HI, sorry to pile in with a problem, but that what friends are for.
***** Problem 1 *****
I have just purchased a 2006 NC with only 43K miles and a clean MOT history with no mentions of rust at all.
However on collecting it had an empty tank, i filled with £20 (gauge shows a 1/3 full) and drove 30 miles to McDonald’s, on restarting the car the fuel gauge now reads empty.
Off to the nearest garage and another ÂŁ20 and now the gauge reads 2/3 full, 40 miles later when i park up the gauge shows 1/4 full.
An hour later i take the wife for a jaunt round the block ( 2 miles max) and the gauge drops slowly to empty.
I start panicking as i now know one of the reasons the car was up for sale.
I have a look in the fuse box and find thisÂ
I cleaned it the best i could before it went dark, and fuel gauge still didn’t work.
The next day the fuel gauge starts working straight away and shows just above 1/2 a tank, parked at work turned engine on and off and gauge has stopped working again, 6 hours later gauge starts working but climbs very slow to the 1/2 way position.
***** Problem no 2 *****
The dash idiots lights for the ABS only shows 1/2 of the top half of the ABS letters, the EML light and the 2 lights below the EML don’t illuminate.
Is problem 1 connected to problem 2 via the corroded connector in the fuse box, or possible damage to that area of the instrument cluster PCB effecting the fuel gauge?
I agree with Rhino what looks like burning in the fuse box is grease. I thought the same as you when I first looked at the fuse box in my mk3 but it’s normal. Stops corrosion I guess. D
I would be more worried the engine check light does not show when the ignition is first switched on.
If you can plug a reader into the OBD port and see if there are any stored codes.
Not sure of how the MK3 dash lights are set up, but half a light on the ABS could mean it has been obscured by something from behind.
I hope this is nothing major but worth getting checked out
Electrics/instruments can act erratically when water gets past the scuttle grommets. The water drips down in and around the passenger side behind the glovebox, there’s also a fuse box at the base of that sides A pillar. Other owners have reported electrical problems as you mentioned with water ingress.
Just to say also, we’ve had a few torrential downpours this week.
If the engine check light is not showing i would get into the dash cluster and check if there is a bulb in there, it could have been removed to sell the car on because of an expensive fault. If so get it back to the seller pronto.
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As for the erratic fuel gauge readings mine does similar things when it has been laid up for six months, or more with this damn weather we have had lately, it rectifies it’s self after a good run out.
Plug has been resealed with grease, fuel gauge has started working again (unrelated).
I have checked for codes and there are none, all the carpets at the back of the seats and under the dash are dry but cold.
Drain holes under the soft-top have been cleaned and checked for water drainage.
I guess the next fine weekend and i’ll have to investigate the instrument cluster for tampering, as in 2013 it had some emission control problems at the MOT and the EML was on, but has passed all other MOT’s with out any problems.
I would check for rust on the crossmember up behind the glovebox in the passenger footwell and check the grommets as mentioned before. Also does it have the original exhaust manifold with cat as a tubular replacement may have heat damaged the alternator or caused O2 related faults in the past.
Ok, I’ll dig out my torch and have a look, as to the exhaust, I have no idea, and do i need to remove the wiper trim to access the grommets or are they somewhere else?
The grommets are at either side below the plastic windscreen cover at the bottom of the windscreen. Take the wipers off, pop off the plastic screw covers at either side, unscrew and remove the two piece cover. You may find the White grommets wth a decomposed foam seal on the back of them, this is the issue with water ingress. You can just apply silicon to these and refix in position. Then reassemble in reverse to taking it all apart. Be careful prising the screw caps off, the lugs are quite brittle and may snap off. Replacements are only a couple of pounds each + P & P if they need replacing. It will also give you an opportunity to clean the paintwork exposed by taking the scuttle panels offÂ
This type of fault can also be caused by a faulty tank level sensor or a bad earth.
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My other car has a very similar fault and on that the fuel gauge runs direct from the tank level sensor, through the gauge to earth and has nothing to do with the ECU. I spent yesterday jury rigging a new type of gauge and it reads exactly the same as the original did. I’m now going to have to look in the fuel tank and possibly fit a new sensor next.
As a follow up, fuel gauge now seems to work OK, what i think happened is the ecu may have got wet.
On the way home from collecting it a had an unavoidable drive through a large puddle/lake and this may have caused it to stop reading the fuel level.
Unusual for a MK3 ecu to get wet unlike MK1 - MK2.5 but any wet ecu is going to cause problems. You will be lucky if this has dried out and resolved itself. Wet ecu pcbs usually short chips, etc out and require replacement.
I was thinking more of if the connector got damp it would short the signal voltage from the sender unit to earth and cause the gauge not to read, rather than water entering the ECU itself.
I think that is far more likely but you did say in an earlier post that you thought the ecu had got wet. The MK3 appears very resilient in this respect so yes unlikely.
Water ingress on the connector plugs should be very obvious with a signature on the ecu pins. If there is sufficient moisture present a short is very possible even if only the plugs affected.
I thought the ECU on a mk3 was on the right of the engine bay, under some of the air intake plumbing. Never heard of any water related problems with it or it’s connectors, but I guess if you drove through “a lake” it may have got wet. If it was that bad, lucky you didn’t get a “ hydro lock” as mentioned in another thread. Scarey stuff.
Are the dash warning lights working correctly now? The closer I look at the picture you posted, with the half eliminated ABS light, the more suspicious I become. I think you’re going to have to take the instrument cluster out and check. Maybe someone has put some tape over the check engine light. Did you purchase from a dealer or was it a private sale?
