77 FI Bus Fuel Leak at Heads

EZ Gruv · Post by **EZ Gruv** » Sun Aug 09, 2009 2:35 pm

Hey all,
So my bus (1977 2.0L Type IV FI) isn't starting. I ended up getting towed home by AAA yesterday.
The bus cranks like mad, but doesnt catch. In my investigation today, I noticed a HEAVY fuel smell. This is what I find:

Fuel dripping from the heads on both sides.
I checked for spark from the coil to the cap - check. From the cap to each plug wire - check. Even popped in some new plugs, no change.
Thoughts? Thanks

Xelmon · Post by **Xelmon** » Sun Aug 09, 2009 3:23 pm

Oh lord... That don't look good...

Uhm, not sure... Ask trisstessa.

vwlover77 · Post by **vwlover77** » Sun Aug 09, 2009 4:51 pm

Were the original plugs you removed wet with fuel?

Check your AFM wiper for smooth movement across the range. It could be stuck open causing the engine to flood. I hope that fuel is coming from not-perfectly-sealed F-pipe to head connections.

The other unpleasant possibility is that your heads are no longer sealing to the cylinders and you have lost compression. But in all 4 cylinders at once? That seems unlikely.

EZ Gruv · Post by **EZ Gruv** » Sun Aug 09, 2009 4:59 pm

vwlover77 wrote:Were the original plugs you removed wet with fuel?

Yes.

all 4 cylinders at once? That seems unlikely

Unless something catarophic happened.

Check your AFM wiper for smooth movement across the range. It could be stuck open causing the engine to flood.

Checked - it moves freely through and is not stuck in the open position.

I hope that fuel is coming from not-perfectly-sealed F-pipe to head connections.

Sure seems that way, as I cannot detect any other source.

Randy in Maine · Post by **Randy in Maine** » Sun Aug 09, 2009 5:27 pm

Eric,

Tell us about your fuel pressure and the staus of your injector seals.

Also (even though you are not a vanagon guy) could you do this AFM test?

http://s105.photobucket.com/albums/m218 ... V02923.flv

tristessa · Post by **tristessa** » Sun Aug 09, 2009 5:27 pm

Leaking fuel injectors are the first thing that comes to mind with that much gas on things, unless there's a broken fuel line someplace .. you *did* check the fuel lines, right?

As to how it's getting onto the outside of the exhaust pipes (if the injectors are leaking), I'm at a loss for anything aside from what's already been mentioned...

EZ Gruv · Post by **EZ Gruv** » Sun Aug 09, 2009 5:33 pm

tristessa wrote:Leaking fuel injectors are the first thing that comes to mind with that much gas on things, unless there's a broken fuel line someplace .. you *did* check the fuel lines, right?

As to how it's getting onto the outside of the exhaust pipes (if the injectors are leaking), I'm at a loss for anything aside from what's already been mentioned...

Yes all fuel lines are good and less than 4 months old. I rechecked them today and they are fine.

I know my F pipes arent as sealed up to the head as they should be; but they have been that way for quite some time. Something had to have occurred to make both sides start convulsing fuel at the same time.

vwlover77 · Post by **vwlover77** » Sun Aug 09, 2009 6:12 pm

Has any of the fuel injection wiring been tampered with lately?

Positive voltage is always supplied to the fuel injectors when the double relay is activated. But they need a ground circuit to turn on and spray fuel.

It's the computer (ECU) that provides the ground for the appropriate period of time each engine revolution.

I suppose it's possible that the ECU has failed and the fuel injectors are running wide open at all times.

Do you have another ECU you can try?

EZ Gruv · Post by **EZ Gruv** » Sun Aug 09, 2009 6:22 pm

No wiring has been touched lately. I checked every ground that I could fine. Unfortunately, I dont have a spare ECU.

bretski · Post by **bretski** » Mon Aug 10, 2009 7:15 am

Another thought to add here: Have you checked the fuel pressure? I'm wondering if the pressure regulator may have failed.

Any gas in the oil?

EZ Gruv · Post by **EZ Gruv** » Mon Aug 10, 2009 7:31 am

No gas in the oil as far as I can tell by sight/smell.

I'm searching for a pressure tester locally, hopefully some FLAPS around here will have one.

bretski · Post by **bretski** » Mon Aug 10, 2009 7:55 am

Your FLAPS should have an Actron/Sunpro brand for a reasonable price. I've seen DIY projects using plumbing hardware, too.

Ritter · Post by **Ritter** » Mon Aug 10, 2009 8:44 am

Are the injectors seated correctly?

Since you were just recently monkeying with the aux air regulator, maybe you buggered up the cold start injector somehow.

vwlover77 · Post by **vwlover77** » Mon Aug 10, 2009 8:58 am

I don't think the cold start injector could spray enough fuel to flood the engine to the extent we're seeing here.

If the injectors are not sealed properly, you'd have a vacuum leak for sure but the engine should still start and run, and the airflow would draw in the fuel without it leaking all over.

The fuel pressure regulator question is a very good one. The return line to the tank may also be clogged. You need to do the pressure test ASAP.
My pressure tester is nothing but a piece of fuel line clamped onto a regular 0-50psi pressure gauge. Not sophisticated, but functional.

In my mind the top candidates for the cause are:
1. Clogged return line / fuel pressure regulator
2. ECU failure

VWBusrepairman · Post by **VWBusrepairman** » Mon Aug 10, 2009 9:23 am

Faulty fuel pressure regulator causing the rich condition? Wipe the fuel away from the exhaust- that is making me nervous.

p.s. Was good to see this this weekend at DB, Don!

Itinerant Air-Cooled

Itinerant Air-Cooled

77 FI Bus Fuel Leak at Heads

77 FI Bus Fuel Leak at Heads