Unidentified electrical problem

[guest6046]

Hi all, new here

History - had a new fuel pump put in in December last year, fuel guage took about 20 minutes to get back up to full after I filled it up for the first time afterwards, then forgot about it as no apparent problems.  Probably only filled it up 3 or 4 times since, perhaps not letting it get too low.  Last week I unwittingly ran it out of fuel as the fuel guage appears to be stuck at 1/4 tank, although still goes down to zero when switched off.

This week - took it to Halfords Autocentre round the corner, who had put in the fuel pump, as I though it was related, they couldn't figure out what was wrong.  They diagnosed it as an 'electrical problem somewhere' - they had unplugged all the spark plugs and the engine kept running!

Taking it back to the dealer tomorrow, who serviced it (not the big service) a few weeks ago, to see if they know anything.

Any thoughts or experiences anyone?

Thanks

[VicW]

The fuel gauge itself looks as though it is OK but if the fuel tank gauge float is near the fuel pump then it may have been disturbed when the pump was changed hence it sticking. If this is the case it is down to Halfords as they changed the fuel pump.

From your comments about the spark plugs and engine running they obviously haven't got a clue !

Vic.

[John Ratsey]

I wonder if the Halfords person knows this this car has 8 spark plugs? They probably only disconnected 4 so the other 4 would keep the engine running happily on tick-over.

And I agree that the gauge problem is most likely due to the float sensor in the tank not working properly.

[guest5589]

It is a well known fact that Hondas don't like aftermarket fuel filters. When you got the pump changed, did you also got the filter changed? If yes then what part was used OEM or aftermarket?

[culzean]

Sounds like someone was a bit heavy-handed and bent or deformed the float mechanism that measure fuel level in tank.

The fuel gauge will indeed read zero when you turn ignition off as this removes power from the fuel level sensor.

Halfords people are OK with light bulbs and wiper blades but i wouldn't ask then to do anything more complicated.

[guest6046]

Thanks everyone

All your thoughts are exactly what I thought, and also the AA man who I (rather embarassingly) called out when I'd run out of fuel last weekend but had no idea I had.  Halfords are busy assuring me that it's not related to the fuel pump work they did (or rather their contractor - they don't do electrics themselevs, they call someone in).

I'm fairly sure they know it has 8 spark plugs - I feel sure they've put new ones in for me in the past!

It had a new fuel filter put in by the dealer at the previous service (Feb/March 2015) - I don't know if they put another new one in with the new pump in December.  Assuming the dealer would have put a sensible part in.

Apologies, rather new to talking about cars and their bits and pieces - please can you explain OEM and aftermarket?

I use Halfords because they are just round the corner from me and in the case of the fuel pump, they had somewhere to dump the car when I need a tow from the AA when the fuel pump went last year on a Sunday afternoon!

I have discovered over the past few years just how different the Jazz is and how much of a challenge it seems to be for run of the mill mechanics...

[John Ratsey]

OEM = Original Equipment Manufacturer (ie Honda) while aftermarket is another manufacturer who makes compatible parts. In many situations the latter work fine and are cheaper.

Modern cars are very complicated and are loaded with sensors and electronics. It's necessary in order to achieve the fuel efficiency and emissions control but does mean that "mechanic" is now the wrong word (or skill). "Technician" may be a better description. Most of the time all this clever technology is very reliable but once it malfunctions then it needs someone who understands it.

[guest6046]

I've been up to the dealer and back to Halfords this morning.

Halfords tell me they did take all 8 spark plugs out.

The dealer had no idea but wanted to charge me for diagnostics.

So back to Halfrods for them to call out the auto-electrician person who did the fuel pump work, at least check all of that out and make sure it's right.  I still feel reasonably convinced that the fuel guage issue is related to that!

[guest5251]

i find it was good of the AA man to take you to a Halfords autocentre
since the AA has owned the Halfords Autocentres for many years now

[JRHPNG]

I wonder if the Halfords person knows this this car has 8 spark plugs? They probably only disconnected 4 so the other 4 would keep the engine running happily on tick-over.

And I agree that the gauge problem is most likely due to the float sensor in the tank not working properly.

I had a similar issue, the previous owner of our Jazz had his "mechanic" son do all the basic maintenance... I removed what appeared to be the original plugs on the back a few months ago and replaced then...

[Hobo]

Halfords people are OK with light bulbs and wiper blades but i wouldn't ask then to do anything more complicated.

Have to agree, I would not trust Halfrauds to do anything on my Jazz or come to think of it on any car I owned.

[olduser1]

In the meantime why not fill with fuel then set trip > 0 and use the trip miles to keep a tally on fuel in tank. Pity you can't locate a mechanic as oppossed to modern day dealearships. You might be lucky via this link to a recommended good  garage here>
http://good-garage-guide.honestjohn.co.uk/

[guest1372]

The fuel pump, filter and level sensor are in a can that sits in the tank. On a Jazz this is accessed through a hatch under the centre console rather than from outside the car. (Pic. attatched*) Whoever dismantled this can to change the pump has affected the level sensor.

An electrical fault would mean the gauge would either work or not, it would not be slow to respond. Looking at the wiring diagram, the fuel gauge along with the low fuel warning lamp (and the speedo & tacho etc.) are driven by a microprocessor within the dashboard unit. This takes an input from the fuel gauge sender unit and processes it for display.  This is not like an old fuel gauge on a Triumph Spitfire.

I believe the level sender is either obstructed or damaged, or possibly something has been over tightened. The fault lies at the door of Halfords, you need to remind them that their work needs to be of 'a reasonable quality' and give them them an opportunity to 'rectify the fault in a timely manner'. The Sale of Goods Act should apply here.

Driving 300 miles on a full tank will leave you enough margin to refill safely (assuming you're no boy racer) I always drive to distance rather than the gauge, as I'm not that keen on it's non-linearity. It hardly moves on the first 100, drops to 1/2 at 200, then heads toward E at 300, I fill up at around 350 miles.
--
TG

* The dirt is not mine, this is a scrapyard car.


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[guest6046]

Thank you TG, good info It will be good to feel like I know what they're talking about, I often feel like technicians could tell me anything and I have to trust them.

I agree that the likelihood is that the fuel guage issue is related to the fuel pump work done at Halfords and the responsibility to rectify it lies with them. Any spark plug issue is likely separate.

I'm no boy racer, lol! I do very low mileage which makes it a little more of a challenge to manage fuel by distance without keeping notes!

Booked in on Friday and I'm keen to keep minimal fuel in until then in case they feel the need to drain it. Hope to have better news for you after then


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[guest6046]

Well I'm still none the wiser,  auto electrician has tested it but still can't see where the problem is!

Booked in again next week for the fuel tank to come out.

At least it's driveable in the meantime and they haven't charged me for anything yet.

Started looking at new cars...

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