1963 FI Surging On Initial Startup

[Lawrence S.]

This is an ongoing issues....and linked a video of the issue.

https://youtu.be/ZcsdRGTdhww

When I initially start the car I have this surge and you can see the economy stop movement on the fuel meter on the video...it continues until the engine warms up. Afterwards...when I give it gas, the engine revs up, holds, and slowly comes backs down to idle RPM's (around 950). I have gone through the choke, checked for vacuum leaks...went through the timing settings multiple times, vacuum gauge checks and still stumped...new plugs but I did switch over to electronic ignition years ago and never any issues with that.

I keep thinking its in the Fuel Meter itself.....I have rebuilt the unit twice over the past 26 years and reached out to some of the FI NCRS Master Guru's to buy rebuild kits and get my wobble pump rebuilt after letting the gas setup and gum it up. So any thoughts...and thoughts appreciated.

Larry

[Jim L.]

Re: 1963 FI Surging On Initial Startup

Immediately before the first instance of the near-stalling, had anything been done to the FI unit? How did you calibrate the Economy and Power stops? Are you running ported distributor vacuum or full-time vacuum? What happens if you turn the Idle Fuel screw to make the idle mixture richer?

Jim

[Jim L.]

Re: 1963 FI Surging On Initial Startup

Larry,
I see that you started a similar thread in 2015. At the conclusion of that thread you said the car was running fine. What happened to the engine to change that?
Jim

[Lawrence S.]

Re: 1963 FI Surging On Initial Startup

Jim...first, thank you for responding. It has never been right after I rebuilt it but I had no ideal it had been that long ago. I likely indicated everything was fine because I just got tired of messing with it and could not resolve the issue...and then I started looking at it again. The car runs great outside of this annoying issue and I do take it out for a quick spin about once a month. Previously...I kept looking at the choke and butterfly based on comments I had received, but it is working fine. Only last week did I notice the economy level moving in and out with the surging so I thought this could be another indicator of what the problem is.

[Dan H.]

Re: 1963 FI Surging On Initial Startup

Just a thought, do you have the correct short cable to drive the wobble pump? I used a long version on my 63 with wobble pump, it twisted it into knots, lucky it didn't break off. Murphy at work etc.
Dan

[Lawrence S.]

Re: 1963 FI Surging On Initial Startup

Immediately before the first instance of the near-stalling, had anything been done to the FI unit? How did you calibrate the Economy and Power stops? Are you running ported distributor vacuum or full-time vacuum? What happens if you turn the Idle Fuel screw to make the idle mixture richer?

Jim

Jim in reference to your questions:
1. Had anything been done to the FI Unit? Response: Outside of rebuilding the unit, nothing was done.
2. How did you Calibrate the Economy and Power Stops? Response: I used the setup and procedures noted in NCRS Corvette Restorer Mag, Vol 9; #2 Fall 1982 "Troubleshooting Rochester Fuel Injection" by Brian Futo. Dialed it in exactly as noted; used this approach before and it seems to work just fine.
3. Are you running ported distributed vacuum or full-time vacuum? Response: I cannot say, I installed a Breakerless SE ignition kit (similar to the Lectric Limited) at least 25 years ago and never any issues. The distributor does have the vacuum advance that has a vacuum tube running up to the top of the air meter...so not sure if its would be called Ported of Full-Time.
4. What happens turning the Idle Fuel Screw. Response: Will do that one in the morning....so thank you...just a real annoying issue. Thanks.

Larry

[Lawrence S.]

Re: 1963 FI Surging On Initial Startup

Dan...thanks for responding...yep its the right size. What happen to you happen to me also years ago...twisted all up and it did break..so lesson learned on that one. Thanks.

Larry...

[Jim L.]

Re: 1963 FI Surging On Initial Startup

Jim in reference to your questions:
1. Had anything been done to the FI Unit? Response: Outside of rebuilding the unit, nothing was done.
2. How did you Calibrate the Economy and Power Stops? Response: I used the setup and procedures noted in NCRS Corvette Restorer Mag, Vol 9; #2 Fall 1982 "Troubleshooting Rochester Fuel Injection" by Brian Futo. Dialed it in exactly as noted; used this approach before and it seems to work just fine.
3. Are you running ported distributed vacuum or full-time vacuum? Response: I cannot say, I installed a Breakerless SE ignition kit (similar to the Lectric Limited) at least 25 years ago and never any issues. The distributor does have the vacuum advance that has a vacuum tube running up to the top of the air meter...so not sure if its would be called Ported of Full-Time.
4. What happens turning the Idle Fuel Screw. Response: Will do that one in the morning....so thank you...just a real annoying issue. Thanks.

Larry

2. Without meaning any disrespect to Brian Futo, his method of calibrating an FI unit in that 38 year old article does not work.

I strongly recommend you obtain a wide-band air/fuel gauge and use it to achieve an Economy Stop air/fuel ratio of 15.0:1 - 15.3:1 while driving at as high a velocity as you can, preferably while on a slight grade.... 1% - 2%. Also, while using the same gauge, adjust the Power Stop to achieve an air/fuel ratio of 12.7:1 - 13.1:1 during wide open throttle acceleration.

After you get these two stops adjusted, THEN and only THEN, adjust the length of the Enrichment Diaphragm rod such that 9" of vacuum has the Ratio Lever just barely touching the Economy Stop screw.

I predict that if you properly calibrate those two Ratio Lever stops, like I just described, your engine's near-death spiral will be a thing of the past.

3. If your distributor vacuum is connected to the port on the '63 Air Meter, you are running ported vacuum. That ain't good. I suggest you connect distributor vacuum to a port, any port, on the FI plenum. Doing so will provide full time vacuum to the distributor and your engine will be much happier for it.

Bottom line: Your FI unit needs proper calibration.

Jim

[Duke W.]

Re: 1963 FI Surging On Initial Startup

When changing to full time vacuum advance on a '63 FI engine the VAC must be changed to a OE 236 16 or a B28 (Airtex 4V1053) assuming it still has a Duntov or any other OE mechanical lifter cam. The OE 201 15 VAC needs 15-16" to pull to the limit, but none of the mechanical lifter cams pull this much vacuum at a reasonable idle speed.

My '63 340 HP engine had the same VAC and suffered from idle instability and stalling that no one including the dealer had a clue of how to fix, but I finally figured it out and installed the '64 - '65 SHP/FI ...236 VAC that only needed 8" to pull to the limit and that fixed the idle issue.

Duke

[John D.]

Re: 1963 FI Surging On Initial Startup

Hi Larry, I see you have big time surging issue going on. You didn't have this before. I read some of the posts here but not all.
Your video is a tad too short. But to see that lever (ration lever) swing back and forth radical like would be the case of a wild cam not putting out enough vacuum.
When you rebuild the FI the last time it sounds like the issue was never resolved. From one I gather in your conversation with Jim Lockwood.
Hardest thing is telling the difference between a vacuum issue or a fuel issue.
So lets talk ABC's for a start. The air meter (throttle body today) tells the fuel meter what to do.
The main signal line goes from the air meter to the brass "T" fitting on the main diaphragm cover.
Where the line screws into the top backside of the air meter did you put a rubber sleeve or at least a small o'ring on that the end of the line?
Now lets go back to the fuel bowl side. Did you have the main diaphragm cover professionally resurfaced using a granite surface plate?
Main diaphragm itself. Did you install it correctly? Is the brass "T" fitting 100 % tight?
How many inches of vacuum is your engine putting out at idle? AT 900 RPM my '63 puts out exactly 16" at this RPM.
15-16" is nice.
Hows your PCV valve? Thinking of other ways to have vacuum leaks. Choke housing vacuum line from air meter to the choke housing.
Do you have the special rubber insert in the fitting? Is the bottom of your plenum flat?
Your small diaphragm aka enrichment diaphragm. Did you resurface the cover and backing plate? The diaphragm itself could be leaking.
Put some epoxy on the round barrel of the diaphrgm to insure its not leaking. Some repros have been know to leak.
Do you have the original hi-pressure gear pump?
You say you have a wobble pump. Do you have that pump or a gear pump? The '63 shop manual only features a wobble pump.
What vacuum advance do you have? I like Dukes idea. Buy a 236-16 vacuum advance. OR get the replacement inexpensive one. B28.
Not sure where you can buy that now.
Calibration. Forgetting that for the moment (only). Try screwing in the economy stop set screw Toward the lever. Look in the manual for an illustration.
It's the screw closest to the headlight. Here's what I say on the phone. Pretending the hood wasn't there and you were in front of the car.
Get a 3/32 allen wrench. Turn the economy set screw clockwise.To the right or toward the firewall. Try turning it in about 2 turns. You can play with idle fuel screw on the air meter but in your case you have to first improve the radial situation.
I don't think I have heard a '63 run that bad in a long time. If all fails call me as it's hard typing all this stuff. 724-832-3786. My name and info in the "Restorer" on page two. You have bought parts from me also I believe. John
PS. Do you have the rubber plenum lid gasket? The 6 long bolts holding the plenum lid on. I learned the hard way you have to torque those 6 bolts about 3 times at various intervals to insure they are tight.
Do you have the aluminum washers under the six bolts?

[Danny P.]

Re: 1963 FI Surging On Initial Startup

Vacuum leak somewhere for sure, you have power brakes ??

[Lawrence S.]

Re: 1963 FI Surging On Initial Startup

John....thanks for responding. I am going to print out your comments and break it down while out in the garage and go from there. Lots of good information and hopefully I can get it resolved....if not...take Jims approach and send it out. I really perfer to DIY, I plan to pass Red down to my son in the future so we work on it together and I keep good documentation of work done on it...but the fuelie unit this time is a real challenge. Thanks again and will provide feedback on the results...cheers!

Oh and it is a wobble pump...can think of his full name but George from NCRS rebuilt it for me around 2013. I think you gave me his name to reach out to.

[Lawrence S.]

Re: 1963 FI Surging On Initial Startup

No power brakes but thank you.

[Jim L.]

Re: 1963 FI Surging On Initial Startup

John....thanks for responding. I am going to print out your comments and break it down while out in the garage and go from there. Lots of good information and hopefully I can get it resolved....if not...take Jims approach and send it out. I really perfer to DIY, I plan to pass Red down to my son in the future so we work on it together and I keep good documentation of work done on it...but the fuelie unit this time is a real challenge. Thanks again and will provide feedback on the results...cheers!

Oh and it is a wobble pump...can think of his full name but George from NCRS rebuilt it for me around 2013. I think you gave me his name to reach out to.

If you are comfortable working on the FI yourself, and it seems that you are, I don't see any need for you to send it away to be calibrated. You can do it yourself if you are armed with the right equipment.

When I calibrate an FI unit, I monitor and record air/fuel mixture with equipment from Innovate Motorsports. I get consistently good results and their stuff is moderately priced.

You wouldn't need to make any modifications to your exhaust system. Innovate sells a tailpipe sniffer that you leave installed only as long as needed to do the job.

If you decide to go this route, I can talk you through the process.

Jim

[Lawrence S.]

Re: 1963 FI Surging On Initial Startup

John...went through the list provided and took your suggestions and others to try and find out whats going on. I put small o'rings on lines coming out of Air Meter to "T" fitting on diaphragm...installed new PVC....checked vacuum on vacuum advance and it just starts to open at 6" (engine not running)...new PVC...found loose screws on Plenum cover.....diaphragm is perfectly flat...installed new B28 vacuum can...but I did find this.

When running the engine and at idle (about 980 RPM)...with the vacuum hose plugged on the can and gauge connected to the main signal vacuum line coming off the Air Meter I am only reading 6"...so it must be a vacuum leak. Will play with it again today.