Distributor cap/ignition leads - What's my problem?

workaccount

Hi,
My car is always cutting out if it's cold and you have to keep the revs up to keep it running. It's very annoying as sometimes I have to use the handbrake to slow down.

It has new plugs and I think the engine is completely fine otherwise.

So what could it be do you think?

It's a 94 sunny btw. In good condition with 109,000 on the clock.

beyondrapid

sounds a lot like my car - may the timing is slightly out?
one benefit is i've perfected toe & heel braking...

crosstownk

I'm no expert on a 94 Nissan Sunny, but it sounds like you could possibly have a problem with intake air preheating. Usually intake air is preheated by drawing the air over the exhaust manifold. If this doesn't happen the engine will usually cut out when cold. Check to see if you have a 'Winter/Summer' setting on the air filter housing. Also check to see if the warm air duct is not torn/missing/broken. Some manufacturers use a thermostatic valve that switches between warm and cold air automatically.

Like I say, I'm no Nissan expert, but it's something that you can check.

JHMEG

crosstownk wrote:

Usually intake air is preheated by drawing the air over the exhaust manifold

I have never seen this in any car ever. Cold air is more desirable as it's denser and therefore contains more oxygen.

OP, get a diagnostic done.

--amadeus--

Cold air is better as it is denser but cold air with high moisture content (cold and humid, if thats the right description - like the cold foggy mornings we had this week) can cause problems for older cars that have carbs.

As the cold air gets sucked in it is further cooled by the venturi and this can cause ice to form from the water in the air. This deposits on and chokes up the carb causing it to stall. Eventually though, when the car is up to temp the engine heat stops it happening. It's rare and more common in carb engined aircraft but not unknown (see this link). There can indeed be a diverter of some description t odraw in warmer air - I had a merc once that was originally built for the Sweedish arket and it had all sorts of wierd plumbing in there!

I have no idea about Sunny's, just throwing it out there!

workaccount

Just to let you know my car is injected.

JHMEG

Bad sensor imho, get a 30 euro diagnostic done.

crosstownk

JHMEG wrote: »

I have never seen this in any car ever. Cold air is more desirable as it's denser and therefore contains more oxygen.

What - you haven't seen this :eek: Maybe I'm showing my age here!

Colder air may contain more oxygen, but what if the water vapour in the air freezes as it passes through the venturi (which can cause the temperature to drop further) and results in ice particles forming.

The link refers to aircraft engines, but the principles are the same. Air passing through a standard car engine venturi can be reduced in temperature by 15∘C
http://www.meadvilleaeroclub.org/Carb%20Icing.htm

Like I stated earlier, I'm no Nissan expert, but I reckon a '94 Sunny would probably be using some sort of mono injection such as (or similar to) monomotronic or monojetronic which means the principles of a carburrettor can be applied to a large extent.


Does the image below make any sense to you? (all manifolds in the illustration are exhaust manifolds)

JHMEG

Even my ancient 1.3 1986 Civic with twin venturi Keihin carb didn't draw air across the exhaust manifold!

I must go look for some really old engines to have a look...

crosstownk

JHMEG wrote: »

Even my ancient 1.3 1986 Civic with twin venturi Keihin carb didn't draw air across the exhaust manifold!

It may not have had the exhaust manifold preheat - it may have had a 'hedgehog' preheater in the inlet manifold. But one thing is for sure - it didn't suck in cold, damp air and expect to fire. It had some sort of cold running option for intake air.

KoNiT

It has new plugs

who set them, are they gapped right?

Try special agent WD40 ont eh leads & Distributor to remove damp.

is it a Distributor or ECU? Check for damage

barthek

you said it had an injection so I presume it has an ECU of some sort.

the problem might be as trivial as coolant/water temperature sensor.
I've had the same issues with my VW polo 1.4 monotronic. Turned
out to be that. 5 euro and 10 minutes later engine ran great

workaccount

KoNiT wrote: »

who set them, are they gapped right?

Try special agent WD40 ont eh leads & Distributor to remove damp.

is it a Distributor or ECU? Check for damage

Back again as I still haven't got this problem resolved and it's getting a little worse. I might sell it soon...not because there's anything wrong with it but because I have my eyes on something much more powerful. I couldn't sell it though until everything is right on it. I want to continue trying to find out what the problem is myself and if I cannot figure it out I will bring it to my mechanic.

A mechanic would have set these plugs but I am changing these tomorrow myself anyways.

What do you mean by distributor or ecu?
Does the distributor not revolve from a shaft connected to the engine to keep time?

A guy I know reckons that it must be the fuel system as opposed to ignition as it runs fine when warm....ruling out spark plugs, leads or dis. cap.

barthek wrote: »

you said it had an injection so I presume it has an ECU of some sort.

the problem might be as trivial as coolant/water temperature sensor.
I've had the same issues with my VW polo 1.4 monotronic. Turned
out to be that. 5 euro and 10 minutes later engine ran great

Interesting. What does this sensor do?
I'm not actually sure if my car even has one.

Thanks very much.

barthek

Interesting. What does this sensor do?
I'm not actually sure if my car even has one.

Thanks very much.

essentially it reports engine temperature to the ECU.
when engine is cold the fuel needs to be 'richer' - more gasoline
and less oxygen. the idle needs to be higher too.
once the temperature reaches certain level, the mixture is changed again
and idle dropped to normal level.
if this sensor reports wrong values to the ECU ('engine is warm' instead of
'engine is cold' - it is done by measuring resistance) you run into problems.

And BTW is your Nissan B13 or B14 series ?
B13 service manual I have has a lot of information you could be interested in reading.

Tea drinker

crosstownk wrote: »

It may not have had the exhaust manifold preheat - it may have had a 'hedgehog' preheater in the inlet manifold. But one thing is for sure - it didn't suck in cold, damp air and expect to fire. It had some sort of cold running option for intake air.

And even with the hedgehog it's not unusual to have exhaust manifold heated air to start with.

Apparently some bikes suffered very badly with this, bit more of a problem there as you are balancing yourself on the power.

Also, depending on the model of injection, there may be some sort of idle enrichment/ higher idle when cold.

Spit62500

JHMEG wrote: »

Even my ancient 1.3 1986 Civic with twin venturi Keihin carb didn't draw air across the exhaust manifold!

I must go look for some really old engines to have a look...

Last car that I saw it on was an Opel Kadett C - it had a summer/winter lever on the air intake to avail of preheated air in winter.

RICARDO1982

Nobody has even suggested cleaning out the throttle plate. Start off with the basics before u jump in too deep.

workaccount

RICARDO1982 wrote: »

Nobody has even suggested cleaning out the throttle plate. Start off with the basics before u jump in too deep.

What's the throttle plate Ricardo? All I can find in the haynes manual here is information on refitting and adjusting accelerator cable and pedal.

RICARDO1982

engine off...Its the plate that turns to allow more air into the inlet manifold when you depress the accelerator. Its underneath the air filter i think under a wire mesh. if you pull the accelerator cable you will see the plate move. Engine off...
Get a can of carburettor cleaner in halfords and clean the plate and venturi.

RICARDO1982

If your not too sure your probably better off getting a mechanic to have a look.

workaccount

barthek wrote: »

essentially it reports engine temperature to the ECU.
when engine is cold the fuel needs to be 'richer' - more gasoline
and less oxygen. the idle needs to be higher too.
once the temperature reaches certain level, the mixture is changed again
and idle dropped to normal level.
if this sensor reports wrong values to the ECU ('engine is warm' instead of
'engine is cold' - it is done by measuring resistance) you run into problems.

And BTW is your Nissan B13 or B14 series ?
B13 service manual I have has a lot of information you could be interested in reading.

I'm not sure if it's a B13 or B14 but I have the haynes manual for it. Funny it does not seems to refer to any of those codes!

In the haynes manual it does have a temperature sensor which is beside the coolant pump that opens when water boils.

THIS MUST BE IT!!!!!!!

workaccount

RICARDO1982 wrote: »

engine off...Its the plate that turns to allow more air into the inlet manifold when you depress the accelerator. Its underneath the air filter i think under a wire mesh. if you pull the accelerator cable you will see the plate move. Engine off...
Get a can of carburettor cleaner in halfords and clean the plate and venturi.

Well mines injected but i'll check it out. It should be similiar.

I'm just thinking though that it's more than likely not this as it's sound when warm.

zilog_jones

workaccount wrote: »

I'm not sure if it's a B13 or B14...

Unless it's a Japanese import Sunny (not Pulsar) it can't be either of those. Our Sunny was a rebadged Pulsar, and it's a '94 so it's an N14. We haven't had any real Sunnys since the B11 in the early '80s.

In the haynes manual it does have a temperature sensor which is beside the coolant pump that opens when water boils.

You sure this isn't just the sensor for the temperature gauge? They can look similar. Though if it's like my Haynes manual it would call that the "temperature gauge sender".