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Discussion Starter · #1 ·
Hi guys i have had my car re-mapped in the last week (R-Tech) and it goes like stink but sometimes it wont boost past 6-7psi (usually 12psi)? I'm currently running the forge SplitR and have been told that could be the prob, has anyone have any experience with this?

also i beleive nick @ R-Tech said it should settle at 1 bar or 14psi but it just boosts upto 12 and holds (most of the time).

any thoughts? Maff / splitR?
 

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Hello,

Could be a few things m8, DV, split vac line, boost leak , weak actuator or MAF.

I dont like using the Forge Split R full stop on a remapped 1.8t, Set up incorrect the can cause many issues, You best option is sell it on and get the Forge 007p fitted to your car with the yellow spring then it will give you a better starting block for your diagnostics and finding whats going on with the boost.

If you can get you car down to us with a 007p fitted I will go over the car and check it all out for you.

Nick
 

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Discussion Starter · #5 ·
UPDATE

I have just changed the Forge splitR for the 007p DV and what a difference its made, no more inconsistent boost its there whenever i plant my foot.

Its still just making 12 psi tho but i'm starting to doubt my boost gauge as it was one of those ebay bargains and has started sticking when going into vac [:cool:]

Next step is chuck a reliable boost gauge on there and if needed pressure test the system i guess...
 

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Discussion Starter · #7 ·
Right so i thought the problem had subsided until i took the car out the day after writing that last post :-(

So here's what happens,

Once the car is warm i open it up and i can get max 12psi reading from the boost gauge and it pulls nicely, but after say 5 mins or so i can plant my foot the boost rises to 8-9 then drops to 5-6 psi (this sucks).

Thought it could be the MAF so i bought a reconditioned bosch unit from eurocarparts & still the same problem :-(

Tested the gauge today with my refco refrigeration gauges, putting nitrogen into it upto 25psi and it read true....

Could this mean my actuator's naffed? it would make some sense in that whenever the turbine housing is getting hot i'm experiencing this boost problem & when it does hold its 12psi it doesnt drop at all until around 6k?

Really need to get to the bottom of this as its driving me up the wall...
 

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Get it VCDS scanned, it may give you something to go on.

My friend has a 1.6T Bora and that was on boost, then off, back on etc., he checked it with VCDS and lambda sensor came up as fault. He changed it and was away again.
 

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Discussion Starter · #9 ·
Good shout on the lambada i'll hook it up tomorrow as i just got my OBD2 cable through [Y]

Hopefully ill get some results....
 

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And I've just read about the same problem afflicting another 1.8T 180 A4 on another forum and another user suggested that too. Is must be 'lambda probe failing' season!
 

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Discussion Starter · #11 ·
Just done a scan only 1 code;

1 Fault Found:
16500 - Engine Coolant Temp. Sensor (G62): Implausible Signal
P0116 - 35-10 - - - Intermittent

This was only replaced around a year ago...?

Could this be the root of my boost issues???
 

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Hello,

There is no MAP sensor on you AGU. The boost is based around the amount of air drawn in from the maf, temps rpm and a ms/rpm load setpoint map\ and N75 duty map. With how the load setpoint and N75 maps are set your car should try and hold 14-15psi with around 2-3psi overboost when you plant your foot down.

Causes for not making the level of load/boost can be sensor related a wrong reading from MAF or ECTS causing the load /boost to offset in the mapping, a weak N75 or wrong N75, actuator or wastegate, cracked turbo, vac or boost leak.

Nick
 

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Discussion Starter · #14 ·
Cheers nick, you've been nothing but help!

Well just incase anyone stumbles across this thread with similar problems i've sorted the boost consistency probs out and this time drove to work and back 110miles.

As i showed in a previous post my car was flagging a code (G62) temp sender, i changed my thermostat at the weekend as my car never made past 60'c when driving along with the sender and WOW it hits 12psi everytime occasionally creepeing to 14psi.

I've even gained 5MPG because my car was running so rich before as the engine temps were so cold!

Sure i've still got lots of diagnosing to do with the boost still being low but it sure is good to be getting somewhere [funky]
 

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Glad youve got it sorted and its excellent reference knowledge thats to yourself and Rtech [Y]
 
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