Getting 14MPG City Driving with ALH

[thekitdev]

I’ve been trying to track down what’s causing my 2000 VW beetle with the 1.9L ALH engine/ 5 speed manual to absolutely guzzle down diesel. I believe the turbo is slightly overboosting at high rpm’s but I don’t think it would cause it to guzzle fuel that badly. I am not running winter fuel (TX). Everything is pretty much stock other than some slightly larger nozzles and I have the IQ turned up to 6 to compensate. EGR is deleted and the vehicle is not tuned. I have checked timing as well and it is in spec. Getting some unburnt diesel coming from the tailpipe (white smoke) when giving it any RPM as well. Fuel filter and Air filter have both been changed.

Adjusting the IQ hasn’t helped at all and I have resealed the pump and haven’t been able to find diesel leaking from anywhere on the vehicle. It’s hard to comprehend just how it’s burning that much fuel without melting pistons.

 

[Lug_Nut]

White smoke? Maybe it's not "burning" that much fuel. Time to check injector spray pattern and cracking pressure and compression.
A coolant leak into the combustion chamber or exhaust can cause white smoke that smells sweet.

And lock the fuel flap to prevent pilfering.

 

[thekitdev]

White smoke? Maybe it's not "burning" that much fuel. Time to check injector spray pattern and cracking pressure and compression.
A coolant leak into the combustion chamber or exhaust can cause white smoke that smells sweet.

And lock the fuel flap to prevent pilfering.

I plan on replacing the injectors either way, I’ll try and check the spray pattern, compression seems to be good but I’m pretty sure it’s not burning coolant, exhaust doesn’t smell sweet at all & no coolant loss. I do have a locking fuel cap already on top of the locking fuel latch. Not sure what else it could be other than potentially injectors. The previous owner did a lot of things to the car unfortunately (definitely all rigged up too) and I’m trying to undo a lot of those things.

 

[Lightflyer1]

I see you're in Texas. If you're anywhere near the Austin area and happen to need vcds, I have one.

 

[thekitdev]

I see you're in Texas. If you're anywhere near the Austin area and happen to need vcds, I have one.

I’m from Tyler, I already have vcds and don’t really see anything wrong sensor-wise other than an over boost at high rpms

 

[Lightflyer1]

I was just offering just in case. You're in Tyler so probably not going to get here just for that.

 

[thekitdev]

I was just offering just in case. You're in Tyler so probably not going to get here just for that.

Ah okay thanks!

 

[privateTDIjet]

Have you considered a fuel leak?

 

[thekitdev]

Have you considered a fuel leak?

I have considered it but I’m not seeing any fuel underneath on the ground, have put it on a lift and ran it for a good hour and didn’t see any fuel underneath, traced fuel lines back to the tank and nothing

 

[ZippyNH]

If you have RAW wet fuel in the exhaust system smoking white....that's downright crazy
I would expect black smoke for unburnt fuel getting injected at the proper time...
But to have unburnt fuel in the exhaust system, causing white smoke....know model train guys who use diesel/kerosene and an electric element to make smoke on model trains,
If an individual injector was streaming I would expect there to be drivability issues... maybe they are all bad enough to be dripping? Perhaps cheaply made Chinese junk?
Check your engine oil...
Is it "making oil"? Fuel in engine oil will destroy it pretty fast..I would suggest you change the oil ASAP.

 

[thekitdev]

If you have RAW wet fuel in the exhaust system smoking white....that's downright crazy
I would expect black smoke for unburnt fuel getting injected at the proper time...
But to have unburnt fuel in the exhaust system, causing white smoke....know model train guys who use diesel/kerosene and an electric element to make smoke on model trains,
If an individual injector was streaming I would expect there to be drivability issues... maybe they are all bad enough to be dripping? Perhaps cheaply made Chinese junk?

That’s the only thing I could think of, I’m hoping to buy a set of used oem injectors since previous owner supposedly put new injectors in it before selling, I believe those injectors are probably in fact Chinese junk.

 

[thekitdev]

That’s the only thing I could think of, I’m hoping to buy a set of used oem injectors since previous owner supposedly put new injectors in it before selling, I believe those injectors are probably in fact Chinese junk.

However, I have been dailying it and haven’t melted a piston yet (to my knowledge) so I’m not sure to be honest

 

[PradoTDI]

Bad injectors don’t necessarily make a noticeable bad running engine if you’re not used to ALH’s. I had a set of unknown injectors in mine and it smoked a lot and ran a bit rougher, but not horrible. However, EGT’s were through the roof (1300°F or more doing 65mph on flat ground). I swapped them for properly set up Bosio injector nozzles and EGT’s dropped by at least 250°.

Honestly I can’t fathom a Jetta getting 14mpg, even with the bad injectors my 2.5 ton LandCruiser still managed 21-23mpg. I’d get a new set of injectors in there ASAP before any serious damage occurs.

 

[fatmobile]

Air in the fuel will cause white smoke.
Sometimes caused by a fuel line restriction.
Not sure that would cause increased fuel consumption.
A vacuum gauge on the fuel line will show if the pump is pulling hard.