00544 - overboosting code

[Bradderz_1988]

Just on my way home from work and in 4th gear pretty low down the rev range went to throttle it (say 75% throttle) and it sort of boosted then just jolted harsh as if fuel pump died for a second, put the code reader on and its giving me this 00544.

Any pointers would be appreciated, just ****** typical to do it now as I've literally just paid allgermanparts £320 for the rear refresh kit about an hour before it happened Sods law i guess lol

 

[aragorn]

Well if it was just a one off, then i guess its probably just a boost spike from the bigger-than-stock turbo, fighting with the stock boost PID.

If its doing it all the time, it could be a split hose to the actuator, duff N75, bad MAF or probably quite a few other random bits!

 

[Bradderz_1988]

All the time and seems to boost alot quicker with less throttle i have a spare modded n75 i can try, maf was replaced maybe 2 years ago off byzan will vagcom help us out here ??

 

[aragorn]

have you got a boost guage?

Sounds like it has lost all boost control?

 

[Bradderz_1988]

Yeah boost gauge is on and it feels alot quicker and seems to make boost alot quicker at less than half throttle load it can make 10psi if i go anywhere more than say 75% throttle load it feels a little shuddery and then around 12/14psi+ up it jolts really bad as the ECU just cuts the fuel. Im going to try disconnecting the N75 valve see how it feels as i now the wastegate is set to 7psi or there abouts. Will try get vagcom on tomorrow and post some logs up. What would i need to be looking at other than the MAF & N75 ??

 

[aragorn]

Its gonna be either the N75 or the actuator itself. A underreading MAF might also cause it but unplugging the N75 would be a fair starting point.

Our avant has a 12psi actuator and runs with the N75 disconnected, and it gets up to 10psi with very little load, like you say half throttle easily sees full boost thru the midrange. Given you have a 7psi actuator and its overshooting that by a long way at mid throttle i'd say either the N75 has failed in some odd way, or the pipework has a split or similar.


Essentially your wastegates staying closed and not opening, you just need to figure out why.

 

[Bradderz_1988]

Well disconnected the N75 and still the same well didnt get it to jolt but got it upto 12psi with it disconnected. So presumably the wastegates not opening like you said aragorn looks like another quality frankenturbo part failure.

Can the N75 be stuck bleeding boost pressure into the tip or is this highly unlikely ?? It was replaced just before i fitted the FT for a genuine one when the penny valve was shot and was a little less knowledgeable about my car lol

Is it worth piping the N75 out and trying it ??

 

[aragorn]

Its certainly worth piping direct and seeing what happens.

It could be a failed actuator (you can test this with an airline i guess?) or it could equally be a siezed wastegate

 

[Bradderz_1988]

Looks like a job for tomorrow/monday then, take it i will need to pipe the 2 N75 valve pipes together incase its the N75 and its leaving the connection open so it doesnt draw air in and run like crap.

No anyone selling a GT28RS cheap lol

What would you say to a Forge adjustable actuator if it does turn out that its goosed ??

 

[aragorn]

Get a brand new piece of hose, and connect it between the actuator and the banjo on the turbo compressor housing.

Dont think the forge one is that reliable. Think BBT does a 12psi actuator upgrade like mine.

 

[Bradderz_1988]

Yeah i have the pipe still that came with the turbo which 'luckilly' is in the garage and not at work. Im just thinking if the n75 is stuck open would i be best off looping the pipes together as not to draw air in and it run lean.

Yeah i did enquire but he supplys them with out the bracket so some modification would be needed on my bracket, i only just threw my standard one in the bin not so long back aswell i could of used that bracket and mocked one up before stripping it all down.

My faith in FT has gone down hill very fast as the manifold has cracked again now this certainly wont be recommending them as a reasonably priced kit again.

 

[aragorn]

dont splice anything, rule out all the factory pipe work by simply joining the banjo directly to the actuator, like they do on the cheap chinese turbos

If you want, you can stick a bolt in the end of the original hoses to rule out it drawing in any air.

 

[Bradderz_1988]

Well i think my actuator is good, had a quick look today and noticed the n75 to wastegate pipe chaffing on the cylinder head. Fingers crossed its just the pipe and not the actuator it smells rich and is popping more than normal so im guessing its just the pipe.

I may just temporarily pipe from the turbo to wastegate and run actuator pressure for now till i fit the F21 then maybe relocate the N75 as i will no doubt have to when i go with the GT setup.