Starting problems - Fuel pump fuse

[Pauld123]

I have had starting problems. I suspected the dizzy but now I am not so sure. I read somewhere to check for over-fuelling. I removed the fuel pump fuse, cranked the car a few times and then replaced the fuse and - BINGO the car starts first time. Each time the car fails to start, if I do this procedure it works.

But the thing is I don't understand why it works. I mean obviously something is broken and it is a common thing (hence the advice I found on the NET). Can anyone tell me what it is that is broken and needs to be repaired in the long-term?

 

[frank]

its pretty common paul, nissan used to sell a piggyback resistor that you plugged into the coolant temp sensor, i wired a 2nd sensor on mine (to lessen the coldstart enrichment)

 

[Pauld123]

Frank, I looked up the resistor you talked about. It seems to cost about £45. Would it not be cheaper just to replace the faulty coolant temperature sensor? Or is that not an option?

 

[SuperUno]

Does anyone know the value of the resistor that they used?

 

[Pauld123]

Sorry Matt. That message seems a bit cryptic to me. What do you mean?

 

[SuperUno]

If we know the value (i.e resistance ) of the resistor they used, you can get one from Marlin / ebay / RS for pennies not pounds......

 

[Pauld123]

okay, but isn't a standard part? Like wasn't the same resistor used in every K11? Perhaps i am missing something.

 

[Micra Paul]

Deleted duplicate file

 

[plmval]

Before adding modifications, it is advisable to check the circuit for corroded & high resistance loose connections on the sensor and also at the related power supply fuses.

Reference: Haynes manual, engine temperature variable resistance sensor range; page 3.1 chapter 3

20° C equals 2500 ohms

50° C equals 850 ohms

90° C equals 250 ohms

These figures can be manually cross checked with those of the actual engine temperature sensor for the approximate various temperatures using a digital volt/ohm meter.
Above tabulated data implies high resistance at lower temperatures and therefore more resistance adds more fuel. Therefore if the Haynes tabulated data is correct, adding more resistance in series will increase the over fueling issue. Perhaps the Nissan additional resistor modification was in parallel to limit the overall base resistance on cold start-up?
Either way it is easier and cheaper to check and ensure operation and compliance of the existing circuit to standard specification before modifying it.

 

[frank]

okay, but isn't a standard part? Like wasn't the same resistor used in every K11? Perhaps i am missing something.

the resistor that was available from nissan was to correct a mapping issue in the early ecu,s apparently paul, else they would have obviously just supplied an uprated coolant temp sensor eh.
some owners were starting their car for a minute, then finding they could,nt restart it soon after (due to flooding, there were numerous threads on the ilexa forum)
the 2nd sensor cured mine no probs, and saves fuel too

 

[frank]

Before adding modifications, it is advisable to check the circuit for corroded & high resistance loose connections on the sensor and also at the related power supply fuses.

Reference: Haynes manual, engine temperature variable resistance sensor range; page 3.1 chapter 3

20° C equals 2500 ohms

50° C equals 850 ohms

90° C equals 250 ohms

These figures can be manually cross checked with those of the actual engine temperature sensor for the approximate various temperatures using a digital volt/ohm meter.
Above tabulated data implies high resistance at lower temperatures and therefore more resistance adds more fuel. Therefore if the Haynes tabulated data is correct, adding more resistance in series will increase the over fueling issue. Perhaps the Nissan additional resistor modification was in parallel to limit the overall base resistance on cold start-up?
Either way it is easier and cheaper to check and ensure operation and compliance of the existing circuit to standard specification before modifying it.

tis true my 2nd sensor is wired in parallel, which reduces the resistance by half i believe

 

[Pauld123]

So basically after giving up on trying to find a solution I took it to the Nissan garage. They have told me that a wiring harness is causing the over-fueling and needs replaced. Ok fair enough the harness is £45 and they say it won't take long to fit but what harness could they be talking about and where does it run from-to?

 

[frank]

thats the piggyback loom paul, they still stock them then eh !

 

[Pauld123]

That's what i was wondering if it was the piggy back loom they were talking about. Problem was the mechanic was transferring the information to me through a receptionist. Got the car started last night. But, boy, was there some smell of fuel when she started. I dropped off a copy of this forum page with it, so that's for the advice. Looks like it did the job.

 

[Pauld123]

Sadly I am back again. The car came back and was starting fine for a couple of days. But this morning it started first time, then I stalled it and then it just would not start again (turned over but no kick). I tried the fuel pump fuse trick but this time on the second crank the car started to beep. I guess I triggered the alarm, but how/why? Anyway replaced the fuse, I closed the doors, locked it with key and pressed the fob button once (there is only one button). I opened the doors, there is no beeping any more, I can hear the fuel pump priming but the car does not kick when the ignition is started.

So firstly, have I dealt with the alarm/immobiliser correctly? (it's my girlfriend's car and I don't ever set the alarm)

Secondly, any idea why it has refused to start after a stall?

Thanks, getting concerned now problem has been ongoing for about two weeks

 

[frank]

aftermarket alarm paul ?

 

[Pauld123]

I don't think so I says NATS on the car and its not the sort of car anyone would have spent money on to fit a new alarm. Anyway supposing I reset the alarm correctly, do you have any idea why it refused to start after stalling? It was my fault I took foot of clutch too quick (it had just started). But then absolutely no restart. There wasn't the big smell of fuel like before. But could I have flooded the car? If the loom is fitted (which the garage say they did) can you still flood the car?

 

[frank]

i,ve never come across any beeping noises from nats paul ?

 

[Agent_Sm1th]

You sure it's not the alarm as you say it's only got one button and the Nissan central locking came with two. Also with the Nats system, you only need the correct key transponder to start the car. The central locking, unless aftermarket doesn't immobilise the car.