Help! Turns but doesn't start...

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ChrisB

Guest
Hi,

The starter is turning the motor over and I'm getting a spark at the plugs. I can smell petrol in the cylinder when the plug is removed. Took the oil filler cap off and I can see the upper timing chain turning the camshaft sprocket but it just doesn't want to start. Called out the breakdown guys who reckon it could be a faulty senser somewhere? Perhaps ECU?

Anyone got any ideas or seen this before?
 

rlees85

Ex. Club Member
engine could be flooded with petrol, try removing the fuse for the fuel pump and trying to start it a few times, then put the fuse back in and try again.

you'd be unlucky for a sensor to stop it starting all together, even with half the sensors unplugged on my car it started eventually lol
 
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ChrisB

Guest
rlees85 said:
engine could be flooded with petrol, try removing the fuse for the fuel pump and trying to start it a few times, then put the fuse back in and try again.

This has caught me out before - one of the first things I tried. It normally starts very reliably. I want to make sure that petrol is getting to the cylinders because I'm not 100% convinced about the "taking out the plug and sniffing" method. What's the best way to check? Take off one of the injectors?
 

rlees85

Ex. Club Member
maybe remove a fuel hose from the fuel rail but put it into a big container, then switch ignition on (dont try and start) and see if it starts filling up..

if it does the fuel pump is working and so is the filter, and i doubt all four injectors would fail at once.


btw ive never tried anything like that before and dont know how quickly the fuel will come out, so if your not 100% on what your doing yourself, i dont recommend my idea ;)
 
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ChrisB

Guest
rlees85 said:
maybe remove a fuel hose from the fuel rail but put it into a big container, then switch ignition on (dont try and start) and see if it starts filling up..
if it does the fuel pump is working and so is the filter, and i doubt all four injectors would fail at once.

Is it the fuel pump which makes the buzzing noise when you turn the ignition on? I can still hear it as normal, so if it is the pump I reckon it's working OK. I replaced the fuel filter about 2000 miles ago and it's been fine. No evidence of a leak. I'll try taking the hose off the fuel rail and see if any petrol comes out. As you said, it's unlikely all 4 injectors got blocked at the same time.

The air filter is due to be replaced but I reckon it's pretty unlikely it would stop the engine starting just like that. Surely it would struggle for a while first?
 
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ChrisB

Guest
Hmmmmm....

The orange engine management warning light thingy is staying on when I turn on the ignition. I'll see if I can get a fault code. Should have checked this first really.....
 

NeX

You're after my robot bee
Club Member
there is fault codes in the haynes i think,

use a paper clip to get it into test mode.

i think 55 is everything's ok
 
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ChrisB

Guest
rlees85 said:
the engine management light is meant to stay on when just on ignition...
Light is supposed to stay on? OK then, my bad.

NeX said:
there is fault codes in the haynes i think,
use a paper clip to get it into test mode.
i think 55 is everything's ok
Code was 55 so everything's fine. Other than not starting at all :)

Craig said:
does your car have NATS?
Yes it does. do you think that's the problem? I'll have a go with the spare key...
 
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ChrisB

Guest
Does NATS just prevent the engine starting or does it stop it from turning over altogether?
 

Craig

Unofficial Member (Gold)
Club Member
It will just stop it starting, check that no fuses are blown (either in the cabin or the engine bay) and then check all earths in the engine bay - there are two on the right-hand side of the engine that ground the ignition wtuff anbd then if you have a multimeter, chek that there is actually power getting to the pump, if not then you could either have a knackered relay or a NATS problem.

But bwefore you do this, try starting with the spare key :)
 
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ChrisB

Guest
Craig said:
It will just stop it starting, check that no fuses are blown (either in the cabin or the engine bay) and then check all earths in the engine bay - there are two on the right-hand side of the engine that ground the ignition wtuff anbd then if you have a multimeter, chek that there is actually power getting to the pump, if not then you could either have a knackered relay or a NATS problem. But bwefore you do this, try starting with the spare key :)
I've checked the fuses already - they all seem to be fine. I've not checked the earths yet but I'll pop out and have a look in a minute. Same problem with the spare key. I'm pretty sure the pump is working properly.

I beginning to think it's a NATS problem as the engine turns over but doesn't fire, even though there's a spark. Does NATS just stop the injectors from injecting then?
 

rlees85

Ex. Club Member
i thought nats stopped everything and caused the engine light to flash

ill be able to tell you for sure later becuase ive been playing pee abouts with my key lol
 

Craig

Unofficial Member (Gold)
Club Member
When I had problems with it it stopped the injectors, if there is petrol in the cylinders then this may not be the case, but it could be residual petrol.
 
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ChrisB

Guest
Just spoke to one of the techs at the local Nissan dealer - he says NATS just stops the injectors working which seems to be the problem I have, but the engine light doesn't flash like it's supposed to when NATS kicks in. I'll double-check the injector fuse and earth...
 

rlees85

Ex. Club Member
i just tried starting my car without a nats chip, it just turned over and didnt fire (but you kinda established that it just stops the injectors already)

the engine light didnt flash either.
 
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ChrisB

Guest
rlees85 said:
i just tried starting my car without a nats chip, it just turned over and didnt fire (but you kinda established that it just stops the injectors already) the engine light didnt flash either.

Riiiiiiiiiight. This is making some sense. I just pulled a plug out again and it's nowhere near as wet as I'd expect after turning the motor over so much. It should be completely soaked by now if there was fuel getting to the cylinders. The injector fuse is fine, there's a spark at the plugs, there's definitely petrol getting to the fuel rail, it's just the injectors aren't injecting.

So...

How do I go about disabling NATS? can I just swap out the ECU? If I swap the ECU can I just swap the chip in my keys?
 

rlees85

Ex. Club Member
swapping to a non nats ecu will sort it out, if its a nats problem

swapping to another nats ecu, and swapping the chips on the keys may NOT work as it could be a problem with the nats receiver behind the ignition barrel.
 
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ChrisB

Guest
rlees85 said:
does the engine light stay on whilst trying to start? mine only did that when trying to start without nats
Engine light is on when the ignition is on but goes off when I start (try to start) the engine.

One of the neighbours came out to have a look. He reckons it may be that the timing chain has slipped (caused by knackered tensioner?) so it's not firing when it should. He also thinks the engine is turning too easily - no compression due to the valves being open when they should be shut? I'm going to see if I can get hold of a compression tester and if it looks bad, pop the sprocket cover off and check the tensioner....
 

Craig

Unofficial Member (Gold)
Club Member
I have never heard of a timing chain slipping, but it sounds like it could be possible, would expect the injectors to still be kicking out their full load so maybe not that though, your best bet is to ge a non-NATS ECU from a scrappy and try that, it should fix your problem, what year Micra is it?
 
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ChrisB

Guest
Craig said:
I have never heard of a timing chain slipping, but it sounds like it could be possible, would expect the injectors to still be kicking out their full load so maybe not that though, your best bet is to ge a non-NATS ECU from a scrappy and try that, it should fix your problem, what year Micra is it?
Um, '96 or '97 I think, it's on an R plate. I'm leaning less towards the NATS problem as rlees85's engine light stays on when he removes the chip from his key and mine goes off as it does normally.

It does seem like the engine's turning too easily and I have had problems with the timing chain tensioner before. If the tensioner's broken and the chain's slipped on the sprocket by a couple of teeth then the timing will be out and I suppose the piston could be in the way of the injector when it injects? It's a long shot I know. The local motor spares place has a compression tester they're saving for me - I'll see what that shows up before swapping the ECU.

Cheers for all your help so far - 'tis much appreciated :D
 

Craig

Unofficial Member (Gold)
Club Member
see what the comp. tester says, sound more like it isn't getting any fuel though, even if the timing was miles off, you would still be gtting fuel in there, unless of course the chain has slipped off, in which case you would only get fuel in one cylinder.
It may be worth taking the cam cover off and giving the chain/tensioner/lobe position at TDC.
 

Fordy

Ex. Club Member
check the fusebox near to the battery, take the bottom of it off and check that there isnt any wires corroded, theres one fuse in there that will stop it from starting if the wire has corroded away from the contacts
 
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ChrisB

Guest
OK, it's bad - the compression tester barely moves. I got 120psi on 3 the first time I tested it then nothing the next time.

:down:

Camshaft cover's coming off over the weekend so I can see how bad it really is. If I'm lucky, the lower tensioner is knackered, the chain's slipped a couple of links and the timing's gone out but I suspect it's going to be a lot worse....
 

rlees85

Ex. Club Member
ah :( you got a 1.0 in there? might be a good excuse to drop a 1.3 in, i picked a CG13 up for 50 quid, with 57,000 miles on it
 
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