D5 (D5244T to 2005) Injector readings (MPG lower than normal)

[RPhoboS]

I'd genuinely would love to have a smoke machine in the garage, it's such a handy bit of kit to own (esp for my track car!).
I guess for now I might have to call around the local garages to see if any of them might do it (not holding my breath)

I'm just trying to think what else can cause the MPG to go down just whilst it's idling, it's not something I've witnessed before (I can take a vid clip tomorrow).

[5cilinder]

Originally Posted by RPhoboS

I just performed the leak back test, all looks ok, colour is a little off on 2 & 3 due to a little rust from the connectors.
This was just an idle test for 4 mins, first photo is at 1 min, 2nd at 4 mins.

The thing is I can see the MPG info going down when I'm just sitting there idling

So it's possibly not the MAF if the car drives fine, no codes at all, all of the power ?

Just to ensure I understand you correctly, you mean remove the intercooler and pressure test it off of the car ? (if so, I'll need to get someone else to do it as I don't have a kit for it, I have a compressor just not the fittings for something like that)
I have noticed dry oil residue on the front left o the intercooler, as well as oil residue inside the pipe that goes to the throttle body, I've just no idea how long it's been there as I inherited the car from my late step father.

Thanks again

-Mpg is going down... because you use fuel but dont increase the distance.

-You need the maf for egr and power or it will throw a code and go in limp mode, you need air mass measurement for knowing the right fuel amount to stay beneath the smoke tollerance

-For isolating the intercooler or other parts its just using your creativity , i used the underpart of a drinking flask to seal one hose , connected to the intercooler of and the upper part of the drinking flask to the other connected hose of the intercooler and a bicycle pump with pressure meter to connect with the drinking part of the upper flask.
You dont need smoke that way its either leaking or not so its good or replacing.
The 2 weak spots for leaking is the intercooler or the rubber gasket of the silencer close to the crankcase .

-you always will have some oil/water condensation in the parts behind the crankcase breatherits normal when not excessive oilconsumption is occuring , a self modified catchcan can reduce it somewhat.


So if after the injector cleaning the correction values in vida stay high, its time for a compression test in the glowplug holes.... but be carefull not to break them put some wd40 in days before and take them out with an warm engine , and torque them back lightly

[Clan]

Originally Posted by RPhoboS

I just performed the leak back test, all looks ok, colour is a little off on 2 & 3 due to a little rust from the connectors.
This was just an idle test for 4 mins, first photo is at 1 min, 2nd at 4 mins.

The thing is I can see the MPG info going down when I'm just sitting there idling

So it's possibly not the MAF if the car drives fine, no codes at all, all of the power ?

Just to ensure I understand you correctly, you mean remove the intercooler and pressure test it off of the car ? (if so, I'll need to get someone else to do it as I don't have a kit for it, I have a compressor just not the fittings for something like that)
I have noticed dry oil residue on the front left o the intercooler, as well as oil residue inside the pipe that goes to the throttle body, I've just no idea how long it's been there as I inherited the car from my late step father.

Thanks again

That is because you recently reset the average MPG reading. the longer you leave it the more stable it becomes, it is always accurate at any moment in time however.

[RPhoboS]

Much appreciated guys, very late last night I opted to buy a smoke machine in the end
Aside from making it easier on this car to identify any issues, I've been desperate to check some possible problems on the track car, especially a potential header leak. So I think it's actually worth having in the garage.

I presume that I can hook it up just past the maf sensor? (Or is there a better option elsewhere)
I've only just replaced the glow plugs, so in theory they should be smooth to remove them if I need to check the compression.

I'll try to look at some data logging options in Vida to see if there's anything else in that that might help.

[RPhoboS]

Right o, so I've uploaded a few screen shots of some live data, this was taken before I cleaned out the EGR valve area/intake pipe.
And yesterday I replaced the swirl flaps, and cleaned out more gunk as best as I could (yes including injector seats/new washers etc).
Cy 5 was the only one that was a little crusty, they all came out easily thankfully.
I'll go for a 30 min or so drive later today to see how it goes.

My smoke machine is excellent, it does pressure as well as smoke, so testing with it is brilliant for finding even the smallest of leaks.
So the Volvo, has none !

Where as my track car seems to have a pin hole leak in the upper intake manifold!

Thanks again for the heads up about the smoke machine, it's super useful especially after taking the intake pipes off and ensuring everything is seated and tightened up correctly.

So now I'm wondering what might be left, unless there is something clearly wrong with the MAF from the graph I uploaded ?

[5cilinder]

I told you what was left.
If your fuel corrections didnt improve after the injectioncleaner , then you need to do a compression test.
Do that first, a bad compression on some cylinders will affect fuelconsumption

Concerning the MAF the ecu also uses the lamda o2 sensor to check what the rest oxygen is in the exhaust to somewhat double check the airflow..
If there is a leak or a bad MAF the obd2 code air mass performance /out of range or something is thrown with limpmode
Also diesels burns under airexcess (even with egr) so air fuel ratios arent as precise needed as in petrol engines .
You can calibrate the MAF in Vida and check resistance values .
But if its broke you already would have some codes and limping

But your priority is now checking compression..... if thats bad on some cylinders i can give some pointers of how to check if its pistonrings , valve stems valves etc

[RPhoboS]

Right back with a bit of resolve for this.

I didn't as of yet check the compression as it didn't seem logical to me but please do say if I'm utterly wrong here. I'd imagine if the compression was down, power would be down. I've had compression issues before on my track car due to rings, so I've experienced it somewhat and yes, power was getting worse with all of the other tell tail signs.

Anyway so the short version is this.
I was sent a new TDI tuning box, fuel economy issue solved.
(actually slightly better as I'd done the other work)

If a problem occurs again (still has 4 years warranty), I keep a couple of appropriate tools in the car to whip off the bumper and unhook it. I've also made a dopey bit of protective covering as rain water goes exactly where the box wants to sit.

Anyway, the car has a multitude of other annoyances now, and I've lost the will to fix anything else on it at this point

[5cilinder]

You had issues with fuel corrections didnt you?
No excessive leakback, injection cleaner
Still excessive fuel corrections , if a compression is slightly less then there is less energy extracted fur usefull work, and then the fuel corrections kick in to keep the idle smooth,
Also your fuelconsumption wasnt optimal ?

Its the most logical thing to check after the other checks that are ok (its also reconmended in vida btw) look it up