76 FI Bus starts fine, shuts down moment ignition switch off

[Velokid1]

I'm going to try to refrain from ranting about having a bus as a daily driver and focus on the problem and fixing it. :)

Bus has been running fine. Little stuttering when it's idling cold and Colin thought a minor vac leak somewhere during his last visit, which I have yet to attend to because I am a loser.

This morning I loaded up the kids to take them where they need to go and turned the key. When I did, I reverted to an old bad habit of mine which is to tap on the gas pedal a little to "help" the engine start, which I have mostly cured myself of since re-installing the FI on this bus.

When I did, I heard a pop! And the engine shut off immediately. Sounded like a vac hose popping off or the sound of a fuse blowing. I turned the key again... the engine will start fine and normal, but the moment the key/ig switch are released, it dies.

I went to the engine compartment to have a look even though I rarely know what I'm looking at and noticed that the vac hose from the brake booster to the decel valve had indeed popped off.

Excellent, right? Just put it back on and be on my way! Wrong. Now the bus won't run. If I start it and give it gas, it will run (very badly), but the moment I let off the throttle, it dies.

Hrrmmm. And old Honda is sounding better and better every day. A friend has a really nice one for $2800... think I could get that for my bus?

Greg

[vdubyah73]

follow the booster vac hose, it may have popped off somewhere else as well. Check other vac lines also. Your airflow meter may have gotten jammed shut. Sounds like you had an intake backfire.

[Amskeptic]

follow the booster vac hose, it may have popped off somewhere else as well. Check other vac lines also. Your airflow meter may have gotten jammed shut. Sounds like you had an intake backfire.

Yeah Greloserg, be patient and observant. You pissed off your engine by making a demand upon it that it could not deliver, So imagine what a several hundred pounds-per-square-inch pressure wave would do to your intake system and check. The booster was an easy one. What about the elbow at the AAR? Did the s-boot dislodge or split? Pull the cap off of the top of the AFM and see if the wiper is parked at its normal spot, then move it counterclockwise. You should feel no scrape or hang-ups. See if you can make it idle nicely by moving the wiper with your fingers. If it will clean up and idle nicely if you move the wiper CCW, that suggests you still have a vacuum leak somewhere.

Oh, and I SEEN Hondas dead on cold mornings. I seen Ford pick-ups that couldn't start. I have seen young Nissan Maximas with rust holes in their floorboards. It . . . it . . . it happens occasionally.
Colin

[Velokid1]

Haha! Thanks fellas. I will report back.

[Lanval]

I had a similar incident. The backfire kicked open the valve in my air flow meter, and locked it open from the force. I had to stick a pen in there to dislodge. After that, start-O-matic as usual.

Best,

L.

[Velokid1]

After my wife invited a "professional mechanic" over to work on my bus while I was outta town last week, I finally had time today to have a peek under the engine hatch. It was running within 5 minutes. Turns out the hose from the oil breather to the whatevermajig had popped off (out, actually).

But I am noticing that moving the wiper a smidge ccw does indeed smooth/speed up the idle. I still need to give my bus a couple weekends worth of TLC.

Thx guys!

[Amskeptic]

After my wife invited a "professional mechanic" over to work on my bus while I was outta town last week . . . . .

uh what? Did the "professional" find the problem? Or was it just you and your God-given eyes?
Colin

[Velokid1]

This feller is a good auto mechanic, I guess, but he had his dog hunting up fuel delivery problems and vac stuff probably never occurred to him. I found it within 60 seconds of looking. I'm really good at the very easy, very obvious stuff.

My wife was trying to be helpful and she sure is a dear, but under my smile I was a little torqued about it. This guy was workin for free, by the way.

[Amskeptic]

This feller is a good auto mechanic, I guess, but he had his dog hunting up fuel delivery problems and vac stuff probably never occurred to him. I found it within 60 seconds of looking. I'm really good at the very easy, very obvious stuff.

My wife was trying to be helpful and she sure is a dear, but under my smile I was a little torqued about it. This guy was workin for free, by the way.

coughcoughgetwhatyoupayforcough HARRUMPH.
Honestly . . . you own that fuel injection system, you put it in, you know its custom quirks. When the energy is peaceful and solution-oriented, do mention to her that the REASON for my EXISTENCE is to get to people just like you and convince you that nobody is going to care as much as you do. Unlike any other car in your driveway, that VW is ready and willing to work with you.
Colin
"Honey I have a great eye surgeon who is going to give you new corneas and best of all, he does it right here in our house . . . for free! Honey? Aren't you excited?"

[Velokid1]

You are so right. I do not like the idea that someone tinkered with my bus at all. I don't really know exactly what all he did.

But, it turns out that this friend of ours is from Brazil, which I didn't know. And he worked as a professional auto mechanic there (had schoolin' and all) for 10 years or so. So apparently he's pretty handy with VWs.

Not handy enough to notice the vac hose staring back at him though.

[highlandmurf]

Um, How do you check to see if the air flow meter is jammed?
Thanks,
Joe

[Amskeptic]

Um, How do you check to see if the air flow meter is jammed?
Thanks,
Joe

Just take the black plastic cap off the top and gently move the wiper. If you feel the vane underneath contact the walls and get stuck or resistant, you have a problem, usually a bad bad backfire will do that.

Think very basic thoughts when trouble-shooting and go from dumb simple to slightly less simple. Be alert and focused.
Colin