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Discussion Starter · #1 ·
Hi everyone.
looking for some help or advice if possible.
I have a pd150 arl Anni mk4 golf. Took it off the road to replace the engine and done a lot of work on it in the process. now my mpg are shocking after getting it back in. I haven’t done a brim to brim reading but know it’s costing me a fortune to run dash showing less that 30mpg on local 20/30 mile runs and lucky to 40 on a 100 mile plus run.

List of some of the things I done when putting replacement engine in.
New turbo
Camshaft inc belt and water pump
Injector seals
Thermostat
Tightened connection on injector loom
Fully serviced inc fuel filter
Replaced boost hoses then pressure checked so no leaks
Had mass air flow not long before engine change.
Replaced tandem pump with second hand as had slight fuel leak

I set my running spot on and torsion value is set at 0.0Ck

Injector readings are different from each other but all in spec

cyl 1 -0.19
Cyl 2 -0.66
Cyl 3 -0.26
Cyl 4 +1.15
Looks like spec is +/-2.8


vcds shows no faults. Performance I would say is down compared to how it originally was. Only thing. Haven’t changed for a while but has been changed in the past is my coolant temp sensor.

I have a friend with a arl and they getting 55mpg on small local runs.
Any help in the right direction would be fantastic.
 

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Discussion Starter · #6 ·
seems to me that the vnt actuator rod is off, meaning it's to short so the ecu dumps in more fuel because the turbo is going on boost way earlier than expected
I’ll double check that but am sure it’s on and turbo kicks in when it should. No boost issues that I know of.
turbos was brand new so should be correctly set up and Ready to fit
 

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erhm yeah it's never spot on unless it's the OEM map with an OEM turbo (and if you replace it with a new one it still needs adjusting) If any of the 2 have been altered than chances are it needs setting correctly. to check if it's boosting as requested use VCDS and log: requested boost vs actual boost. Needles to say you'll have to drive to do that as sitting stationary it won't tell you anything.
 

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As you have changed the camshaft have you checked the torsion value in VCDS? Timing being slightly off can change the fuel consumption a fair amount on these.
Another thing to check is the fuel temperature sensor, located on the return line by the tandem pump.

Edit: you've checked the value. I should pay more attention 🤦
 

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Discussion Starter · #9 ·
Thanks for the reply. I changed the cam ans set it bang on zero. Know o there’s recommended a plus or minus setting on the torsion value. Today I’m gonna to change the coolant temp sensor that the ecu read and the thermostat to make sure it right. When I’ve had it on vcds my gauge reads 90 on the dash but only 75 thought ecu on vcds.
Since looking into this I’ve spoken to the folk that did my custom map on a rolling road so think my mapping could be incorrect.

then to top it off both back calipers we’re sticking sto replaced them yesterday maybe make a little difference if they were dragging but don’t expect to see a 20mpg ish raise to be fair 😂

Thanks to everyone who’s look at this so far.
much appreciated
 
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