im getting a -21psi reading from the tb mounted map sensor.
its a d series obd1 with a gsr throttle body. from my understanding, it is impossible to get a negative value. what should i be looking for to fix this problem.
i tend to think that with that kind of reading, the rest of the engine wont run right.

 

bump

 

I'm no engineer but vacuum isn't measured in PSI but in/HG. So essentially what you're saying is your negative PSI is actually vacuum, so -21 "PSI" is actually 21 in/HG which is normal for the range at idle for your car. When pressing the throttle it will drop "down" closer to 0, anything above 0 is PSI or "boost". I know it's not an scholarly explanation but does that make sense?

A boost gauge for reference



http://autospeed.com/cms/title_Using...3/article.html

 

Is the car having any problems?

 

yes, its sparratic. most always the ECT is acting up. code 6.
this in turn will make the engine idle higher than usual at like 1800 rpm's. sometimes a lobing idle at a stop light.
i can shut it down and try to restart, but it acts just like it is flooded.
so most of the time i do that while i am rolling, then it bogs and spits and sputters until it seems like it burns off excess fuel. idk.

i did some research and found that the ECT and the MAP share a common ground in the ECU. correct me if i am wrong.
by the way, the ECT sensor is fairly new. maybe a year old.

 

ok just replaced the ect, and everthing seems to be fine.

 

car is running fantastic. and no trouble codes
still puzzled about the negative reading from the map sensor though.
at WOT, it almost zeros out.