Motors A Nissan Primera With P0171, no idea what to check next

Afternoon folks.

I recently told to go a fix a Nissan Primera which wasn't running. Turning over and smelling of fuel, but not running.

Owner said it had been running rough then just died.

Its a Nissan Primera 2002-2008 with all sorts of electric gubbins that make it seem like a space ship to me.

From searching, a P0171 error is bank 1 being too lean.

Did some searching and its either;

a) 02 sensor - So changed that. Not fixed it.
b) The MAF - gave it a clean, but I have no idea how to check to see if it works.
c) The spark plugs - which I haven't checked yet.
d) Air leak - Have yet to find one.

So, I need help with;

1) Does anyone know how to test a MAF to see if it works right? From searching I've been told it can be done by checking the resistance is within spec, but I don't know the spec for the part. Is there an off hand general way to test/check it?

2) Suggestions for other things to check while I'm at it?

Guy has no money, so I'm the "Adam doesn't have a job, so his time is worthless. Let him fix it" mechanic. I'm just guessing at this point as to other things to check. Owner just wants it running so he can trade it in, so all options are open.

Ta for any advice.

 

What engine size is it? I have a copy of autodata here so could give you all the sensor resistances etc.

One thing to mention is not to turn it over too much if it's smelling strongly of fuel - for one, excessive fuelling can destroy a catalytic converter, and secondly you'll get a mighty big bang if it did start!

 

Yo, been told its a 1.8 engine (from when I first had to find an 02 sensor.

On the cat / blowing the engine up. Thing has 120,000 miles on it, the owner doesn't service it, and its had "Car Overdue For Service" on the dash for 2 years.

I fully expect this thing to just not work again.

I always get wrangled in to work on utter buckets. I ask thing, when did you check the oil/water?, how long has it made the noise?, why did you not stop driving it?

They never check the oil/water, the car has made the noise for 3 weeks getting worse, they always keep driving it.

 

Hah, sounds familiar. Unfortunately my copy of Autodata doesn't have any figures for testing the engine management bits, which is rather poor.

 

If the dude has no money I don't understand why you are messing with this especially as the owner has neglected it out of pure stupidity.

That code looks like a manufacturer specific code?, without the correct reader you will not get too far but from the neglect aspect it prob wont be a minor sensor that just needs looking at.

Just had a read around and these may have a timing chain. Timing chain and bad/low/no oil is a baaaaaad combination.

 

Ah rats. Thanks for having a look though. I'll pull the MAF off again and see if I can find a part code / number and punch that into google. See what comes up.

Well, being a unemployed bum, my time is near worthless so I get to work on buckets. Also having no confidence in ... 90% of what I'm doing, I tend to go "well its broken right, so I can't break it anymore" and away I go.

On the reader, its a generic OBD 2(?) thing. Plug it in and set it to scan, see what it spits out. Its been on the money so far with my father's car. So I'm putting some trust into it. It has a book with tells you what codes mean.

Oh well, going to go check the spark plugs in a bit. See if they tell me anything.

 

Autodata confirmed the OBD code you mentioned, whether some Nissan diag software could tell you more I'm not sure. I'd have a look at the plugs (and inspect the cylinders to check them for damage), then start with the MAF, from the sound of it that could be malfunctioning badly causing very rich running indeed...

 

Okay,

So went down to pull the spark plugs. Black, covered in gunge, electrode gap of about 5mm, with a nice BIG arch burnt out on all of them.

So went to the part shop, paid £15 and got a new set.

Still not working. Got told off for buying the part. I was about £5 a head in costs terms, which is now down to £1.60 after going back and forth for few days and parts cost.

Not sure I can be arsed to try anymore now.

 

if it stinks of fuel and it wont start surely there will be no spark?

take a spark plug out and crank the engine see if its sparking?

 

Did you try to start it without MAF - wiring attached?

When a MAF is dead and produce a strange value. Thus it might be f*cking with the ECU when still connected. If you disconnect the MAF, the ECU will detect the MAF is disconnected ( no signal ) and thus might try 'emergency mode' defaults, and might just run abit rough..

(Did this on a Renault, Opel and various Volkswagen related cars, and has not yet failed on me ones, but hey: Nissan.. )

And: lots of fuel might cause the oil to dilute.. causing damage ones the engine starts again. Be sure to smell the dipstick for excessive fuel!

 

Worth a shot, shall try it tommrow.

You ... you can do that?

Know what I'm trying tommrow then.

In the mean time, stuck the multimeter on the MAF (took it off and its in the garage currently). Got 1.1ohm (I have no idea what I'm doing) across everything. Ohm setting to the lowest my multimeter reads.

Older cars are simpler than all this. Fuel, spark, air, works. Not some sensor throwing a wobbler.

 

You can, but it doesn't always work! Sometimes engine management systems won't start with certain sensors unplugged... Crank and cam sensors are usually the only culprit though, as they time the fuel injection and variable valve tech off them - get that wrong and you're in a world of hurt.

 

My Hyundai wouldn't start with the MAF removed. I had driven from Jersey to Ohio (about 17 hours) and the air hose split and the MAF got wrecked. It was running stupidly rich.

I'm also pretty certain a Merc won't start with the MAF removed either. Mate had an AMG recently with a dead MAF.

 

Owner doesn't want to splash any more cash, so I'll try it. If it don't work then its scrap I guess.

 

BTW if you clean a MAF (the actual sensor itself) you will instantly kill it. It has a coating on it that will come off if you even so much as wipe it hard enough (the Bosch model on my car was like that).

Basically my turbo intake hose split (air) and peppered my MAF with grit and dust. I tried cleaning it and it just got worse. Thankfully I found one in a yard for $15. They were well clear of $300 new

 

I looked into it, and the internet being what it is I got loads of conflicting results.

Some say acetone is fine with cotton buds, some say brake cleaner, some say MAF cleaner ONLY, some say if you look at it funny it will bork it.

I'll say this. There's a little wire mesh on the front of the MAF (covers the whole intake). It was covered in a fine black dust. I then doused the whole thing in brake cleaning spray.

But yeah, owner doesn't want to pay any more out. So I'll give starting it without a shot.

 

Well, no MAF connected, didn't start.

Sort of annoyed it almost coughed into life.

Also, have a all new error to go with the P0171. A new P0113 error! Which also has to do with air.

I am now assuming the whole thing is FUBAR.

 

P0113 is an odd one to go with P0171 - could the ECU be on its way out? Could be that leaving the MAF unplugged has messed up the grounds if they share one (IAT and MAF could well be at the same point in the inlet).

 

I got no idea, no other tools or tricks to try.

It just doesn't want to start. It sounds like it wants to catch but then just spins away and stinks of fuel.

Something has pooped itself inside out and I have no idea how, why or what else to check now.

 

Is that with the new plugs? Is it sparking?