A rather thirsty March 1.0

[CMF_Bogchook]

The results are in!

And they're not encouraging. Driving around the city today I witnessed little coherence in the readings on the multimeter. I mostly saw a randomly fluctuating voltage no matter what the car was doing.

The only time I ever saw a solid voltage was at moderate to high revs under hard acceleration when the meter settled at about 0.9V. Otherwise it simply fluctuated up and down, no matter the load or the revs.

Every now and then when the car had been idling for at least a minute or so the voltage would stop fluctuating and settle at a little over zero. But the moment the throttle was prodded the random fluctuating recommenced.

Is it time to take a gamble and spend $90 on a new lambda sensor?

 

[CMF_Bogchook]

If you swat up on lambda sensors, you will learn that a square-wave voltage fluctuation is normal behaviour. But how random should it be? I couldn't see any pattern in what mine is doing.

 

[CMF_frank2]

Bogchook WROTE:

"If you swat up on lambda sensors, you will learn that a square-wave voltage fluctuation is normal behaviour. But how random should it be? I couldn't see any pattern in what mine is doing.

warren, one of the links you posted said that the signal fluctuates 8 or 10 times/sec or 1hz (i thought 1hz was 1/sec btw ?) and most digital meters have a refresh rate of 1/sec.
so mine only see,s an average of those signals, ie .4 to .6v on cruise and it,s quite random at other times, (but mine has a 1.6 throttlebody and injectors, but should still be similar to yours)
and a v of .9 may be way off the scale eh ? (these are only narrowband lambda,s)

frank

 

[CMF_Bogchook]

You're right, that Topbuzz article contradicts itself. 1hz is by definition 1 cycle per second. Most of what I've read seems to indicate 1hz is pretty much standard.

If using the multi-meter method of testing the sensor then obviously the relationship between the frequency of the sensor and that of the meter will produce some strange results, which may account for some of the randomness of the measurements I've seen.

However should I be seeing repeated full-scale deflections (ie, 0.0V to 0.9V) while driving at a steady speed. I thought that smaller deflections centred around a mid-point voltage would have been more likely.

PS> The way this thread keeps growing I hope it turns out to be useful to other Micra/March fans in the future.

 

[CMF_frank2]

warren, mine is VERY consistantly showing .4 to .6 at cruise, your lambda seems to be detecting the values correctly but the ecu "seems ?" not to be closed looping properly ?

frank

 

[CMF_Bogchook]

The ECU diagnostic showed no fault. But I suppose it is a possibility.

Starting the engine cold results in a steady voltage that climbs from zero up to about 0.3V. As soon as I start to back the car out of the garage (introducing load) the voltage starts to go silly.

I've looked up the specs for the Fluke 79 Series II meter I'm using, and its bar graph mode is theoretically far more than capable of handling the switching of the lambda sensor.

I should perhaps drive around a little more and see if I can detect any more signs of a pattern.

 

[CMF_Bogchook]

Hi Micra fans,

We haven't used the March much lately thanks to catching buses to work, etc, but I've had it out a couple of times in the last week after learning how to put my multimeter into an "averaging" mode which dampens the mad oscillations of the digital display. I can now see the following results:

Idling/overrun: 0.0V - 0.2V
Cruising: 0.3V - 0.7V
Moderate/hard acceleration: 0.9V

The bar display still shows the regular oscillations of the sensor.

So to recap:

- Vehicle seems to run very smoothly and happily.
- Lambda sensor appears to be OK.
- Engine diagnostic test reports no problem.
- Coolant sensor tests OK.
- Vehicle does not show signs of rich running (see photos of spark plug/exhaust above).
- There are no binding brakes etc.
- The driving style used is gentle, and the aircon is not used.
- Vehicle is achieving approximately 10km/litre.

Any more ideas?

 

[CMF_qwerty132]

Hey,

You car seems to be exactly like mine..

Mine is a 1.3l 5spd SLX with A/C and PS.
This is actually the second micra that Ive had that is pretty much the same economy.

It doesnt really matter how I drive it I still get around 10L/100km.
I use the a/c a bit as I dont really notice any difference using it or not.

In the first Micra(same as specs as above) I replaced the O2 sensor. It didnt really make much difference. I dont think the original was really working properly.

I have recently got a consult cable and found some software for my laptop so I can actually see whats going on. I havent had much of a chance to look at it yet.

I did do a fair bit of highway driving the other week. I managed to get 550km and the light only just came on. It was 300km at half tank.

If you find out what the problem is, Let me know.

Thanks
qwerty132

 

[CMF_Bogchook]

Yes, it's quite frustrating isn't it?

Without a cable, the software or sufficient knowledge to use it properly, I'm wondering whether paying for a diagnostic check would be worthwhile, or simply flushing money down the drain?

There has to be something going on here - other Micra/March owners get very good economy out of theirs. Yet there's a large group of us who don't, and while some seem to fix theirs by replacing the lambda sensor I'm not convinced it's going to help me. But I'll persevere for now - my wife loves her little yellow "Lily" and won't entertain thoughts of another car.

I've certainly learnt a lot about lambda sensors while this thread has been underway!

 

[CMF_qwerty132]

Hey,
Ive got a bit of an update...
I filled up tonight. It was a little bit better. I got 375km off 33.7L which works out to be just under 9l/100km.

I have been driving a different way to work - strangely its been stop-start through about 12 traffic lights instead of going the freeway.

Im also thinking that I may be filling up to early. It seems that the fuel light on this micra(compared to my old one) starts coming on with about 9-10L left in the tank.

I think I might stick a tin of fuel in the back and see how far I can get.

qwerty132

 

[CMF_LonePhantom]

Gee, my Micra sounds rough as guts (need to replace bearing in the water pump tensioner pulley), but the engine with 192000 kms on it pulls average 6.7lt per 100km. I can get past 450kms before the light comes on, and fill 33lts in the tank to fill it. I don't get these high readings on Micras when mnie sounds terrible, but still pulls a reasonable figure.

 

[CMF_Bogchook]

That's the crunch - our March sounds great, goes great, doesn't appear to have any obvious problems, yet the fuel consumption is rotten. Where do I look next?

 

[CMF_frank2]

Bogchook WROTE:

Where do I look next?

the new tyres ?

 

[CMF_nz_aj]

Assume overdrive isn't switched off? My half deaf mum was driving hers around like that for a while.

Wheel alignment.

Dragging brake shoes or pads. With the hub caps off, do any of the wheel rims feel warmer than the others after driving for a few km?

22,000km is real low for an 11 year old car, sludged up? Have you taken the rocker cover off & checked?

The temperature sender can appear ok & actually be sending a signal for 20 degrees less than the actual water temp, making the car run richer.

I think mine (1L 5spd) had leaking injectors when I was getting similar mileage, although I replaced them & the throttle body all at the same time.

Another guy I know got an ~3mpg improvement when he replaced the fuel pump, all I can think of is that the old one wasn't giving as much pressure resulting in the injectors not atomising fuel as well.

I also have a Rover V8, P5B.

 

[CMF_Bogchook]

Frank, the new Dunlops would have to be an IMPROVEMENT on the ****ty factory Toyo Kogyos with their floppy sidewalls! Wheel alignment and brakes are good, I can confirm. However I'll do the hub caps off check just to be sure. Overdrive is on! Engine is very clean - I checked it when I bought it. Also no sign of sludge in the sump. Oil is changed every year.

I've now had the temperature sender out and checked it against my digital meter in varying water temperatures and it matches up perfectly with Frank's resistance figures (somewhere above). And recall that the car doesn't appear to be running rich (see above).

NZ_AJ, is that a P5B saloon or coupe? And I'm convinced it's easier to diagnose a Rover V8 than a Micra/March at this point in time. My V8 is running beautifully!

I might have to think about a diagnostic test by a suitably qualified person.

 

[CMF_nz_aj]

Another thought, how strong is the spark? The coil in the dizzy can break down. Which brand have you got? Hitachi has been the more reliable, Mitsi the most problematic.

Getting a consult cable & software certainly helps diagnosing exactly whats going on. I've used this cable & datascan software on 3 or 4 K11 & a number of other nissans. http://www.plmsdevelopments.com/consult_if.shtml

1968 Rover P5B Saloon, white with Black leather interior. Last had a WOF in 2005, rego is on hold. Had issues with the brakes when I bought it (hoses were swollen closed causing them to jam on). Drove it home thou, handbrake was good. Some rust to deal with in the LH sill, some small spots in the boot lid & in a couple of door skins. Needs a paint. Front carpet is rough, need to make up some door rubbers and one side indicator lens is missing. Otherwise tidy. I've taken it for a drive now & then but is otherwise just sitting in my garage. Trans is shifting roughly, one lifter is sticky, needs an oil change, all requiring time that I haven't got right now. Apparently the engine had been reco'd not to long before I bought it, no smoke. There's a water leak I haven't tracked down yet, hopefully a hose & not a frost plug.

 

[CMF_Bogchook]

Lovely car, worth keeping sequestered if you don't have time to fix it right now.

Mine's a '72 P6, "Tobacco Leaf" with the tan interior. I've owned it for 13 years, gave it a bare-metal respray 10 years ago. For various reasons it hasn't been on the road since 2002, but I'm currently resurrecting it. 98,000 kms, the interior is in exceptional condition excepting a small crack on the dashtop and a little surface wear in the leather on the driver's seat where the driver's right shoulder rubs climbing in and out. Mechanically excellent although I'm about to replace the inlet manifold gasket due to a slight chuff, and I'm in possession of all the parts needed for a conversion to PAS which I'll undertake soon. In case you are unaware, all the rubbers are available for P5s and P6s - let me know if you want details.

 

[CMF_Bogchook]

I've been out in the March today, and for the trip home I pulled off the hubcaps. Once back in the garage I felt around the wheel centres for heat. The rear wheels (drum brakes) were slightly warm; the front wheels were moderately hot. There may have been a slight difference with the right hand side a little warmer than the left, but I couldn't be conclusive about that. I might have to try the same trick after a longer run.

Having said all that, the brakes work beautifully and evenly, with no pull evident. The car tracks straight and true when cruising with hands off the wheel.

In fact everything about the car seems PERFECT! with the exception of the fuel consumption. It's very annoying.

 

[CMF_nz_aj]

If one is dragging you probably won't notice when you're driving, i.e. they'll seem even. If it's one of them dragging that caused the mileage you're getting, it'd be obviously hotter than the others after driving around for a while, possibly not if you're braking all the time.

Yes I know you can get rubbers but they're too expensive for my current financial position. There are instructions on the net for glueing up 3 different standard rubber sections to do the P5 door seals. This will be my likely course of action.

 

[CMF_Bogchook]

I've got a short open road trip to make over the weekend. It's all straight and flat (ie not so much brake use) so I'll see how hot the front wheels are after that. I suspected the right hand wheel might have been a little hotter than the left after checking the other day, so going on your advice just above, AJ, it might still be in the running as a possible cause.

All my Rover P6 rubbers came from an outfit called Scotts in Australia, but that was about 10 years ago. Nowadays I get stuff in from J.R. Wadham in the UK - they have just about everything for P4, P5 & P6 Rovers. I've got a few bits coming in the next few weeks, but you're right, if the money ain't there then it's time to look at practical alternatives.

 

[CMF_qwerty132]

Hey,
I haven't checked to see if a wheel is binding on mine yet.. I may be able to borrow one of those infra red temperature thingos to check the actual temps. Ill let you know if I find anything.

qwerty132

 

[CMF_Bogchook]

I didn't make that trip in the March due to changing requirements - needed a bigger vehicle in the end. Now it's been sitting in the garage all week so I haven't got any further. I'll be interested to see your results Qwerty132, when you get them.

 

[CMF_frank2]

i took my misses,s 1.0 (with 1.3 cams) on a 300 mile trip yesterday, and it used 26 ltrs
not bad going, methinks

frank

 

[CMF_Bogchook]

Frank, that's nearly double the mileage I've been getting out of CHK259.