K12 multiple cylinder missfire

[chris810]

Hi
My daughters micra has been stood for about a year i have just started looking at it re getting it back on the road and i have an issue i would like to put out to the collective


The car starts well ticks over nicely and drives very well, for about a mile and a half, then a missfire starts and the car becomes difficult to drive. I origionally had the following codes

P0301 cylinder 1 missfire
P0300 random multiple missfire
P0113 intake air temp circuit high
P0107 MAP pressure circuit low

I have cleaned the MAP sensor and replaced the coil pack on cylinder 1 and cleaned the carb, now i am just getting P0300 random cylinder missfire and i have to say its right.

It sounds like either fuel starvation or possibly something electrical breaking down due to heat although i have run the car at idle for an hour and not had this issue

Anybody any thoughts fuel filter mabye ?

 

[EK10]

Hi Chris810

Have you checked fuel injectors for blockage? Spark plugs could be worn , timing chain tensioner protrusion? Inlet manifold or throttle body possibly vacuum leak maybe even air intake blocked. I would suspect either a vacuum leak at the inlet mani or fuel injectors fault. The fuel filter is a combined unit with the fuel pump.and not servicable if you replace you have to replace whole. Hope this helps.

 

[chris810]

Hi Chris810

Have you checked fuel injectors for blockage? Spark plugs could be worn , timing chain tensioner protrusion? Inlet manifold or throttle body possibly vacuum leak maybe even air intake blocked. I would suspect either a vacuum leak at the inlet mani or fuel injectors fault. The fuel filter is a combined unit with the fuel pump.and not servicable if you replace you have to replace whole. Hope this helps.

Thanks for that im going to go through it tomorrow my bet is on the fuel pump or a blocked filter or injector.
I changed the engine before it was laid up so the tensioner and chain is ok i suspect its gunge / rust in the tank getting through to the injectors or blocking the pump reducing the pressure. But gling to work through it methodically i dont think its a big issue just a bit slippery to tie down. I have a lot pf spares so i can change fuel rail if i have to

 

[EK10]

Grand keep us posted , if you want any more advice. I shall try my best.

Best of luck.

 

[chris810]

Grand keep us posted , if you want any more advice. I shall try my best.

Best of luck.

Ok so not fuel, pump pressure is steady at 3.5 bar and holds pressure for a good while 15 mins

To check for a vacum leak can i use a gauge and a temp bung ? I have a vacumn gaugewhere would i check from ?

Would a leak only show at high revs ? It ticks over nicely for hours with no problems drive it a mile and a half missfire !

New air filter and spark plugs also added

 

[chris810]

Grand keep us posted , if you want any more advice. I shall try my best.

Best of luck.

So after a full day at the car and a test drive where a front brake seized on i removed all the coil packs replaced them with the middle two reversed order then i cleaned the earthpoint from the alternator bracket amd the earth point at the rear of the engine near the battery and went for a drive to see if i could fault the coil packs.

And it drove like a dream no stuttering no hesitation , i have tried to make it misbehave but i can't done over 50 miles in it over two days and i have to say its fixed

How. Earth points mabye ?

 

[EK10]

Great news . Im not sure myself about bad earths but alot of people say bad earths can have a direct effect on idling and bad performance. Maybe the earth to the alternator was corroded abit and the electricity produced by the alternator wasnt getting the full juice and affecting the performance of the car. Fair play : ) .