New to Mk1 and possible metering head issue.

Hi all,

I have recently bought a Mk1 Golf GTi 1800 with a bit of a hesitation issue.
I thought it needed a tune up but it turns out to be a little more in depth that first expected.

I book the car in with Roy at Autobarn to see if he could service the car and identify the cause of the hesitation. Unfortunately he ran out of time due to a stubborn thermostat housing.

Anyway I have booked it in today for it to be investigated and had a phone call to say that he's done all he can to the car but he is unable to take it any further as he doesn't have the experience or knowledge about the intricate k-jet system.

The car has had new injectors and intake manifold 6000miles ago.
Fuel Lines are all new.
The Co2 levels are OK. They were a little lean and have now been adjusted.
The timing is bang on for unleaded fuel.
Plugs, HT, Dizzy and rotor arm are all new.

He has told me that I may have a faulty metering head or the head might be coked up as it seems to get slightly better when warm. The car has been maintained very well and has just done over 152k on the standard engine. Roy commented that the engine is in really good condition considering the age and mileage.

I'm ideally looking for someone or a company that can help locally or if anyone has a metering head that they don't mind me trying then I would really appreciate it.

I will be popping along to the Berkshire meet tomorrow so would love to speak to some of you that might be able to help.

Hi Again.

I have used the guide to test the injectors and can confirm that I have a faulty metering head as I swapped injector one to a different pipe and pipe and it still read low. I also swapped line's on the metering head with the same results.

I guess I need a new metering head.

maybe not. the fuel line can be shimmed to achieve higher/lower fuel pressures. the pressure at the injectors can be individualy adjusted via the metering head. can you be a bit more in depth about the symptoms, when they started, and what you have done, since experiencing them or what you may have done that preceded the symptoms.

Hi Wooders,

Just reading my post I don't quite make it clear how it's actually hesitating.

Well I bought the car recently and it had this issue when I bought it. When driving with slight acceleration the car seems to hold back alot feels like it's missing. The same can be said for any partial or full acceleration.

Under deceleration, coasting or cruising the the problem seems to disappear.

When cold it seems to be worse and since the full service which was performed by Roy at autobarn the car seems slightly better.

Going through the mountain of receipts it gives me the impression that this has been investigated in the past and everything from a tune to new pipes, injectors and manifold have been replaced.

I'm very much interested in how to shim the fuel lines but already have another metering head from Paul C winging it's way.

To be honest I'm quite good with cars with ECU's so this Mk1 is proving to be quite difficult for me.

Still haven't had that grin on my face yet as this issue is kind of getting to me now.

well a spare metering head is never a bad thing anyway. it could be a problem with the ignition not retarding correctly. there is a vacuum pipe from the vacuum canister on the side of the dizzy to the back of the throttle body. worth checking. there is an article paul c done wich entails shimming the metering head. you'll need a fuel pressure gauge to do it properly though.

Wooders,

is there anything I can do to categorically know for sure if it's a vacuum issue.

I have done a leak test with some carb cleaner and it's fine. No vacuum issues.

I also blipped the throttle with the tube on my finger and I can feel a good vacuum. Is there anyway to check whats going on inside the distributor with the engine not running?

You can check the vacuum retard is working by using a timing light. Firstly with the vacuum connected, then disconnecting it, should give a big difference in the ignition advance. (It should advance a lot when its disconnected). If you're able to measure the number of degrees difference in the two, you could compare it to specs.

As said before (can't really add much) you should check fuel pressure before writing off the metering head, to be sure. A second, known good, metering head, is another way round it but you'd obviously need to set up the mixture on it too (since the WUR is different). It could also be a duff WUR - again the way to check this is using a fuel pressure gauge.

I see.

I'm pretty sure Roy checked timing using this method.

He did connect and disconnect something when checking the timing.

Is the fuel gauge meter easy to make out of spares or is the only readily made kit available for Crazy Quiffs.

Also can you send me a link to the how to guide aswell.
Not asking for much am I Paul LOL.

Cheers

Tony.

tbcuprat said

I see.

I'm pretty sure Roy checked timing using this method.

He did connect and disconnect something when checking the timing.

Is the fuel gauge meter easy to make out of spares or is the only readily made kit available for Crazy Quiffs.

Also can you send me a link to the how to guide aswell.
Not asking for much am I Paul LOL.

Cheers

Tony.

Crazyquiff is not an exclusive supplier of the fuel presure gauge, although you can't simply make it from scrap lying around. You're basically looking for a fuel pressure gauge for a K-Jetronic fuel injection engine (there's loads of other cars as well as the Mk1 Golf which use it). ebay is probably your friend here.

I can never remember where the link is myself! In any case, you'd still need to search through the 20 or so pages to find the relevant bits. Try a few choice words in the search feature with my name as the author and you'll probably find it, let me know if you dont.

Oh something else I omitted but only just remembered.

I have some unusual behaviour when starting the car from cold.

It seems to start first time and idles slightly higher and then it drops after a minute to around 400-500rpm. Once the car is warm it idles back to normal and sits at 800rpm.

Could this be related. I have read that this could be due to a faulty auxiliary air valve.

disconnect the aav and see if it's worse or the same. could be the wur or co likely too lean.

All good advice above - but I'm not sure each injector pressure can be adjusted individually???  Sure the system pressure can be adjusted to some degree.

The only real way to understand where the problem is is to run a full system pressure test, injector test and pump delivery test.

You can throw away hours of messing around and tons of cash if you don't know where the problem is.

I have a customers car in at the moment - I said I'd sort it for them as they were about to give up - they had thrown ?1000+ at the problem.

Turns out the pump was not able to deliver the system pressure needed  - no problem delivering fuel quantity - hence they had a hot start problem.  The engine also died when hitting the throttle when cold - warm up regulator problem.

Took me about an hour to diagnose both faults and now the engine is running sweet.

Go and make or buy one of my guages and do it properly.

Cheers

Rich

quiffies bang on as far as throwing hours and ??s away.

where the injector lines are at the metering head, there are allen key caps next to each one. if you undo these there is another allen grub screw inside. these adjust fuel/pressure on that fuel line.

wooders said

where the injector lines are at the metering head, there are allen key caps next to each one. if you undo these there is another allen grub screw inside. these adjust fuel/pressure on that fuel line.

Ooooh - Mind you the metering heads wern't meant to be adjusted so if you've got one port way down it's probably due to corrosion or dirt.

Hi Rich,

I really don't want to throw mindless money at it and also have very little time to tinker and not really know what I'm doing.

Would you be able to diagnose the car for me if I was to travel to you and pay you.

Cheers

Tony.

tbcuprat said

Hi Rich,

I really don't want to throw mindless money at it and also have very little time to tinker and not really know what I'm doing.

Would you be able to diagnose the car for me if I was to travel to you and pay you.

Cheers

Tony.

Tony,

Only problem is will need the engine stone cold - can do all the hot tests though.

Cheers

Rich

Rich,

You have a PM.

Just like to say thanks to Rich for sorting out my motor today.

It was the metering head in the end and although we replaced this we also found some other untoward issues which he happily helped me fix.

Came away with loads of bits that I needed but could have easily spent a lot more.

p.s the exhaust split in two completely on the way home.
I couldn't hear a thing by the time I got home.

PARDON?

Good to see you yesterday and glad your Mk1 is now performing so well it blew the exhaust off  

Very nice Mars Red Campaign that one.

Cheers

Rich