TheSamba.com :: View topic - Help-- Bus won't idle '78 FI

Fri Aug 16, 2013 6:56 pm

Bought a Bus recently-- and guy told me it was running but stopped.

I have put these new parts on it in the past few hours.
New Fuel Pump
New Fuel Filter
New Points
New Rotor
New Distributor Cap
New Plugs, New wires
New Air Cleaner.

Good news is, I got the bus to run now, but I have to put the pedal to the floor to start it up... and it won't stay running on idle. As long as I am giving it gas, it will run. Any thoughts/suggestions?

Also, it has a new air flow meter, Bosch Rebuild from Bus Depot last year- thanks.
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Fri Aug 16, 2013 7:18 pm

Clean all your grounds: battery to body, body to transmission, all of them in the engine compartment. A likely source for no idle is a vacuum leak. take each hose coming of the S boot and cover the holes with duct tape (be sure it wont get sucked in). Do one hose at a time and you can see if any of those are leaking. Leaking injector seals could be culprits, hold a unlit propane torch or spray starter fluid around the seals while its running to see if it changes speed. Also the TS2 could be bad. Test it as per bentley.

Fri Aug 16, 2013 7:22 pm

TS2? Thanks! I'll keep playing. I've gotten this far. FI and don't get along too well. :)

Fri Aug 16, 2013 7:26 pm

With that much new stuff my guess is intake leak, like cracked S-Boot or loose hoses connecting to S-Boot...

or double relay.

Also make sure the AFM is plugged in, I've forgotten that more than once after doing an air filter or what not.

Sat Aug 17, 2013 12:33 am

Ian wrote: With that much new stuff my guess is intake leak, like cracked S-Boot or loose hoses connecting to S-Boot...

or double relay.

Also make sure the AFM is plugged in, I've forgotten that more than once after doing an air filter or what not.

I disconnected the fuel line, and put a bottle into the fuel line in the engine compartment and turned the engine over, bottle filled up with gas, so gas pump is working properly. That would illuminate the double relay, right? Fuel pump is working correctly (new) and that's the point of the double relay, correct?

AFM is hooked up.

Sat Aug 17, 2013 4:19 am

Do you know how to do a fuel pressure and volume test?

http://www.itinerant-air-cooled.com/viewtopic.php?f=42&t=213

If that passes, inspect and test the Temp Sensor II.

Might was well download the L-Tronic manual from there...

http://manuals.type4.org/ljet/

I like a vacuum leak myself. I would remove that big S boot and inspect it in the bright sunshine for cracks in the pleats. "Shoe Goo" is an acceptable short term fix.

Sat Aug 17, 2013 2:11 pm

A quick test that might eliminate the TSII is unplug it and ground the wire going to it from the computer. If it idles that is your problem, though this is not a failsafe test. Your best bet on testing is make sure it is around 67 degrees and connect a voltohmeter, it should measure about 2700 ohms. As it heats up it should read 200-300 ohms max. Try that and report back.

Sat Aug 17, 2013 7:12 pm

Woo Hoo! Found the culprit tonight.

You can't buy these new anymore, but I was able to get a 1/2" fitting "T" from lowest tonight, and replaced it... WALLA!

Thanks everyone!

Sat Aug 17, 2013 7:16 pm

Actually you can buy those. Airhead parts started stocking them just recently.

http://www.airheadparts.com/vintage-vw-parts/vanag...22133083-d

And congratulations!

Sat Aug 17, 2013 7:22 pm

Thanks, but yikes... $20!?

I got the Plastic T fitting from Lowes... $3.50. :D

Sat Aug 17, 2013 8:43 pm

VW Addict wrote: Thanks, but yikes... $20!?

I got the Plastic T fitting from Lowes... $3.50. :D
And how much in gas, time, clamps, etc... did it cost?, betcha' it's close to $20 when the dust clears :wink:

Sat Aug 17, 2013 9:17 pm

it isn't plastic - it is a type of plastic and most likely PVC. PVC won't play well long with oil vapors. Get the real thing. As for $20 - what you think these buses are inexpensive to maintain? I just looked at a NOS sunroof cable - didn't buy it cause it was over $300. One cable. Of course a new MDX is what $52,000 and you see those on the freeway all the time - a new AWD Ford Edge is $36,000+/- . What is $20?