Fuel Pump Relay Issues

[SuperUno]

I went to start the Girlfriends Micra this morning (to take her to the station) and it failed to start. After a few tries i gave up and used my car. When i got back i tried again, and after a few more i tries i had success.

I think the fuel pump relay (is there more than one ?) are playing up, when starting i think they are failing to 'stay-on' and i think from listening to them when it does work that they should 'switch over' and this is point at which they stop working. It is very random over when they do and don't work. Car is quite well used 100K plus miles.

Is it likely to be the relays at fault or more likely to be the wiring to the relays at fault (i can see a past owner has bodged the wiring here before).

Thanks in advance

 

[Suze]

hehe this is my car......thanks all in advance

 

[frank]

matt, suze

the relay is behind the o/s kick panel/A post and i think the ecu switches it on for 5 secs only if only turn the ignition on (and dont throw the starter)
i think they,re pretty reliable tho

 

[Alienfish360]

I think the engine had just got flooded, if this happens, remove the fuse for the fuel pump and turn it over till it's all gone, and plug it back on. I've never had a problem with the relay.

 

[Suze]

Don't think it was that to be honest as had that before and was different sounds etc than today. This would start over and over again this morning but just die / not idle as soon as it had started which didn't happen when it had flooded previously, then it wouldn't fire at all.

 

[whipit]

What you normaly find is the pump goes before the relay, this will most likely go on and off just as you have described.

 

[Alienfish360]

Weird question, do you have NATS?

 

[Suze]

erms......I wouldn't know what that is, prob best for Matt to advise!

 

[SuperUno]

I'm new to Nissan stuff, but i'm guessing NATS is a alarm / immobliser option. If so then the car doesn't have this.

 

[frank]

matt, suze

mine will still tickover with the fuelpump fuse removed (but dies if you gas it), so if yours dies, even on tickover, maybe its a corroded fuse or some electronic breakdown in the dizzy ?

 

[Luke Davis]

Guys,

done so more investigating.

I know what the problem is, not sure what needs to be done to fix it (maybe same prob as you).

I have noticed that when you turn the key to 'ON' there is an audible realy click (either fuel pump or something else).

NOW - under normal starting conditions when the key is turned and the engine fires there is no extra click.

HOWEVER - when my engine is dying, there is a second click just before dying, which i bet is that first relay turning back OFF, therefore cutting fuel or power to the ignition circuit.

I am not sure if the realy is bad (it clicks on and off fine) or more likely the igntion barrel is dodgy, so when i am releasing the key, it is effectvely turning the starter/whole ignition circuit off, cutting power and fuel to the engine.

Does that make sense??

try it on yours and see if you get that click when you release the key after starting. Its difficult to explain but it makes sense.

Im certain either a new main relay, pump relay, or barrel would cure fault, but not sure which as yet!!

I think the issue lies in the spring return in the barrel, i.e, it is not returning to the 'ON' position, but is shorting to ACC or OFF.

Hope that makes sense, let me know what you find - this also explains my lack of indicators or battery lights when the car stalled.

Luke

 

[Suze]

yeah there is normally one click, not sure about any others....

 

[TONEY]

the relay clicks on then off to prime the fuel system
ive had the same problem for a few weeks now

im going to change the relay and pump today so if i fix it il tell ya

 

[Luke Davis]

All,


Amazingly i fixed the problem - you would never guess.

Thanks to a handy tip given in my thread, i have found that the weight of my keys on the ring must be causing some kind of problem with the ignition barrel.

I have removed the car key from the rest and now i have no starting problems at all!!

What a weird fault, the odd thing is i only had 3-4 other keys on the chain, so if you have a problem where your car fires then dies immediately try just starting it with the key only and no other weighty things on the chain.

I can only assume the weight of the keys was swinging the key when it was turning back to 'on' after firing the starter, but the inertia was moving the kay in the barrel too far back therefore cutting the power.

I know it sounds stupid but its worknig as far as i can see

Luke

 

[Suze]

hms can try but not sure that'll work in my case as I've tried with my keys and Matt's tried with his and they're both different.....I think his are light!

 

[SuperUno]

My copy of the Micra key was on my house keys (loads of keys) i tried using the car with the key on its own and hey presto it works first time no problems. I suspect that the ignition switch is a bit worn and causing it to switch off for a moment.

Thanks for the heads up on that one, would have taken my ages to work that out

 

[K-rusader]

matt, suze

the relay is behind the o/s kick panel/A post and i think the ecu switches it on for 5 secs only if only turn the ignition on (and dont throw the starter)
i think they,re pretty reliable tho

indeed
indeed
this is what you should do-when ever i see a stranded k11 on the road this is the first thing that i do for them and so far 100% it has proved successful
:k11green:

a nissan serice manager taught me that one...saying it only happens very very once in a blue moon

 

[SuperUno]

Well perhaps not.................. :suspect:

Went to start the car this morning, and the same old issue even with the key on its own. Got running in the end, and once running its fine. Tested it a few times after it had warmed up and it never really caused an issue. I think when it is really cold (like this morning) the fuel demand is muh greater so the 'gap' between the fuel pump being off means that the engine dies. Whilst when hot it uses less fuel so can survive the gap in power to the fuel pump as the gao is quite small.

I also found that the by moving the key around with the ignition on i could make the radio go on and off, and make the fuel pump go on and off. So i now think it is a worn ignition switch.....

 

[Suze]

Still think there's a problem with the ignition switch ie that turning the radio on and off, but changed dizzy cap and rotor arm a couple of weeks ago and since then it's started fine every time....touch wood it continues!