VW Golf Mk2 Owners Club

Technical => Technical => Engine & Gearbox => Topic started by: Martin109 on June 08, 2022, 07:53:38 AM

Title: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on June 08, 2022, 07:53:38 AM
I've been having some intermittent problems with this.  Drove down from Slough to Southampton without problems on Friday, but after stopping on an upward slope in the town to check my route, the car would not start, and I saw that there was no fuel in the see-through fuel filter.  The AA man I called out suspected I was out of fuel, even though I knew I had half a tank.  He towed me to level ground and got the car started by spraying brake cleaner into the side port of the Weber carb while I cranked the engine.  As he still suspected low/no fuel, he accompanied me to a petrol station where I topped up, which confirmed I had had half a tank all along.  Finally, he suspected a weak fuel pump (this is mechanical cam-driven on the Driver), and suggested it be investigated further.

I was next due to drive to Bristol, and this went without any problem at all.  The next day I did a short run for shopping with no problem either.   However, yesterday, having gone locally into Bristol again, initially without problem, suddenly the same issue arose, this time on level ground.  The engine died and wouldn't start.  Again, the fuel filter was empty.  I found a GSF store some way away and purchased a new fuel pump, but also got some brake cleaner, in order to emulate the AA man's trick, which worked!  Got back the 8 miles to home without further problem, until setting out again in the evening, when the problem arose again, but this time the brake cleaner trick didn't work.

I intend to swap out the fuel pump today, but what if the problem is not that?  A couple of years ago, when my trusted garage in Slough were sorting out an intermittent issue which they couldn't decide was fuel or electrically related, they replaced several units such as fuel pump and coil and distributor cap, but also removed the reservoir.  Since then, until now, the car has been running problem free, but now I can't help feeling having the reservoir in there might help to even out fuel delivery if the pump is occasionally struggling to pull sufficient fuel up from the tank (this is the only pump in the driver; there's no pump in the tank).

Is it worth renewing all the 32-year-old fixed fuel lines?  Is it an idea to have the fuel tank drained and cleaned out, if there might be 32 years worth of crud in there?  Any advice gratefully received.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Monkey on June 08, 2022, 08:06:39 AM
It's been a while since I've played about with a Driver.
But do they have an electrical in tank pump?

If so, that could be your problem.
They're pretty cheap and while messy, not to difficult to swap out.

The way to tell would be to lift your boot carpet, open the round inspection panel and look at the connector going into the tank.
If it has two wires, it'll be just a level sender.
If it has four, it'll have a level sender and a pump.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on June 08, 2022, 08:08:32 AM
I don't believe they have a pump in the tank, but I stand to be corrected if this is not so.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on June 08, 2022, 08:30:46 AM
Just checked Haynes and there is no mention of a lift pump.

I would however check the pick up point in the tank.  It could be partially blocked so not allowing fuel to pass when the tank is half full.  My logic is that more than half a tank gives the head to allow the fuel to pass.  Parking on a slope allows fuel in a part full tank to move to the back of the tank reducing the pressure at the pick up.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Monkey on June 08, 2022, 11:02:42 AM
Just checked Haynes and there is no mention of a lift pump.

I would however check the pick up point in the tank.  It could be partially blocked so not allowing fuel to pass when the tank is half full.  My logic is that more than half a tank gives the head to allow the fuel to pass.  Parking on a slope allows fuel in a part full tank to move to the back of the tank reducing the pressure at the pick up.

Also, would there be a gauze on the pickup? This could be blocked.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on June 08, 2022, 11:06:44 AM
Just checked Haynes and there is no mention of a lift pump.

I would however check the pick up point in the tank.  It could be partially blocked so not allowing fuel to pass when the tank is half full.  My logic is that more than half a tank gives the head to allow the fuel to pass.  Parking on a slope allows fuel in a part full tank to move to the back of the tank reducing the pressure at the pick up.

Also, would there be a gauze on the pickup? This could be blocked.

That's exactly what I suspect the problem is.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on June 08, 2022, 11:49:00 AM
Thanks for the replies.  Is it a relatively simple job to check the pick up point and gauze?
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on June 08, 2022, 12:33:53 PM
Thanks for the replies.  Is it a relatively simple job to check the pick up point and gauze?

Yes there is an inspection cover with three screws in the boot.  Remove it and you have access to the fuel sender secured by a big plastic retaining ring.  I'd recommend a new seal when reassembling.

Make sure you are not filled to the neck, about 1/2 tank should be fine.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on June 08, 2022, 03:52:27 PM
Thanks.  It's  not going well!  Could not undo the big grey knurled ring.  It shows signs of brute force on previous attempts.

Then, to try and test existing pump, tried to remove rubber fuel pipe from connecting T-piece (which garage must have fitted in place of the reservoir they removed) the plastic T-piece snapped, so I will have to source a replacement.  Will need to wait until next week when I can get back to the vehicle.  As I already had this piece of pipe open, I tested the pump by getting the engine turning over using the AA man's brake cleaner trick.  Seemed to fill the fuel filter but not send any regular reliable spurt of fuel out of the hose end.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on June 08, 2022, 04:35:22 PM
You need tools, I think the strap wrench got mine.  I think there is a fabric version of the filter chain that would fit easier.

(https://i.imgur.com/7TmiWOk.jpg)

Just tell yourself the T piece snapped because it was not fuel grade.  Get a fuel tolerant replacement.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on June 13, 2022, 03:08:47 PM
I can confirm that the filter chain wrench does a good job.  Used it on mine this afternoon. To tighten up but I'm sure it will shift a sticky securing ring.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on June 18, 2022, 05:58:32 PM
Thanks for the tips.

I see you have the advantage of the fuel tank out of the car, giving easier access to the grey knurled ring; it's much less accessible when in the vehicle.

I did swap out the fuel pump, and various bits of fuel line, and fitted a nice brass t-piece instead of the broken plastic one.

All this was successful, in that I got the car back the 100 miles between Bristol and Slough, and it's now at my trusted garage in Slough (Rosewood) for MOT and I've asked them to consider replacing the 32-year-old fixed fuel lines and to check on the pick up point gauze and general crud in the tank.  I imagine the there's all sorts of dirt and water at the bottom of the tank after 32 years!
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on June 18, 2022, 06:16:11 PM
No my tank was quite clean after 33 years but that depends who has owned it and what they have put in it.  I've seen some really nastily gummed up gauzes on the web.
The filter chain worked well through the boot floor pan, could well be what your garage uses.  Pleased you have a brass T-piece.  Don't replace the solid fuel lines (I don't think they are available anyway); it is the rubber bits on each end that fail.  Replacing them is worthwhile. 
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on July 03, 2022, 10:40:15 AM
New Developments:
The 1.6 Driver has a mechanical fuel pump, where an eccentic cam in the engine actuates the arm of the pump.  My trusty garage (Rosewood in Slough) have come up with a suggestion; their theory is that over 33 years successive fuel pumps have become less effective as the cam has worn, exacerbated by each pump gradually getting less efficient as it ages.  This is their explanation as to why my swapping out the latest fuel pump for a new one hasn’t quite sorted out the longstanding fuel starvation problem the car’s been having (and I mean for years!).  Their solution: fit an electric fuel pump.  As you see, they have fitted the electric fuel pump (http://www.martinsawers.co.uk/links/ElectricFuelPump.jpg) under the offside rear seat floorpan.  It works, and the carb seems quite happy with it.

The only problem is that it makes a noise.  As you see from the picture, they’ve only secured one side of the bracket, and loosely fitted an ordinary sponge in an attempt to deaden the noise!! :-\  Here are a couple of mp3s, demonstrating the noise outside the car (http://www.martinsawers.co.uk/links/OutsideCar.mp3) (NB the engine is of course running in the background, but the main noise is the pump!) and inside the car (http://www.martinsawers.co.uk/links/InsideCar.mp3). 

I’m wondering whether I could refit the pump with a piece of sound-deadening foam between it and the floorpan, with appropriate length self-tapping screws?  Maybe something cut down from this (https://www.ebay.co.uk/itm/374160944057?hash=item571dbaebb9:g:hjwAAOSwFZhiv1Y~)?  Would it be OK to screw into the floorpan?
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: PWardy on July 03, 2022, 12:21:40 PM
Did the garage test the mechanical pump?  Jar of fuel into an empty jar.  If the fuel flows it's not the pump.

That said perhaps there is something in it if the electric pump has fixed your running problem.  But why is it so noisy?  Again I'd test it sucking from a jar but delivering to the engine.  If it gets acceptably quiet then there is some problem other than the pump just being noisy.  I would get rid of the foam and not put a screw through the floor pan.  Ideally you need a mounting plate with rubber feet for the pump.

Edit are the pump electrical connectors sealed?  If not it will not last long.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on August 18, 2022, 12:50:51 PM
Yes, I've now learned that that is the site of a GTI supplementary pump, so the plan is to use such a mount to fix the pump and damp it at the same time.

Still having some intermittent issues, though, and now the fuel supply is OK, it must be something else.  What would be the symptoms of a failing coil?  Can they fail intermittently?  Maybe loose connection in the wiring associated with the coil.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: kartman on August 19, 2022, 09:33:40 AM
Yes, I've now learned that that is the site of a GTI supplementary pump, so the plan is to use such a mount to fix the pump and damp it at the same time.

Still having some intermittent issues, though, and now the fuel supply is OK, it must be something else.  What would be the symptoms of a failing coil?  Can they fail intermittently?  Maybe loose connection in the wiring associated with the coil.
I would put money on it being the wiring that feeds the coil from the ignition amplifier. I feel the factory routing leaves little slack and the cable over the years is stretched and breaks down inside. I found my break with the car running and wiggling the wire about and got a massive shock, not recommended! Best bet is to continuity test the wires at each end with a tester with a built in buzzer. Wiggle the wiring and if the buzzer stops you have found your break. I cut the wiring back past the break and added in a new slightly longer section of wire so it didn't happen again and it has been spot on ever since. Mine still has the original coil from 1990 too.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Eddypeck on August 19, 2022, 10:14:20 AM
The under-car fuel pump assembly from a GTI looks like this
(https://eddypeck.files.wordpress.com/2017/07/2016-08-30-20-46-15_zpshrupdv84.jpg)

But the base of this is the metal bracket it fits onto
(https://eddypeck.files.wordpress.com/2017/07/2016-07-02-14-44-48_zpsphv6uqqx.jpg)
(https://eddypeck.files.wordpress.com/2017/07/2016-07-02-14-44-54_zpsmfzml9oa.jpg)

This is what fixes to the floor pan using the threaded lugs that are already on your car body.
There are rubber mounts that take out the vibration, so my thinking was if you could get one of these brackets you could mount your electric pump to this then mount this to the underbody of the car in the same way the original equipment would be mounted.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on August 19, 2022, 09:10:33 PM
Thanks, EP & Kartman

That's really useful to see.

I'm planning to get Rory in Berkley to do that for me along with some painty stuff.

Would you happen to know a part number for that bracket?
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on December 13, 2022, 08:59:43 PM
There seems to be a lot going on at the moment with this car!

I’ve recently had a stalling issue where the car would just die when stopping at a traffic light or junction.  Trusty garage decided the carb base plate/gasket was leaking and it needed to be replaced, but they couldn’t get one in time for my next journey, so I had to use the car again and try and work around the same stalling issue.  However, not just this, but on my regular 100-mile journey to Bristol the running got rougher and rougher, and more and more erratic, and I only just got home, with the car refusing to start and I had to wind my way backward to park by using the starter motor.  (Thought the battery would die at that point, so I put it on charge but it was showing the green light in less than an hour).  Phew!

Had to call AA Home Start, we tried starting and it wouldn’t, so he removed each plug in turn and these proved to be wet, so the engine had been flooding.  We thought this might also be a result of the leaky base plate, and once he’d dried out the plugs and vented the cylinders, the car started just fine.  Got back the 100 miles to Slough OK, though not an easy drive, just better than before.

Back in Slough my garage replaced the carb base plate, and enthused about how beautifully the car was running.  And indeed it was doing great around town in Slough.  So I set off again on my 100-mile trip to Bristol.  The car seemed a bit under-powered, and about a third of the way in started running rough and being really low on power, but using more fuel.  I was able to struggle along at around 60 (M4, this is), and then off the motorway at Bristol I really had to work hard to manage it and prevent stalling at lights, fearing I wouldn’t be able to restart.  In fact, I did have to restart a couple of times, which it did, but reluctantly.  Then, suddenly, it was back to normal and running as sweetly as anything again!! Justlikethat! [Tommy Cooper].

That’s strange enough, but what is stranger is that during the nightmare motorway journey, while it was misbehaving, the temp gauge dropped and went right down to zero.  When later the car started to behave properly again the temp gauge was back up to its normal position (first white line on the dial)!

This suggests there’s an intermittent electrical issue going on, which reminds me of your comment upthread @kartman:

Quote
From kartman
I would put money on it being the wiring that feeds the coil from the ignition amplifier. I feel the factory routing leaves little slack and the cable over the years is stretched and breaks down inside. I found my break with the car running and wiggling the wire about and got a massive shock, not recommended! Best bet is to continuity test the wires at each end with a tester with a built in buzzer. Wiggle the wiring and if the buzzer stops you have found your break. I cut the wiring back past the break and added in a new slightly longer section of wire so it didn't happen again and it has been spot on ever since. Mine still has the original coil from 1990 too.

Would the wiring you refer to have any association with the temp gauge sender or the wiring to the gauge itself?  If this is an electrical issue, what would be causing these two things to be happening simultaneously?  Does the wiring you refer to just consist of a single wire or multiple strands.  Where is it on the wiring diagram?

Any ideas gratefully received.
[Edited To replace 'fuel' with 'temp']
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: kartman on December 14, 2022, 08:48:03 AM
Would the wiring you refer to have any association with the fuel gauge sender or the wiring to the gauge itself?  If this is an electrical issue, what would be causing these two things to be happening simultaneously?  Does the wiring you refer to just consist of a single wire or multiple strands.  Where is it on the wiring diagram?

Any ideas gratefully received.
As far as I am aware, the coil wiring has nothing to do with the fuel sender/guage.
From your descriptions however, it does sound a bit like an poor earth issue.
If you have the original battery earth cable it is probably past its best (as it has no covering).
You could try cleaning up all battery contact points, and all the earth points too (battery/gearbox and rocker cover).
A good upgrade is a battery negative cable from a mk4 golf, as that has the connector in the middle, but also is shielded so will not corrode as quickly.
I don't have a diagram to hand but it should be easy to trace the wiring from the coil (should be 2 wires) back to the igniton amplifier, under the drivers side scuttle.
Test for continuity along these, whilst also giving the wiring a good wiggle.
If all of these check out fine that electrically there is not a lot it could be, either: coil, dizzy (hall sender), ignition amplifier.
But seeing as your guage misbehaved too I would definitely check and clean all the earths and cables first.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on December 14, 2022, 10:01:22 AM
Many thanks @kartman, that's really helpful.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on December 23, 2022, 09:22:09 PM
If I were to replace the wiring between amplifier and coil, what ampere rating of cable should I choose?
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Eddypeck on January 09, 2023, 04:45:03 PM
Fuel gauge or temp gauge? I think you switch between them in your post so not sure which it is. But I think you mean temp.

If temp, would I be right in thinking the carb if hooked into the cooling system? Sorry, never had a carbed version only ever had GTIs.

My thinking, is could it be a thermostat issue?

Rather than stuck shut which would have different effect if it were stuck open then on the motorway the airflow would overcool the car, putting the gauge to cold. I'm not sure what effect this might have on the carb, but since this in winter, with cold airflow and wind chill on the motorway I suspect it could be carb freeze. And I'm fairly sure there's a coolant supply to the carb which under normal conditions would prevent this.

Other symptoms would be taking a long time to get up to temp.

The gauge should reach the optimal half way mark in about 10 mins. Lots of local small journeys may mask this.

Here's a test you can perform to check for good circulation (although you need the car running reasonably well).

Start the car and let it idle, you can give it some revs if you want to speed up the process.
From the engine bay grasp the bottom radiator hose. It should remain cold, stone cold, and not even start to get warm and be easy to hold for a while with no change.

This will prove the thermostat is closed and the engine is keeping the water within the block till the engine gets up to temp - this is what you want.

If the thermostat is operating properly then at the point the engine gets up to temp, the thermostat will open and very suddenly the bottom radiator hose will get very hot, it's unlikely that you'll be able to hold it for very long. This is what you want, that quick change from cold to hot, as it the tap has been opened.


However, if the bottom radiator hose starts to get warm and warms up slowly from the start then this will prove the stat is stuck open and letting water freely flow around the system. Eventually with the car not moving and on idle the car will get to the correct operating temp. If this is the situation when driving, especially on the motorway, or when freely moving the airflow through the radiator will cool the water before it gets chance to get warm. The engine may never get up to temperature properly under these conditions, although it may in traffic, and overheating will be managed by the fan so this issue can go unnoticed in city cars.

I have had the above on my last two GTI's pretty much as soon as I got them. But on a GTI, the water temp doesn't effect the running of the car. But as said, I think it may have more effect on a carbed car.

If you find this is indeed the problem then my advice is to be prepared with a good quality water pump and thermostat housing as well as a good quality thermostat (including the o-ring seal - cheap brands don't always come with this).

Although the housing should be a reusable part it's plastic and my experience is they warp. They are cheap and not worth refitting an old one as it's likely to leak.

The water pump itself is metal and should be fine for the lifetime of the car (assuming the bearings last) but both times I've done this job I've had the studs snap off, due to corrosion. The pump is about £30, so it's just not worth the hassle of driving to get out snapped studs.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on January 09, 2023, 05:04:58 PM
Thanks, EP, for you very detailed reply and thanks for pointing out the typo, where I erroneously stated 'fuel' instead of 'temp' (corrected in my post upthread, but still extant in kartman's quoting of my post).

You have a very good point about the thermostat, and this is something I will check.  Not sure if carb itself is connected to the cooling system.

I acquired a Golf Mk4 negative earth cable, which is indeed beefier, but I couldn't undo the bolt fixing it to the engine block.  This is currently being sorted out by my garage man.  But just applying vaseline to the battery terminals and the first earth point near the battery seems to have eased things.

As always, I suspect more than one intermittent issue with this car - been the history all along.  Carb seating sorted.  Earthing getting sorted.  Thermostat to be investigated.  Just hope the wiring between the amplifier and the coil isn't the issue as suggested upthread!
The puzzling thing was how quickly the car returned to normal once I was off the motorway and onto the ring road.

I'm intrigued now to investigate the functioning of the thermostat once I get the car back, unless my garage man gets there first!
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: kartman on January 10, 2023, 02:19:14 PM
Sounds like you are getting there with it fella, as you say a mixture of niggles more than likely.
Weber carbs have no connection to the thermostat as they are manual choke unlike a pierberg carb.
Worth checking and renewing for piece of mind though.
EP makes a good point about carb icing and you symptons seem to match, motorway road speed and airflow will not help with this.
You should have a corrogated pipe coming of the top side of the exhaust manifold into the underneath of the airbox.
This carries hot air from the exhaust into the carb to prevent carb icing.
If it is missing or damaged then it may not be getting the hot air that is needed.
If you have an aftermarket airfilter and no airbox then replacing with a standard airbox setup is best in winter as the k&n type have no hot air feed/flap and are notorious for carb icing in winter.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Eddypeck on January 11, 2023, 12:17:40 PM

Weber carbs have no connection to the thermostat as they are manual choke unlike a pierberg carb.


I wasn't sure what carb was fitted and assumed it was still the original Pierberg. If it mentions this elsewhere then my mistake for not reading back through the thread properly.

Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on February 22, 2023, 10:23:40 AM
Sounds like you are getting there with it fella, as you say a mixture of niggles more than likely.
Weber carbs have no connection to the thermostat as they are manual choke unlike a pierberg carb.
Worth checking and renewing for piece of mind though.
EP makes a good point about carb icing and you symptons seem to match, motorway road speed and airflow will not help with this.
You should have a corrogated pipe coming of the top side of the exhaust manifold into the underneath of the airbox.
This carries hot air from the exhaust into the carb to prevent carb icing.
If it is missing or damaged then it may not be getting the hot air that is needed.
If you have an aftermarket airfilter and no airbox then replacing with a standard airbox setup is best in winter as the k&n type have no hot air feed/flap and are notorious for carb icing in winter.

Thanks kartman.

Can confirm that corrugated hose for warm air is intact, and air filter housing is standard.
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: Martin109 on February 22, 2023, 10:24:49 AM
A bit of a progress report.

I’ve had the 10-year-old Weber carb serviced by an old-school VW specialist in his 60s – a dying breed!  He also checked the gauze on the fuel uptake pipe in the tank.  I’m reasonably confident now that the carb is in good nick.

Intermittent problems persist, however, which lead me to wonder whether the long-standing intermittent rough running has been a combination of things, so now excluding the carburettor might be helpful.

Current issues: occasional rough running and stalling.  Today's example – rough running almost from the start on a short local trip (usually it’s been OK whilst warming up and problems only arose after running at normal temp for a while).  This time, very marked stalling whenever the car not in gear under motion.  Restart every few yards in traffic!...

BUT

Suddenly, back to normal!  No stalling, smooth running, all purring sweetly again!  The question is: what is going on?

What might be the symptoms of faulty ignition in the distributor?  The only electronics in this 1990 Golf Driver 1.6 are the amplifier and the distributor I believe.  Can such electronics malfunction intermittently, or are they a case of binary working vs not working.

Up-thread was a suggestion to check the wiring between the amplifier and the coil, which I admit hasn’t been done yet (new coil a couple of months ago).  There was also a suggestion of upgrading the battery earth wire to that of a Mk4, which has been done.

My theory at the moment is that some kind of electrical problem has been masked by a carb fuelling problem.  Does that sound reasonable?
Title: Re: Mk 2 1.6 Driver Fuel Problem?
Post by: kartman on February 22, 2023, 10:41:55 AM
Hopefully you have ruled out anything other than electrical now.
I still think it is worth checking continuity on the coil feed wire seeing as the problem persists with a new coil.
If thats ok it can really only be the ignition amplifier, distributor (hall sender may be breaking down) or wiring between them.
The only other thing could be a vacuum leak but due to the on/off nature of the problem I still suspect electrical, a vacuum leak would be all the time.