Faulty fuel gauge

[Bolla]

I drive a 2007 Navara D40 4x4 D/C 2.5 diesel(128kw). The fuel gauge is not indicating at all after I drove on a badly corrugated dirt road. When switching on the ignition I hear 3 beeps and then start as normal. Is this a fuse,wiring or sensor in the tank problem. ?
Please help.

 

[Old.Tony]

Welcome to the forum!

Not sure what the beeps are, your car is almost identical to mine and mine didn't do that when my fuel gauge showed empty.

My problem was the level sender connector on the top of the tank was not quite connected completely. Reach up and onto the top of the tank and plug it in properly and away it went.

The fuel gauge itself doesn't use the ECU, it's actually fed a voltage to the fuel tank (from the instrument cluster) and the return voltage is fed directly to the needle. If there's a short in the sender unit it should just read 'full'. If there's damage to the wires leading to the fuel tank it might be causing the instrument cluster to have problems.

Check the connection on the top of the tank. Check that the instrument lights are working (with the ignition on) and if there's no joy, careful inspection of the cable runs back to the cabin would be next.

Good luck!

 

[Aussie Frontier]

Is your low fuel light on?The 3 beeps is the low fuel warning I think

 

[Bolla]

Thanks to both. Yes the Empty light is on so that`s the beeps then. I shall check the wiring and plug. Can I test the sender unit in the tank with a multimeter ?What voltage is send to the level sensing unit and what will the return voltage be like for a healthy unit(empty and full)?

I did check the plug on top of the tank and from what I can feel it is Ok.

 

[Old.Tony]

The voltage isn't mentioned in the book but I'd assume zero volts for empty and whatever you're reading on pin 4 of the instrument cluster, the signal returns on pin 9. I would suspect it to use 5V.

 

[Bolla]

The problem was solved. The float came of in the tank and was fixed with two wine bottle corks. Thanks for all the help.
I have another problem and I can see I am not the only one but I want it solved with your help. The Navara started to smoke black soot(unburned diesel?). First time I saw it was after I put in some 500ppm (cheaper) diesel at a filling station at a pump standing to one side and used to fill large trucks. Right after that I towed my 1.3 ton caravan and found that the bakkie(In SA) was without power and smoked excessively. A mechanic rightly diagnosed a vacuum leak on the turbo control and after that the turbo was working again but the smoking remains. Since then the diesel filter was replaced, I blanked the EGR by removing the spring and plunger(this helped with the power as well),the copper pipe is now cool. A friend checked the waistgate operation and soot buildup in the turbo-all OK. The air sensor was cleaned with contact cleaner. Air filter ok. All I can think is that the bad? diesel damaged the injectors? but if water was present it should have been removed by the diesel filter? If not the injectors can it be an ECU program fault? Besides the smoke it is still not at full power according too those who knows these bakkies.
This is a manual and no DPF or Cat.

Please help.

 

[Old.Tony]

I'm not sure the 500ppm diesel (referring to the sulphur content) would have caused that problem, but given the pressures inside the common rail it can't be discounted completely.

The 2007 D40 that I know of uses a variable vane turbo, there's no wastegate. The vacuum lines are used to control the vanes, which adjust the flow of the exhaust gas over the turbine that drives the impeller that creates boost. Wastegate turbos were used on the D22 series, but Nissan have shipped different spec cars to different parts of the world so there's no telling, really, without a visual inspection of the turbocharger. I'm not sure with any certainty that your problem lies in the turbo or the injectors though.

To be thorough, you might consider putting a bottle of a good injector cleaner through. I just ran a bottle of Liqui Moly Injector Cleaner through mine and it did fixed the slight surge in cold idle that I was noticing.

I'd also closely check the EGR, hoses and intercooler. The EGR is a two-way street - it will allow exhaust gas in, and will let boost pressure out. Blocking it by replacing the gasket with a blanking plate is the best way to deal with it, and make sure to use gasket sealer to ensure a good seal (on both sides of the plate). The hosing between the turbocharger and the intake manifold could have leaks - look for what appears to be an oil leak. I've just found my second one - the hose that joins to the intake manifold was leaking, and now the one on my baffles is leaking. I'm about to replace ALL of my intercooler hosing with silicone hose.

I'd leave things like injector replacement for when you've finished trying the less expensive things and haven't solved the problem. Injectors can be tested, but even that's not cheap.

I doubt an ECU program fault, but a fuel mapping fault is possible: just reset the ECU and it will go back to factory settings. It's easy to do - take the negative battery lead off, go press the brake pedal, then put the battery lead back on. Make sure your radio PIN is handy, and write down the trip meter values (if you use those for recording economy) first, because you lose this info.

Water can still get past the filter. It's not a perfect water trap, and some of the guys here have been putting separate water traps in. Water can damage the injectors - it becomes quite a powerful cutter at 30,000psi. Let's hope it's not that.

 

[Bolla]

Thanks Tony. I found something. The vacuum are supposed to move a shaft/plunger with a bellows on the turbo as far as I can see. If I pull a vacuum with my mouth the plunger moves about a centimeter+ but with the hoses connected nothing moves. I have someone revving the motor up to 3000rpm ,up and down and keeping it there but nothing moves. I followed the piping all the way to the right side of the engine. One goes to a dead end and the other to the vacuum pump I suppose. Tested the vacuum there as well with my tongue and nothing that I can feel.1. What should the vacuum be in kpa? I can also pull a vacuum with my mouth towards the pump.2. The vacuum lines goes to a 3 way type of solenoid just behind the left headlight. The line from the pump goes to VAC and the 2nd outlet to the turbo bellows and then the 3rd back across the engine to a blanked off pipe close to the vacuum pump and also split in a Y to join the intake pipe from the airfilter.. What is the purpose of this solenoid? Can you please explain the whole working of this vacuum? Am I suppose to see the plunger on the turbo move with a standing/revving engine? I did connect the line coming from the vacuum pump across the engine directly to the bellows and still no movement while revving the engine. When does the turbo supply maksimum boost, with the vacuum applied/plunger pulled towards the bellows or in the rest position? Can I use a long pipe and connect it to the bellows and then while driving pull a vacuum with my mouth just to see what the effect is or will I damage something?

 

[Old.Tony]

The 'bellows' is the turbocharger actuator, which moves the vanes inside the turbo directing the flow of gas across the turbine itself. That's what makes it a variable vane turbo. At idle, the little arm underneath should be moving in and out about 3mm constantly.

If you can create the vacuum and see the actuator work then at least it's not a complete failure in there - inside, as with most vacuum-operated mechanic devices, is a diaphragm that moves according to the amount of vacuum and a spring that pushes back. Break either spring or diaphragm and it stops. You need to test its operation at specific vacuum levels (see below) to be sure it's good, this might still be your problem. It might have a faulty spring or it might have some gunk in it that's causing it to stick.

If you're not developing ANY vacuum the pump may be faulty (not a common thing, usually it's just hoses). Connect a vacuum hose to the pump and measure the vacuum with a gauge, you should read -94 to -96.1 kPa. Changing the vac pump isn't simple - you have to remove the primary timing chain to get it out. Let's hope it's not that and it's just a hose!

The vacuum line should maintain a fairly constant vacuum and the solenoid adjusts the amount delivered to the turbocharger actuator. The vacuum is also used by the brake booster and the hose there contains a check valve - I suspect this is probably okay, because you haven't reported any fault in braking, just in power & smoke.

At the actuator, you should find that around -53kPa moves the actuator rod about 0.2mm and between -32 and -40kPa moves it about 5mm. This adjust the vanes - you can watch a video on their effect here.

 

[Bolla]

I traced all the vacuum pipes, made sure they are open and for some reason the vacuum is back and strong. But now with engine switched off the bellows rod is extended and pulls in as soon as I start and then sits there. I stopped the engine and it releases and when I start again it does not retract. I can ref it to 4000 rpm and nothing happens . The vacuum is still coming from the pump but the vacuum control solenoid does not put it through to the bellows. Should it?

I can ref to 4000 and the rod just sits there extended, not moving at all. I took the solenoid off and put some solvent through and put back. At first start it again fully retract and sits there and then afterwards(next start) just sits extended. Is the solenoid faulty?Sticky?

How should this operate. At low refs should it retract towards the bellows or not? Someone says it should continiously move but it does not.

What voltage is used for the solenoid control and how is it applied so I can test it? It may be a wiring intermittent problem.

edit: I did check the voltage on the power plug of the solenoid when removed from the solenoid and found 14V while on idle or 3000rpm. Stays on 14V> coil resistence of solenoid is 13 ohm.

 

[Bolla]

I took off the power plug on the solenoid and found 14V DC while it idle or ref to 3000rpm. No change. Solenoid coil resistence is 13 ohm.

 

[Old.Tony]

You've narrowed down some of the issues: you know the vanes are still working and that at some point vacuum is available and working. It's just not working when needed. I would not worry about the actuator, it sounds like it is working too.

It must be the solenoid or its electrical connections, it should be under the alternator.

The solenoid doesn't get a solid voltage, but the multimeter will still read it. At idle you should get 6.3V and at 2000rpm you should see 8.6V on it. It's actually oscillating at around 500Hz, but it's a DC oscillation driven by pin 6 of the ECM.

It should absolutely, definitely move, even at idle. Mine does, has always done, and my car produces boost exactly as it should.

 

[Old.Tony]

14V on the solenoid is too high, has there been any cable damage in the engine bay?

 

[Bolla]

Not sure about the damage,I bought it secondhand but it does not look like it. I retested now and definitely 14.2V on the 2 wires, the same as the battery terminal volts while running. The wire loom goes to a flat box mounted to the side of the engine bay on the right of the engine. It has 2 plugs connected.Is this the ECU? Do you have any diagram that tells where the wires physically goes,which plug and where on the plug? I shall trace the 2 wires from the solenoid and check for any damage. I have a green and brown wire. Brown seems to be negative as I get the voltage from it to earth.

When I take the plug off the solenoid should it not put the vacuum through to the bellows? Or is it the other way around? The more volts the less vacuum to the bellows?

Does both wires go to the ECU or does it pick up earth somewhere else?

Thanks for helping.

 

[Old.Tony]

The earth looks to be separate.

Another user here (DieselTuner) in another thread has said that the solenoids are more common problems than we've read about - probably one of those "doesn't bother me so much" issues like he explained. If you apply battery voltage to the solenoid you should hear it clicking - if not, it's busted so get a new one.

If you're getting battery voltage on the solenoid, it appears that it might be correct - and for once, the manual is in error.

 

[Bolla]

Thanks a lot. That`s good news. Will keep you posted.

 

[Bolla]

I Checked the solenoid, put power on and could not hear it operating so I opened it. It is difficult to figure out how it`s working because it does not have a spring to extend it after the 14V applied pulled in the plunger. Does the ECU switches the polarity on the solenoid to make it work both ways?
Thats the only way the operation can make sense.
The 3 inlets to the solenoid chamber(vac,out,atm) is through to each other. The atmosfere inlet is restricted and always open to the OUT to the bellows. At start the ECU applies 14V to the solenoid and that gives the vacuum access to the OUT. What should happen it seems is that the vacuum should be stronger than the ATM inlet and actuate the bellows. Then at one time to release the bellows the vacuum inlet are plugged with a disc in the solenoid giving the ATM chance to overpower the vacuum and so releases the bellows.

To plug the vacuum inlet the solenoid needs to be driven in the other direction ,is this now the ECU with a reverse voltage?

Am I correct with the operation?

Mine does not work because at start the 14V is applied and the vacuum inlet unplugged and then the vacuum is supposed to operate the bellows but its not and I believe the reason is that my vacuum is to little. I checked the vacuum of another Navara and it feels stronger than mine. I shall try and measure the vacuum tromorrow.

The vacuum is a tie off from the thick pipe from vacuum pump going to the brake booster? Is it possible that the booster may have a leak and that reduces the available vacuum for the turbo? The brakes is quite spongy and soft with a lot of travel.

 

[Old.Tony]

A leaking brake booster is entirely possible (and you didn't mention poor braking performance before).

Let's conduct an easy test. Either clamp the line to the brake booster, or unplug it and block the end (either way, you want to stop any vacuum from reaching the booster). Drive the car (preferably NOT in a busy street!!) - how does the turbo feel? Is the braking any different? You will have your answer very quickly if the turbo starts behaving itself.

I'm glad you didn't go and get new injectors straight away!

 

[Bolla]

Thanks, I shall block it and check. I just hope I did not stuffup the boost solenoid. I first have to get the actuator moving.

At one stage I blocked the atmosfere vent on the solenoid and the actuator start retracting and when fully retracted the engine went silent and then started to shudder and felt like its dying so I released the vent and the actuator extend again and went back to normal Idle. Why does it want to die? This is at Idle? Is something wrong in the turbo?

 

[Old.Tony]

The solenoid might still be okay, let's hope so anyway.

When you close the vents in the turbine completely so that the turbocharger doesn't get any 'spin', the impeller becomes quite an obstacle for air - the engine is probably starving for air and you might even see the hose heading to the intercooler collapsing from vacuum. Fully open won't matter - diesels can run very lean, but you can't starve them of air especially at idle.