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Fri Jun 20, 2008 6:35 pm

I have a 1985 Golf GTI with a swapped 16V in it.

The whole fuel system has been replaced. It runs fine.

But when the weather is hot and the car is at idle for a long period of time it seems as if the fuel is getting vaporized and causing a vapor lock. It will stumble then stall. Then I cannot get it started until about 5 or ten minutes. Once the car stays moving it is ok.

The car has a new VW thermostat in it and new coolant. The temp level is pegged at the center of the gauge.

My question would be could I still have a faulty component even if they are all brand new? Could the radiator need replacing? Should I wrap the fuel lines to the injectors? The after run fan works fine.

Just wondering if anyone had similar problems.

Roger

Sun Jun 22, 2008 1:28 pm

Since the fuel is constantly circulating through the fuel distributor back to the tank, it should be immune to vapor lock. Have you verified that the pressure is right? You might also intentionally get this to happen to you when you have time to work on it, and pop out the injectors, bypass the fuel pump relay and lift the airflow meter flap to do a spray/delivery test.

I've seen fuel pump relays that were starting to go bad cause restart problems. I had that happen to me on my own 85 Golf (original 8V engine and I believe, original fuel pump relay)

One thought that comes to mind, is the dreaded 16V oil-leaking-into-distributor issue. I've seen that cause hot restart issues.

-Andy

Sun Jun 22, 2008 5:32 pm

You are correct. I have not verified that the pressure is right. I did do the spray test after I put all the new stuff together. It seemed ok but I cannot say for sure if is optimal. I think I will also adjust the fuel metering a tick and see if that helps.

The relay to the fuel pump is new. But that does not mean it could not be going bad already. :) But the car does crank after it stalls.

I also noticed that it will have these symptoms described in the above post even if the hood is up on the car. (I did that to see if it would be cooler and not cause the failure.)

It appears that something gets to a certain heat level then causes problems.

I am not ruling out the distributor as you have said. The car still misses quite a bit but once the car gets past 2000 rpms it is not noticeable. I did not see any oil in the distributor cap but could it get into the Hall Effect area of the distributor that one cannot see?

Roger

Mon Jun 23, 2008 2:55 am

I forgot to mention one of the most common things to check for, the fuel transfer pump inside the gas tank, have you verified that is working? When they start to go bad they can get intermittant and cause problems. Usually the main pump will "buzz" a lot louder when that happens though, as it's working a lot harder to pull fuel.

You can see into the bottom half of the distributor, but you have to remove the rotor and the dust shield first. That rotor might be glued on, so it can be difficult to remove.

Messing with the fuel metering, you mean the airflow meter mixture adjustment? That's kind of playing with fire, because if you get it off, the computer starts trying to compensate - the O2 sensor and differential pressure regulator. If you know it was set up properly already, then if you mess with it, keep track how many "faces" of that Allen that you turn it, so you return it exactly to where you found it before!

No, what I was suggesting was to get it so it does not start, and have all your tools ready to go so you an do a fuel spray test at that time. You know it was good at another time, just wondering what it's like when the car is acting up.

Sat Jun 28, 2008 7:28 am

I found out the old coil was on its last legs. When it would get hot it would start to cause problems. I have a new coil now.

I did change the distributor, so my missing problem is gone. (I knew it did not look too good but was not sure it was entirely my missing problem.)

By the way you can save money if you don't but the complete re-manufactured distributor. Buy the unit without the rotor and cap. Then go to a auto parts store and get them there. The rotor and cap cost me 17 dollars. So I was only a little shy of two hundred dollars for the whole thing. It costs 250.00 or more for a whole unit.

Now I will get a new timing belt for the car and all should be good.

Andy, thanks for the help.

Roger

Sat Jun 28, 2008 7:45 am

Ah, weak coil, not very common but it happens. Probably will become more common as these cars get older.

If you do the timing belt, do the tensioner roller as well, on an 8V engine if the old tensioner feels and looks good I'll reuse it, but on a 16V, you don't want to take any chances.