Julio77270

Hi everybody,

Firstly, I'm very glad to see a forum like this one because we haven't it in France.

I explain you my engine problem...

The car perfectly starts and runs well at low and mid revs (full boost).
But after 5000 rpm, the power slows down at full pedal gas position. It only occurs after 5000 rpm, never before.
It's sound like a problem with throttle position but I'm not sure.


I don't see any codes on my diag tool (it's not a professional diag).

My setup is : 181mm pulley, DCAI, NW tweaked manifold, 255 walbro fuel pump, Oil catch can, tune.

Changed parts: IC pump, speedriven IC, wire and sparks.

Thanks for your help!


Nb : I'm sorry if my english is bad because I'm french

Julio77270

I have reseted the ECU (throttle body also) and the power has come back.

After several runs, I have had a P0108.
I have already changed my MAP sensor.

I notice my IAT are too high around 190/200°F @ high revs. I'm gonna to install a supercooler.

Do you have any idea of this P0108 ?

Maybe a pressure too high due to a high temperature (physic formulation is P*V=m*R*T, if the temperature increases so the pressure also in the same physical condition...).

Could it be due to a high air intake temperature ?
Could it be due to the tune ?

Thanks

Speedriven1

Make sure the system is bleed correctly.

Julio77270

I've bled it several times and every time I notice presence of bubbles.
My IAT are too high.

I need to have a supercooler.

Speedriven1

There shouldn't be any bubbles

Julio77270

Is it normal to do it several times ?
There is less and less bubbles...

Speedriven1

I good bleeding process takes around 20 min

Julio77270

My IAT are now good (around 160f) but I still have P0108...(as intermittent with no light).

I have changed the sensor by a Bosch one (0261 230 191). Is the Fuji sensor is better?

Who could help me?

Thanks

Speedriven1

Make sure that you don't have any vacuum leaks

Julio77270

I check the vacuum line and I don't notice leak.

Normally, with a 181mm pulley, we don't reach the boost limit ?
I'm a quite lost...

Speedriven1

You can vacuum leaks not just in the lines but also with gaskets for the supercharger

Julio77270

Excatly, I have changed all gaskets excepted two of them:

- Gasket between the inlet supercharger and the Y
- Gasket between Throttle body to the Y

1) Is it possible to change it without taking off the supercharger from the engine ? (I'm speaking about the gasket in the inlet supercharger)
2) Do you think that a bad ignition coil cover could be the cause ? (misfire not visible from the scan tool...?)

Thanks,
Jules

Speedriven1

Misfire(coil) is less likely. Either the sensor is on its way out or you have leak. You need to remove the charger for that gasket. Just boost test it and make sure you don't have leaks

Julio77270

The sensor is a new one but I have ordered à new one to make sure.

I'm gonna test it to make sure I don't have leak.
Is there no risk to put 2.0bar of air pressure throught the throttle body?

Speedriven1

Whatever the car is boosting

Julio77270

I have checked with air boost and I have no leak.
I'm quite sure that is not the sensor because I have changed it twice.

To resume :
-P0108 hidden
-Car is fun to drive but after 5200rpm, I feel sudently less torque.

I have installed tweaked manifolds after the tune (Rob from NW said me that is no necessary). Maybe I need to update the tune? Or my AFR?

Julio77270

Is a bad cat could be the cause?
Or the CPS?

Julio77270

I think I have finding my problem!!!
I have my exhaust manifold which is cracked (passenger side). I can smell exhaust gas in the engine bay at IDLE.

I have order a new one but I wonder if is it possible to install it without removing the engine?
Someone is able to answer me?

Thanks,
Julio

HarisC

Hello,

Did you solve your problem?