IT'S FIXED!!!!!!!!!!!!!!!!!!!!!

Mmmm????

Odd that when Al changed his metering head the problem went away!

I might just swap one over to test that theory!

Quick update:

Changed metering head
Warm up valve
HT Leads
Coil
Ignition Module

Same symptoms  :twisted:

Tomorrow I'll look at:

Fuel pump
Hall sender
Injectors
Water in fuel
Injector pipes

Any other ideas?

when you say ignition module do you mean the small block with the heatsink that sits in the scuttle behind the coil? I was going to suggest changing that as my friend's had similar trouble with his Caddy  :dontknow:

The hall sender unit in the Disi is the bit that normally fails. Not heard of the black unit in the scuttle failing.  

turbtechnicsMK1 said

The hall sender unit in the Disi is the bit that normally fails.

I didn't know there wa a hall sender in a Gti dizzy?

Anyway, I seem to have fixed the problem, well 95% of it anyway!

Last night I went home to try out a few things.
Started off by pulling the leads one by from each of the cylinders. Surprisingly this seemd to have no effect  :dontknow:  I think the fact that it was missing anyway was hiding the miss that resulted from me pulling the lead?!?!?

With that test being inconclusive, I pulled out all of the injectors to do a flow test and check the spray patterns.
To my surprise all of the injectors came out with little hats on the end!
I was surprised because when I pulled them out last week, none of them had hats! (They must have been shopping!). On closer inspection, they were not sitting correctly on the end of the injectors. I pushed all hats on securely and continued with the test.

Results:
None of the injectors produced brilliant spray patterns unless on full chatter where only No. 1 seemed a little less misty than the others.
After about 30 to 40 seconds of lifting the plate, I switched off and measured the output. 2,3 and 4 were almost spot on when compared to each other but No.1 was a bit low - about 15% less

Re-assembled everything ensuring that the injectors were pushed in firmly (on the old seals as I forgot to call in GSF on the way home… ).

Turned the key and started her up and lo and behold - the miss had gone  
I took it for a spin up the road and it seemed great. Came back down the bypass and found it to be a little flat in the top of the rev range, with a small-hardly-noticable miss now and again on full throttle only!?!

I am now unsure if the metering head I took off the car actually has any faults. I think I will swap it back on to the car when I have built up some bonus points with the wife (she's not too happy I have spent so long fixing the car…).

I am also puzzled as to why the problem started in the first place, as it seems to have gone away (mostly) on its own?!?!?

What do you think then guys?

AL_Mk1 said

turbtechnicsMK1 said

The hall sender unit in the Disi is the bit that normally fails.

I didn't know there wa a hall sender in a Gti dizzy?

To my surprise all of the injectors came out with little hats on the end!
I was surprised because when I pulled them out last week, none of them had hats! (They must have been shopping!).

What do you think then guys?

Yep, under the plastic cap inside the disi is a hall sender unit, connects to the little 3 wire plug on the side of the disi itself.

Ummm…. mk1 GTI running caps - they only came on MK2's with the air shrouded injectors. The air shrouds must have been stuck in the injector holders last time you pulled them out. Might have been limiting the spray pattern but would have thought the injector would nto seat properly. Perhaps you had a small air leak making it run weak ?


I think your Cars on a wind up AL - it clearly has it in for you      

turbtechnicsMK1 said

I think your Cars on a wind up AL - it clearly has it in for you      

LOL - I think you are right!
I was planning on going to the local Club Gti meet last night. I don't think the car wanted to go, so has been pulling a sicky on me!!!

As for the capped injectors being in Mk2's, I think the engine I have is actually an early Mk2 unit. My mate commented on something when we pulled it out of the Mk1 I had it from - Can't remember what it was now but something about the position or type of one of the attachments?!?

Good to hear you may have got on top of the problem Al. As turbo says, you should only have the hats on a mk2 engine whats the engine code? Someone on the forum (can't remember who) found it ok running without these hats anyhow :?

I've had numerous, fuel injection problems that I fixed without knowing how or why? Seems the K-jet system, although in the main reliable, is capable of having little fits.

Cheers

markwon said

you should only have the hats on a mk2 engine whats the engine code?

Not sure on the code - can't read it off the block… Didn't the early mk2's have DX's too though?

markwon said

Seems the K-jet system, although in the main reliable, is capable of having little fits.

You're not wrong there mate!

Overall it is a perfectly sensible system - It's actually kind of like a giant, disjointed Carburettor. Can be a right pig when you have probs though!

Think I've sussed my problem - No 2 injector mostly blocked.  Swapped with Injector one to proove pipe is OK.

Did prowler's test and got vitually nothing from the injector.

This was after replacing the fuel pump - which I found held on with cable ties!!!!!!!  :twisted:  :twisted:

And draining the tank looking for water….

I've got a 90 cab and the injector thread is different to the earlier injector I've got.  Will try and clean out the one I have.

Al - glad yours seems to be sorted  

Seems like missing problems can be down to a single blocked injector or blocked injector pipe or i guess blocked metering head!!

AL_Mk1 said

markwon said

Didn't the early mk2's have DX's too though?

No, even the earliest Mk2's had a different engine code, becaue they have different cams to give a little more power* to pull the heavier body, so a different engine code was assigned by VAG, although the engine is almost identical to a DX in every other way (sorry, can't remember the Mk2 engine code though)

*They didn't give it enough extra power though - the the 1.8 Mk1 GTI is a quicker car than the Mk2 (8v) version  8)

There we go - Cheers Type17!

 I still don't know if it is a DX or a ?? though!!

(Donning anorak)… early mk2 GTI engines were EV code, may have changed when digifant was brought in? Think the cab kept the DX engine code until digifant? If your engine needs the hats to run it would appear to be a mk2 engine as no mk1s require these. Do you know if it has a shimmed or hydraulic head?

Cheers

markwon said

Do you know if it has a shimmed or hydraulic head?

Cheers

No… ops:

Don't think I have ever had cause to look in there…
I remember doing the shims on one engine, but I think that was the 1500 I had on 40's…

No…   ops:

Thats ok - probably means you get out more than me . Think I'm right in saying a hydrualic head has a splash gaurd over camshaft. This means when you top the oil up you cannot see any cam or rocker gear through the filler hole. Older style shimmed heads camshaft and rocker gear is visable through the oil filler opening.

Cheers

markwon said

[probably means you get out more than me

Actually - i probably Don't! I've become a hermit over the last 2 years or so…

I deffo don't have the splash guard fitted, though I seem to recall fitting one to the 1500cc shimmed head - they do actually fit both the early and late engines don't they???

It's difficult to say when the cam-splashguard was introduced - I've always found them inside all of the DX engines that I've looked in, or owned (about 5 or 6 over the years).

However this doesn't mean that they weren't added during overhauls by careful owners…  :dontknow:

My 'early-1800' DX didn't have a splash guard, the firm that did the machining said the early ones didn?t, but someone may have removed it in the previous 165,000 miles. But then again looking at the condition of the car I don?t reckon the camcover had ever been removed?..

I think the later MKII digi-pants engines are coded PB?

have you got total compression to all cylinders? because i take you have spark?  8O

***UPDATE***

Right - Last night I changed the fuel filter, rotor arm and injector seals.

(Fuel that came out of the inlet side of the old filter was full of black particles and injector seals looked knackered!)

Result - MUCH better, though still there.
Again, on full throttle only, but now, once the revs pick up to around 3.5K, it stutters. I can now give it much more throttle than I could before.
It also idles much better than it has done recently.

So - What do you guys think.
More than one problem reared its head at the same time and I have only fixed one?

More feedback welcome!

AL.