Micra getting increasingly harder to start

Well since I've had the car now, a little over 10 months its always been reluctant to start when its not either cold or at operating temperature.

Over the past week this condition has been getting worse.

Noone else seems to suffer this difficulty.

So far I have inspected the whole fuel system and replaced the filter. The old one was very clean. It runs on a diet of either 95 or 98RON. It all appears to be good and the fuel pump doesnt cause any problems (isnt drawing excessive current). Only thing I havent checked is fuel pressure - BUT the fuel pump primes for the same period of time no matter what temperature the engine is at so I'm guessing the regulator is probably not stuffed.

Now to make this very clear what the issue is:

Cranking with engine at ambient temperature (around 25deg. C) - instant start.
Cranking with engine temp over 60deg C (measured with Consult) - instant start.

Attempting to start anywhere in between say 30deg C and 60deg C results in an extended period of cranking (usually around 4 seconds worth, sometimes it is less if i start it with the throttle fully depressed) and it lets off quite a bit of brown/unburnt fuel vapour from the exhaust and struggles for a few seconds while it sorts out the mixture.

Consult computer logged no sensor issues - the AFM records the same signals when starting every single time EXCEPT when I depress the throttle where of course the metered readings are higher. So I am going by the assumption at the moment that the AFM is not suffering typical micra problems.

The weather also plays no part in this starting issue - although when it is damp she does develop a slightly lumpy idle. I guess this indicates a distributor problem, but it doesnt seem like it would be related to the starting issue.


It has been suggested to me that a leaky injector could be the cause here but before I go replacing stuff I'd really like your opinions on the matter.

Also - anyone willing to lend me a known working injector rail that I can swap out with mine to see if it does the same thing?

Thanks for any suggestions!

I have a spare rail floating around somewhere. I will dig it up & lend it to you. It was in my car before the turbo convertion & my car starts fine everytime.

A slightly lumpy idle on start up when its wet, could indicate ignition leads on the way out.

Yeh the recepits indicate the leads were replaced at 90,000km so it is indeed time for them to be replaced.

Garh, great time to quit work because of a stupid back injury.

I might take you up on that injector rail mate - won't have time to go for a drive until after tuesday night though.

How about next weekend?

YOM:

I have a the same problem as you for about 6months...

What have i donne:

Changed the t.B. a 2nd hand one that was in perfect condition
Changed Spark plugs
Changed fuel filter
Check battery
Check injection rail
Check fuel pump

The last time my mechanbic put a valve between the fuel filter and the injection rail.... AND like a miracle the car starts like ever before! unfortunately after 24hours of perfect starting the FUC**NG problem comes back agian. Tommorow i will go back to the mechanic, and i'm pretty sure it has to be something like few fuel in the injection rail... WHAT DO U THINK?

put a fuel pressure guage on the car. start it & let it run to normilise the fuel pressure. stop the car. watch to see if the fuel pressure drops. if it does then there is a problem somewhere. either leaking injectors, regulator or the one way valve in the pump. The pressure has to go somewhere.

Yeap that should be it... do u know how many valves there are in the fuel injection system?

There really is only one. Its internal in the pump. However if the regualtor leaks then rail pressure can bleed back to the tank. If the injectors leak then you will usually get a little black smoke on start up. If there is leaking hoses/clamps you will normally smell fuel.

I'm almost 100% convinced it is a leaky injector. Its pretty much the only way the darn thing could overfuel upon this startup condition.

I'll wait for a new rail to test my theory. Otherwise I might break something or start replacing stuff I don't really need to be replacing hehe.

Ok i see... i have black smoke, and sometimes fuel smell!

Sorry my lack of knowledge but were is the regulator? because it seems to me that its lack of pressure and there isnt enough fuel in the rail

The reg is attach to th fuel rail. It on the return end. Try the pressure test first. If the guage drops, try clamping off the return line. If this stops the pressure drop then most likely the reg is the problem.

A slight drop in fuel pressure is normal over a period of time. I cant remember how many psi over how much time is acceptable. I will try & look it up.

I will also have a look at mine. It is hesitant to start sometimes. It also uses a little more fuel than I think it should which could be explained by a leaky injector.

Okay bad news too.

Latest fuel consumption figures.

9L/100km

:(

Ok My mechanic check the entire fuel lines... is believing that it might be the rail....

have you already tried the new rail YOM?

Please let me know as soon as you figure it out whats the prob.

Pulled the rail & injectors out of inlet manifold.
Turned ignition on so fuel pump would pressurise.
No leaks.

Started engine, injectors sucked back into rubber seals on inlet manifold.
Pulled injectors out of manifold again with engine running.
Engine stalled, no leaks.

Is yours hard to start only when it is in a certain temperature range?

I'd suggest doing that same thing when you know its going to be hard to start.

Well it looks that its hard to put the damn thing starting perfect.

i can only imagine the problem is in the rail...

YOM: havent you tried another RAIL?

I will be very soon mate. 2 weeks I should have an answer for you.

Yorn! I have the exactly same problem that you. The others on my post gone by when I decided adjusting the distributor myself and realized the mechanic was advancing it in reverse. Now with a little idle adjustment its OK.

With leads you mean spark plugs? Mines are new and are the factory NGKs

But the same trouble wanting it to start when it was already running. No matter how many time it was on and the temperature. Here its very cold now but last week was hot. I don't think it can be the fuel system as it also happens if you let run the pump several times before cranking.
And remember I also swapped the fuel rail and same result. It could be possible for me having two bad fuel rails.

1300super, i think your mechanic has swapped in a one way valve on your fuel line, but this things only lasts 'til the gas melts it. I'ld try a different pump.

PROBLEM SOLVED!!!!!!

there were two injectors leaking fuel...

so everytime you turn off the car the injector leaks fuel to the engine, the engine gets a lot of fuel and then its hard to start!

anyway my mechanic get me a 12000k fuel rail with injectors, and changed for the old one... and now its running so perfect!!!!

I can 100% garantee the prob was the leaking injectors cause i saw with my own eyes them leaking.

So YOM and Sergi and everyone having hard start search for a leaking injector!

NOTICE: the diagnostic machine from Nissan dont detect any problem, so you have to go oldschool way!

GOOD LUCK

What did the leaks look like?
How much leaked?
How obvious is it?
Was this found by removing the fuel rail & pressurizing with the car fuel pump as I described above?

You must remove the fuel rail without removing the fuel tubes then you ask someone to put the key in on position so the fuel pump can pressure the rail... then turn it off.. after some seconds you see a drop coming down the injectors in the rail.... you must pay attention cause the fuel drops evaporate very quickly and you might not see them!

hope i can help...

I will have to have a closer look at mine again, I was expecting more than a slowly forming drop. If this is the case I may have a leaking #2, I noticed it felt a bit wet.

hi i have a similar problem my micra a 96' is very hard to start but only on the first start of the day i have replaced battry as the other was poor however i have the same problem after the first start its fine can anyone help

Okay. Well the verdict and solution to my problem is in.

3 out of 4 injectors were leaking visibly and quite severely.

#1, 2 and 3 were leaking. #4 was nice and dry. So I left #4 in.

Grabbed the injectors out of the jap fuel rail I have on my spare engine and replaced the injectors. The Jap engine seems to have done alot of idling and the injectors are very dirty. One of them refused to work correctly and caused all sorts of issues.

One jap injector appears to be working absolutely perfectly and seems to shoot a much finer mist of fuel rather than the UK injectors which seemed to throw rather large "blotches" of fuel - more like rain drops. Serial numbers on the injectors were the same.

Who knows why this is.

Ideally I should have got the jap injectors cleaned and flow tested but the whole operation was a thought of the moment (and also because i found the imact driver which allowed me to undo the screws on the rail).

Engine now starts easier than ever!


Oh yeh, I don't recommend going around fiddling with your high pressure efi fuel systems unless you half an idea of what you're doing because if you're not careful you could end up with leaks and fires etc.