My 63 has been running like a top for the past 5-6 years. But............

On Saturday, I took the car to a cruise sponsored by my Corvette Club. Ran great. About a 10 mile round trip. On Sunday (the next day) I was planning to go to a Cars N Coffee event at 8:00 AM. Car fired right up. Left my housing development and got on the main street leaving my area. Car started surging. Difficulty accelerating above 30-40 MPH. Got me worried so I turned around and came home. Probably drove it about 4 miles. Was not "bucking and snorting". Felt like fuel starvation.

I started to methodically check things.

Air Cleaner was OK
Pulled the FI drive cable. Like new. Nice square ends. Re-lubed and reinstalled it. Took a test drive. Still the same problem

Pulled the cover on the fuel meter to observe the economy and power stops. They were moving freely. Car would idle smoothly. You could balance a champagne glass on the FI unit.

Changed out the cranking signal valve.

Went to the distributor. Cap like new. Rotor too. Everything tight. Checked dwell. 28*. Checked timing. 8* BTDC

This morning, I removed the gas line and filter. Clear as a bell. Could easily blow through it. I didn't have a new filter on the shelf, but the old one was good.

Fired the car up............. and it would run for 3-5 seconds, then stall, like it was running out of gas. Tried that a number of times with the same result. Cracked the fitting to the fuel meter, and gas was pouring out of that............so gas getting to the fuel meter.

I'm thinking one of two things.

#1. The FI gear pump, but I had that rebuilt by Rollin Jones a number of years ago, and it has few miles on it. Maybe 1500? I never got around to checking the squirts from the spider where the connect to the nozzles.

#2. The shutoff solenoid that I added to the fuel spider. I wonder if that has failed? I need a helper with good ears to evaluate for a "click" when it's energized. IIRC, I got it from John DeGregory. Can they be rebuilt?

Does anyone have any other thoughts? Suggestions? Are all of these cutoff solenoids the same as far as plumbing goes? I'll have to remove the unit to check and see what I have.

 

Bad gas?




hi Chuck

 

I filled up a month or more ago with 93 octane no ethanol fuel, so I don't think it's a gas issue.

I've driven it a fair amount since the last fill up. Had a full tank. Now down to 1/2 tank.

 

crud on the sender pick up?

 

Clean as a whistle. I took a flashlight and examined the inside of the tank. Pick up looks perfect.

 

I'm sure Jim Lockhart will chime in with ideas/suggestions/analysis etc. If not PM me for longtime F/I expert I can put you in touch with. begee22

 

Hi Chuck,

Have you given any thought that it's not a fuel problem but maybe a coil or firewall connection issue., (electrical). Did you hear about Jim J??

Tim B

 

I didn't check the coil. I have a spare. When it was running, it idled perfectly. Now, it won't run for more than 3-5 seconds. Worth a try looking at the bulkhead connectors.

Yes, I heard about Jim J and also Fred C. We're all getting older, Tim.

 

I'm open to all suggestions.

 

Chuck, I probably can't diagnose the FI trouble by long distance, but maybe I can provide some thoughts which will let you do more investigative work and find the problem.

1. For a '63 FI, if the engine runs at all, even for a few seconds, the high pressure gear pump is working. Too, about the only way the pump could fail completely would be if the drive pin on the main shaft were to shear or if the main shaft itself were to fracture. I've never heard of either of those failures happening.

2. The anti-siphon valves JD use to sell were, AFAIK, crimped-together valves, not rebuildable. That said, on a Sting Ray FI, anti-siphon valves are plumbed for reverse flow. Anti-siphon protection comes from a spring which closes the valve once flow from the gear pump stops. I think (but have never tried it) that once the engine starts, you could probably remove power from the valve and the engine should continue to run. IOW, I can't think of a way the valve could cause the symptoms you're seeing.

3. You say the engine will now run for a few seconds after starting. Did that behavior develop after you changed the Cranking Signal Valve? If so, how does the engine behave with the old CSV re-installed?

4. If the rubber connector between the CSV and the tube to the "T" over the main diaphragm is cracked or loose, you could probably get enough of a signal to start the engine. I suspect it would leak enough, though, that the venturi signal couldn't keep the engine running.

5. If the needle/seat at the fuel inlet is beginning to unscrew itself, fuel delivery to the engine will be reduced. In the extreme case, it will be only a trickle, not enough to sustain engine operation.

6. To promote flow to the nozzles, the spill valve inside the fuel meter must be able to pinch off fuel return to the bowl. Some things which would prevent this:
a. The roller at the end of the axle/link lever has come off. I've seen this happen.
b. The nut securing the main diaphragm to the link of the axle/link could work loose. The factory prevented this by applying a dab of red Glyptal to the nut and threads. Most rebuilders leave the nut and threads dry.
c. Loss of vacuum signal to the main diaphragm. See #4.
d. Torn/damaged main diaphragm.
e. Extreme spill valve wear which allows the thumbtack to not seat properly. I've seen this but it is a wear phenomenon, not something with sudden onset.
f. The entire spill valve has slipped down, limiting the influence of the axle/link. There should be a very stiff coiled spring under the spill valve preventing this. But if the last rebuilder left it out.....

Going forward, how comfortable are you with doing some partial disassembly to check for some of the physical possibilities I've identified?

Jim

 

Hi Jim.

Thanks for responding. First of all, at Tim B's suggestion, I swapped out coils and checked my bulkhead connectors. No effect with the new coil and my bulkhead connectors are clean as a pin and straight as an arrow.

Changing the cranking signal valve had no effect. So, I put the original valve back in. The little hose is tight and not cracked. Swapping out the CSV had no effect on the engine symptoms

I'm very comfortable taking the unit apart. I should mention that Jerry B rebuilt the unit 10 or more years ago. Doesn't have many miles on it.

I thought that the solenoid shut off the fuel flow to the distribution spider, preventing gas from filling a cylinder... and causing a hydraulic "situation".

I want to try the "click test", but I need a buddy with good hearing to help me. Right now, the power to the solenoid comes off the ballast resistor. I want to disconnect that, turn the key ON, then touch the power ON again to see if I hear a click. That way I know that the solenoid is at least going in/out.

I have no problems tearing the unit apart. Only issues I have is that I do not own any sophisticated test equipment. I have basic backyard mechanic stuff. I've had the unit off a number of times over the years.

 

Chuck,
Maybe a distributor cap or Rotor gone bad. It’s rare but could cause intermittent spark issues.

 

Ah, since Jerry restored your FI, that tells me the quality of the parts in the unit. He used the absolute highest quality stuff. Have you checked with him?

I've had one additional thought. A main diaphragm that has developed wrinkles can cause symptoms consistent with what you've reported. Ideally the diaphragm should look like this:



Notice the smooth "hump" all around the magnesium disc. **Any** wrinkling of that "hump" region **will** cause operational issues. I've even experienced no-start conditions due to nothing more than a few wrinkles. So take a look at the diaphragm with your most critical, suspicious eye.

Any doubt about what you find, post some pictures.

Jim

 

Cap and rotor are like new. And, when the car was running, it was running smoothly.

 

Thanks, Jim.

I'm gonna pull the unit off tomorrow. Only 8 nuts and one fuel line. FIRST thing I want to check is the main control diaphragm. I have spares, new ones in kits I have.
I haven't talked to Jerry B. He's retired now.

I still want to check that solenoid.

 

A fella would likely want to kick himself in his own *** if he went through FI disassembly only to discover a bad condenser. Fuel system failures are less likely to come from nowhere whereas electrical failures love to come out of the blue. Could very well be the FI, but I'd be ruling out ignition every which way beforehand.

Dan

 

Sounds like the best available minds are with you Chuck .

Will follow this thread and enjoy the learning appearance opportunity .

 

Good advice. I can swap out the condenser later today. I leave for my volunteer job at the local State Park early this AM. I'll get home at about 3:00 PM. Easy enough to swap out condensers.

I did swap out coils the other day with no change.

On Sunday, three days ago, the car was still running. That's the day I turned around and came home going to a Cars N Coffee event. When I've changed things out, I had taken the car around the block to check my changes, and it was still running/driving. I did have a timing light and a dwell meter on it a few days ago, and those readings were fine. It was still running/idling.

Now, it'll start immediately, and run for 3-5 seconds, then stumble to a stall, like it's out of gas.

 

If you'll call me this afternoon, I'd be glad to help. Please don't take anything apart before then. I just need a little time to pull your unit's records and note all the tests you've already run.

You're right, Chuck, I've closed my business and sold most of my leftover parts. But I'm not dead or even disabled. I still help people with their FI systems by phone almost every week. My phone advice is free to anyone who asks me for it. I especially intend to support my past customers for the rest of my life.

Jerry
(251) 478-4003

 

Great customer serves Jerry /.