Broke down - dont know whats happened

S

stokefan

Hi all,

I broke down on my drive earlier, tested the battery and its fine,and I have plenty of petrol.

The RAC man said he thinks the ECU isn't telling the fuel injectors to release fuel to the engine. He said he squirted fuel into the engine and it was fine and I could rev it when the fuel was being squirted in, but when the engine was left to its own devices it would just cut out.

Its currently on my local garage's forecourt and the only thing I can think of is to go and arm/disarm the immobiliser incase that has malfunctioned.


Could anyone help me please?
 
Right ok, what year is it?

I'd say it's either the fuel pump or NATS.

Can you hear the fuel pump priming? Should be able to hear a motor sound when you switch the key to the 1st or 2nd position
 
Can't remember whether nats cuts the spark or cuts the fuel pump though.

I think it cuts the fuel pump, as mine ran shortly after having nats die, assume it was burning the fuel off that was left.

So NATS, is still a possibility.
 
Remove one of the plugs of the injectors. Get a voltage meter and put it to the neg terminal on the battery, put the other lead on the injector wire(s) one should read 12v. This will establish if there is a problem with the supply to the injectors. (the fuse box by the battery sometimes causes problems.)
 
Thanks for the replies guys.

Its an M reg, which I *think* is 1995.

I don't think I have NATS as I have no engine icon on the dashboard.

I can hear the fuel pump prime then click off when it has primed.

Ed - can't check the voltmeter thing as I've now left the car at the garage I use, but the RAC man did unplug an injector plug, and plug his own device into it from which he summised that the injector wasn't receiving an instruction from the ECU to let fuel in.
 
check cam/crank posistion sensor maybe only thing i can think of, that or ECU is had it.... (or as ed mentioned the fuses by battery)
 
rlees85 said:
check cam/crank posistion sensor maybe only thing i can think of, that or ECU is had it.... (or as ed mentioned the fuses by battery)
Click to expand...


thanks for that. What do you mean by the fuses by the battery causing problems, as in the fuse could need replacing?
 
yer its really obvious when u take a fuse out and its blown cause that wire has a big gap in it!

electronics_fuse_blown.jpg
 
oh right its the same type of fuses as under the steering wheel then is it, thats good I thought they might have looked different being in the bonnet instead. I'll definately check those out.
 
stokefan

if it ran with fuel poured in the throttle body, it must be a fuel problem
you need to check the fuel is being fed to the fuel rail (70 psi), if it is ,the injectors can,t be opening for some reason !
 
All he needs to do is check thefuse box. They corrode - its a known problem.
 
I rung my mechanic who says he's checked the fuses and they're ok.

Frank - you're right, the ECU isn't telling the fuel injectors to let fuel into the engine.
 
cheers for the offer Frank, I dont think the ECU is completely gone as when I revved the engine with fuel being put in directly, it worked, as if the ECU knew where abouts the engine was at....but thanks for the kind offer and I'll certainly keep it in mind.
 
stokefan

i think it usually goes into limp home mode if you have a sensor problem but you could be right !
 
Its likely to be the fuses/connections in that fuse box by the battery.

It either corrodes so that the passenger headlight wont work or the injectors dont work. get that looked at before swapping ecu's etc..
 
hughes_16v

good point there, it looks like the injector to ecu signal wires are negative and are fed thro fuse 16/17 via a white/green wire
 
sorry guys not really sure I understand, what should I look for on the fuse box under the bonnet?

My mechanic called to say that he thinks if he replaces the throttle body (which he told me has loads of sensors in it) will probably fix it, what does everyone think about that?
 
stokefan

hughes_16v might be on to something here, the injectors are powered via fuse 16 and 17 ( a fusebox under the bonnet )
your breakdown man pinpointed, injector supply prob so if theres a fault with the wire or fuseholder, then thats a very likely cause
 
cheers hughes_16v, what do you suggest I should ask my mechanic to check again when i ring up tomorrow then? The Fuse box under the bonnet and the wire? (What wire is that pls?)

I dont know if he's well up on this sort of stuff with him not being an auto-electrician btw...
 
stokefan

ask him to check for a 12v feed to the fuses
haynes says the 12v+ (or 5v+) wire from the fuses to the injectors is white/green
 
thanks for the tips.

is it easy to remove the fuse box?

Are you pretty confident its fuse box related then? Seems weird whatevers happened that its just gone like that all of a sudden. Was working perfectly Chrismtas Eve, next time I tried it New Years Eve.

EDIT : I suppose this means i'm on the lookout for a throttle body as a last ditch attempt (this might be the end for my beloved Micra if this fails) so i'll post in the wanted section....
 
OK I'm planning to go to see my car tomorrow and try a few things as suggested by you kind folks.

Could someone please tell me where abouts the cam and crankshaft sensors are located please just in case I need to have a look at these? Cheers.

Just for my own record I'm giong to

1) Do the ECU fault code diagnostics with a paperclip
2) check the condition of all fuses under the bonnet and the fusebox
 
maybe check crank sensor then, becuase if this not working then the ECU wont know where the crank/cams are... therefore wont know when to fire fuel into the cylinders... so therefore wont send the signal.

at a guess...
 
rlees85 - sure there is a crank sensor? Frank reckons there's only a cam sensor inside the dizzy.

Frank - cheers mate, is that sensor easy to change?
 
stokefan

if the car runs with petrol tipped in the t/b, you,ve gotta concentrate on the injector 12v supply FIRST !
 
Hows it going with the car?

Im fairly certian its not the throttle body. Its the fuses, If the connections corrode it wont work. Frank also pointed out the fuse numbers 16 and 17. It either affects the injector or your headlight, it got my headlight so i bodged in an inline fuse and got it working, suppose you could possibly do so with the injector one? Its fairly easy to remove the box, once its free you can look on the underside of it and check for corrosion. but before you do that, find the injector fuse then get someone to push down on it really hard to see if it will make a connection. And see if it starts.

Ever noticed how you see alot of micras without a passenger headlight working?
 
hughes, cheers for the post, its good to see people checking up on problems they've helped with - especially seeing as I can't actually find this post to browse to any more!

My update is that I've not even asked for a throttle body as I trust you guys that it's not that. I havn't been able to access my car though for one reason and another, so havn't had chance to check out the fusebox. I aim to check Sat morning, although havn't a clue if the fusebox is corroded how I would fix this, suppose call out an auto-electrician to the garage or something......

What you've said just though has rung a few bells...A while back I had problems with my headlight, and I can't quite remember what happened, but I ended up taking it to an auto electricians who did a bodge solder of a fuse on to the fuse box - so you know I reckon the rest of the fuse box might have corroded. I didn't think that at first though a) as I forgot that I had some work done on the fuse box and b) seems weird that after a week of it sitting still on the drive that all of a sudden it would fail becuase of the fuses.

anyway - cheers for the check up and i'll keep you posted.

In the meantime - does anyone happen to have a photo of the fuse box with it's top off so I'm not going in blind on Sat?

I do wonder why my mechanic hasn't picked up on the fact the fuse box's corroded tho......

can anyone tell me please how much they think an auto-electrician will charge for replacing my fuse box under the bonnet if this is what needs doing?

Also - will it be easy to take a fuse box out of another K11 if i can find one in a scrap yard?

thanks.
 
OK I went to see my car at the weekend.

I tried testing for a connection with a multimeter from the negative terminal on the battery to one of the injector connectors, I got no current.

I also tried to read the ECU diagnostics, and nothing on my dash flashed at all.

I then checked the condition of the fuse boxes, specifically the one beneath the battery where I’ve had problems before. I couldn’t read which fuse was meant to be for the injectors on the plastic case, but none of the terminals were corroded like I’ve had before, any my mechanic told me he’d had a look at the fuse boxes already.

I'm at a loss, but my mechanic is fairly certain a new full throttle body would work, but obviously couldnt guarantee it. It pains me to say this I don't want to let it go - its my first car and I love it to bits, but I'm at the point where if you guys really think the throttle body wouldn't cure it and my mechanic doesn't know what it is, then i'm really really close to going and spending £5k on something else ~2000. :-(
 
hi retepetsir, what do you mean sorry? I put one of the prongs from the multimeter on the negative terminal and one inside the connector of the injector on to the metal bit.

Should I have done something differently?
 
i tried loads of different settings on the multimeter to be honest, I started with the one that just checks to see if there is a connection, tried volts and amps, nothing on any of them.....should I try something different?
 
stokefan

stab a sewing pin into an injector wire and connect it to your red m/m lead, black m/m lead to earth, set on 12v dc
one of the inj wires should be live with the ignition on
 
black m/m lead to earth
Click to expand...

where do I plug the black lead from the m/m sorry? Is it the negative terminal on the battery? Sorry i'm confused on that one.

I'm tempted to get my car towed to my house without bothering with the throttle body so I can try all these little things before I try and find a throttle body.
 

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