This is the first turbo car I’ve owned so not entirely confident in dealing with issues that may crop up, but I’ve noticed that my car is making a loud whooshing noise under load and then off throttle the recirculating valve sounds more like a dump valve if you know what I mean; it was all a comparatively silent operation when I first got the car only a few weeks ago.

Also last night coming home from work I noticed a very obvious flatlining in power at around 3k rpm which the car doesn’t recover from. This was at full load and was what made me determine it’s a boost leak, I have since continued to drive but taking it very easy.

I had the car jacked up this morning and inspected all the boost pipes; nothing abvious in terms of leaks using a handheld sprayer with soapy water on them. The solid inter cooler pipes are corroded but not leaking. I unplugged the recirculating valve and drove around and still the same.

Is it worth noting that I could not replicate the noise while the car was jacked up on axle stands? Revving the engine full throttle jacked up it sounds normal, only once I’m out on the road does the noise return

It’s hard to determine exactly where the source of the whooshing is coming from when inside the car driving along, but it does sound like it’s up top in the engine bay and not low down, can the PCV valve have anything to do with this?

Your feedback is appreciated

You need to use MES to create some logs+graphs.

The issues you are describing could be cuased by multiple things:
-boost leak
-bad recirc valve
-bad wastegate solenoid (or split hosess)
-cracked exhaust manifold,
-cracked turbo manifold
-any number of sensors that are not giving correct info (map, temp, boost sensor, throttle position., accelerator position..etc)


As to why you can't get it to make boost standing still: this is how it's tuned. it needs engine RPM, vehicle speed(from ABS sensors) and throttle input... based primarily on those it will calculate required torque output... since the engine is at a standstill torque is ~0 => 0 boost.

The noise yow are hearing as a boost leak is probably the ECU keeping the throttle plate closed... because it determined there is a problem somewhere, i know the noise very well ... heard it when i had a bad wategate solenoid... no error or anything.....it would pull up to 3k rpm, accomanied by the noise you mentioned , then WHOOSHHhhhh (recirc valve opening) and no more power after that.

Ok plenty to look into then, can you recommend a suitable OBD interface for MES?

Is the wastegate solenoid the part inside the turbo that actuator acts on? Or is that the part with the three small hoses coming out of it attached to the air intake?

MES works best with USB elm327 interfaces.(bluetooth/wireless ones don't always work)
Not sure which one to recommend as they are all pretty much OK, and most will probably have the termination resistor on the CAN lines, making it impossible to connect to certain modules in the car.
Have a look on the multiecu page/forum to see some of the more expensive compatible interfaces.
I have always made due with the cheaper ones.


The wastegate solenoid... is the electronic boost controller solenoid, is the bit with 3 small hoses.

Add to the list of possible things wrong:
-wastegate actuator (broken diaphragm)
-wastegate solenoid hoses connected the wrong way around.

I will have a look into the elm327, in the meantime I have been to fiat to price the wastegate solenoid...thought I meant the wastegate actuator and told me I could only get it as part of the whole turbo for £750. I swiftly corrected them and they got the right part up but we’re asking £148, so I left without ordering but with the part number and ordered it online for £36 delivered from Germany.

For the price I don’t mind paying to at least rule the solenoid out, the drive ability is getting worse though, I can barely use it on boost now. As soon as I even try and apply enough gas to spool the turbo the system bleeds it out and there is a rapid chirping noise along with it.

No need to replace it.. it can be tested.
Don't just replace parts, without diagnosing the issue; then complain that you wasted to much money on the Fiat and it's junk.
use a 9v battery, connect it to the 2 contacts while blowing through the line (the one that has pressure on it from the turbo)... when connected it should click and change the direction of air in the from the turbo intake to the wastegate...(or the other way around)

Test the wastegate actuator with a bike pump (tat has a gauge)... see if it holds it's position at a certain pressure and make sure it's not leaking air.

aurick86 said:

No need to replace it.. it can be tested.
Don't just replace parts, without diagnosing the issue; then complain that you wasted to much money on the Fiat and it's junk.
use a 9v battery, connect it to the 2 contacts while blowing through the line (the one that has pressure on it from the turbo)... when connected it should click and change the direction of air in the from the turbo intake to the wastegate...(or the other way around)

Test the wastegate actuator with a bike pump (tat has a gauge)... see if it holds it's position at a certain pressure and make sure it's not leaking air.

Click to expand...

Pretty sure I've found the source of my problem in the PCV unit. Found a thread with a very helpful post by yourself outlining how to test it for proper function and mine failed terribly, on both the turbo and manifold side. Even spending an hour cleaning it has not made it any better.

I think the issue is a vacuum leak on either the manifold or turbo side, the loud whooshing I've been hearing can be put down to the stuck valves on the PCV unit, this is accompanied by the wastegate solenoid cutting in rapidly if I'm hard enough on the gas.

Obviously I should replace the unit but preferrably I'd have a catch can or breather filter in its place instead and blank off the PCV inlets on the air intake and the manifold, is this something I can do?

Malarky191 said:

Pretty sure I've found the source of my problem in the PCV unit.

Obviously I should replace the unit but preferrably I'd have a catch can or breather filter in its place instead and blank off the PCV inlets on the air intake and the manifold, is this something I can do?

Click to expand...

You can block off the hose going from oil separator to intake... it will be fine to run it like that for a while.
You can replace it with a new part.. not that expensive...and a 5 minute job with a 10mm socket.
You can still install the catch can on the boost side of the new oil separator (as i have done).

I don't think that's the only problem.
You are probably hitting boost cut, sign that the wastegate can't control boost.
You can test this with MES... you will be able to graph a run and see the throttle position, desired intake pressure, measured intake pressure, boost pressure, wastegate solenoid duty % ... etc

aurick86 said:

You can block off the hose going from oil separator to intake... it will be fine to run it like that for a while.
You can replace it with a new part.. not that expensive...and a 5 minute job with a 10mm socket.
You can still install the catch can on the boost side of the new oil separator (as i have done).

I don't think that's the only problem.
You are probably hitting boost cut, sign that the wastegate can't control boost.
You can test this with MES... you will be able to graph a run and see the throttle position, desired intake pressure, measured intake pressure, boost pressure, wastegate solenoid duty % ... etc

Click to expand...

I blocked off the separator pipe going to the intake with a pair of mole grips and it made next to no difference, still heard the noise. Boost side of the separator is the pipe going to the pre turbo intake right?

I’ve already changed the recirculation valve and wastegate actuator for new ones a few days ago and that didn’t help, I have a wastegate solenoid on its way and I ordered a new separator last night. Once they come and I fit those two new parts that’s literally everything that could be causing the problem changed for new ones so if neither of these work then it’s a cracked manifold?

Malarky191 said:

that’s literally everything that could be causing the problem changed

Click to expand...

Really?
Haven't you been reading what i've been writing?
GET MES ON IT!!

Make graphs, check values.. check what's going on... as i always say DON'T REPLACE PARTS then complain that it's not working.
Those parts aren't just thrown in to the engine bay.. they have wires, connectors, hoses.. have you checked those?

aurick86 said:

Really?
Haven't you been reading what i've been writing?
GET MES ON IT!!

Make graphs, check values.. check what's going on... as i always say DON'T REPLACE PARTS then complain that it's not working.
Those parts aren't just thrown in to the engine bay.. they have wires, connectors, hoses.. have you checked those?

Click to expand...

I know it’s not the smartest decision but I’ve double checked everything plus all hose connections and replaced the circlips on all of them to be sure. I have the oil seperator off again and have manage to free up the valve on the intake side (can suck, can’t blow), still having problems with the manifold side (can’t blow, valve won’t close when sucked) so is there a vacuum leak here caused by this valve?

On both ends of the oil separator: suck not blow.

Again:that is not the problem!
Post a few pictures of your boost solenoid so i can see where the pressure lines connect to.

Since you already clecked everything....i guess it just can't be fixed. Get another car....it's clear this one is junk.

aurick86 said:

On both ends of the oil separator: suck not blow.

Again:that is not the problem!
Post a few pictures of your boost solenoid so i can see where the pressure lines connect to.

Since you already clecked everything....i guess it just can't be fixed. Get another car....it's clear this one is junk.

Click to expand...

I hope that is sarcasm, or frustration that I’m doing something wrong...

I can’t use MES, wish I could but I have no computer, haven’t got the software nor have I got the interface.

Your post in this thread https://www.fiatforum.com/grande-punto/352905-gp-t-jet-oil-consumption-2.html led me to believe otherwise.

Here’s the connections at the wastegate solenoid:



EDIT: I've now ordered a VAGCOM 409 interface on express delivery for Saturday and managed to get hold of someone for that day to use their laptop and download the free MES software with their permission, is the free MES software adequate for what you want me to do?

I'm starting to regret my eagerness to change parts early on in my attempts to fix this probelm, I'm sure you understand how it's frustrating for me to deal with; having just had the car for a couple of weeks before this happened and you saying get another car as it's junk isn't what I'd like to hear, but I sense your frustation in me not following your instructions and I thank you for your help so far!

What are the parameters you want me to select when plotting out the graphs in MES and what should be the things that I should look out for?

Thanks again for your help

Yep. that's sarcasm+ frustration.
You have to understand that cars have multiple interconnected sensors. You can't just hope that changing some sensors at random will solve the problem.


What i said in that thread:
With the cap and membrane+spring taken off you should be able to :
-blow and suck air through nozzle to the valve cover
-suck air through the nozzle to the intake manifold. Not be able to blow.
-suck air through the nozzle to the pipe before the turbo. Not be able to blow.
So: suck+ not blow on both ends.

Yes, the KL (VagCom 409) interface will work to connect to the Bravo t-jet engine ECU:
go here: https://www.multiecuscan.net/SupportedVehiclesList.aspx
find car + engine and you will see what the different interface are needed for each computer.

Go here:
https://www.multiecuscan.net/
Scroll to supported functions... seems you will be able to see some things.


Again the noise you are hearing is probably the ECU closing the throttle plate and make it act like a whistle.
This is a protection function
The ECU has detected a problem and it's limiting boost to stop the engine blowing up.

First read the errors, take a picture, post here. clear the erros...see what comes back.

The free version of MES will limit you to 4 parameters at a time(not the worst thing in the world because more parameters make the read speed much lower). So you will need to make multiple tests, select the various parameter, then go to the Graph Tab and click on Start..when you are in position to record each test, at the end click Stop then export it and also Make a screenshot of MES.

The ones you need:
test1:
-intake pressure
-boost pressure
-throttle %
-speed from CAN (you need to graph while in 3rd gear, from 1000rpm to 3500rpm, with accelerator pedal fully pressed.

test2:
you need to graph while in 3rd gear, from 1000rpm to 3500rpm, with accelerator pedal fully pressed.
-intake pressure
-wastegate solenoid%
-throttle plate%

test3:
With engine off, key on:
-intake pressure
-boost pressure
-intake air temperature
-engine/coolant temperature

test4:
With engine off, key on:
-accelerator pedal %
-throttle plate %

One more BASIC thing to check: Brake switch (if the brake switch isn't reading correctly it won't let you boost)
Have somebody check if your brake light go on and off when pressing the pedal... if they are constantly on the switch needs resetting.
If the light aren't on the switch might still need resetting.
With MES you will be able to see 2 Brake parameters (the switch has 2 contacts built in....when one closes the other opens); so you can use MES for this as well.

To reset the switch:
-Under the dash... follow the brake pedal... you will find the switch that is acted upon by the pedal arm. This is the switch.
-remove connector
-turn sensor 90 degrees ...should now pop out
-take some pliers, grab the switch tip and pull it out (~1cm)
-with car running press brake pedal
-put sensor back, release brake pedal.. now the switch tip will automatically reset
-plug in connector.

Thanks, I’ll run through those tests and post the graphs here on Saturday if all goes to plan. I’ll have a look at the brakes tomorrow, check a few weeks ago when I got the car with someone looking and they were working fine, will double check that.

It seems I got confused in the wording of your post for the oil seperator, it would appear that mine is working then...at least it’s clean now.

I’ll get back to you on Saturday with those graphs.

Amazon screwed up my delivery yesterday so had to wait till this morning to get this done but here are the graphs of the four tests aurick86

Test 1:



Test 2:



Test 3:



Test 4:



I hope these are good graphs for you and maybe show something that points to my problem?

Clearly overboosting.
Can see the point where the throttle is closing.
Boost is a bit to much almost 1.4 bar.
Has this been remapped?

You need to do a few more tests:
-3rd gear as before, mes
-wastegare solenoid
-intake pressure
-throttle angle
-accelerator pedal possition


Make a few runs where you connect the pressure line from the turbo, directly to the wastegate actuator.
You shouldn't have any more oveboost now, as long as the wastegate is working corretly.

aurick86 said:

Clearly overboosting.
Can see the point where the throttle is closing.
Boost is a bit to much almost 1.4 bar.
Has this been remapped?

You need to do a few more tests:
-3rd gear as before, mes
-wastegare solenoid
-intake pressure
-throttle angle
-accelerator pedal possition


Make a few runs where you connect the pressure line from the turbo, directly to the wastegate actuator.
You shouldn't have any more oveboost now, as long as the wastegate is working corretly.

Click to expand...

To my knowledge it has not been mapped, 1.4 seems high?

I’ll do that test ASAP

Connect the line from boost side directly to the wastegate actuator? Am I bypassing the solenoid doing this?

Exactly, bypass it for testing purpouses.

aurick86 said:

Exactly, bypass it for testing purpouses.

Click to expand...

OK I'll get onto that asap

Here's a new graph for you...

Test 5:



I see what you mean now with the throttle plate being shut off