said to check the dizzy aswell then I found this thread so it maybe why it keeps doing it well I'm hoping.

Timing definately set up alright?

I haven't got a clue to be honest mate anything I could check?

Edited 24 June, 200719 yr by pinky

I just bought another black GT with the wrong dizzy fitted. It seems common that people have the wrong part fitted over ownership.

I changed the hall sender from a spi to A gt dizzy, works as a normal GT dizzy should.. I'm happy!

mines running badly checked it today guess what AA code arse :(

Edited 7 August, 200817 yr by kev...

Been chasing an idle problem for months and just come across this thanks to MartyB... mine's an AA. D'oh! It's defo been changed as it's a '94. Makes me wonder what else on the car is off an SPI too, hope the blocks correct etc. Seems like changing it to a P/T/AB dizzy should solve the problem. Cheers all for the help!

Ha ha glad i read this! Turned out i had a AA - Spi dizzy on my gt. Will be slapping a 030 905 205 P on! Noice

my dizzy's part no finished with 205 h???

is this the correct one or?

H is another version of an SPI dizzy, the predecessor to the AA version.