Corvair quit running - I've done all I know to do, need help

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Gas Giant
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Corvair quit running - I've done all I know to do, need help

Post by Gas Giant »

I apologize in advance for this being a looong post.

I'll summarize everything first, and then go into greater detail below, to make it easier.

1964 Corvair convertible, non-turbo with a Powerglide. Unknown mileage on motor, but its old. I've spent the last few months waking it up from a long slumber. I had it running pretty well, and thought it was about time to head down to the DMV, get a tag for the Vair, and have some fun this summer. That was on a Friday. Went to fire it up on the following Sunday, and it wouldn't stay running. Would only run if I kept pumping the gas, and even then it ran horribly and only for a few seconds. This was in the early May time frame.

Long story short, thats the basic problem. Won't start unless you've got it floored (will sputter, but not start, unless its floored) and even if it starts it runs horribly and only for a short time. Oddly, last Saturday, I decided to give her another shot after letting her sit for a few weeks. On the suggestion of a car club buddy, I disconnected the vacuum line going to the transmission and capped it off. Viola, the car fired right up and ran great. The next day, without changing anything, it was back to its original problem.

That's the condensed version. Here are some more details on the car:

New Parts:
-New fuel tank
-New sending unit
-New fuel pump
-New distributor (the ENTIRE distributor)
-New spark plugs
-Rebuilt starter (it went bad when trying to diagnose a different problem)
-New carburetors

Other details:
-I checked the compression; and although I don't remember what the numbers were anymore (it was in May), they weren't cause for alarm. I don't have the the equipment to do a leakdown test
-Timing was set at 14 deg with the vacuum advance disconnected
-When I replaced the fuel tank, I blew out the fuel line with compressed air, and added an inline filter between the line and the pump. There is no debris in the filter, I checked.
-Several times before replacing them, I tore the old carburetors down - there wasn't any debris in them either, but they did have gas in them
-I checked the fuel pump by having it squirt fuel into a beer bottle when cranking. Its pumping fuel, but I don't know the actual pressure reading


The fuel tank, sending unit, fuel pump, distributor, spark plugs and starter rebuild all occurred before this problem began. I replaced the carburetors with rebuilt ones after the problem began, but that had no effect on the problem whatsoever. I did use new gaskets on both sides of the plastic "spacer" that the carburetors sit on, and I don't remember seeing any cracks or holes in the spacers when I replaced the carbs.

Thinking I might have a fuel tank/line problem, this Sunday I tried running the car using a rubber fuel line directly from the fuel pump to a gas can with fresh gas in it. This had no effect on the problem at all.

To me, it seems like its a fuel related problem - essentially its only getting fuel when the accelerator is pumped. If you push the throttle, you can see fuel squirting into the carbs. I've checked everywhere I know to check for a vacuum leak. The choke pulloffs are new, with new hoses, the vacuum advance hose is hooked up and is only a few months old, and the modulator line to the transmission is still capped off from before. (Don't worry, I won't be driving it anywhere like that)

The only other clue I can offer is that the transmission developed a sizable fluid leak at approximately the same time that it stopped running (the first time). Not even sure if that would be related, or just another headache to deal with.

Anyway, at this point, I'm out of ideas and really frustrated, so if anyone has any ideas I'd be glad to hear them. I just don't know what would cause it to go from running great to running badly overnight, and then randomly run great for one afternoon, and revert to running badly the next day. (So far, its only run well once in the many times I've tried to start it since the problem began)
jonj
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Re: Corvair quit running - I've done all I know to do, need

Post by jonj »

Just a guess, but check the coil, and condensor.
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bbodie52
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Re: Corvair quit running - I've done all I know to do, need

Post by bbodie52 »

:goodpost: Thanks for the detailed troubleshooting summary. With many owners getting detailed historical information is like pulling teeth! Your summary details a lot of your past efforts, which can be very helpful as readers review your description of symptoms and the efforts you have already made to isolate the cause of your frustrations.
I disconnected the vacuum line going to the transmission and capped it off. Viola, the car fired right up and ran great. The next day, without changing anything, it was back to its original problem...The fuel tank, sending unit, fuel pump, distributor, spark plugs and starter rebuild all occurred before this problem began. I replaced the carburetors with rebuilt ones after the problem began, but that had no effect on the problem whatsoever. I did use new gaskets on both sides of the plastic "spacer" that the carburetors sit on, and I don't remember seeing any cracks or holes in the spacers when I replaced the carbs...To me, it seems like its a fuel related problem - essentially its only getting fuel when the accelerator is pumped... I've checked everywhere I know to check for a vacuum leak. The choke pulloffs are new, with new hoses, the vacuum advance hose is hooked up and is only a few months old, and the modulator line to the transmission is still capped off from before. (Don't worry, I won't be driving it anywhere like that)
It still sounds like a significant vacuum leak... perhaps associated with the vacuum balance tube. Pumping the throttle momently enriches the fuel/air mixture as each pump produces a shot of gasoline from the two accelerator pumps. But that will not sustain the engine if the fuel/air mix is extremely lean because of a vacuum leak from an as-yet unknown source. The fact that disconnecting the transmission vacuum modulator tube temporarily provided some degree of relief and gave you normal operation for awhile is interesting. Could there be a split or improperly seated vacuum tube -- perhaps at one of the large-diameter short rubber tubes that are hidden from view at the base of each carburetor? There are no hose clamps there, and those aging rubber tubes can become hard and brittle. Perhaps your fiddling with the vacuum modulator connection temporarily improved the vacuum seal elsewhere along the vacuum balance tube... but subsequent engine vibration loosened the seal again so the original problem returned.

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Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
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UNSAFE
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Re: Corvair quit running - I've done all I know to do, need

Post by UNSAFE »

Would only run if I kept pumping the gas,
This indicates a fuel delivery problem .

Regardless of what you already did it is likely an air leak in the supply line or a restricted carb.

To confirm this either dribble a LITTLE gas down the carbs as a helper operates the key for you or spray a LITTLE starting fluid .

If this makes the engine run longer or better you have confirmed a fuel problem.

Not likely that it's compression or timing .
Kevin Willson
1965 Monza 3.1
Juneau Alaska
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tiger13
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Re: Corvair quit running - I've done all I know to do, need

Post by tiger13 »

You could start with checking the nuts that hold the carbs on, to make sure they are tight, just in case. Also check the hose on the balance tube as Brad suggested. It may be a coil going bad, you could, temporarily run a jumper wire from your positive wire on the battery to the positive wire on the coil, that will give it a full 12 volts, just like it has when your cranking the engine, but all the time it is running. See if it makes a difference, if the coil is weak, the extra voltage may make it run better, BUT do not leave it connected for too long as it WILL burn out your coil and points.
Something else you could try is check the fuel delivery of your "new" fuel pump. Take a line off of the carb, and force a piece rubber gas line over the end of the metal line, put the hose in a clear bottle and have someone crank the engine to start it, and watch how fast it fills the bottle, DO NOT LET IT OVERFLOW! Be careful doing this, common sense is required, keep hands , tools, and the bottle in a safe spot. Good communication with your helper is essential here when you do this.
Are the spark plugs fouled? You said it was running bad, I have found that is does not take much to ruin a set of spark plugs these days. It may be helpful to you to remove them and give them a real good cleaning and gapping, so you are sure to be starting from square one.
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Gas Giant
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Re: Corvair quit running - I've done all I know to do, need

Post by Gas Giant »

Thanks for all the suggestions. I'll try them all out hopefully today, if the weather holds, and report back.
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bbodie52
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Re: Corvair quit running - I've done all I know to do, need

Post by bbodie52 »

I was looking back through your previous posts and I noticed your initial posts in 2013 indicated an interest in Corvairs, but at that point you did not own a Corvair. FAST FORWARD... the next 2015 posts indicated that you now own a 1964 Corvair convertible! Congratulations! I hope you will post some pictures and tell us more about it!

Image
I wanted to suggest that contacting one of the two CORSA (Corvair Society of America) club chapters in your area might be beneficial. The Corvair Forum is great, but it is often helpful to have face-to-face contact with local Corvair enthusiasts as well. The two clubs in your area are based in the Orlando area (Saint Cloud) — about 43 miles west of your city, and in Ormond Beach — about 73 miles north. CORSA clubs are family-friendly and often offer technical training and assistance, car shows, group scenic drives, picnics, competition events, and other social gatherings. If you are interested I have posted some contact information below...

The Orlando area website appears to be somewhat out of date, so I'm not sure what you will find if you contact them. The Central Florida club is a little farther away, but appears to be more-active.

Image

Greater Orlando Corvair Club

:link: http://govairs.net/Home_Page.html

For Information on the club events and activities Contact Titus Stewart (Club President) at 407-892-5999
or Craig Schielke (Club Vice-President)
at cschielke@cfl.rr.com


Central Florida Corvair Club
Florida's Largest and most active club. With over 70 family memberships.

We are very active participants in all Corvair Shows as well as AACA shows and local cruise ins. We also are very heavily involved in autocrossing and time trials.

We have a club shop where members can come and work on their cars.

Central Florida Corvairs also has a club car which our membership did the body work . This Corvair is used in parades, shows and very heavily used in racing.
:link: http://www.motortopia.com/car-clubs/cen ... r-club-683

Central Florida Corvair Club
12 Pine Trail
Ormond Beach, Florida 32174
Contact:
Sarah Beltrami, Secretary
Sarahvair@juno.com
386-615-0072
Est. 1976
Members: 75


Common and Useful Corvair Websites

Corvair Forum :link: viewtopic.php?f=225&t=6007

:dontknow: I would like to encourage you to expand on your initial post and tell us more about yourself, your Corvair, and your goals for your Corvair. If you can describe your personal assessment of your mechanical skills and abilities, that would help a lot. Members of the Corvair Forum love to be helpful in assisting other Corvair owners with technical support and advice, but it helps a lot if we have some understanding of your technical background and mechanical abilities, Corvair-related knowledge, etc. Helping us to know more about you and your Corvair will help us to write comments to you that are tailored to your needs and experience. Pictures are great too, because pictures of your Corvair will help us to visualize where you are with your Corvair and its condition at the present time. Knowing your location is also useful, because knowing where you live can sometimes suggest possibilities to resolve some issues or problems.
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
64powerglide
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Re: Corvair quit running - I've done all I know to do, need

Post by 64powerglide »

Other details:
-I checked the compression; and although I don't remember what the numbers were anymore (it was in May), they weren't cause for alarm. I don't have the the equipment to do a leakdown test
-Timing was set at 14 deg with the vacuum advance disconnected
-When I replaced the fuel tank, I blew out the fuel line with compressed air, and added an inline filter between the line and the pump. There is no debris in the filter, I checked.
-Several times before replacing them, I tore the old carburetors down - there wasn't any debris in them either, but they did have gas in them
-I checked the fuel pump by having it squirt fuel into a beer bottle when cranking. Its pumping fuel, but I don't know the actual pressure reading
Did you replace the plug & coil wires? Can you post an engine compartment photo, maybe someone can spot something. Take a close up of the coil & dist & a full engine one. Make sure the dist. is tightened down. If it won't stay running by pouring gas in the carbs check the coil for a crack. Try starting it in the dark with someone watching the engine, look for sparks where there should not be any. :my02: :dontknow:
64Powerglide, Jeff Phillips

Kalamazoo, Mi..
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Re: Corvair quit running - I've done all I know to do, need

Post by NMVair »

I am not a techie as these guys but it sounds like it is definitely a fuel starvation issue. That seems to be common among Corvairs whether it is a vacuum leak or a fuel delivery problem both can prevent the engine from getting enough gas just narrow it down by doing the tests that have been suggested. I remember this type of thing happened to me and it just went away and i never figured it out. I remember at the time i tested the fuel pump, cleaned the filters at the carbs etc etc. The car started back up and I wasn't sure what happened. Interestingly both a vacuum leak developed later and the fuel pump (of course) quit working . My guess is that the fuel pump was starting to give up the ghost and worked intermittently. I now have an electrical fuel pump but I theoretically only use it as an assist.
Melb-Mike
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Re: Corvair quit running - I've done all I know to do, need

Post by Melb-Mike »

Perhaps I can help you. You're in Cocoa and I'm in Melbourne, about 20 miles south of you. Give me a call 321-749-9735 if you want some ideas.

You said you have "new" carbs......maybe rebuilt ones. Sometimes these "rebuilt" carbs have not been properly cleaned. I bought 4 rebuilt carbs and had issues with running, idling, and mid-range power. I ended up taking them apart, running them thru my ultrasonic cleaner and rebuilding myself. Problem solved.
Prior Corvair owner 30+ years ago
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adding to 69 Corvette BB, 67 GTO,
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Gas Giant
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Re: Corvair quit running - I've done all I know to do, need

Post by Gas Giant »

Ok guys, first report back.

In an effort to be reasonably scientific in my approach, I decided to try this suggestions in the approximate order they were posted, and try to run the car after each change.

I had forgotten to mention in my previous post that the coil, cap, and wires were all also new, and that I had been dribbling a little gas into each carb during the prior tests before I posted this.

So, I decided my "control" experiment would be to try and start the car as it sat, using the same methods I had been using. I hooked the battery up, dribbled a little gas in each carb, and tried to start it. As usual I had to give the accelerator a good shove to get it to fire up, but it actually revved up nicely for about a half second, then returned to sputtering and died. Sounds like fuel starvation....

But....

Since I had already gotten one, I decided to swap out the condensor in the distributor per one of the first suggestions posted here. Granted, the distributor was one of the things I had replaced, but I decided to try it anyway. And to my surprise, it fired right up and kept running!

Now this car has deceived me before, so I decided to let it run for a bit to see if it would return to its old ways. I let it idle for a good 15 minutes. It should be noted that it was still running on fuel out of the 2 gallon gas can from Sunday, not its own gas tank. Never in that 15 minutes of run time did it sputter, or give any indication that anything was wrong. (Other than the stuff that was already wrong, like the muffler being completely shot). I didn't try to make any adjustments or balance the carbs; I just let it run. I revved it up several times, and it revved up smoothly and returned to idle without any issues when I let up on the throttle.

I decided to give it another test. I shut it down, went inside and ate dinner. Probably took about 15 minutes to eat dinner (it was cooking while I was tinkering), and i went back outside and tried to start it. It fired right up without me touching the gas. In fact, I didn't even get in the car, just leaned over and hit the key. Started and ran with no fuss.

I let it run for another 10 minutes or so, and shut it down. I disconnected the battery, and then decided to try running it off its own fuel tank. Unfortunately, me being the buffoon that I am, accidentally spilled some gas from the fuel line into the alternator when I was swapping the fuel lines. :nono: So I've decided to let that air out for a few days before trying it start it again.

I don't want to call it too soon, but we may be in business!
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66CorsaConv
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Re: Corvair quit running - I've done all I know to do, need

Post by 66CorsaConv »

Please keep us informed. I rebuilt my distributor and kept the points and condensor. Long ago I was a K-Mart "certified" mechanic. Actually NIASE Certified General. :woo:

Motohead will know the difference from NIASE and now ASE I bet. :my02:

I had numerous tune ups come back using the K-Mart brand points and condensers. So from early in 1977 on... nothing but name brand parts. Of course I had to "sell" that idea to the customer. About 5% of those condensers went bad fast. One 64 Mustang 6-cyl never made it out of my sight! :assault:

Are there any "dents" or pin pricks in your "suspect" one? Mechanics call them condensers. Us Electrical Engineers know them as capacitors.

As long as mine works, I'm leaving it alone. I'm cheap.
Gas Giant
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Re: Corvair quit running - I've done all I know to do, need

Post by Gas Giant »

I had to teach myself to call them condensers lol
Gas Giant
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Re: Corvair quit running - I've done all I know to do, need

Post by Gas Giant »

What a freakin morning. Picked the boat up at the marine mechanic (after fighting with this Corvair, I was in no mood to diagnose the boat - I let someone else handle it for a change), and I dropped her in the water. Got about 100 yards from the dock and she lost power and died again. Fan-freakin-tastic, my 18 foot boat just became a large, unwieldy paddleboard. Anyway, after paddling back to the dock, it went back to the mechanic for another try.

I feel compelled to quote from the movie Spaceballs, "Even in the future, nothing works."

Anyway, there is a silver lining to this. After that fiasco was over, I decided to go for broke and try the Corvair again. I pulled it out of the garage by hand. (I had this really irrational fear of burning the house down due to the gas-in-the-alternator incident). Hopped in, hit the key, and she fired right up no problem. No sputtering, no fuss, just fired right up. I didn't have the chokes hooked up so I had to rev her a bit, but after few seconds she'd idle on her own. Ran ok, but seemed like it was idling a bit lower than it was on Wednesday. No matter, I let it run for another 15 minutes or so, and for the first time in a long time, drove her back into the garage under her own power.

I'm starting to think we may have this problem licked. Thanks for the help guys. :ty:
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Re: Corvair quit running - I've done all I know to do, need

Post by cad-kid »

Thanks for the update :tu:
Jeremy (cad-kid)
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Gas Giant
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Re: Corvair quit running - I've done all I know to do, need

Post by Gas Giant »

One last update - the engine quicky let me know it was not happy about being awakened after all these years. Everything seemed ok, until I took her on a little test drive. After about 20 minutes of driving, the OIL light would come on whenever I came to a stop. If I popped it in Neutral, the engine would speed up and it would go away. However, whenever I tried to pick up speed after being stopped, it sounded terrible back there....lots of unpleasant mechanical sounds under acceleration (but not at a steady speed, it turned out - moving along at a constant speed, it was quiet)....so I very carefully babied it back home, and when I was pulling it into the garage, there was the unmistakable sound.....knock-a, knock-a, knock-a...

So, the engine has been dropped out of the car and is being torn down for a rebuild. Better to start my Corvair relationship with a fresh engine, and the knowledge gained is always useful.
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