Alto Works F5A Turbo Problem?

[gilly]

Hi all, I have a bit of a problem with my alto (CA72 Alto Works RSX F5A Twin Cam 550cc turbo).

It was off the road for about 6-8 months due to a seperate propblem which has been resolved now. When I finally did get it back on the road, I noticed a turbo problem.

It seems as though the turbo just wont kick in. So the car drives normally, and is happy to rev past 6000rpm - provided you ease the throttle in gradually. If you try to put the foot down for instant boost response - it gives you nothing! It sends out a big puff of black smoke from the exhaust, and refuses to accelerate until you take your foot off and ease up the revs slowly.

It seems like the turbo is working though, when you gradually build the revs, because I am pretty certain I can hear it spooling up. Another thing I have noticed is that it is using up 3 times more fuel than normal.

There is a bit of oil in the intercooler piping - although this was there before this problem developed.

A few things that I have been told it could be:
- blown turbo
- vacuum leak
- the stock boost control valve is stuffed?
- spark plugs
- leads
- coil pack

So far I have changed the spark plugs, removed the aftermarket BOV and replaced the piping with stock.

Any ideas? If it is a vacuum leak, where should I be looking?

Cheers guys

[Brayden]

Sounds like the MAP sensor is broken or disconnected.

[gilly]

Sounds like the MAP sensor is broken or disconnected.

Is that connected to the air filter?
What does it look like?

Thanks Brayden.

[Brayden]

MAP sensor is screwed into the inlet manifold, should be orange with a 17/19mm nut on it.

It gives an air pressure reading to the ECU. I accidentally disconnected the one on my F5A turbo van and it did exactly what you described.

[gilly]

Braden, your an absolute legend!

The tube wasnt plugged in at the other end! It wasnt hanging loose though, so I didnt notice it - coz it was down below some other tubes.