No Run Condition

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VairsRule
Posts: 103
Joined: Fri Oct 26, 2018 6:36 pm

No Run Condition

Post by VairsRule »

I'm nearly done restoring my '62 Monza 900 sedan, just need to install carpet and seats, finish the new door panels, and get new window sweeps... AND figure out why it won't run. I've had this car for years. It sits for long periods, but it's always been easy to get running and runs and drives great. Now it's decided not to run. It will fire if I add gas or starter fluid to the carbs, but will only run for a second or two, then dies.

There are few obvious possibilities that I need to check out, but the car is currently stored in a place where I can't work on it at all. I will be trailering it to a new storage facility where I will be permitted to work on it here and there, but it's always so inconvenient working on cars aways from home. I can't take my entire collection of tools there, and I always manage to NOT bring all the tools I end up needing.

To make matters worse, the computer I have all my records for this car and the corvair shop manuals on is also in storage and inaccessible until next week. I'd like to hit the ground running on this ASAP, while I have some downtime and the weather is fairly friendly.

Here is what I have done or tried to get it running since it stopped wanting to:

1. Installed new choke coil on driver's side (was refusing to close). Was really hoping this was all it needed. NOPE.

2. TRIED to test the ignition coil using the cheesy Harbor Freight multimeter I got for free (first two did not work at all). I've been using this meter for several years. Replaced the battery with a "good used" one, but still getting wildly varying readings for the primary coil test. Bought a new battery, but was not able to get it installed and try again before I left. I may need to get a new multimeter.

The last time I tested tested the coil, it tested good and the engine started and ran fine about a year ago. As previously mentioned, it ran fine before, but it's been a long time since I last checked the spark plugs and points, which were good then, but not new. It's been a long time since I had to go through the entire troubleshooting process.

About 7 or 8 years ago, I replaced the gas tank and sender with excellent donor parts from a '65 Monza, flushed the fuel line and blew it dry, cleaned the filter stones, and installed an inline fuel filter. The fuel pump passed the volume test. Did the carb setup and balancing. Both carbs need new throttle shafts, but engine has always run well enough to get by fine as-is.

SO... while I'm sitting around waiting to have access to the car, if you have any good suggestions like what to check and in what order, and anything I can test without a multimeter, I'd appreciate it. Thanks!

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terribleted
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Re: No Run Condition

Post by terribleted »

Check for fuel flow. The fact that it runs after giving it a little fuel points to a fuel delivery issue...will not run without fuel:) Fuel pump may be bad at this time. Check point gap and condition easy to do and can shift over time sometimes. After you have verified fuel flows at proper volume from the pump the carbs become suspect. Gummed up internally from gas evaporating in them is another good possibility. Id there is fuel and spark at anywhere near the correct times they will generally run.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

joelsplace
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Location: Northlake, TX

Re: No Run Condition

Post by joelsplace »

Take a squeeze bottle with a small tip and some gas to fill the carburetors through the vents. If it starts and runs good for a couple of minutes it is just not pumping fuel. Check the rubber line in the left rear wheel well and the one by the tank. I've seen them get mushy and collapse.
Filling the carburetors a couple of times might be all it takes to get it primed and going again.
If you fill the carburetors and it still doesn't run right then they are probably stopped up as Ted mentioned.
114 Corvairs, 5 Ultravans and counting
Northlake, TX

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bbodie52
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Re: No Run Condition

Post by bbodie52 »

Plenty of good, accurate multi-meters are available via mail order, like Amazon.com, or from local hardware stores, electronics outlets, etc. Without one you are "flying blind". I prefer a meter with an analog (meter with needle) display over a digital display. The rapidly changing and flashing digital display can be a little confusing.

:link: https://www.amazon.com/s?k=multmeters&c ... b_ss_i_1_5



Cranking the engine provides voltage to the coil positive terminal from the starter solenoid as long as the starter is engaged. The moment the engine starts and you release the key, the starter solenoid power source to the coil is discontinued, leaving only the primary ignition wire from the ignition switch, via the main wiring harness and engine compartment multi-connector, and through the ballast wire to provide a nominal 7 VDC to the coil positive terminal. If this primary ignition circuit has a fault, voltage may only reach the coil while the engine is being cranked. Power could be disappearing with the key only in the ON position.

Left-click the image to enlarge it for better viewing or "Pan & Scan". Click a second time for maximum enlargement..
1962 Passenger Car Combined Schematic
1962 Passenger Car Combined Schematic

These two diagrams show the difference between 1962 and 1963 wiring. They are electrically the same, but in 1962 two separate wires were routed to the coil, and they joined together at the coil positive terminal. In 1963 the two power sources were joined at the small connector near the starter solenoid — leaving only single wire to be routed the rest of the way to the coil.
1962 Corvair Engine Compartment Wiring Diagram
1962 Corvair Engine Compartment Wiring Diagram

1963 Ignition Wiring Diagram
1963 Ignition Wiring Diagram
==================================================================================
bbodie52 wrote::think: The Corvair mechanical fuel pump is usually pretty good at pulling gasoline the length of the vehicle to prime the fuel pump so that gasoline can be pressurized to fill the carburetor float bowls. But a small air leak or crack in one of the short rubber hoses at either end of the fuel line between the tank and the pump can create what amounts to a vacuum leak in the fuel feed line that supplies the pump. The pump can cycle many times as the engine cranks and the battery drains while sucking mostly air from a fuel line air leak instead of getting a good "drink" of gasoline from the tank.

An improperly inserted mechanical fuel pump may also limit the motion of the pump diaphragm, if the pump insertion is too shallow and not allowing the push rod to take a full stroke. Refer to the notes and illustrations below to see how the pump set screw is supposed to insert into the tapered hole in the side of the pump shaft, and not just push against the side of the pump shaft. Proper installation ensures that the pump is properly positioned in relation to the push rod, so that the pump gets a full stroke with each rotation of the crankshaft. Good fuel volume from the pump is considered to be 1 pint of fuel in 40 seconds or less at cranking speed.

To check for the possibility of fuel starvation, you should measure fuel pump pressure AND volume! It is easy to have a pump that delivers correct pressure, but cannot produce adequate fuel volume. A feed line leak or cracked/damaged/loose rubber hose between the tank and the pump can create an air leak that will keep the pump from being able to create a solid vacuum to pull a good supply of fuel from the tank. Without adequate fuel supply, the pump can generate adequate fuel pressure to the carburetors, but only until it is starved for gasoline from the tank. The pump must also be installed to the proper depth and anchored properly using the tapered bolt that is screwed into the tapered hole on the side of the pump.

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:link: http://www.corvair.com/user-cgi/catalog ... nd_page=65



Part number C259: 62-69 FUEL PUMP ROD-REPRO (3 13/16") 60-61 ROD=C7256

Weight: 0 lbs 4 oz
Catalog Page(s): 11(28),65
Price: $ 19.15


Part number C1604: FUEL PUMP SPRING

Weight: 0 lbs 2 oz
Catalog Page(s): 11(34),65
Price: $ 3.55


bbodie52 wrote:The pump push rod is driven by a cam lobe on the crankshaft. The repeated "upstroke" causes the pump to form a vacuum in the feed line from the fuel source (tank or gas can). As the fuel is drawn into the pump chamber, the one-way valve in the pump inlet closes at the top of the stroke, and the spring in the pump forces the diaphragm back down to push the fuel out of the pump through the other one-way valve, toward the carburetors. The spring tension determines the fuel pump outlet pressure.

Check to make sure you are fully inserting the pump so that the pushrod driving the pump gets a full stroke to drive the fuel pump. Proper installation of the new parts is critical,,,
To remove and reinstall the fuel pump, be sure that you have installed it properly. It is important to ensure that the fuel pump is correctly seated and installed. There is a hole in the side of the pump shaft that the tapered bolt tip must seat into. If the pump is sitting too high and the bolt is simply pressing against the side of the pump housing, rather than seating inside the tapered hole, the pump push rod will not be doing its job. Fig. 57 in the shop manual page shows the tapered hole that the tip of the bolt fits into. This ensures proper installation and seating of the pump.

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Also...
There are two relatively simple tests outlined in the Corvair shop manual. These tests measure output pressure and fuel delivery volume. The output pressure test utilizes a common vacuum/pressure gauge that is relatively inexpensive. The output pressure is regulated by an internal spring that is contained in the upper pump housing. Unless your pump springs a leak in one of the diaphragms or seals, it is likely that the output pressure will not change with age. However, new pumps may be fitted with a spring that produces an output pressure well in excess of the 4-5 psi standard. High-pressure can cause carburetor flooding, and is particularly a problem with the Carter YH carburetor found on turbocharged Corvairs, which is sensitive to excessive fuel pressure.

A new fuel pump should always be tested for output pressure. If the pressure is found to be excessive it may be possible to cut the spring or to exchange the spring from the old pump and fit it into the new pump. This may correct the output pressure.

The second test measures fuel flow at the fuel pump outlet. The standard in the shop manual states that the pump should be able to deliver 1 pint of fuel over a period of 40 seconds or less at engine cranking speed. If your pump does not appear to have any leaks and can pass the output pressure test, but fails to deliver the needed fuel volume, the problem may not be with the pump itself. There is a long fuel line that runs the length of the car from the fuel tank to the fuel pump. In order to pressurize and deliver fuel to the carburetors, the pump must be able to create a continuous vacuum in that fuel line to draw the fuel from the tank to the pump. Most of the fuel line is made up of steel tubing and is unlikely to develop a leak. However, there are two short lengths of rubber fuel hose in the fuel path. One section of hose is found at the fuel tank outlet, while the other is found adjacent to the starter motor — just before the line enters the engine compartment. The purpose of the second hose is to absorb vibration from the engine and prevent it from reaching the rigid steel fuel line. If either one of these two hoses develops a leak, the leak itself may not be apparent because the line is not under pressure so fuel will not be forced out. Instead, the leak amounts to a vacuum leak, which can allow air to enter the fuel line. This can prevent fuel from being drawn from the tank to the fuel pump, much like you might experience with a drinking straw if the straw was to split and developed an air leak in the side of the straw. What appears to be a faulty pump that is causing fuel starvation problems in the carburetors often turns out to be a leak in the fuel line at some point between the gas tank and the fuel pump. So if fuel starvation becomes a problem with your carburetors, there is a tendency to question the condition of the needle and seat valve inside the carburetor, or to blame the fuel filter at the carburetor inlet (thinking it is clogged), or to blame the fuel pump itself. Before you blame the pump and toss it, or abandon it and replace it with electric fuel pump, be sure to check the condition of the rubber fuel hoses at each end of the long fuel line between the fuel tank and the fuel pump. You may find that a couple of hose clamps and a few inches of replacement fuel hose is all that necessary to get you back on the road!
:doh:

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For a quick check on fuel availability in the carburetors, you can peer down the throat of each carburetor while holding the choke open. Open the throttle quickly. You should see a squirt of fuel injected into the carburetor throat from the accelerator pump. This confirms the presence of fuel in each float bowl.

With the air cleaner assembly removed, when holding the choke open and peering down the throat of each carburetor, do you see a squirt of fuel from the accelerator pump in each carburetor when you open the throttle rapidly? If the jet of fuel is not observed, the float bowls may be dry, possibly due to stuck needle and seat assemblies blocking the fuel inlet.

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Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

joelsplace
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Re: No Run Condition

Post by joelsplace »

Harbor Freight often has free digital volt ohm meters that work fine.
114 Corvairs, 5 Ultravans and counting
Northlake, TX

64powerglide
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Re: No Run Condition

Post by 64powerglide »

I see some long answers so i'll give my thought, stuck needle valves in the carbs. That would be my first thing to do.
64Powerglide, Jeff Phillips

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VairsRule
Posts: 103
Joined: Fri Oct 26, 2018 6:36 pm

Re: No Run Condition

Post by VairsRule »

Thanks for the suggestions and info. I'm looking forward to getting it running again.

One observation: Even though it fires when I pour some gas down the carbs, it only runs for a second or two. Normally when I do that, it runs longer. Maybe the old mechanical fuel pump has finally gone to fuel pump heaven. I would have tested it, but did not have anyone around to crank the engine, and don't know where my remote starter switch ran off to. Of course, I could always pull it out and bench test it. It's not had any problem with the points not staying adjusted, but they might be corroded, the plugs may also be corroded. It's been in a portable garage, which is a breeding ground for moisture certain times of year around here. Sometimes it "rains" inside".

My old trusty Radio Shack analog multimeter finally gave up the ghost a few years ago. It lasted a good 30 years.

Has anyone figured out a way to keep the engine bay on the EMs from getting so much water in it when exposed to wet weather? I can see why GM re-engineered the cold air intake system for the LMs. Those louvres in the EM engine lid let so much water through, and the flat air cleaners have a divot that lets any water that gets on them drip into the carb if the wingnut is not tightened down. I had the air cleaners loose for awhile there...

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bbodie52
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Re: No Run Condition

Post by bbodie52 »

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As I described in detail above, apparent mechanical fuel pump failures are often not the pump at all. A crack in a rubber fuel hose between the fuel tank and the pump can make it impossible for the pump to create a vacuum in the fuel line to suck fuel from the tank. Also, failing to insert the pump properly and secure it at the correct depth with the tapered bolt can deprive the pump of a full push rod stroke from the driving crankshaft cam lobe.

Image
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

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