Car cuts out as warming up...
Car cuts out as warming up...
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Discussion

Digby

Original Poster:

8,357 posts

276 months

Monday 2nd December 2019
quotequote all
The old Nissan PAO I have has developed an issue where at the exact moment it appears to come off the choke from a cold start and the temp gauge has moved just a fraction off cold, it will instantly just die. It doesn't really cough and splutter etc, it just dies.

It starts fine from cold (although when left for some time takes a few cranks), will idle perfectly and in fact, if you can be bothered to drive it as it is, it even drives fine but will cut out when you stop at lights etc unless you keep the revs up.

PAO fans keep telling me to change all the vac hoses, but could that really be the issue here?

It's a 900 odd cc K10 micra engine (automatic) with a carb

Anyone had something similar? There is no variation on the time when it cuts out when started from cold, it's always exactly the same. Once it does cut out, you then have to keep the revs up yourself if you wish to drive it. Once moving, you wouldn't even know there was a problem.

This is really one of those issues I feel that will result in you trying ten different things before going "ahh, so it was the...."

I know heat can cause issues to things like dizzy caps etc, but where do you start?!

E-bmw

13,566 posts

182 months

Monday 2nd December 2019
quotequote all
I am agreeing with who advised you on a vac leak.

At least as a starting point if nothing else.

Theory is:

Engine cold, "choke" is on running it rich to compensate for an air leak, as soon as the "choke" is dropped then it is too lean to carry on running.

GreenV8S

31,027 posts

314 months

Monday 2nd December 2019
quotequote all
If you wanted to dig into it, you could check the lambda readings at low throttle openings to see whether it was running lean. The vacuum leak suggestion explains all the symptoms though. Also, conveniently, likely to be cheap to fix.

Digby

Original Poster:

8,357 posts

276 months

Monday 2nd December 2019
quotequote all
Great, thanks chaps. I just didn't want to start tearing off hoses which seemed to be ok in appearance at least before getting a second opinion.

I'm not sure exactly how many vac lines it has, but the engine bay is full of hoses so I will do some more digging!

The problem with the PAO forums is that vac lines crop up quite often relating to various issues, so you get the impression it would be suggested as a solution if you were to tell them one of your wheel bearings had gone. hehe

E-bmw

13,566 posts

182 months

Monday 2nd December 2019
quotequote all
Be sure to fully remove the relevant hoses & bend them liberally as cuts/splits in hoses are good at hiding in bends in the hose.

Digby

Original Poster:

8,357 posts

276 months

Monday 16th December 2019
quotequote all
Just wanted to say, I had a play with the car over the weekend and decided, as I had them anyway, to change the leads and plugs. The plugs which came out were quite sooty and once fitted, she fired up lovely.

As I waited for it to get up to temp, suddenly, oil started appearing. Once warm, it was dripping like a tap. Looking at where it is coming from which appears to be behind the cam cover, I assumed maybe a seal had suddenly gone, but my mate suggested it could be the head gasket and on closer inspection, there was evidence of a lot of oil around the bottom of the engine etc, so it may have been weeping away for some time.

This could, I assume, also relate to the idle issues due to compression loss and possibly explain why you can keep it running with a bit of gas and obviously whilst under choke conditions.


paintman

7,860 posts

220 months

Tuesday 17th December 2019
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Thoroughly clean the area of the engine where the oil is so it's all clean & dry as oil spreads all over the place & makes leaks harder to find.
Then start the engine & wait for the leak to reveal itself.
If you have a rubbery type cam cover gasket these harden over time & will leak. Trying to reuse one is false economy.

Digby

Original Poster:

8,357 posts

276 months

Tuesday 17th December 2019
quotequote all
paintman said:
Thoroughly clean the area of the engine where the oil is so it's all clean & dry as oil spreads all over the place & makes leaks harder to find.
Then start the engine & wait for the leak to reveal itself.
If you have a rubbery type cam cover gasket these harden over time & will leak. Trying to reuse one is false economy.
Going to have a player during the Christmas break and just to cover a few bases have ordered new gaskets (including rocker cover, manifold and head), cam belt, water pump, oil, filter, coolant and a few other bits. Will update.

Not sure if the head will need skimming if it turns out to be that. It didn't overheat on me, but then for all I know, the last owner may have had that happen and chucked some bars leaks type stuff in it to get shot!

Auntieroll

543 posts

214 months

Tuesday 17th December 2019
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Check its not an engine breather hose which has split , if the breather feeds into the inlet manifold it could produce the symptoms you describe.