79 Bus hard start / rough running after a short rest

[vetterdog]

I have heard this is common, but I haven't heard how to remedy it. My 79 Westy starts up and runs great, but after a short stop (say for a cold drink or grocery shopping) it doesn't want to idle. Also if it should stall after being re-started (after it's little rest) it's a real chore to get it fired up again. Turns over fine, but won't fire up.  As for the bus itself, it has a '74 type IV motor (1800) with the 79 heads and I just installed electronic ignition, which makes it run real nice, but the problem existed before the switch-over. Can anyone advise? All help/advice is, as always greatly appreciated.
-Dave

[MrLiMBO]

Nothing comes to mind right off that might be causing your problem.  Though it sounds like a sensor. The sensor and the cylinder head might be the place to start.   My advice would be to get out your muli-meter, test light and Bentley book and start troubleshooting. The book has all the specs for each sensor and its fairly easy to troubleshoot that old Bosch system.

[vetterdog]

I feel kind of stupid admitting this, but my bus was about a quart and a half low on oil, so was running hot. It's always the simple things that are overlooked. My temp gauge isn't working. Gotta fix that.

[St.Bus]

Is it fuel injected?
if so sounds like a fuel problem.
temp sensor 2 is located near the #3 cylinder, may as well get a new one, if it is old, that can make the bus run rich if there is not the proper resistance.
First off get or borrow a vac gauge ($20) to look for vacuum leaks.
Verify that all vac hoses are sound, check all the lil clamps with a 1/2 turn of the screw driver to be sure they are tight.
Second , use a multi meter to test the cold start valve, again improper resistance will allow it to stay on like a choke even after the bus is hot, which sounds like the problem to me.
#3 replace the fuel filter, after a short drive , the pressure builds up and there may be small debris causing problems.
#4 does the idle go up when you pump the brake?if so there could be a major vac leak in the brake booster line.
when you first start the bus it'll run fine cus the cold start injector is adding fuel to help mix out the ratio of air from the brake booster leak, but when the cold start valve shuts off, there is  to much air..the possibilitys are endless,
look at richard atwells site. its like the Bentley online
http://http://www.ratwell.com

[vetterdog]

Changed the #3 cylinder sensor no help, checked all vacuum lines, nothing. Cold start valve OK. Changed the fuel pressure regulator and it runs much better. Still sputters abit after a restart when it's warm, but I still have to change the fuel filter. Getting there by degrees. Snapped the clutch cable yesterday, but that's another story. Life is more of an adventure with an old VW don't you think?

[vetterdog]

Changed fuel filter but problem still persists. I stopped yesterday for 5 minutes, then it started, but it konked out on me and wouldn't restart. Frustrating as all get out. It will start when push-started though, so I've learned to shut it off on slopes.

[St.Bus]

remove and inspect the lil elbow that is attached to the aux air regulator, its worth a shot.
I replaced the elbow with another piece of tubing all together, when there is a crack in that the bus will idle fine, but give it gas and it dies, I think you have a major vac leak on a hose that when shifted opens a crack in it. if you get it to idle, go do the wiggle test while its running, careful though, you dont want to create any new leaks or cracks, ...................Joe

[vetterdog]

i have now replaced the ignition wires and the cold start valve, timed the thing, but it is getting worse. Now that the weather is warm, it is a pain to start, (turns over but takes a while to come to life) and when the engine gets warm, it doesn't want to idle. Seems like heat is a factor, but not the only one.  Next I will check the coil. I am thinking of offering a reward to anyone who can figure this out. Maybe at Westies in West Milford?

[beebrew]

Sounds like a possible vapor lock problem to me. If so, it's caused by parts in the fuel delivery system getting to to boiling point of gas. I am no familiar with this vintage to know if is a common problem. Is the motor overheating? Dipstick too hot to handle?

[vetterdog]

I though about that too, but it's not getting that hot. Unfortunately, my temp sensor (cyl head) guage isn't working. I am going to spend some time today on it, trying to assess weather my timing marks are in the right place, fixing temp guage, etc. I'll post any progress. Thanks,  Dave

[vetterdog]

OK, timing is fine, got the temp guage working too. No change in the issue at hand though. I stopped at the supermarket for a few things (express checkout no less!) and when I got back in the bus and started it, it wouldn't idle. It would die like it had a vacuum hose off. Stopped at a red light coming out of the supermarket parking lot and it stalled again. Started it and I drove for two monutes down the road, stopped at a light and it idled OK, maybe a little slow. By the next red light it idled fine.  So it's not teperature related, as it was a lot cooler when restarted than when I shut it off.  So far I've replaced points, ignition wires, fuel pressure regulator, cold start valve, fuel filter, fuel lines, spark plugs, cap and rotor, and clamped all vacuum lines.

[beebrew]

Please follow up on your results. You have my interest! If it were a vapor lock problem, I don't think letting it cool would make allot of difference. Once the gas boils, the vapors would have still displaced the fuel. Of course this assumes vapor lock is the problem. Did you replace the condenser along with the points? Just another piece.
Good luck.

[beebrew]

Oh, another thought. If this is carburetor engine, did you go through the choke? I have had one that did not close well when only marginally cool. It ran crappy until the engine warmed up more.

[St.Bus]

where do you live?
If you are near me Id be glad to help take a look with ya...
Im in western Mass. Have you tried putting an Ohm meter on temp sensor #1? ( white nub inside the afm ) also do you have the bentley?  Joe

[vetterdog]

I live in central West/Jersey, and the bus is fuel injected. it's actually got an 1800 motor from a Porsche 914 (I know, everyone has heard that one before, but I checked out the numbers) with the FI setup from the 2.0, (which needs a bottom end rebuild, whenever I get to THAT). I think we'll be at Granny Grose's and Westies in the Woods (Stokes State Forest), both in May. As I mentioned, I think I might offer a reweard to whoever can get this figured out. I also replaced the ignition coil and fixed the Cyl head temp sensor. It never reads above 350 at plug #3. It has been suggested that maybe it's a leaking injector, which would flood one cylinder while the bus sits. But it also exhibits this stalling behavior if I'm in stop-and-go traffic. Once I get to open road it's fine. All fuel lines are routed as original. I'm running out of things to check/replace! Another thing, went through state inspection and it failed for unburned fuel, they said it was pretty bad, but my spark plugs are a nice tan/gray color, just like they should be. Could there be an issue with the fuel delivery since the FI setup is from a 2.0 and the current motor isa 1.8???Thanks again to all for your intersest and advice.