1979 shortbus - Chevy - starting problems

Vons Osmin · 11-16-2011, 05:05 PM

Hey all - i just purchased a 1979 chevy short bus. When inpurchased it everything was running fine. Since then I started it up twice - both times turning over right away. The second time I warmed it up but I fear not long enough. The second time I drove it and turned it off after a short drive (everything fine) What has happened now Is I can't get it to start again. The engine turns over and it's seems like it's running (albeit rough) but then it just doesn't seem like it's getting enough gas and ultimately sputter dead within 30-45 seconds. If i pump the gas I can get it to keep sputtering but not for long. It had really old gas in it, but it was almost empty so filled it wiu medium grade gas. Any help, suggestions, tips?

frank-id · 11-17-2011, 10:02 AM

Remove air clearner. Disconnect fuel line into carb. Remove coil center wire. Turn engine with a clear jar under fuel line to notice rate of fuel into jar and color and dirt. The fuel filter may be clogged. Turn engine long enough for the jar to be filled at least half full. Look at fuel in a good light to determine fuel condition. frank

sdwarf36 · 11-17-2011, 10:59 AM

From the various Chevy vans I've owned:

There MAY be a fuel filter along the frame-basically right under the passenger seat--and (assuming its a Quadrajet carb) one right in the carb itself.

Vons Osmin · 11-19-2011, 11:12 PM

Hey guys thanks for the reply. So the fuel coming into the carb seems clean - that being said I went ahead and changed both of the fuel filters - one at the carb and one between the tank and the fuel pump. Both seemed to be doing their job as the one at the carb was rust colored ( most likely because fuel was sitting for so long) and the one inline also poured out a bunch of brown sediment on the tank side of the filter. All this being said - I still have the same issue. I can get it started and running, but only if I have the accelerator floored. And even then it's running really rough almost as if the firing order is off - which it's not because it was running fine just days ago. Just all of the sudden its running rough and won't stay running unless it's floored and then it's still very rough. One thing- if I open the choke to let more air in it seems to help it a little bit - as if it's running rich - also lots of gas smell - also pointing to richness. Any ideas? And any ideas as to why all of a sudden kaput?

bapos · 11-24-2011, 01:03 PM

I more or less went through this with my 3/4 ton chevy that I use as a farm truck to work in the pasture. It isnt ran very much so I can tell you pretty much you need to disassemble the carb and clean it out. There are some passages in there that are not all the way clean. You can try that but I would suggest a rebuild.

If your getting fuel and spark (hence its running ruff) you can rule those elements out. Not sure if you have a spare carb of some sort that will fit to put on there and test but it would rule things out.

I tell a lot of people this... if you have a vehicle that sits... Its a good idea to have a spare to put on. yes I know its a lot expense but so it being in a run and finding out your carb is not going to work and you need it to happen.

The gas out there is terrible when it sits for any length of time. I have seen carbs in lawn mowers gum in in less than 2 weeks. Things like Stabile work to a degree. But theres nothing wrong with having a spare

sdwarf36 · 11-24-2011, 06:51 PM

Barring anything like crap in the floatbowl-Have you looked at the cap + rotor? Are you able to get the motor on TDC and look at you dist. rotor? And tell if its off? If you had a timing chain jump (unlikey-but it wouldn't be the 1st chevy to do so) you would see your rotor is out of position.

Jarlaxle · 11-26-2011, 06:51 AM

Sounds to me like the fuel pump might be on its way out. Should be mechanical, paassenger side of the engine just above the oil pan; it will run you about thirty bucks.

freakn · 11-26-2011, 11:10 AM

Sounds like your choke pull off has failed ( little vacum diaphram on side of carb) It is supposed to open choke up once vehicle is started. When you hold your foot all the way to the floor the linkages actually force the choke open about 30 degrees (to help clear flooding). Hold the choke valve completely open and try to start the bus, it will take a bit for it to clear the excessive fuel and run smooth. Once you get it running look down inside the carb, you may be able to see a light spray of fuel, this is good. If you can see it pouring in there than you probably have a stuck needle in your float bowl. Hope this helps, Carl

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