Power loss problem unknown

Hello, so where do I begin.. My Micra developed a misfire (I changed the injector and sorted that) but during it's time misfiring it developed a long hesitation when I put my foot down, the revs would build slowly but the car failed to accelerate, then suddenly -as though a turbo kicked in- it would regain full power and pull.
I was hoping it would fix with the misfire but it got worse once fixed. About a week after fixing the misfire I was parked on a hill with not much fuel in the tank and it wouldn't start.. It would turn over all day but never fired up. I filled it with fuel. Wouldn't start. Checked it was getting fuel to the rail (tick) and it wouldn't bump start either... The next morning it started up second time but was cutting out once under drive. (It hated second gear)
I put 2 second hand throttle bodies on and soldered my old one (my old one now works the best) so it ran but was lacking all power.
It also seemed to run better with the air box off.. I replaced the air filter but no improvement.
Next we turned to the carbon canister while looking if pipes were split or blocked to the throttle body. I disconnected the pipe on the top of the canister that ran to the bottom of the throttle body and hey presto! All power restored... Or so I thought...
I took it to work (31miles) and it was losing power again like it had with the misfire but unusually it was always after putting my foot back on the accelerator after I was coming down a hill or turning a corner where the loss in power occurred. There is also a small oil leak which is only noticeable when I'm parked down hill over night.. Could that be anything to do with it?

Please help!
 
How does it idle? better with the throttle position sensor removed or the same?

Just throwing ideas at the wall, but could be blocked fuel filter or seals in the fuel pump, block seems somewhat likely if it only seems to pull in some situations. Could also be an electrical issue with an unreliable grounding somewhere. Do you know if the timing is set correctly? the timing adjusts depending on RPM so if it starts off bad it can hesistate when you accelerate. Do you have a spark tester to test the strength of the spark? Sometimes you can have a spark that will allow the car to idle, but when it starts picking up speed and the air/fuel mixture is changing the spark isn't always igniting, which would also go some way to explain the misfire. That could be anything from distributor problems, problems with the continuity of the leads, problems with the sparkplugs, grounding of the engine etc

edit: also, if the RPM is increasing but the car is not accelerating that would possibly point to a clutch issue. How quickly does it stall if you dump the clutch in 3rd?
 
It was idling fine once I got it started, then cutting out under strain. The we tested all the sensors by running the car on idle and removing one at a time (the one that made no difference being a prime suspect).
All sensors including that one made it worse, the only thing that made it dramatically better was removing a pipe from the emissions canister. Now it started fine, idled fine and ran fine (so I thought) on a longer journey I realised this was not the case and the old problem of power loss was back.
It isn't clutch related, I know what that feels like and the revs build slowly as does the speed but it's as though a switch is flicked and it drops from 70hp to 30hp.
I will try a new fuel filter and try to look at the pump.
Timing is something I've never done on a car so I'll ask my mate but this is a low rpm problem. Which is intermittent. Before and most of the time now I could accelerate in 4th gear at about 35mph (mines a 1.3 btw) and it was fine - not mashing the throttle at low rpm but it would pull gently.. Now if I do the same in all gears it will loose power or pull as it should.
It has had new spark plugs and tried two distributors with no joy.
 
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I would definitely check the timing, You can get a timing gun for £20 or so on ebay. I've had 2 distributors on mine and tried my best to put them on in the exact same rotation as I took them off, the first time I think I got it right but the second time I had some trouble with it being too far advanced, which causes overheating. Mine was on 5 degrees when it should have been on 15 degrees.

Too far retarded (after 15) would cause hesitation, which would get worse the faster the RPM

I know that if you remove some sensors the ECU tries to compensate in some situations. Removing the throttle position one makes the ECU set the default value. So some sensors could still be bad and you might not know from removing them.
 

frank

Club Member
does sound like fuel starvation to me, you can diagnose it by fitting a meter to the lambda sensor wire (and an earth somewhere)
it should be closed looping at cruise (bouncing between .3 and .6v) and then hold at .9v on acceleration and then drop to zero on lift
 
Hello all, quick update..
I played about with the distributor to experiment with different angles once mounted and it seamed to have some effect but does anyone know a way to find the exact point which it needs to sit easily?
Also gave it a service so the fuel filter was changed..
However the best thing I found was unplugging the lambda sensor. Before my car was being lumpy when I put my foot down (example: through the full range of second gear it would loose power on average 5 times) but after unplugging the sensor it ran fine until higher in the rev range and became lumpier again but only once or twice...
 
I've been reading this with interest but I can not tell how strong your spark is. Weak spark doesn't help you with fault finding. Curious to learn if your problem description is based on a strong or weak spark.
 
I haven't hooked it up to a tester but when I've pulled a sparkplug out and ran it on 3 cylinders you could see a good spark on the plug. (I did this when I was diagnosing the misfire prior to the power loss)
Also an update too! - as my car stands now it has new service parts, freshly soldered throttle body, a different distributor, NO emissions cylinder and I have recently disconnected the lambda sensor (cable). The car runs, only does the sudden power loss/jerkyness when the lambda is plugged in however it is still down on power over all.

My throttle cable is held on with a cable tie at this point as I snapped the bolt by over tightening it :/ going to get a spare one tomorrow and sort that out. Also going to attempt to clean the lambda but will probably have to buy a new one too.

Waiting for my mate to test timing with his gun too
 
Did you check your TPS for correct voltage? I have similar issues and am told air regulation if not TPS, but I do not take in account known Micra MAF issues.

I think the order is, verify correctly working MAF
check and adjust TPS
air regulation, AAC and FICD, (AICV), Nissan is a bit mysterious, just like their ECM, TCCM, fuel pump relay, ecu relay and therefore I'm sorry I didn't read the k11 FSM properly, after searching and scanning, it seems to miss parts another time and skip to page 7000 and up here and there which isn't helpful.

Keep in mind I was told to have a look at my air regulation and that I'm in the process fixing my issue which is pretty sure a air regulation issue.
 
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So I should have sorted the MAF with the soldering of the throttle body (it's 1994 so the MAF is built in and cannot be removed) I was unaware the TPS required calibration so I have googled it and found tutorials on how to do it. So I'll attempt it tomorrow along with a new throttle cable and lambda sensor. Fingers crossed!
 
Yes, it was the lambda sensor.. Should have been one of the first things to check but it was changed less than a year ago. Anyway while fiddling I had knocked the ignition timing out so got that reset and a new lambda and everything is fixed!
 
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