91 Civic DX hatchback, b16a1 swap, pr3 ecu, new timing belt, no name intake pipe, new air filter, new spark plugs (bkr6e11), new cap, rotor, wires, new o2 sensors, new iacv, new fitv, new vacuum lines, changed fuel filter 4 months ago.

my car runs way rich. i have been tracking my gas mileage since i bought the car. with the 1.5L dpfi motor, i got 30 mpg. with the b16a i used to get about 25-27 mpg. now i get somewhere between 15-18 mpg. i can smell it running rich. my plugs are covered in carbon deposits as are my o2 sensors. i can hear it misfiring.

about 2 months ago, my car had major problems. i couldnt keep it running and i was getting cel's with no codes (solid led). found out that my rotor was loose under the cap. i replaced the rotor, cap, and wires. since then, i cant get better than 18 mpg. i have 2 pr3 ecu's, same results with both. i have 2 distributors, same results with both. checked my vacuum lines, adjusted the tps to spec, checked timing. i dont think its the timing belt, this didnt happen till a few months after i replaced it. my fuel pressure is correct as well.

it runs rich at idle, and runs rich cruising on the freeway (i can even smell it on the freeway). the car doesnt stall, it starts right up, no problems. it actually runs pretty well, except for the crappy gas mileage and the carbon deposits from the engine to the tail pipe. it even sounds healthy.

if im cruising on the freeway, i notice changes in the sound of the exhaust when going a constant speed. kinda like its missing. almost every 7 to 10 seconds it will lull for 2 seconds then back to normal and repeat. happens mostly when im going downhill, doesnt happen when im going uphill. throttle response seems very jerky as well.

i really dont know where to look next. if anyone has any suggestions, they are welcome. i dont know if this is just one problem, or several presenting themselves all at once.

thanks in advance for any help.

 

Make sure the injectors are not fouled. If they are, then one of them may stick open giving you too much fuel. Or the computer may be throwing a fit for some reason, espscially if it is afterarket, because they ususally do not work as well in conjunction with the stock components.

 

Sounds like fucked up ignition. Did you spray wash your motor? What kind of wires did put in? What's your spark plug gap.

Also how did you adjust the TPS. Are you running Bosch O2 sensors now?

[Modified by Rocket, 11:42 AM 5/9/2002]


[Modified by Rocket, 11:45 AM 5/9/2002]

 

i did not wash the motor, im running 7mm wires (kragen special), and NTK o2 sensors. my computer is stock, and i havent checked the injectors cause i thought that if it was the injectors i would be getting the opposite effect, running lean??

oh, sparkplugs are gapped to .44


[Modified by 91 Civic B16, 2:39 PM 5/9/2002]

 

Have your fuel pressure regulator checked out for the correct pressure range.... Also, pull the plugs to check and see if there all close to the same color. That should help tell, if you do have a hanging injector.


[Modified by 88_SC_CRX_Si, 6:44 AM 5/9/2002]

 

Try your old wires your old wires just in case.

 

It could be a bad MAP sensor...

 

would a map sensor go bad and not give a cel? all of my plugs look the same. jet black with carbon deposits. my fuel pressure was checked and i was told it was ok. i set my tps to .45 closed and 4.5 wide open.

thank you again for your replies.

 

Is the MAP sensor conected to this port?



[Modified by Rocket, 7:40 AM 5/12/2002]


[Modified by Rocket, 11:15 PM 5/13/2002]

 

i dont see that picture.....

 

try replacing your plugs if they are all black.

keith

 

I e-mailed you the pic.

 

thanks for the pic, yeah, my MAP sensor is hooked up right. all my sensors are. i have also changed my sparkplugs 3 times, no difference.

 

Map sensors can stick and become biased causing problems like you indicated. Are you still getting a MIL with a solid LED?

 

is a solid LED an indication of that? I rarely get those. I do get cel's for my primary and secondary o2's, but they are brand new. Is there any way for me to check the MAP sensor, or do I just replace it and see if that works? what MAP sensor should I replace it with? '91 SI? '90 integra?

thanks

 

You can test your map with a graphing meter and a vacuum/pressure pump. A solid LED can indicatre a power source problem, shorted sensor(s), or a bad ECU. If you have your primary and secondary O2 sensors switched you will have problems. Hondata has more info on the two O2 sensor setup on the JDM ECUs.


[Modified by fixhondas, 5:25 PM 5/14/2002]

 

I checked hondata for info on the o2 sensors. how do i know if i have them wired correctly? which o2 is which? is the primary on the drivers or passenger side of the manifold?

 

if i were to replace my map sensor with a new one, which one should i ask for?

 

CRX Si works for a MAP sensor.

Oh I should mention that if you have the O2s wired in reverse it will cause 1/2 of the cyls to lean out to the point of detonation. Your car will buck like a bronco at part throttle. Ask me how I know .


[Modified by raene, 2:27 PM 5/18/2002]

 

which o2 is which? if i had them backwards and 2 cyllinders were leaning out, wouldnt i be able to see that in the plugs? all 4 of them are jet black with deposits on them. i could try to reverse them, but does anyone know which o2 is primary and which is secondary?

 

What are both O2 sensor readings when warm (voltage)?This may sound *** backwards but try disconnecting both O2 sensors and driving for a while. Be sure to clear the ECU to reset the learned maps. See if that improves your driveability.

 

have you checked or changed the O2 sensors try changing them and see if that helps sounds like your getting TOO much gas that why your car is chockin out