93 civic vx. d16z6 swap. p28 ecu. throwing code 3 map sensor. i replaced it with 3 different known working map sensors and still the code would stay on and the car runs rich as hell black smoke when you get on it and it reaks, and missfires sometimes pretty bad in low rpm. Replaced intake manifold gasket, throttlebody gasket, and map sensor x3, also gutted cat incase it was clogging, didnt fix anything. I start the car and it will idle low and rough for a second then boom CEL kicks on and idle kicks up and stays steady. tried my other ecu and same thing. I dont think it could be the wiring because if i unplug the map all together it wont start. What else could be causing the map sensor code? should i look at vacuum or fuel? maybe injectors? also noticed a gas smell when i changed my oil but heard that could be from running so damn rich. im lost with this... any input would be appreciated

 

bump, anyone?

 

It might be ur wiring harness, i had the same problem a couple months ago with my b16a swap n ended up being that the harness was no good n when i bought a new wiring harness it fixed the problem.

 

The MAP sensor connector plug has three wires. The middle one is ground and the two outer ones should have 5 reference volts to body ground. Test the wires for voltage and ground.

 

thanks will try that as soon as i get ahold of a tool to do it

 

had my buddy bring his electrical tester and when we went to test it i saw a plug dangling under the intake manifold so i unplugged the plug that was on the map sensor reset the ecu and plugged the one in that was dangling and now no CEL and runs good. idk what the extra plug is for but i guess it doesnt need it

 

hmmm. now when the car warms up it starts missfiring anything over 1/4 throttle. and when im slowing down it pops and ****. if i get on easy it hesitates and pops every few hundred rpms but pulls decent but as soon as i really lay into it it will make a real fast popping noise and not accelerate barely. thought maybe the plugs were fouled from it dumping so much fuel before so i changed them and no difference

 

Wow, your case is an extreme one. Mine is running rich throwing code 43 and i replaced the O2 sensor and everything else you can think of and im running rich (litttle black smoke, plugs fouled, 19mpg) on a D15B7. Did you ever find out the problem?

 

yea the map sensor had the wrong plug on it. still missfiring tho havent had any time lately, im guessing it just needs a good tune up

 

Instead of starting a new thread I figured I'd piggy back off this one. Did you ever fix your problem? I'm having the same problem you're having, my idle is higher than usual but only after it bogs at startup. It's dumping fuel like crazy but I didn't start having this problem until I used ethanol free gas at a brand new gas station up the road from me.

Does anyone think maybe running all the fuel out until the tank is almost empty might fix it? Also does a fuel pressure regulator fix the issue?