1994 Accord. Engine surging

94 Accord 2.0i. Engine is surging between 1000rpm and 2000rpm when
stationary or the clutch is dipped when driving. Engine light has not
come on and there appear to be no fault codes present. Otherwise, the
car drives perfectly ok.

Any suggestions? Failing lambda sensor perhaps?

Please help....this is the mother in law's car and it would make my
life much more peaceful as well as earning major brownie points with
the wife!!

Matt
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Check the coolant level in the radiator with the engine cold. If it is low
the sensors drive the ECU nuts and the idle hunts. If the level is low, you
have a leak hunt ahead of you. The radiator is probably like the one in my
daughter's '93; it has a flat spot on top where a brace crosses. Look for a
crosswise hairline crack there where the flat spot flexes.

Mike

 

Mike,

Does this particular model also use an Idle Air Control Valve? Can a bad
IACV also produce this same type of idle surge?

Ron M.

 

I am pretty sure it does, though it may be called an EAC
valve on this model.

I agree that's possible.

I concur with Mike's suggestion. In the same vein, do an air
purge of the cooling system; a thorough one, where the
radiator fan comes on twice (which may take 45 minutes of
idling, so be patient).

Also, the oxygen sensor is suspect, too, particularly if the
problem only occurs after the car is warmed up.

 

I had an earlier model Integra with a bad airflow regulator and it
would display similar results, though it mainly happened when the
engine was cold. The valve contained a "thermo-wax plunger" which had
become deffective, resulting in differences of airflow into the
injectors (or that's how it was described at least). As opposed to
slowly closing proportional to engine temperature, it was erradic.



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