04/08/2010

I've decided to tidy up this post as it's a bit cluttered. In summary, check the part number on your GT's distributor. It should be either:

030 905 205 P Original Part

030 905 205 T Replacement Part (Superceeds P) Bosch Part Number 0 986 237 668

030 905 205 AB Mk4 MPI distributor

All three of these distributors are proven to work properly with the digifant ECU GTs have.

Distributors known to not work properly:

030 905 205 H Mk3 Single point injection Distributor

030 905 205 AA MK3/4 Single point injection Distributor

030 905 205 AC 2.0 8v MK3 Golf Distributor

All of these are for non-Digifant applications and will send incorrect signals to the ECU, causing improper ignition timing and reduced performance.

Image of an SPI and MPI distributor. SPI is on the left, MPI is on the right. Note the difference in the size of the gaps in the trigger wheel

Original post - 31/10/05

Turns out mine didnt. Its had an SPI one ever since I put it together. Good job i found that scrapped GT. 8) The dizzy it had on came off Steve-O's GT's original engine, which had been reecently replaced with a "new" one (read - from scrap yard)

Now some people say that this dizzy works ok on a GT, but mine had never idled right, and when I looked at the advance with a timing light with the old dizzy on a few weeks ago, the area it was firing at idle in "normal" mode was way after TDC, but in service mode the timing was perfect. I put this down to my car being a bodge. ( ) But putting this dizzy on from the scrapyard gt and it was perfect. firing before TDC like it should. 8)

I put the part number in etka (030 905 205 P) and it said part number could not be determined. The GT/G40 one is supposed to end in T. Presumably this is like the GT inlet manifold part number that changed later on to a G from a B (summat like that anyway) can someone confirm?

Thank you please.

030 905 205 P is the correct one, glad you've got it running even better! Will be interesting to see what power it makes now, and whether it can still spit flames.

Personal experience agrees with your findings too. Barningfield's GT never ran right on a CL dizzy and the GT setups I ran in my car didn't either. Hardly surprising really, as the hall sender trigger wheel spacings are different - so it'll give a different output waveform to the ECU.

Cheers Andy. Gonna go for a run for a bit to see what its like. 8)

So, hold on hold on.

What are the findings here? Gaz - you've had an SPI CL dizzy in your GT and it was poo. But you replaced it with a correct MPI GT dizzy (number 030 905 205 P) and it's now working smoothly?

We replaced ours right at the beginning. I'm sure it was a brand new GT one we put it... but maybe it wasn't? Is there any way to determine which is which? 'Cause I've never had good idling and almost EVERYTHING has been replaced - not directly related to the problem, but items that would cure it.

yeah the dizzy itself has a part number stamped on the bottom. Oh and yes - your analysis of the situation is correct.

Sweet buns. Gonna go have a look.

Ok, I just snapped a pic of my dizzy. Looks like my part number reads "030 905 205 AA"

What does this conclude? I have the wrong dizzy? For which model is this dizzy - SPI CL?

Doh, looks like youve got the wrong one too. And yeah same one as I had (SPI 1.0/1.3)

So I may have found the source of my shitty idling and response!

Can you buy the GT dizzy new still?

Thats an SPI dizzy, was the same as that on Doughy's old GT. It probably will be common place due to age of cars. A lot easier for someone to get hold of an SPI one from a scrappy than a GT one. The G40 engine conversion i got hold of had a MK4 polo dizzy on it

only from vag, or possibly a bosch agent.

You can get them from Bosche, the part number above the VAG one is the Bosche part number. GT/G40 dizzy part numbers end in P or T.

Gonna go check mine now...

How much are they new?

they're around £100 I think.

Can someone please confirm VAG and Bosche part numbers for the GT dizzy so I can go about getting a new one if it's not too heavy on the wallet.

they're around £100 I think.  

At least :( Lambda probes are getting on for £50

pff not cheap then. I'm buying a new Lambda probe this week, £45! just checked my dizzy, its the right one (thank god). I bought it off DK recently, tested etc, so it should be ok! it seems fine. Is there any signs their on their way out, because my old one just died, and i dont want it to happen to this one.

i can get the number from mine tomorow. And yeah they just stop working when they go wrong.

I better check mine tommorow now..bought the engine off a right dodgy looking guy :p

I put the part number in etka (030 905 205 P) and it said part number could not be determined. The GT/G40 one is supposed to end in T.

The original VAG part number is 030 905 205 P, but this has been superseeded so if you get a replacement now from VAG it will be 030 905 205 T

Ok nice.

Confirmed part number for VAG then:

030 905 205 P (original)

030 905 205 T (new number)

mine runs fine with a 1L dizzy, and when I got my car originally it turns out that it had a repelacement dizzy less than a year old without any markings but thats also a 1L dizzy.

at the RR day last year my GT had 88 bhp and yoof's had 90bhp this year, and I was running a fairly similar setup e.g. golf AFM and 4 branch exhaust, but I did have one of Dans chips in it.

Just looking at ETKA and there is only two dizzy versions for the MK4 polo, so one of these may be better than an SPI mk3 one as a standby.

What mk4 engine is the AEV?

I think AEV is 1.05 SPI

I put the part number in etka (030 905 205 P) and it said part number could not be determined. The GT/G40 one is supposed to end in T.

The original VAG part number is 030 905 205 P, but this has been superseeded so if you get a replacement now from VAG it will be 030 905 205 T

yeah thats pretty much what i said in the next sentence, (but badly worded.)