Map Sensor Questions

[jsawduste]

My stroker (OBD1) keeps setting a code 14

Map sensor output voltage to high.

Using the FSM I have measured the voltages several times.

Circuts
A-Ground
B-Output to ECM
C-5 volt reference

Keyed up
A to C gives 4.8-5.0 volts. Within specs
B 4.8 volts

Engine running
A to ground 5 volts. Within specs
B 1.8 to 2.0 volts Spec is .6 to 1.5 So I am a bit high in output voltage.

Have run a dedicated vacuum line from the manifold to the MAP port. Clear line with no leaks and plenty of suction via the "finger test" but perhaps not enough.

Have replaced the MAP once but the problem is still there.

Thinking the cam (Hesco 274/480 on 113 centers) is not pulling enough vacuum to keep the MAP happy. Thus the voltage is a bit on the high side throwing the code 14.

Comments ?

[cruiser54]

Have you ever hooked up a vacuum gauge and monitored it?

[Cheromaniac]

Thinking the cam (Hesco 274/480 on 113 centers) is not pulling enough vacuum to keep the MAP happy. Thus the voltage is a bit on the high side throwing the code 14.

Yup. That sounds logical.

Have you ever hooked up a vacuum gauge and monitored it?

Good call. A vacuum reading at idle should tell the story.
Unless the code is likely to be a problem with the smog inspection gestapo, I wouldn't sweat it if the engine runs perfectly.