HELP!. 1989 Nissan Maxima 300k miles with a Japanese exchange engine 30k ago. I've been dealing with black smoke and the car missing really bad along with 13mpg. It will run 20 minutes perfect, let the car sit for 2 hours and then this. I revved it up and you could hear it missing and sputtering, then it might run good again. I am very familiar with when an injector goes out and this does not feel like that miss. Idle is also affected as it goes up to 2k and back down. I am also getting a code 45 which is injector leak. I replaced the injectors (along with the o-ring around the injector but not the other rubber parts) oxygen sensor, TPS, fuel pump and filter. Tonight the light came on and then 5 minutes later started to miss. The other night the car died but easily restarted. Appears to start messing up after you floor it. Any ideas? Not sure what my mileage was before the injectors replaced, but i was having code 45 before the new injectors.

 

Sounds like its running pig rich, given the black smoke and bad MPG.

Coolant Temp SENSOR (not the SENDER, key distinction) will make it run rich as ****. Does it have problems starting when its cold outside? I found when my CTS was failing, my car got progressively worse about starting when cold outside with a cold engine, until eventually it just stopped wanting to fire up. I'm admittedly not clear on the testing procedures for it, but it was a cheap part if you just want to wing it. Alternatively you might try unplugging it, see what it does.

I'm just spitballing here, mind. An injector leak code consistently even post repair could still be a leaky injector. Are you sure you got them seated correctly and completely? Are they new, remanned or used injectors?

 

I forgot to mention that I did replace the coolant sensor. Cheap enough it was. As for the injectors that I bought new on eBay, that probably is a good idea, but why does the car run perfect(expect for gas mileage) then bad?

 

I see this is a quiet thread. Car was running good and I pounded on the Mass air flow sensor and it started to miss, I kept experimenting to the point of black smoke and up and down throttle. When I unplugged the MAF, it stopped revving and blowing black smoke, but will not go over 2k per backup software. does anyone think that might be a viable option, because all the other parts you replaced you think its fixed but its not.

 

Levsimus,

OK where is the Coolant Temp Sender and where is the Sender located on a 91 Maxima VG30?

Thanks