Engine wont boost properly! Grrrr!

Radeon · Post by **Radeon** » Fri Dec 01, 2006 8:34 am

Hi there,
I have a 1990 liberty (legacy if your in NZ) GT turbo, automatic, AWD. I picked it up real cheap cos the rear crossmember had been stoved in. But anyway after fixing that i noticed the engine has a problem when it boosts.
The engine runs fine and works perfectly well except when u put your foot down and the turbo kicks in. While it boosts u get little hick-ups which give the car a little jolt and acceleration is very poor.
Now heres what iv done:
The check engine light used to be on. I found out this was due to the knock sensor being stuffed so i replaced that. Problem remained. I then decided there were leaks in the inlet manifold as some of the pipes were broken. So i replaced the ENTIRE inlet manifld. problem remains!. I then replaced the spark plugs and fuel filter... yes, problem still there. I replaced the air flow sensor which also did not make it boost properly. I am getting really fed up with it now as i cant think of anything else to do on it!
I found if u clear the computer it will boost properly for about 5 mins but then the problem comes back. If anyone has any thoughts about what could be causing this i would be most grateful as i REALLY want my sub to run like it shud!
Cheers

Oversteer · Post by **Oversteer** » Fri Dec 01, 2006 9:53 am

Fuel pump pooped.

OS

AndrewT · Post by **AndrewT** » Sat Dec 02, 2006 12:48 pm

Also try swapping out the coils.

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Sat Dec 02, 2006 8:47 pm

I vote again for the fuel pump or possibly the fuel reg

Radeon · Post by **Radeon** » Wed Dec 13, 2006 8:38 pm

Well i swapped the fuel pump over with one i knew was working properly and it has seemed to make the problem worse! now i get 100m down the road and the car just dies and it keeps doing it. It doesnt make any sence to me, thought i knew subarus!!

subanator · Post by **subanator** » Wed Dec 13, 2006 11:19 pm

I will suggest AFM, if its a hotwire it may just need a good clean with Contact Cleaner.

tim_81coupe · Post by **tim_81coupe** » Wed Dec 13, 2006 11:38 pm

I think AndrewT's on the money with the coils, especially if you've swapped the fuel pump with a known good one.

Shauno · Post by **Shauno** » Thu Dec 14, 2006 8:14 am

Plugs? Had this prob on my mates car.

AndrewT · Post by **AndrewT** » Thu Dec 14, 2006 11:47 am

Radeon wrote:.........I then replaced the spark plugs....... I replaced the air flow sensor .........

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Subaman · Post by **Subaman** » Thu Dec 14, 2006 9:42 pm

I had a similar problem with my Lib, turned out the fuel reg was stuck open, which means under normal driving conditions the car went fine but under load because the reg was letting too much fuel raturn to the tank the injectors were starved of pressure and the car would cough to a halt, once stopped the fuel pressure returned again and away you went. May be worth a look anyway.