156 jtd slow acceleration(sometimes) - Alfa Romeo Forum
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156 jtd slow acceleration(sometimes)

Hello,
My 02' 156 1.9jtd has been acting weird these days, I have done about 600km so far and I have been experiencing this problem. This was after I installed a new stainless pipe from intercooler to Engine(my previous one was cracked, tons of boost leak), after installing the new pipe I got to feel much more powerful acceleration, but after driving a few kilometers the car becomes very slow, barely going uphill at second gear, sometimes I have to go into first gear to get it uphill, I don't feel the boost at all and the engine accelerates very slowly, but suddenly it becomes powerful again. It happens randomly, sometimes shutting off the engine and turning it on again can help bring back the power. I have disconnected the EGR it feels slightly better but even without the EGR it keeps loosing acceleration(EGR is clean and functioning properly). Also sometimes when the engine is struggling to accelerate, it suddenly pulls fast and the problem disappears ...
I have tried original good condition hose to make sure it is not the stainless pipe but still the same problem. Fuel filter is new and OEM, not a diesel problem but I am expecting it to be the Turbo, I have tried to move the VNT valve but it barely moves almost stuck, hooked up the car to a diagnostics tool everything is working fine.

Any idea ?

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Investigate the vacuum that operates the vnt. Plenty of posts here.
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Sounds to me like an EGR leak into your inlet manifold - even without turbo the engine has plenty of natural torque and you shouldn't need 1st gear for an uphill.

I would fit a physical blanking plate between your EGR valve and inlet manifold - also check for airleaks around here at the same time - this will generate a P0401 error code after a mile or two but it should prove whether your problem is down to an EGR fault or not. Although as you're running an 8v, the error code will not cause the engine management light to come on, only the 16v and 20v with EDC16 ECU do this.

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(Post Link) post #4 of 6 Old 27-08-16 Thread Starter
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it is definitely not the EGR, as I replaced the whole EGR block with a new OEM one..
I did check the vacuum that operates the VNT and there are no leaks, the weird thing is, sometimes shutting the engine off and turning it back on again can bring back the power..., i didn't experience this before when Ihad a cracked intercooler- intake hose.
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Quote:
Originally Posted by GuHKS View Post
it is definitely not the EGR, as I replaced the whole EGR block with a new OEM one..
I did check the vacuum that operates the VNT and there are no leaks, the weird thing is, sometimes shutting the engine off and turning it back on again can bring back the power..., i didn't experience this before when Ihad a cracked intercooler- intake hose.
Some new EGR valves can be faulty on fitting.
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If the VNT is blocked it will cause you major problems you describe. It should move freely at the actuator. I used mr muscle to clean mine and it worked a treat.
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