Cylinder no 1 running rich others cylinders ok

Hi,

Golf 1982 mk1 1800 gti

I have small misfire and rough running at low rev (<2000) but at higher revs the misfire disappears.  Looking at the spark plug no 1 is black and sooty, rest are pai brown and look fine.  Have replaced the obvious, leads, plugs, dizzy with new cap and arm, even replaced no 1 injector.  I have checked cold start injector which operates correctly.  Recently replaced fuel pump for a new one.  I am hoping that its not a valve problem, the engine is a recon and has only done 14000 miles.

Could the metering head be faulty in this manner only feeding 3 injectors correctly?  Could an injector line cause this problem i supose with CIS i could swap a line over and see if the problem moves to another cylinder.

Any suggestions appreciated.

Thanks
Cussco

Cusso

I have a lazy cylinder no2 and have swopped over the cis line this has moved the problem !

The lazy part only happens if the car has been on a long run and is still hot . It i should ad it clears with a few revs . Have you replaced the plug ?
Swopped the injector ? Just in case . A good quality fuel cleaner may also help .


Cheers ………….

I have replaced plug and replaced injector with new one.  Also it never clears, cold or hot it is always there.  I will swap the line over tomorrow and recheck.

Got any other suggestions.

Cheers Cussco

You said the deposits are black and sooty, which probably means the following doesn't apply. If the deposits are black and oily on the other hand…

Try checking the valve clearances - could be a leaky valve stem seal or sticking valve (I'm not exactly sure how you would differentiate between these different faults without taking the head off). Is the car burning oil?

It could be that the clearance of the valves for number one cylinder is out - this is easy to sort. Might also be worth looking over the camshaft in situ for obvious wear.

NB - When you check valve clearances, it's not hugely difficult to do,but make sure you turn the engine over using the crankshaft sprocket bolt, not the camshaft sprocket bolt - or you risk stetching the cambelt.

Ali Cabrio

I have a sooty no. 2 plug also! I don't get any missing, though I did until I changed the HT leads.

I've changed the injector and spark plug but it still remains. I also get really poor fuel economy too. Average about 25mpg. I checked the CO2 and it seemed fine but then I checked the timing afterwards! I've reset the timing as it was slightly advanced, so I need to check the CO2 again.

I havent tried swapping over the CIS line yet, hadn't thought of that.

If that does move the problem I have a practically new metering head spare to try out. I know I have a bit of muck in the tank so I really need to start from square one with a clean tank.

The car goes ok, just has a bit of a lumpy tick over, its also had some engine mods in the past but I dont know what they are so maybe theres a different cam that has made it lumpy on idle :dontknow:

I have a sooty no 3 plug, the rest are perfect, replaced leads, cap, plugs all replaced,  no change. Where and What is the CIS lead you all refer to. car is also very heavy on fuel.

Its the braded fuel line that runs from the injector to the metering head. Basically Chudd has swaped the line, injector and metering head outlet all in one go to see if the the problem moved to another cylinder and it did which would indicate a faulty metering head I guess :dontknow:

CIS means 'continuous injection system', which is the k-jet mechanical injection system used on the GTis.

The lines are the braided lines which run from the metering head to the injectors. As the injection is continuous, i.e. fuel flows to all 4 injectors all the time, it's possible to swap the lines between the injectors without affecting the running of the engine.

Seeing as yours is running rich, have you tried adjusting the fuel mixture (3mm allen key, recessed in a tube just next to the metering head)?

HTH

Rich

On the metering head, there are four allen key headed bolts. These are just caps - underneath them there are four adjustment screws which individually control fuel amounts to the four injectors. These should not normally be touched, but if someone has in the past, then one outlet could be supplying more fuel than the other three…

Just a thought… :roll:

Suppose one of those pressure testing like (like Crazyquiff is planning to stock) would be ideal for such adjustments.

Wow, many responses, thanks, looks like the metering head then, is the 1600 unique or can I get one off a 1800? I have messed with the 3mm screw and set it to the optimum setting as per another thread i read without a co meter, and it runs smoothly, the 3 other plugs are a nice beige colour and the overall mixture seems dandy. I will look at the individual pipe, it cant get any worse and see what happens. that may answer my poor performance aswell. will still do a compression test though, i think its worth checking.

Thanks for all the suggestions.  I have not had time to try anything yet, when I do I will post results.  Has anybody ever tried adjusting the metering head as suggested by AL_Mk1, if so how sensitve is the adjustment.

The car  goes fine but fuel consumptions seems poor and the car often smells rich.  I have adjusted the mixture with colortune on a good cylinder but cannot get number one to match.  Idle pulses could this be a timing issue.  I shall have to recheck again.

Cheers Cussco

cussco said

Has anybody ever tried adjusting the metering head as suggested by AL_Mk1, if so how sensitve is the adjustment.

I have turned one while poking around in the past. Only when I played about did I realise that they are not screwed all the way in. I carefully turned one of the others inwards, Quarter turn at a time until it stopped, so I had a reference. I think they were 2 and a quarter turns out from fully seated. I re-set them all to that level and it made no difference to the running of the car…
You could check one of your good ones for the standard setting and then see if the bad one is out  :dontknow:

I have heard talk of Bosch tuning specialists being able to squeeze a little more power than standard out of the system without mods - I imagine it is these that are adjusted at the expense of lower fuel economy.  :dontknow:

Thanks AL

I have been too busy (made redundant and started new job) to try anything till lately so here is what I have done:

No1 running bad Black Rich (brand new injector)
No2 running ok not black but a bit rich (old injector)

I have swapped the fuel line from No1 to No 2 = No1 still the same so not fuel supply.

Double checked cold start injector thinking it was dribbling extra fuel to No1 as its on the same side in the inlet manifold = Ok

I have swapped leads, plugs, new dizzy (other problem), new ignition module, new fuel pump + relay (rusty filler replaced another story), replaced fuel filter twice in 6 months.

I bought a gunson colortune to check mixture and this also tells me No1 is rich if I set the mixture on No2.  Anyway ended up setting up on No2 and rechecking the timing best I can do.

I have adjusted the metering head (adjustment on actual metering head not the mixture screw) carefully counting turns and with the colortune but this adjustment does not make any difference at all.  I reckon these are for fine tuning at high speed revs i.e. top end speed.

The missfire continues and becomes more noticable as the car gets warmer.  Cold start is fine, with high tickover at first then settles to 1000 rpm.  Tickover is bit lumpy and the engines seems to pulse.  This missfire continues now till 3000 then goes away.  Car pulls ok and has been doing allot of miles lately (65 a day) with no problems except the missfire and thirst for fuel.

I must do a compression test (need to buy tester) to check the cylinder, I hope its not loosing compression as its a recon thats only done 15k in nearly 5 years.

Anybody with any ideas as I am completely stuck.

Cheers Cussco

not a technical solution, but as youve changed fuel pump etc it might be worth running  forte injector cleaner through, before you get into more serious answers, i had a rusty filler neck and used this after id changed the fuel supply.
http://www.vwgolfmk1.org.uk/modules.php?name=Forums&file=viewtopic&t=15756
hth (cheaply!)

Thanks cabriaulait

I hope its that simple.  I have tried redex lately but no joy.  I shall still try the forte stuff wont do any harm.  

I starting to think it may be compression or valve problem as there is not much left to change on the injection except for the fuel lines and tank.  Hopefully its going to be valve clearences need checking which I can do, if its the cylinder then thats a big job.  The only thing that gets me is that the recon engine has only done 15000 miles, so you would not suspect the engine unless I got a dud.

Cheers Cussco

Update on the sportline's sooty number 2 spark plug…
I ran prowler's injector test over the weekend to see if there was more fuel getting to number 2 cylinder. Looks like there is a bit more but not much. I've swapped the injector so I dont think the problem lies there as its been sotty since. Next I guess I'll swap the lines over at the metering head and see if another plug gets sooty instead.
Here are the results…

The top line on the bottle is 100ml bottom one is 85ml I went a bit over though! So no.2 isn't much more and not sure if its enough to be worried about :dontknow:

  Getting the injectors out was a real pain. 2 seals got left behind and when I pulled the injector out of one the hat on the inhector got left hehind! Managed to get it out with some tweezers though after removing the injector insert and it fitted back on the injector no probs.