K11 Lack of power and huge consumption

[Sven Hinka]

Hello guys

I'm having a bit of trouble with my K11 and I really hope you can help me on this one. Personally, I have done whatever I thought it can be done.

So, here it goes. I've bought 3 weeks ago an 02 K11 from a woman. The battery was gone and the spark plugs were almost non existent(by spark plugs I mean that electrode in the head). Changed all of these and discovered that, even with so-called "good sparking", the engine runs a bit lumpy. Thought it was the fuel filter, so I've changed it. Now it's even worse. Lacks power when start driving(it gets worse when the engine is cold - barely takes 20mph), when stopping at roundabout or at traffic light tends to stall and generally consumes a lot of fuel(full tank a week).

Now, I understand that an automatic usually consumes a lot than a manual one, but this one puts me on my knees. I need it to run almost to perfection due to a road trip in may to eastern Europe.

Can anyone guide me to the source of the problems?

Thank you

 

[pollyp]

clean the MAF sensor with carb cleaner.

clean the idle control valve behind the throttle body till it operates smoothly to control idle better.

remove the 2-pin ECU coolant sensor behind the thermostat housing and check the ohms/degreeC matches this test graph. faulty temp sensor makes it always run too rich.
https://www.micra.org.uk/threads/pollymobiles-rebuild.35251/page-119#post-704079

check non of the catalysts have collapsed & blocking the exhaust.

check for binding brakes.

now if it still runs badly after all that, I think the primary O2 sensor in the manifold may have been faulty for some time,
making the ECU short & long term fuel trim run too rich. so I'd test before replacing the O2.

the old fuel filter may have also been quite blocked, so replacing it restores full fuel flow/pressure which then injects more fuel with the already rich long term fuel trim, resulting it very poor rich combustion and bad for the catalysts too.

preferably plug in a OBD2 diagnostic consult tool to check all sensors are working correctly before replacements.

 

[Sven Hinka]

You're on to something. I mean, all started when I've changed the rear and middle exhaust. Unfortunatelly, my OBD2 reader is at a friend and he's in holiday.
Anyway, can you explain me how to clean the MAF sensor? Never done it before and to be honest, I don't want to make it even worse.

Thanks

 

[.Maarten]

Maf is a common failure. Pull off the airbox and you can see it if you look into the throttlebody. Just give it a few sprays with a maf cleaner.

Or even better. Screw off the throttlebody and give it a good clean. Do mind the gasket underneath it.

Also check the small filter in the airbox. Thats there to filter the oil vapes from the carter and gets clogged. Thats one of the main causes of a dirty maf. Its even better to vent the oil vapes to somewere else so that they wont get sucked back into the engine. (I dont know the MOT things and dont know if its legal to do.)

 

[Sven Hinka]

Progress:

I think I've cleaned the MAF sensor. Goes a lot better. But I've noticed a couple of things:
1. There is a small filter in the air filter box(the pipe connected to it comes from the rocker cover). And that filter is dirty beyond any known limits(actually it's black)
2. My throttle cable is kinda loose, althrough is tighten at max

Any ideas where I could find these two components?

 

[.Maarten]

That small filter is something hardly anybody checks or replaces. Also check the PCV valve. This is something that clogs up with the oil vapors as well. You can clean this valve. You can test it by blowing tru. It should allow air to go one way but not the other.

The nissan part numbers are:
Filter (micra airbox) - 16565-53J01 €4.26
Filter (Primera airbox)- 16565-73C00 €9.67

The prices are estimated in euros and i have listed the filter for the micra airbox and for the primera airbox because the micra one is often swapped to the bigger primera one.

 

[pollyp]

the PCV filter in the airbox only costs pennies at the dealership.
if it's truely blocked full of oil & dirt, it will affect the PCV system causing a high crankcase vacuum during light throttle and high crank pressure during heavy throttle.
yeah good idea to check & clean the PCV itself with carb cleaner annually.

if the throttle cable nut is fully tightened up and the pedal doesn't hit the floor at WOT and still feels loose at rest, you can thicken the throttle pedal rubber rest

or make an adjustable rest stopper to take up slack.

https://www.micra.org.uk/threads/pollymobiles-rebuild.35251/page-127#post-717108

 

[Sven Hinka]

Just as a question: should I add to the PCV an oil catch tank?
And about the pedal: goes all the way to the floor BUT when pressed, it's like 1-2cm of pushing the pedal without actually any revs

I'll let you know tonight if the car goes better after the MAF sensor cleaning

 

[fuzzy-hair-man]

Could it be a fuel pressure regulator? Or an exhaust leak before the O2 sensor.

 

[Sven Hinka]

Ok, soooo.....I don't know what the cleaning of the MAF sensor achieved, but it goes a bit better, but still, no power when leaving. Gains power and speed on the way I should say.

check non of the catalysts have collapsed & blocking the exhaust.

How should I check that?

 

[.Maarten]

Also check the temp sensor.

You can check the cats by removing the exhaust and see how they look.

ID say get a odb reader and get a log. IT can tell you a lot.