on my carbed 305 (cc) i'm getting code 34 and 41- no vacuum signal the vacuum line to my map sensor- also called the differential pressure sensor is very clogged. it's full of nasty grimy crap that doesn't feel like being cleaned. the line is a very small hard plastic one that runs through wire looms across the engine compartment. Should i just spend time getting the line out and thentry to clean it, or try to obtain a new one. i believe thiis is the cause for me not passing emissions because the map sensor helps the ecm determine fuel mixture and ignition advance, and my car failed, running extremely rich. it also has no power and bogs ridiculously. the mixture solenoid cycles fine and it usually idles fine. it just drives horrible. any help is greatly appreciated.

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'84 Berlinetta, LG4, 700R-4, starwars interior, falling headliner, T/A t-handle shifter, trans cooler, more to come in time and $$ www.hipergp@aol.com

 

I encountered this on quite a few CCC cars. Just run a new vac line if you can't clear the plastic one. If the MAP sensor's still good your problem should lessen if not totally clear up.

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D.R. Stevens
1984 Trans Am 305HO L69
all the usual external/free mods, original engine
1991 Firebird 305 L03
bone-dead-slow-stock

 

thanks for the help, i'll do that today or tomorrow. i believe the sensor is still good. i tested it w/ a voltmeter and a vacuum pump, and the voltage varied up to .5 volts- i thought reference voltage should have gone up to 5 volts though. how much would a sensor cost if i needed one??

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'84 Berlinetta, LG4, 700R-4, starwars interior, falling headliner, T/A t-handle shifter, trans cooler, more to come in time and $$ www.hipergp@aol.com

 

A new MAP sensor will run anywhere around $30-$50 depending on where you go to get it. The reference volts can go as high as 5V with no vacuum applied and as low as 3V with 5in-Hg vacuum. But .5 sounds really low. Was the meter reading in volts or millivolts?