Tuning Stilo JTD OverBoost Question/Cure?

[Shadeyman]

Problem:

Remapped 115 JTD 8v is producing more boost than the standard boost(MAP) sensor can handle, its maxing out at 2.5 bar.

I believe this may be the reason the engine management light to comes on and the car to loose power momentarily when accelerating hard in 3rd and 4th gears.

Possible solution:

Would replacing the standard 2.5 bar boost(MAP) sensor with an aftermarket 3.0 bar boost(MAP) sensor cure this?

 

[cledan]

How much is the 3.0 bar boost sensor?
Surely if it doesnt cure it, it wont hurt any way.

 

[sussexa]

i have a spare(not bosch) 3 bar map sensor that i suspect was u/s as my boost was cutting out and it gave random low readings at idle well below 1000mb, you can try it if you like but be aware it will need the scaling mapped properly otherwise will read well below for your car and your ecu will increase boost more.also its a 4 pin plug as its also reading temp, youl need to rig a plug.
if your 2.5 bar map reads 2.5 bar at 4.8v say the 3bar map will read 3 bar at 4.8v so your ecu will increase boost till it gets to 4.8v which will now be 3bar.
whether your turbo will last long trying to supply 30 psi ??
id ask your mapper if he knows how to rescale map sensor?(linearization)
better off dropping remap to max 2450mb or similar to leave margin for now

 

[Shadeyman]

i have a spare(not bosch) 3 bar map sensor that i suspect was u/s as my boost was cutting out and it gave random low readings at idle well below 1000mb, you can try it if you like but be aware it will need the scaling mapped properly otherwise will read well below for your car and your ecu will increase boost more.also its a 4 pin plug as its also reading temp, youl need to rig a plug.
if your 2.5 bar map reads 2.5 bar at 4.8v say the 3bar map will read 3 bar at 4.8v so your ecu will increase boost till it gets to 4.8v which will now be 3bar.
whether your turbo will last long trying to supply 30 psi ??
id ask your mapper if he knows how to rescale map sensor?(linearization)
better off dropping remap to max 2450mb or similar to leave margin for now

Using data recorded by FES(http://www.fiatecuscan.net) I just produced these 2 graphs using Excel, just to make reading the data easier.

The remap is now limited to 2,400mb as you can see from the Desired Boost graph on the left but Actual Boost is still maxing out at 2,500mb, so its over boosting, yeh?

At about 28 seconds on the graphs you can see they both drop drastically when his engine management light comes on. A P0235 (Turbo circuit malfuntion) error code is recorded and he was told its because the boost is out of range of the standard boost(MAP) sensor. Is that true and if not any idea's what could be causing this as I'm 100% sure its not the remap?

 

[rattystilo]

shadey, sounds like you have a similar problem to me. If the eml light comes on and engine fault is displayed just dip the clutch. The car then drives normally.

 

[Shadeyman]

shadey, sounds like you have a similar problem to me. If the eml light comes on and engine fault is displayed just dip the clutch. The car then drives normally.

Its not me, although I have had similar problems before.

He did say if he lifts completely off the throttle the car drives normally again even though the engine management light is still on.

I cleared the EML for him and then took the car for a spin with FES connected. I saved the log and have been looking at it now i'm back home.

 

[rattystilo]

The EML will come back on when he floors it again. mine started coming on more frequently/quicker after i ran an injector cleaner through the engine.

Has your man done this recently.

 

[Shadeyman]

New exhaust, new tyres and a remap but no injection cleaner.

No fault when the remap was first done but it gradually got worse until the EML comes on almost every time he accelerates hard in 3rd and 4th.

 

[sussexa]

is there any overboost map location on edc15? the desired is set to 2400mb but there may be an overboost map somewhere that could be set to 2480mb to allow for overshoot on spool up? overall it looks very controlled compared to desired which seems odd.

 

[Shadeyman]

is there any overboost map location on edc15? the desired is set to 2400mb but there may be an overboost map somewhere that could be set to 2480mb to allow for overshoot on spool up? overall it looks very controlled compared to desired which seems odd.

No "overboost" map, just a boost limiter.