My brothers 92 integra LS is throwing code3.
And getting bad MPG (160 miles per tank)
We've already tried different map sensors & resenting ECU.


So i'm checking to see if it could be wiring issue.





My testing thus far:

*** with car OFF and key on ignitII ***


I checked if map plug was getting voltage to the 3 pin plug.

I did this by putting black prob into {middle} green wire/ground & red prob to each outside pin.
from the connector they both read 5v.

Next, i checked both d17(map signal) and d19 (map voltage)

I did this by putting black prob on green/ground wire of D21, then red wire touching D17 (map signal) it was 3.5v
and red prong touching d19 (map voltage) it reads 5v.


So what conclusion can be drawn from this thus far?
a) map sensor plug is getting power....
b) but is map sensor still sending too much voltage back to ecu?

 

I assumed you have an LS. Remember that pin locations are on the wire side of the connector.

According to the trouble shooting flow chart, you may have a bad ECU. Can you test with a known good one?

 

disregard this post

 

come again?

 

Well according to everything that you've told me from your original post: since you have 3.5v at D17 (should be about 3v so good) and 5v at D19 (should be around 3 v, so bad), the trouble shooting flow chart I have says that you may have a bad ecu. So is there a good ecu you can barrow from a friend? Maybe from the same place you got all those MAP sensors?

 

hum... interesting.
where did you find the flow chart?

Also if the ECU was bad, wouldn't it not run at all?

would i be able to tell my looking at the board to see if anything is fried?

 

Sorry dude. Guess I misread the flow chart last night. I just re-read it. Looks like you have a bad MAP sensor. Here's a screen shot of the text. The site would not allow me to copy/paste. Do us both a favor though and you read through and make sure I got it right this time.

 

i just decided to run the 3 wires from map sensor to the ECU....
i figured there must of been a short somewhere.

NO more code 3 BUT car does have slight backfire at idel.... just not when you rev it.
Still running rich.

I'm going to try new ecu