61 Fuel Injection losing RPM's

[Don H.]

I have a 61 fulie that starts losing RPM's as the temperature reaches 195-200 deg's. It keeps ideling down and unless I keep pumping the gas it will die.
Also, I live in upstae NY. Is there a mechanic in NY that knows fuel injections that I can take the car to.

[Joel F.]

Re: 61 Fuel Injection losing RPM's

Is the choke functioning properly? What is your hot and cold idle set at?

Any issues off idle?

[Don H.]

Re: 61 Fuel Injection losing RPM's

Not sure if all is working. I ordered the Corvette Service Guide ST-12 yesterday from NCRS to get a better understanding on fuel injection units. The car was running great up to last month. Had no problems starting or ideling.

[William C.]

Re: 61 Fuel Injection losing RPM's

That is about when the oil companies switch from "Winter" to "summer" gas blends. You might try a different brand of gasoline to see if there is a difference.

[Joel F.]

Re: 61 Fuel Injection losing RPM's

Bill raises a good point. Use up the gasoline you have and switch to a new brand.

Also definately read the FI theory in the ST-12. That is about as good a reference as there is on FI theory and service.

[Bill M.]

Re: 61 Fuel Injection losing RPM's

Also, I live in upstae NY. Is there a mechanic in NY that knows fuel injections that I can take the car to.

Jim Neuffer advertises in the Driveline. He's in Brockport. 585-637-9562. jneuffer@rochester.rr.com. I haven't dealt with him yet...just seen the ads.

[Richard T.]

Re: 61 Fuel Injection losing RPM's

Your suffering from fuel percolation in the spider. That's why it runs fine in cool weather. Better gas or Av gas is an answer. If you can get race gas from a nearby drag strip it would be fine also. Rich

[John D.]

Re: 61 Fuel Injection losing RPM's

Don, Lets pretend you have a carb instead on an FI. Also lets pretend your ignition is absolutely on the money. You almost answered your own question when you said you had to keep pumping the gas to keep it running.
If you gas is not an issue, if your engine fuel pump is not an issue, then it could be your accelerator pump called a spill valve. When you get the Corvette Servicing guide or ST 12 manual (my all time favorite) notice the spill valve illustration showing two different styles. If your unit has the one with the piston, delicate spring and bi-metallic piece holding the spring up let me tell you they are trouble. I only use the other type nicknamed thumb tack spill valve. I use them on all 58 to 65 FI's with the exception of one of the 59 FI's. They are trouble free.
Here is a biggie also. If your FI has one of the reproduction cranking signal valve keep in mind that heat effects their reliability big time. They run good on the test engine for a little while then break down when they get hot. A better alternative is to have your original one rebuilt as they are the best.
Your cold enrichment may not be working. Read the theory on it. We nickname it the choke but there is no choke on a 61 per say. Cold enrichment illustration in the theory section will help you a lot. In fact that may well be your problem. Is the choke cover getting hot. Is the car coming off fast idle. What does it idle at.? When the engine warms up does the ratio lever (lever that swings back and forth on the plenum side of the fuel bowl) does that lever swing forward toward the headlites when the car reaches 180 or so??? If not then big trouble. Look inside the choke housing for two pins. Big pin is called power boost. Little pin-toward the plenum-little pin is the enrichment pin. When that pin is depressed which happens as the engine warms up or the electric choke warms it up the signal goes out to the ratio lever and it swings forward to the economy stop. See in the ST 12 nice illustration of the economy and power stop.
Recap:Spill valve piston sticking. "Choke" not working. Main diaphrag bad-located on top of the fuel bowl under the round cover held on with 8 screws. Incorrect calibration not a plus Plugged fuel lines-dirt. Plugged nozzles.
Make sure drive cable is not rounded off where it goes into the distributor. I don't know of anyone in NY that restores FI's right now. Frank Domini (sp) and his son did or do. But I don't here their name much lately.
Jim Neuffer doesn't work on FI's that I know of. My pals aren't taking on any work because we are buried. My good friend Jerry Bramlett would be an excellent individual to talk to. Jerry is in Mobile, AL.
Gary Hodges-our NCRS Carb guy in Salem, OR is buried but you might talk to him. His number is in the Restorer. There are others also but again not in your area.
Check the gas filter. Yours is readily available. GF 157 or go to NAPA and get one for 3 buks. Might be clogged. Dirt may just be your problem. Sorry for the unorgainized notes. In a hurry.
Dont touch one screw until you read the theory 3 times. The more you read and understand the theory the more you will realize the old FI's are not that difficult. But they can be if bubba worked on them before you. Good luck, John D.

[Don H.]

Re: 61 Fuel Injection losing RPM's

WOW John, Thanks for all the good info. I sent you the pictures of my FI unit. Hope you have the rod I need for the choke. Also, when we talk again, I would like to get the parts you mention in your reply.

[William B.]

Re: 61 Fuel Injection losing RPM's, John, great reply

John, Very GOOD REPLY. I enjoyed reading it and it made a lot of comon sense for us that are not all that familar with fuel injection.

[John D.]

Re: 61 Fuel Injection losing RPM's

Bill raises a good point. Use up the gasoline you have and switch to a new brand.

Also definately read the FI theory in the ST-12. That is about as good a reference as there is on FI theory and service.

I had my 63 FI car(LWC) at the Seven Springs regional this time last week for flight judging. I only burn 100LL in it no matter what I read or hear. So anyhow I tried and tried to get the car to perculate.Tried to get the FI to go bonkers and cough and spit,etc. The engine was running for a very long time for ops and before ops. The hood was closed. So I started the 63 while the engine was roasting and it ran perfect. No stumple -nothing. The 100LL came thru once again. Had I been running pump gas I am positive I would have had problems. It's the crapola fuel guys and girls causing a lot of grieve to our old Corvettes. Leave the hood off and then maybe you have a shot if you are burning 87 Hess like a certain VH does.

[John D.]

Re: 61 Fuel Injection losing RPM's

ssshhh. I don't mix NCRS with business Don. I did not realize that you were the same guy on the phone today as my lengthy letter. JP