is it possible to just change the trigger wheel? (doesnt help if youve not got the right dizzy to start with though.)

It is the hall sender that is a different part number for the GT/G40 dizzy. Looking at the diagram of components, you get a new trigger wheel with a replacement hall sender part. Like i have said you can use the mk4 dizzy with the part number 030 905 205 AB

Gaz, do you wanna lend me that SPI dizzy to have a go at swapping the trigger wheel over

is it possible to just change the trigger wheel? (doesnt help if youve not got the right dizzy to start with though.)

Can't see why not. I've swapped one between two GT/G40 dizzies before, and it'll definately fit into an SPI housing.

It is the hall sender that is a different part number for the GT/G40 dizzy. Looking at the diagram of components, you get a new trigger wheel with a replacement hall sender part. Like i have said you can use the mk4 dizzy with the part number 030 905 205 AB  

Gaz, do you wanna lend me that SPI dizzy to have a go at swapping the trigger wheel over

Only if you dont break it. I know it works on the car ok so its good to keep it as a spare. but I wont stop you from trying (And then you can show me)

Since I scrapped the ranger though, I've now got 2 spare SPI dizzys.

My theory is to make a GT/G40 dizzy from a mk4 AB one and a mk3 AA one.

I've checked mine and its 030905205AB does this mean is a MK4 one? its on my GT which would be better this or a proper GT one?

Yes, the AB version is a mk4 polo dizzy, probably just as good as the standard GT one. Best alternative at the very least.

I had the new owner of PHATBOYDAVE's car round the other day. Car was suffering from a really bad stalling problem. The only thing wrong I could find was - youve guessed it - it had the wrong dizzy on it. So he is currently getting a new dizzy from bosch to see if that cures the problem. Watch this space...

Hey Gaz! i just checked the one i had free off Steve for my GT engine, and that is 030 905 205 A.

Any idea what that's off?...and if ill encounter problems with it?

Mind you, I'm not running it on mpi, running it on either a 1.3 pierburg carb or bike carbs (if i can get em to work )

Thanks for the cam by the way!...will stick it in the ABD once I've finished polishing up my new cam cover.

If youre running carbs it should have vacuum advance on it, so presumably its a mk2 dizzy? As long as you have the mk2 amp and loom to go with it itll be fine.

Yep, definately got the other bits for it....cant think if its got vac advance though....recon its electronic ignition.

Ta

Oh, me etka's being a bugger to load up! keeps crashing my pc?.....any ideas?

A late mk2 dizzy has vacuum and centrifugal advance with electronic ignition. (early ones have contact breaker instead) How long is the dizzy? ones with built-in advance are about 2" longer than ones that just have a hall sender in them (mk3 style) Like I said if youre running carbs and dont have any type of advance mechanism in the dizzy, you need an ECU to advance the timing (The GK engine does it like this)

I'm not trying to confuse you, honest. I'm sure steve has given you the correct one for your desired application.

I had the new owner of PHATBOYDAVE's car round the other day. Car was suffering from a really bad stalling problem. The only thing wrong I could find was - youve guessed it - it had the wrong dizzy on it. So he is currently getting a new dizzy from bosch to see if that cures the problem. Watch this space...

Dizzy should arrive tomorrow, so I'll keep you all updated as to how it plays. Although I've since changed the Lambda sensor and the cold start sensor on the stat housing, mucked around with the CO pot and the idle speed and it's much better, just still not quite right. Here's hopin the dizzy makes it and lets me run it harder

Cheers Gaz :)

I just got a new dizzy other day, its a beast

Just a random concerning hall senders.

My mate had a VAGcom check the other day and it said the hall sender was dodgy. His car is a 2.0l simos managed Mk.3 Golf. Not having any of these senders in stock, I suggested that we try and fit in a Polo part and removed one from an SPi distributor (205AA part number ending). It slotted straight in and worked fine and has eliminated that particular problem on his car, although I think his MAF sensor is buggered which is where I'm gonna look at next time he's around...

Just noticed this thread whilst searching for solutions to the common GT idling problem and i've just check the dizzy on my car.

Part number for my current dizzy is 030 905 205 AC.

I'm guessing this isn't quite the right one?

This was replaced about 10k ago due to random stalling problems and its never idled properly since and gets worse every time we attempt to adjust it.

After endless new parts like temperature sensors and idle valves i'm wondering if this could be my problem too.

Any help would be much appreciated.

Stu

on etka, it is listed as a part just for the mk3 golf and vento. After a bit of searching it looks like it is used solely on 2litre engines. I always thought the dizzy on big block engines was driven off the crank, but I guess not. From what you descirbe, and what steve (86c) mentions in his post, it sounds like it has the same design as the polo SPI distributor, which is not compatible with a GT.

Thanks for your help Gaz, this all sounds quite strange and a little worrying to be honest.

I'd been browsing the online etka at vagcat.com and had so far found AA, AB and AD varieties of the dizzy all found on various polo's but hadn't found the AC variety.

As you say tho i've found it on various 2 litre dubs; mk3 golfs/vento's etc.

Now begins the search for the right dizzy.

Thanks again mate.

With the help of Steve, who sorted me out a new dizzy, (P coded) and my brother, we fitted the new dizzy tonight and boy am I a happy man.

It's solved my awful idle problem, removed all flat spots and generally made the car drive and feel like it used to.

I can't tell you how pleased I am as I was sick of spending money on parts that didn't appear to be making any difference.

So moral of the story: Check your GT has the right dizzy before spending any money.

Big shout out to Steve (86c) for testing and sending me the dizzy quick time and Gaz for starting this thread!

Glad you found this FAQ useful.

so it the number ends with AA its not gt/g40 dizzy?

Correct!

just checked and thank god i have the right one, if this breaks what will be the first thing u noticed, cause when ever i put my foot on the clutch while drving it just dies revs just drop stright past the limiter and the car stalls

any help?

It's unlikely that the dizzy is at fault. More likely the idle stabilisation valve or the throttle position sensor. The most common failure on the dizzy is the hall sensor. If this goes the engine will just cut out. Doesnt matter what revs youre doing.