nissan micra 2000 k11 - excessive fuel consumption

lampsie

Hi,

OK at my wits end with this K11 Micra - its using what I reckon is excessive fuel (about 280 miles on 42 litres), and has a rumbling/vibrating idle. Everything else ok (plenty of power etc).

Here is what I've done so far:
1) Replaced sparks
2) Replaced HT Leads
3) Replaced Lambda (o2) sensor
4) Replaced Throttle Body with second hand replacement
5) Replaced fuel filter

...nothing seems to have improved the fuel consumption. Any takers on what it could be?

thanks,
lamps

trad

Either a heavy right foot or a fuel leak.

Anan1

Air filter?

ianobrien

What revs is the car doing at idle when warm?

Did you replace the HT leads one at a time, or did you take them all off together?

I'm thinking that the car is running on three cylinders, and I'm wondering if you got HT leads crossed?

Where is most of the driving done? Town? Motorway? Short Journies?

Oh, I know if you've a heavy right foot, the Micra's drink like a fish, ours does....

Anan1

Mind you, the idle would be awful if it was only running on three.

Mr Benevolent

OP, next time bring it to a garage as you've spent lots and haven't got anywhere with the problem, no offence. On topic, I'm surprised no-one's mentioned the MAF... lumpy idle is one sign of MAF failure.

lampsie

Hi all,

Thanks for all the replies

Type of driving: Mostly city, occasional motorway...motorway seems to really kill it travelling at 100k/m (120k/m you can practically see guage going down!)

Heavy foot: I have tried eco driving for a good while now (easy acceleration, coasting to red lights, have ecodrive on with th satnav etc). I did recently try driving with a heavy foot on a full tank, but funnily didn't make a major difference

Air filter: sorry yes, was replaced

HT Leads: Are definately installed correctly, have checked both myself and independently

MAF: The MAF on the K11 is on the throttle body, which I had replaced to see if it was the dry solder problem that hits this model...no difference

Fuel leak: None, have checked

Idle: The clue, I think, could be in the idle...its lumpy, watching the RPM is idles at around the correct rate (600), but the bounces up and down by about 60 RPM on a regular cycle lasting about 2 seconds.

Taking it to a garage: I've taken it to two indies and then main Nissan in Ballybrit; all could 'find nothing wrong', diagnostics report no issues

Thanks all,
lamps

Mr Benevolent

lampsie wrote: »

Hi all,

Thanks for all the replies

Type of driving: Mostly city, occasional motorway...motorway seems to really kill it travelling at 100k/m (120k/m you can practically see guage going down!)

Heavy foot: I have tried eco driving for a good while now (easy acceleration, coasting to red lights, have ecodrive on with th satnav etc). I did recently try driving with a heavy foot on a full tank, but funnily didn't make a major difference

Air filter: sorry yes, was replaced

HT Leads: Are definately installed correctly, have checked both myself and independently

MAF: The MAF on the K11 is on the throttle body, which I had replaced to see if it was the dry solder problem that hits this model...no difference

Fuel leak: None, have checked

Idle: The clue, I think, could be in the idle...its lumpy, watching the RPM is idles at around the correct rate (600), but the bounces up and down by about 60 RPM on a regular cycle lasting about 2 seconds.

Taking it to a garage: I've taken it to two indies and then main Nissan in Ballybrit; all could 'find nothing wrong', diagnostics report no issues

Thanks all,
lamps

What year is the K11 and do you know what year the donor throttle body is from? The pre-'01 K11 had MAF issues that were solved in the 2001 facelift. I just Googled it, don't know much more than that.

http://www.micra.org.uk/archive/index.php/t-33014.html

lampsie

Confab wrote: »

What year is the K11 and do you know what year the donor throttle body is from? The pre-'01 K11 had MAF issues that were solved in the 2001 facelift. I just Googled it, don't know much more than that.

http://www.micra.org.uk/archive/index.php/t-33014.html

Hi confab,

Thanks for checking into this Yep both throttle bodies are pre '01, and the pre-01 K11's are prone to 'dry solder' problems that kills the MAF. For the original throttle body, I tried the solder fix (reheating the joins to solve any dry solder issue), which made no difference. Not being too confident of my (non!) soldering abilities, I picked up a second hand throttle body which runs pretty much same as the pre and post soldered original throttle body.

I think at this point I've exhausted pretty much anything I can find on Google about this, and having eliminated most things I could find, at bit of a loss other than to simply get rid of the car. If anyone could suggest anything else I should try, please do let me know, much appreciated.

thanks,
lamps