Ownership Verified: My 1986 Volkswagen Polo Classic

Does it have a fuel filter? could be something like that?
 
The only fuel filter is the one-euro transparent one in the engine bay. There's apparently a "sieve" in the tank but if the fuel's all clear...
 
What does "fuel?s all clear" mean? Because what ever there might be in the tank would be lying on the bottom. How did they check that without removing the tank (as it would be more than convenient to check the sieve at the same time)?

If the fuel?s all clear the pipes should be fine (unless those are leaking, but that would be something else) as there is a sieve before the fuel lines. Weird...
 
public said:
The only fuel filter is the one-euro transparent one in the engine bay. There's apparently a "sieve" in the tank but if the fuel's all clear...
Click to expand...

You could just run a piece of fuel hose from that filter to a jerry can to see if it really is fuel system related? Although if driving around is nesseccary for the problem to occur, that might trigger external combustion mode...

:blowup:
 
Posambique said:
What does "fuel?s all clear" mean? Because what ever there might be in the tank would be lying on the bottom. How did they check that without removing the tank (as it would be more than convenient to check the sieve at the same time)?

If the fuel?s all clear the pipes should be fine (unless those are leaking, but that would be something else) as there is a sieve before the fuel lines. Weird...
Click to expand...

Removing the tank automatically means a brand new one should be put in; the costs are virtually the same.
 
public said:
Had the coolant swapped for winter-proof stuff since the old coolant looked gnarly. The shop had a look in the fuel tank and didn't see anything out of the ordinary, the fuel in there was clear, the tank insides looked "as new" and no reason for the occasional running issue could be found. Wonder if it's something in the fuel lines.
Click to expand...

The coolant job resulted in a very significant coolant leak that was most likely mostly quenched today by the shop redoing some clamps. Coolant dripped around town afterwards too, so I'll have to keep an eye on it and whether it's still something coming from the system or just some sprayed around coolant.
 
If theres something in the fuel line, simply undo both ends and blow it clean with compressed air.
 
If the fuel lines are degrading and shedding rubber particles because of ethanol content in the fuel, I'd rather replace them in their entirety.
 
public said:
The coolant job resulted in a very significant coolant leak that was most likely mostly quenched today by the shop redoing some clamps. Coolant dripped around town afterwards too, so I'll have to keep an eye on it and whether it's still something coming from the system or just some sprayed around coolant.
Click to expand...

The radiator leaks like a mofo when the coolant is cold. With a warmed up engine the leaking subsides.
 
The car now has a new #60EuroRadiator, and there's no leaking detectable near the radiator anymore. However, there's a coolant flange close to the block, under the radiator and that one is leaking on the engine and onto the ground. One solution is obviously running the engine hot enough so the coolant disintegrates before it reaches the ground :p
 
Coolant flange, o-ring and thermostat have been changed. Leak persists, so it's again going back.
 
The shop said they seem to have gotten the o-ring installed wrong. They're re-doing the job.
 
For no extra charge, I guess?
 
No, they didn't charge anything this time. They're thinking there might be a crack in the plastic housing that the flange bolts to, since the bolt got wet. They quenched the proper leak today, though.
 
So, the Polo more or less kept its coolant to itself during a 1000km trip to the cottage and back. However, the running issue hit it hard 150km into the trip and made the rest of our Friday night drive a bit of a pain.

To rectify it, I initially replaced the vacuum hose to the distributor vacuum cell as it was kinked in one end and the fittings seemed perished. While the car ran beautifully with that replaced, it again started bucking after 30 minutes of driving today.

So we replaced the coil, the distributor cap and the rotor at a parts store parking lot with my dad. Coincidentally luokyio also happened to appear and he graciously let me use a few of his sockets for a tidier job.

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The car started right up, and km by km, 100km after another it seemed to run just fine. Plenty of power, no bucking, good starting, the way it's supposed to be. So either we fixed something or the fault mode just didn't come on.
 
Hmph, I let the car sit for a couple days and drove it a couple km now. Giving it some gas from low revs made it sputter and jerk again, braking to a junction made it stall, and there wasn't a proper idle when I parked it. It took a number of tries to keep it running, and when it settled to a decent idle I could take it around the block without it stalling. Still not sure if the coil was the actual problem or if it is still the vacuum cell just not working right when it feels like it. Luckily I don't have any long drives planned. Maybe I should change the plug leads.
 
Have you checked for vacuum leaks on and around the carb?

Edit: Also, are you sure the coil is getting a good 12V? Maybe the power supply cable has intermittent issues.
 
I replaced the vacuum hose going from the carb to the vacuum cell, not others. I don't have a multimeter so constant power supply is anybody's guess.

Edit: I looked at the fuel filter when it stalled from idle. The fuel flow nearly stopped and the car died, the pump sucked almost all fuel from the filter. But I don't know if that's the cause or a symptom.

Edit: VW forumite suspects faulty/sticking accelerator pump in the carb, since the issues often surface when giving gas from low revs. One is included in the service kit, luckily.
 
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The car now has a new fuel pump and the issues haven't returned. Throttle response and feel is back to very normal, with little to no hesitation; I still need to drive the car more to make sure it's alright in all occasions, but so far it seems like the fuel pump's sticking valves were to blame. That might be fuel quality related.
 
When i rebuild the m20 i'll also attach a small fuel filter near the fuel pressure regulator, just to make sure the engine is getting clean fuel and to be able to inspect the fuel quality.
 
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