K12 micra running rough/not starting

[AlexJZ]

I never really turned to asking on the forums as the issue shows itself quite easily usually but I’m lost on this micra and could use some help, it’s a 2003 1.4 K12 SX.

I will hopefully have videos attached but basically it ran fine for ages, but suddenly during a drive we started to lose power. At first it was like limp mode. But over an hour it started to bog down even more and just died , it would start but die quickly or run at 500 rpm, felt like 3 cylinders.

Now anyone would assume it could be spark or even fuel.
A few months ago- However I had issues with this car before where it would lose power, (not to a standstill, not every time atleast,) when it gets hot after a while of driving, and turning it off and on quickly would get it to work.
I thought it might be spark plugs so I replaced them and tested the plugs, the spark was great but the car still died when it got hot.
So I tried taking the fuel pump out to inspect it and it looked fine, putting it back in it ran fine for days after that until one day it suddenly bogged and died fully after a fuel up 20 mins ago, so we suspected that we put diesel in the car by mistake and got it cleaning the tank out, but really all the fuel smelt like petrol and evaporated quickly..
So I just bought a spare fuel pump from a scrapyard to put in as mine didn’t feel solid anymore, and that fixed it ever since.

But fast forward to now where it’s barely starting and running rough, I ruled out the spark plugs and fuel as I’ve already replaced all that and tested it again, so I thought it must be air, maybe MAF or throttle body sensor, when I first tested the car after it died with my diagnosis reader ( I got OBD2 and manufacture diagnostics, live read etc) but I only used OBD2 here I got codes for multi cylinder misfire, and an ECU code (maybe it could’ve been water damage? But the ECU looked dry and fine when I unplugged cleaned it and plugged it back in.)
And most of these codes I got might have been historic codes, so when I cleared them and ran the car at idle while it was running rough with an engine light, no codes came back up.
(I have one ongoing code for an oxygen sensor or my cat so that might be the engine light)

I’ve started tinkering with the big air box ontop of the engine, cleaning the throttle body, and even finally bought a whole scrapyard box with sensors and not even that worked.
I haven’t tested any sensors and I’m not sure how to when they’re plugged in.
But unplugged the MAP sensor while it runs sometimes did nothing or sometimes made it die, during my testing it was running rough the whole time, but towards to end of my testing the car wouldn’t start at all, so now I can’t get it to even run even if it’s rough.

And honestly I’m lost on what else to test from here and I don’t really wanna throw anymore money at it however this is my only car so without this I have nothing.

Any help would be appreciated.

 

[Mach1]

I had a bad patch of rough idling on my Suzuki (my Micra is diesel) however your problems seem to mirror my problems and as electronics run the engine management I hope the following might help:
your problem may lie in the bottom crank sensor also top cam sensor or a combination of both, these send signals for engine firing order etc, they tend to play up when hot (when they are getting worn out) and fault disappeared when cooled down. also try ignition coils again appear to be OK when cold and play up when hot. I recently replaced all the above to finally get rid of the erratic running and cutting out problems.
Hope this info helps to narrow the problems with regards to the electric side of the engine.

 

[AlexJZ]

I had a bad patch of rough idling on my Suzuki (my Micra is diesel) however your problems seem to mirror my problems and as electronics run the engine management I hope the following might help:
your problem may lie in the bottom crank sensor also top cam sensor or a combination of both, these send signals for engine firing order etc, they tend to play up when hot (when they are getting worn out) and fault disappeared when cooled down. also try ignition coils again appear to be OK when cold and play up when hot. I recently replaced all the above to finally get rid of the erratic running and cutting out problems.
Hope this info helps to narrow the problems with regards to the electric side of the engine.

That does help as I was thinking (and got advice from a friend) to replace the cam and crank position sensor so that makes me more confident in doing so, along with the top o2 sensor and maybe even the VVT solenoid, which we’ve already got out so might as well get it from a scrap micra, they fit in your pocket.

We’ve actually put another fuel pump in a few days ago and the car ran mint for 20 miles until it started losing power on the way to somewhere and limped back, I tested the car later that night and it ran great again up to what seems like the running temperature of 70 degrees ( stayed around there on my live read on my diagnostics tablet)
So it sounds as tho somethings failing when it gets hot and backs up what you’ve said but I’m not sure why a different fuel pump solved it ( I’ve done the same before)