vanagon fuel issue

[vegasvic]

I'm trying to help my son out but know little about VW engines...OK, nothing about VW engines!

Its cold out here and his van wouldn't stay running so we rolled it into my shop. Jacked up the back to put some jack stands underneath the back end and oil and gas came off the engine.

Now that both ends are on jack stands it looks to have stopped. The fuel injectors are dry, fuel line is dry, cannot see a leak anywhere on top. On bottom, gas was dripping out of heat exchanger. I removed it and the exhaust portion looks dry as ever so maybe gas leaked into it the casting somehow. With heat exchanger out of the way I opened the cylinder head cover and about 2 ounces of black looking gas came pouring out. The front push rod tube was full but maybe because its lowest.

Anyway, I have no idea where this gas is coming from. When it ran it ran roughly, so did it not catch on fire because it was so cold out or is all the gas collecting because it was so cold out?

Any help would be appreciated.

vic

[perrib]

Hot wire the fuel pump so you have system fuel pressure with the engine not running.

[wildthings]

It sounds like you have an aircooled Vanagon? Any excess fuel on top of the engine should be coming from an obvious leak. On an aircooled Vanagon I think you can just prop the door in the AFM open (with the ignition on) to get the fuel pump to run.

Fuel build up in the oil is likely caused by a cold engine running very rich, maybe from a bad cylinder head temperature sensor (TSII).

[vegasvic]

Yes, its air cooled. Its an 1982 vanagon thats a little rough. Err, what is the AFM?

vic

[perrib]

It is the Air Flow Meter. Chances are by now the AFM hose is hard as a rock and may break/crack when attempting to remove it. Back when they were new and flexable that was the quickest way to find fuel leaks.

[vegasvic]

OK, we let everything dry out for a couple weeks. Today I opened up the breather assy and toggled the air flow thing, it allowed the fuel pump to come on and nothing leaked. I decided it must have been the cold effecting something, allowing gas to flow but its getting warm out again and no gas is leaking so we’re OK…

We put the valve cover on and was putting the exhaust manifold thing back on when I saw it leaking again. It looks like it is coming out of the farthest forward, push rod sleeve. Upon closer observation the sleeve was full of fluid and was leaking where the sleeve fit into the block. The sleeve slants down toward the center of the engine. I wondered if the gas could be just sitting inside the sleeve and just needing removal so we jacked the driverside rear to make the sleeve more level. Lots more of this gas/oil mixture came rolling out and I thought to measure it, about 800ml, when I lowered the van again. That's a lot more than will fit in the sleeve so its coming from somewhere. Its mainly gas that looks black so I’m assuming there is some oil in there somewhere.

Where could this gas be coming from?

Thanks
vic

[Bart1958]

I have a 78 air cooled and have been recently working on a fuel injection problem. I am not going to be the resident expert. Is it possible that an injector is leaking? I think I would turn the fuel pump on like you did before, with the injectors out of their ports so you could see if one is leaking. Maybe the one nearest where you are finding the excess fuel. I can't think of any other way for fuel to be getting inside.

[wildthings]

Your crankcase is full of fuel/oil mixture. Not good!!! The gas has to be entering the crankcase from somewhere. The most likely cause of the symptoms you are seeing is a bad temperature sensor or the temperature sensor's wiring. The sensor is screwed into the head on the #3 cylinder just forward of where the manifold bolts on. It is best to check it through the wiring harness from the plug on the ECU. The sensor has a variable resistance depending on the temperature of the engine. If the resistance of the sensor is too high or the wiring to the sensor is bad causing a very high Ohm reading it will flood the engine.

A less likely alternative, but one which will cause significant fuel build up is a bad ECU. This will cause the injectors to be spray continuously. Check the voltage on one or more injectors and see if they have power on one terminal and are grounded on the other at all times when the ignition is "ON". If you read the power across the two terminals of an injector it should pulse when you crank the engine. If you have power across the injectors continuously then your ECU may be bad.

You also have a bad push rod tube o-ring which should be fixed some day. Not a hard job on one of these engines.

[raygreenwood]

Your crankcase is full of fuel/oil mixture. Not good!!! The gas has to be entering the crankcase from somewhere. The most likely cause of the symptoms you are seeing is a bad temperature sensor or the temperature sensor's wiring. The sensor is screwed into the head on the #3 cylinder just forward of where the manifold bolts on. It is best to check it through the wiring harness from the plug on the ECU. The sensor has a variable resistance depending on the temperature of the engine. If the resistance of the sensor is too high or the wiring to the sensor is bad causing a very high Ohm reading it will flood the engine.

A less likely alternative, but one which will cause significant fuel build up is a bad ECU. This will cause the injectors to be spray continuously. Check the voltage on one or more injectors and see if they have power on one terminal and are grounded on the other at all times when the ignition is "ON". If you read the power across the two terminals of an injector it should pulse when you crank the engine. If you have power across the injectors continuously then your ECU may be bad.

You also have a bad push rod tube o-ring which should be fixed some day. Not a hard job on one of these engines.

Everything Wildthings noted is possible and should be checked. If the fuel appears to be mainly leaking from one spot....I'm betting that either that injector is locked open (rust is possible)....or you have a problem in the grounding loop of the injection system. Since all injectors fire at once on this system....one improper ground can cause them all to fire all the time.
In this system, the injectors have one hot wire and one ground to each injector. The hot side is hot all the time. The ground is applied by the ECU (brain) to turn the injectors on and off.

I think.....someone just had this problem recently over on the Samba. With the car off....check the ground side of each of the injectors with a volt meter. The red probe goes on the ground wire in the injector plug and the black probe goes to the block. If you seea constant ground...follow all the ground wires back to their source for each injector plug and make sure you have no cracked wires grounding out.
Then...also check the resistor pack as per the manual. Come back and let us know what you find. Ray

[vegasvic]

Well I’ve thrown in the towel. After spending a considerable amount of time looking thru the really fat VW manual to check the sensors I’ve decided to call in the professionals.

I had the multi-tester out checking out the temp sensor tabs and all but one checked out. Does this mean its bad or I’m just not doing it right? So I decided to check another sensor on the injector like it was in the picture but my engine wasn’t like the picture so what does that mean? Too many unanswered questions so I told my son I was going to have to have a real mechanic look at it.

We started putting it all back together again and when we changed the oil it was more gas than oil, I was amazed! Let’s hope somebody else can fix this wreck.

Thanks for everyone’s help this VW is just too different for me.
vic

[wildthings]

Why don't you pull the injectors out put leave them both plumbed and connected electrically. Turn the key on and see if any of them squirt or seep fuel. Pretty much you will be doing the spray test shown in the manual, but not cranking the engine. After you have check for leakage, you should go ahead and do the rest of the spray test since you are there.

You should also put a pressure gauge on the test port on the fuel rail and see if the pressure leak down is within spec.

[raygreenwood]

Well I’ve thrown in the towel. After spending a considerable amount of time looking thru the really fat VW manual to check the sensors I’ve decided to call in the professionals.

I had the multi-tester out checking out the temp sensor tabs and all but one checked out. Does this mean its bad or I’m just not doing it right? So I decided to check another sensor on the injector like it was in the picture but my engine wasn’t like the picture so what does that mean? Too many unanswered questions so I told my son I was going to have to have a real mechanic look at it.

We started putting it all back together again and when we changed the oil it was more gas than oil, I was amazed! Let’s hope somebody else can fix this wreck.

Thanks for everyone’s help this VW is just too different for me.


There are only two engine temp sensors...and neither can Not check out. So whichever is badm replace it. Also....as wildthings noted...pull the injectors out and see if they are leaking.

In reality, none of the sensors could ever cause rich enough running to really cause you to flood the crankcase. This is caused by injectors literally continuing to inject.......OR....the cold start injector injecting full time when it should not.....or one or more injectors rusted open. Ray
vic