1958 fuel injection question

[Benjamin C.]

I have an early 58 fuel injection car #97. I bought the car as an unfinished project. The engine and fuel unit were rebuilt over a year before I bought it, so the engine did not get started for at least 2 1/2 years. Motor, fuel unit, distributor are all original. The car starts easily, goes down the road without a problem, cold and warm idle are also good, restarts easily when hot. My problem is that it will idle for at least five minutes and for no reason it will almost stall. It will recover on its own and will idle five minutes or more and do it again. It sounds like it is starving for fuel for those few seconds. Any ideas on what may be wrong?

[Tom D.]

Re: 1958 fuel injection question

Exhaust tips look black inside?

[Dan H.]

Re: 1958 fuel injection question

Check for vacuum leaks at main line to main diaphram, if they leak just a little, they lose the signal and engine will act like it's leaning out. This can be hard to detect, grease over the fittings to temporarily seal them. Good luck.
Dan

[Dan H.]

Re: 1958 fuel injection question

Using the GM manometer will also tell you if vacuum signals are in the zone of correctness and may show problem areas. Happy hunting.
Dan

[James G.]

Re: 1958 fuel injection question

If you spray WD-40 around all the suspected vacuum leaks, and the engine picks up speed then you ''may'' have vacumn leaks.ALSO............What kind of gasoline are you using? And how fresh is it? Old FI motos don't like modern gasoline with ethanol mixture. Treat the car to a 108 or higher leaded racing fuel. You will find 60-90 more hp and a real treat in drivability.

[John D.]

Re: 1958 fuel injection question

Benjamin, Being your '58 is #97 then it most likely has a left over '57 fuel injection unit.
Is your car high HP? You probably have a 7014800R or a 7014960.
But you didn't discuss this. I only mentioned it because the later '58 HP used a 7014900R. Different things to talk about.
Starving of fuel you say. Try adjusting the idle fuel screw on the air meter. It looks like a carb screw. Taking a wild guess turn the screw all the way in and back it out about 2 turns. Then go over the the fuel mete/bowl side (passenger side) and remove the sheet metal fuel meter shield at the front side of the fuel bowl. It's about the size of a curved pack of cigarettes.
There are two allen head set screws on the back side. Refer to your manual. Adjust the economy stop also called lean stop by some. Turn it in-turn it in- clockwise with a 3/32 allen wrench after first unloosening a 3/8 lock nut. The screw is blackened.
Both of the above will give you more fuel at idle no matter which unit you have.
Vacuum leaks could cause you condition. Make sure all the hoses are squeaky tight with no cracks. And it goes on from there. John

[Benjamin C.]

Re: 1958 fuel injection question

Thanks you everyone for your help. It is a high H.P. car. The engine will only try to stall when up to full temp.

[Dan H.]

Re: 1958 fuel injection question

Benjamin, does FI unit have the full base gasket or the four individual ones? The full one will help prevent vapor lock when hot, keeps the fuel spider cooler etc. Making the fuel ratio richer may help as John suggested.
Dan