My friend has an 81 FWD hatch.It has a 5 speed and the 1.6L.Not to mention the feedback carb.

 

anyway the car has no problems idling or reving up and going but if you cruse at steady throttle the car will start violently surging.Atleast enough to rock you in your seat.pressing the gas more or letting off will help but as soon as you try to be at a steady RPM it will surge again.

 

Its a DL so no tach to look at while its doing this. I've heard that surging would be a lean condition.In this case lean while cruising, so that's controlled by the low rpm circuit in the carb.Is there a screw I can adjust to richen the mixture at cruise and low throttle? Or any other way to fix it?

 

surging only really happens at low throttle/low load.If you start climbing up a hill,the little bit more throttle needed will straighten it out.

Surging is most likely due to a lean condition.

 

Id start first by checking for vac leaks. Cleaning the EGR and making sure it is 100% functional would be on my list of things to do as well.

Yep - lean condition. Either too much air or not enough fuel.

 

GD

if the EGR was plugged wouldn't that cause a rich condition?computer is expecting a certain amount of air and it gets less air than that.right?Unless the EGR was open to the atmosphere letting in more air..

EGR does not affect mixture. Unplug and cap its vacuum line to eliminate it as a possible problem.

 

I would be looking at the carb and of course you have checked for codes from the ECU right?

 

GD

I wasnt aware the feedback carbed ones would give codes.learn something new everyday.How do I check and identify codes for a feedback carb?

The car was low on gas so we filled it up,and the problem went away for 15 minutes then it came back.Any ideas of what it might be?acceleration is fine,only happens at steady throttle.

I doubt the fuel re-fill has anything to do with it.

 

I bet it is more related to engine temp than anything. Stopping for fuel allowed it to cool down.

 

EGR does not affect mixture.

 

While it doesnt effect the A/F mix, it certainly effects the volume of A/F mix in the combustion chamber when it is allowing gas to enter the intake.

I doubt the fuel re-fill has anything to do with it.

 

I bet it is more related to engine temp than anything. Stopping for fuel allowed it to cool down.

 

 

 

While it doesnt effect the A/F mix, it certainly effects the volume of A/F mix in the combustion chamber when it is allowing gas to enter the intake.

 

 

except that he didnt shut the engine off before,during,or after fueling.I know shame,shame.

I found a website that deals with troubleshooting ford and GM computer controlled carbs.The carb has a solenoid that directly controls the A/F ratio.The solenoid has a needle vlave with a rubber tip.Overtime that rubber tip corrodes and falls off the needle valve right into the solenoid,restricting its movement.When that happens the car will surge and in some cases backfire at low throttle.Idle and full throttle are fine because they work on different carb circuits.

 

so with that being said will a normal 2 barrel EA81 carb bolt on to the 1.6L's intake manifold?