Bus starts then dies

Bus, Microbus, Transporter, Station Wagon, Vanagon, Camper, Pick-Up.

Moderators: Sluggo, Amskeptic

Bus starts then dies

Postby mentalQtip » Sat Apr 09, 2011 2:56 pm

Ok. '77 2 liter fuel injected bus. Lately I had noticed that my bus had developed a stumble when starting from a  stop. As it picked up rpm it would suddenly pick up power until I shifted again. Looking back I realize that overall power was down also. Yesterday it started to die on me when I left the rpm drop. Today I went out to check the timing(was about 3 degrees BTDC), adjusted to about 8, went to start it and it started ok but lasted about 5 seconds and died. Started easily again and died. Lasts about 5 seconds.
Before when I had something like this it turned out to be a vacuum hose loose but I can't find anything loose now. I'm thinking, "what could I have done while adjusting the timing?"
I'm at a loss. Any thoughts?
mentalQtip
Getting Hooked!
 
Posts: 201
Joined: Wed Jan 23, 2008 10:54 pm
Location: Portland, Oregon

Re: Bus starts then dies

Postby bajaman72 » Sat Apr 09, 2011 3:35 pm

Adjust the points first.. then set timing. Points that are off will affect timing.
Projects:
1972 Bus (2nd Driver) 1700, dual Dells, Bug Pack exhaust
1973 Baja (another 2nd Driver &Toy) Stock 1600 DP, dual Kadrons, Stinger
User avatar
bajaman72
Addicted!
 
Posts: 445
Joined: Wed Aug 12, 2009 9:47 pm
Location: Quartz Hill, CA

Re: Bus starts then dies

Postby chitwnvw » Sat Apr 09, 2011 5:55 pm

bajaman72 wrote:Adjust the points first.. then set timing. Points that are off will affect timing.


2nd. It is the starting point.
User avatar
chitwnvw
Resident Troublemaker
 
Posts: 7588
Joined: Tue Aug 08, 2006 7:32 am
Location: Chicago.

Re: Bus starts then dies

Postby mentalQtip » Sun Apr 10, 2011 5:08 pm

ok. Checked the points at .016. Timing is 7.5 BTDC. Still starts easy and dies after about 5 seconds. The fact that it dies after running suggests to me a fuel delivery problem, right? What else could it be?
As I said in the first post, first noticed a stumble, some power loss, then started to die when I let the rpm drop, and now won't keep running at all, even when I try to give more gas.

Possible fuel delivery problem? Maybe a vacuum leak?
mentalQtip
Getting Hooked!
 
Posts: 201
Joined: Wed Jan 23, 2008 10:54 pm
Location: Portland, Oregon

Re: Bus starts then dies

Postby Randy in Maine » Mon Apr 11, 2011 3:46 am

I am only on here for a second today, but go over here and look at what they suggest....

http://manuals.type4.org/ljet/
79 VW Bus
User avatar
Randy in Maine
IAC Addict!
 
Posts: 1130
Joined: Mon Aug 14, 2006 4:26 am
Location: Old Orchard Beach, Maine

Re: Bus starts then dies

Postby vwlover77 » Mon Apr 11, 2011 9:54 am

Are you sure the 90 degree rubber elbow air hose for the aux air regulator is OK? These are hard to see and if they split or break, you'll have the symptoms you describe.
Don

---------------------------
78 Westy
71 Super Beetle Convertible Autostick
99 New Beetle

"When we let our compassion go, we let go of whatever claim we have to the divine." - Bruce Springsteen
User avatar
vwlover77
Moderator
Moderator
 
Posts: 2565
Joined: Mon Aug 14, 2006 3:08 pm
Location: North Canton, Ohio

Re: Bus starts then dies

Postby chitwnvw » Mon Apr 11, 2011 10:50 am

Have you checked with the AFM wiper to make sure that the fuel pump power is switching over successfully. You might just be getting that initial spray from the cold start valve and that is it.
User avatar
chitwnvw
Resident Troublemaker
 
Posts: 7588
Joined: Tue Aug 08, 2006 7:32 am
Location: Chicago.

Re: Bus starts then dies

Postby soulful66 » Mon Apr 11, 2011 6:42 pm

vwlover77 wrote:Are you sure the 90 degree rubber elbow air hose for the aux air regulator is OK? These are hard to see and if they split or break, you'll have the symptoms you describe.


+1 0n this, I had the problem and this was the cause.
Regards,
john
'72 westy 3TC
'73 westy 1700 dual solex
'79 westy 2000 F.I.
User avatar
soulful66
Addicted!
 
Posts: 310
Joined: Tue Aug 08, 2006 8:28 pm

Re: Bus starts then dies

Postby mentalQtip » Tue May 03, 2011 5:08 pm

Since I am very intimidated by the fuel injection part of this, I replaced the dual relay just because it was easy and I had a spare. Fired right up and idled fine. I drove it and it ran crappy so I checked the timing again (ooops) set it at 7.5 BTDC and it ran great.
Feel guilty that I didn't do any proper diagnosis.
Thanks to all for the input.
mentalQtip
Getting Hooked!
 
Posts: 201
Joined: Wed Jan 23, 2008 10:54 pm
Location: Portland, Oregon

Re: Bus starts then dies

Postby chitwnvw » Tue May 03, 2011 5:24 pm

mentalQtip wrote:Since I am very intimidated by the fuel injection part of this, I replaced the dual relay just because it was easy and I had a spare. Fired right up and idled fine. I drove it and it ran crappy so I checked the timing again (ooops) set it at 7.5 BTDC and it ran great.
Feel guilty that I didn't do any proper diagnosis.
Thanks to all for the input.


Don't feel too bad. Part swapping was how I discovered my series resistor was bad.   In theory, proper problem solving is the way, in my case it was an intermittent problem that kept leaving me SOL in the  middle of busy intersections...  Finally, it happened where I could run home and swap out probable bad parts, and voila problem solved.
User avatar
chitwnvw
Resident Troublemaker
 
Posts: 7588
Joined: Tue Aug 08, 2006 7:32 am
Location: Chicago.

Re: Bus starts then dies

Postby Amskeptic » Fri May 06, 2011 8:28 am

chitwnvw wrote:Finally, swap out probable bad parts.


Ouch, baby, ouch.
Headmaster
Itinerant Air-Cooled Academy
BobD - 1978 Bus . . . . . . . . 101,001 miles
Chloe - 1970 bus . . . . . . . . 153,230 miles
Pluck - 1973 Squareback . . 55,480 miles
User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
 
Posts: 18568
Joined: Sun Apr 02, 2006 8:47 am

Re: Bus starts then dies

Postby fractal_man » Wed Jul 11, 2012 10:47 am

Right on the nose for me with the vacuum leak at the 90 degree fitting.  Thanks to all you folks who post this valuable information.
fractal_man
I'm New!
 
Posts: 1
Joined: Wed Jul 11, 2012 8:10 am


Return to Type 2

Who is online

Users browsing this forum: No registered users and 0 guests