1978 Bus 2.0 FI jerking

Carbs & F.I.

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khargis
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Location: Boise, ID
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Re: 1978 Bus 2.0 FI jerking

Post by khargis » Tue Mar 05, 2013 8:25 pm

Latest post of the previous page:

:cussing: :cussing: :cussing: :cussing: :cussing: hello again, the bucking and jerking is back and badder than ever! the short of it, recently tuned her up, valves good, new distributor and bosch points - check, dwell between 40 and 50, new temp sensor II. I was going thru Eugene, south 2 hrs from portland and the bucking began. I checked the fuel filter and it had some rust chunks, replaced it and the bus ran solid for about 45 min and the bucking slowly reinstated itself, by the time i got to Redding, CA (about 6 hrs south) it was pretty out of control. Tomorrow i will check the filter again and blow out, reinstall, etc. So I guess my tank is in bad shape? I will double check all connections to the dbl relay, coil, etc. If I do have more rust chunks in my fuel filter tomorrow, do I just keep cleaning the filter until i can pull the tank? I am headed to san francisco tomorrow for a months work and want the bucking to stop. I feel like i have been rode hard and put away wet! Thanks people, kris (any thoughts?)
'slow n' steady'

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dingo
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Re: 1978 Bus 2.0 FI jerking

Post by dingo » Tue Mar 05, 2013 10:22 pm

If you need help pulling the tank or whatever,gimme a shout... i have tools and time. and glad to help.....but i dont have a square inch of space in which to do any work in this metropolis(SF)
'71 Kombi, 1600 dp

';78 Tranzporter 2L

" Fill what's empty, empty what's full, and scratch where it itches."

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khargis
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Re: 1978 Bus 2.0 FI jerking

Post by khargis » Tue Mar 05, 2013 11:10 pm

thanks dingo, very cool of ya, as i have never pulled a tank before. i may have a spot to pull the tank. i will holla at ya WHEN we arrive to the city. thanks in advance. kris
'slow n' steady'

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dingo
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Re: 1978 Bus 2.0 FI jerking

Post by dingo » Wed Mar 06, 2013 12:19 pm

i havent done it either..but i plan to,as soon as i find a workspace ! does it fly out over the top ? or does engine have to come out ?

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'71 Kombi, 1600 dp

';78 Tranzporter 2L

" Fill what's empty, empty what's full, and scratch where it itches."

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IFBwax
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Re: 1978 Bus 2.0 FI jerking

Post by IFBwax » Wed Mar 06, 2013 12:28 pm

Was the fuel filter full of rust again? I had a mysterious bucking problem on my 79 that would go and come again. Finally my helpful VW expert mechanic figured out it was the AFM which was of all things too rich at some points. Never had the problem since.
The best navigators aren't sure where they're going until they get there. And then they're still not sure.

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khargis
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Re: 1978 Bus 2.0 FI jerking

Post by khargis » Wed Mar 06, 2013 4:55 pm

hey there. so this morning, I pulled the fuel filter and a couple older threaded hoses and drained the tank (about a gallon) and i did find a fair amount of rust (fish food looking) in the drained gas. I blue out my filter and reinstalled the new hoses and blown out filter and then filled it up with gas. I made it to SF and the bus ran pretty darn good and seemed to be back to her old self with a fair amount of power, granted from redding to SF is a fairly level jaunt whereas coming over the siskiyou and shasta pass are not. I still bucked occasionally, but not for long and not hard. I feel that the problem is not fixed, but i wonder is the next thing I should do is pull the tank? we are got only around 11 to 12 mpg, i usually get around 18 or so on highway with a full load of tools. Could these 2 be related? Do i keep draining the tank every so often to rid the rust and or keep blowing out my fuel filter. As far as the AFM, that thing scares me, but am willing to learn or should I say, I need to learn! Dingo I may still give you a message if you are still interested in giving me a hand. Thanks everyone. Kris
'slow n' steady'

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dingo
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Re: 1978 Bus 2.0 FI jerking

Post by dingo » Fri Mar 08, 2013 12:00 am

Sounds like youll have to pull the tank at some point..depends on where youre most comfortable doing it.

Also, if some of the junk got past the filter..it might be clogging your injectors a wee bit. The later style injectors have tiny filters to catch such residue(and be replaced or cleaned)..not sure if the early L-jet have them too?
'71 Kombi, 1600 dp

';78 Tranzporter 2L

" Fill what's empty, empty what's full, and scratch where it itches."

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SlowLane
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Re: 1978 Bus 2.0 FI jerking

Post by SlowLane » Sat Mar 09, 2013 11:39 am

If you haven't read it already, check out ratwell's Fuel Tank Restoration article to give you a good idea of what you'll be getting into.

You may be doing more damage than good by blowing out and re-using the filter. When you blow it out, you're compromising the filter's ability to subsequently filter out fine particles, which are now free to make their way to the injectors. Don't know if the Bus filter is the same rectangular plastic one as on the Vanagon, but if it is, they're pretty inexpensive at NAPA. Get a bunch of them and replace the filter frequently. You might even benefit from just creating a filter-pump-return loop with some spare fuel hose and circulate the fuel through the filter by powering the pump with an external 12V power supply. If you're lucky that'll catch the bulk of the existing rust in your tank.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"Wisdom comes from experience. Experience is often a result of lack of wisdom."
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