77 FI Bus Fuel Leak at Heads
- EZ Gruv
- Getting Hooked!
- Location: Las Vegas, NV
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77 FI Bus Fuel Leak at Heads
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
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
77 Westy
74 Super Beetle
74 Super Beetle
- vwlover77
- IAC Addict!
- Location: North Canton, Ohio
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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.
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.
Don
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78 Westy
71 Super Beetle Convertible Autostick
"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
---------------------------
78 Westy
71 Super Beetle Convertible Autostick
"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
- EZ Gruv
- Getting Hooked!
- Location: Las Vegas, NV
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Yes.vwlover77 wrote:Were the original plugs you removed wet with fuel?
Unless something catarophic happened.all 4 cylinders at once? That seems unlikely
Checked - it moves freely through and is not stuck in the open position.Check your AFM wiper for smooth movement across the range. It could be stuck open causing the engine to flood.
Sure seems that way, as I cannot detect any other source.I hope that fuel is coming from not-perfectly-sealed F-pipe to head connections.
77 Westy
74 Super Beetle
74 Super Beetle
- Randy in Maine
- IAC Addict!
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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
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
79 VW Bus
- tristessa
- Trusted Air-Cooled Maniac
- Location: Uwish Uknew, Oregon
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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...
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...
Remember, only YOU can prevent narcissism!
- EZ Gruv
- Getting Hooked!
- Location: Las Vegas, NV
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Yes all fuel lines are good and less than 4 months old. I rechecked them today and they are fine.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...
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.
77 Westy
74 Super Beetle
74 Super Beetle
- vwlover77
- IAC Addict!
- Location: North Canton, Ohio
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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?
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?
Don
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78 Westy
71 Super Beetle Convertible Autostick
"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
---------------------------
78 Westy
71 Super Beetle Convertible Autostick
"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
- bretski
- Ellipsis-Meister
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- bretski
- Ellipsis-Meister
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- vwlover77
- IAC Addict!
- Location: North Canton, Ohio
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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
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
Don
---------------------------
78 Westy
71 Super Beetle Convertible Autostick
"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
---------------------------
78 Westy
71 Super Beetle Convertible Autostick
"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
- VWBusrepairman
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