running rich

[navysnail]

hey, i did a search, didnt find what i needed. first, when i accelerate, black smoke comes out of my exhaust, the white center is half black on one side, it is like that on all 4. there is some soot on the bumper too. i have a 1990 240sx, just replaced the injectors, o2 sensor, fuel filter, no aiv, new clutch, air filter, i belive the spark plugs were last done in 99, do you think that would make much difference?. i have 127,xxx miles. i checked on my coolant temp sensor, there was green corrosion, i got that off, and its still rich. is there a way to check that or do i just need to replace it? any help is appriciated, thanks in advance.

[NISTECH]

could be your airflow meter. do a search on testing that. I have explained it meany times recently as this week.

[navysnail]

i pulled the ecu and it came up code 55, all clear. the voltage from the black and white wire is 13.5 at idle, the white wire is 1.5 at idle, the resistance from the black one to ground is .9 ohms. do you think the spark plugs could cause it to run rich like this. and when i tried to check the mixture ratio on the ecu, both led's were off, and they never came on

[NISTECH]

do a voltage check on the meter ground wire with it plugged in and the car idling it should be less then .2v.

[navysnail]

i just checked that, it is .o24v. any other ideas, could it be the trottle position sensor

btw, thanks again for all your help

[JNM240]

Myguess would be coolant temp sensor. That would still send the code 55 no problems to the ECU, because the ECU still thinks the engine is just cold. Most likely the connection has corroded (mine did that and had the exact same symptoms).

[navysnail]

mine was a little corroded, but i cleaned it. did you replace yours and did it fix it, the sensor is ok i checked it hot and cold, both are within specs

[navysnail]

is the o2 sensor suposed to have a zero ohm resistance to ground, when i checked the outside resistance to ground, it was like 384? is this bad?

[JNM240]

Cleaning the connection didnt help i had to replace the pigtail connector completely. And DONT crimp it! Solder it!!

[navysnail]

how much was it and did you replace the sensor too

[Nismo_Freak]

It's a ground... run it anywhere.

The only grounds you can't run anywhere are the grounds that are switchable. Like the fuel pump ground on a Q45.

[navysnail]

ground from the coolant temp sensor or the o2 sensor. i checked the ground on the o2 sensor yesterday and it is 384 ohms or somthing like that

[maik21]

i have a similar problem with the ground of the o2 sensor... i put the ohmer(one to chassis and the other side to the ground of o2 sensor ) and the result is not 0 ohms. i have to put a second ground to o2 sensor (o2 sensor to chassis) . i solder all the terminals electricals of my car because it was leaky!!!

[navysnail]

and grounding it fixed the problem?

[maik21]

maybe yes... because de ecu is not detect the o2 voltaje for a leaky ground. if you try to conect a bulb without the ground, it never on!! =)) ; it work for myy car!!

[navysnail]

ill try that tomorow, i guess its cuz my exhaust manifold is rusted to hell

[maik21]

oks fine !!