no cold start intermittent missfire

[CMF_Lx_Micra]

The car wont start when cold once it starts up runs normal. When warmed up starts no problem. when driving normal car runs fine but when i give the gas harder the car seems to miss a beat here and there not always.

ive recently done the head gasket and ive changed injectors and alternator and new battery maybe ive bumped something while doing all this.

 

[CMF_frank2]

coolant temp sensor readings ok ? lambda readings ?

 

[CMF_Lx_Micra]

lambda sensor i have a spare one at work and am going to swap that tomorrow the coolant sensor haven't checked resistance but the plug was on. i will try do that aswell i had trouble getting the plug of with out pulling things of to get to it easier before dark.

 

[CMF_Lx_Micra]

ok plugged in the spare lambda sensor made no difference (spare was working when i removed it so i assume its still good). unplugged the coolant sensor cant get to it with my multimeter so i grabbed a 2.6K ohm resistor and placed it over the two pins on the socket made no difference.

Is there a better way to test this or could it be something else?

 

[CMF_frank2]

the lambda readings while driving will tell you if the coldstart enrichment is working ok, and if the ecu is closed looping ok (valuable maf/cts/lambda/injector diagnosing info)

 

[CMF_Lx_Micra]

Hey Guys
I Havent been using the car too much so ive put up with the problem

i have a bit of time this weekend and wouldnt mind trying to get this fixed.
It seems to me like it might be losing fuel pressure over night therefore when trying to start an airlock is created so after cranking for a bit it starts up.
If this sounds far fetched tell me.

How do i do this lambda readings test?

 

[CMF_frank2]

yes very
the middle wire on the lambda creates a voltage when hot, so a voltmeter from there to an earth somewhere

 

[CMF_Lx_Micra]

ok will try get that done tomorrow and i will post up a video hopefully on a dropbox link.

 

[CMF_Lx_Micra]

hey guys so i made i little video hopefully its clear enough. i tried to keep the car at 80km for no paticular reason. first its in 4th gear then youll notice i change to fifth and then down to 3rd thinking maybe that will help with the different readings. this happens after 2min 40sec on the video. i hope this helps.

https://www.dropbox.com/s/m3mqilm8pgkh3hy/20150306_113631.mp4?dl=0

 

[CMF_frank2]

it seems to be closed looping ok, but the k11,s have a speed sensor that holds it in closed loop in 3rd/4th/5th, it should do the same as this vid if the sensor wire is disconnected (or if you try in 1st and 2nd gear)

ie, it should bounce around .3 to .7v (closed looping) at cruise, then raise to .9v at wot, then 0v on lift

 

[CMF_Lx_Micra]

mine dosent sit that consistent between every reading it goes down to zero. so it looks something like this.

0.650v
0.045v
0.570v
0.050v

there not actual readings but that's what seems to be happening.

 

[CMF_frank2]

the readings will depend on what refresh rate the voltmeter has, so yours is closed looping ok from what i can see
does it hold at .9v at wot, and 0v on lift in 2nd gear tho ?

 

[CMF_Lx_Micra]

It appears to work as you have described in second gear wot its .9v
and 0v when i take my foot off.

So at low rpm its .9v as the rpm increases near its rpm limit it tapers of with the pedal all the way down. so it goes to 0.2v before i have to back of or change gear.

Does that make sense?

What else can i check on the car?

 

[CMF_frank2]

so thats ruled out a number of causes, does it start better from cold if you wet the air filter with a drop of fuel ?

 

[CMF_Lx_Micra]

ive never tried that but ill try do that in the next couple of days and get back to you.

 

[CMF_Lx_Micra]

i tried pouring a bit of petrol on the air filter maybe a cap full off a drink bottle didn't make a difference if anything it made it worse for little while.

is there anything else i can try?

 

[CMF_frank2]

valve timing out 1 tooth maybe ? post a pic of the lobes @ tdc like in the valve timing threads on here

 

[CMF_Mistikal]

Distributor cap.

Had the same issue on one of my K11s I wrecked, changed the entire dizzy and issue went away.

Also a common fault on the 4E motors in the EP91 Starlet, issues with the points inside the dizzy cap arcing out or not arcing at all, and once the cap is warm, issue seems to go away.

Pity you're not in Perth; I got a complete dizzy unit here you could use for testing. There are a few Sydney-siders on this FB group who don't frequent the forums much, they might be able to assist -- https://www.facebook.com/groups/238640209650320/