allright, getting code 34 now. dont have a vacc. leak sorry azz Haynes is saying .......differential pressure sensor.....yet theres nothing about it in there......where is it?is it the egr sensor?and if thats not it, any ideas on what else can trigger a code 34(tried a search,said 34 isnt a word, basically)

 

More info on your car would be nice.
I am assuming that you have a MAF car and code 34 means that MAF reading is lower than it is suppose to be.

This topic has been covered. Just do a search.

 

LG4 in the signature. That means an E4ME, MAP/BARO sensor, mild cam, EVAP, EGR, O², PCV, and EFE.

On that scheme, a "34" is for a low voltage condition from the MAP sensor. That indicates an absolute pressure that is too low for current engine conditions (too much vacuum), a failed MAP, a disconnected MAP, or open circuit to the MAP. Make sure your MAP is connected and there is a 5VDC reference signal and ground at the connector.

The MAP sensor can be checked with a vacuum source and a digital voltmeter. The sensor should output a 0-5VDC signal at the 'B' terminal. The output voltage is based on absolute pressure at the hose connection. The sensor should output full voltage (5.0VDC) when there is one BAR (barometer, or atmosphere) of pressure applied. This means there is basically no vacuum (0" Hg) and the Absolute Pressure is at 14.7 PSIA.

When the Absolute Pressure decreases (due to vacuum) the voltage output on the 'B' terminal should decrease as well. Test the sensor down to about 20" Hg of vacuum, or 0.33 BAR (4.9 PSIA), where the output voltage should be around 0.8-1.2 VDC. The voltage should vary in direct proportion to the Absolute Pressure, or amount of vacuum applied. If the MAP output "jumps" or "sticks" at a given point, the sensor bridge circuit or the mechanical diaphragm is failing. Since there is no practical way to repair a MAP sensor, replacement would be indicated.

 

85 carbed, auto. berlinetta, stock cept for headers an small cam.in upper left says 85 berlinetta, never seen one with MAF.. tell me how to get the search to accept code 34 an i will.i thought it had MAP. have no idea what a diff. pressure sensor is

 

thanks, Vader you da man

 

No, but this is "Da PLACE!" Weez got all the shizznit...