I've had a problem in the past where my boost was sticking. This problem is not a boost issue as I'm always hitting full boost 1.1 bar

Over the last 2 weeks I've been off working so I have been driving the 4 every day.

I have noticed that when I floor the car I'm hitting full boost yet the car feels under powered. At a guess I'm loosing 50 - 100 hp
I can hear the intake and exhaust are not as loud even at high rpm.
After a while of driving its like somone hits a switch and hey presto she goes like a rocket and sounds much louder.
I have noticed that the car pops and bangs from the exhaust a lot when running well. This seems to completely stop when it's underpowered.

This problems seems to come and go while driving. I can't put my foot on what is triggering this problem. It can be fine for a couple of hours.

The only thing that I thought is that it has been very hot here recently.

I'm wondering if I should be measuring inlet temps to see if that has any bearing on this problem. Is there an easy way of doing this?

Thanks.

Check for stored error codes. Some codes don't bring on the engine light.

What fuel do you run and is it a JDM car ?

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If at first you don't suck seed, try drier grain.

Yes it's a jdm car.
The car was mapped on shell 99. I always ran 99 untill shell shut down both garages. I now have to use tesco 100.
I haven't checked for codes recently I'll check today if it stops raining.

Could be the warm weather is pushing it over the edge into detonation and the ECU then pulling timing.

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If at first you don't suck seed, try drier grain.

That's what I was wondering.
Is there an easy way to measure intake temps?

Would a sticky waste gate not do this as it sounds like the same problem I had on mine, where the waste gate was sticking open?

Sticky wastegate would certainly give the symptoms described. If the engine was detonating and the ECU pulling timing then based on my experience you would usually feel the car hesitating but doesn't feel like a massive difference in power.

Checking for a sticky wastgate is fiddly as you really have to take the downpipe/collector off. Owen Developments had to do this on my car after a trackday testing a new hybrid turbo. Fortunately they covered it under warranty and replaced the actuator spindle with an inconel item which is less likely to 'gall' under heat stress on track.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

If the boost is there but power is down, then I would guess it's either over fueling or retarding ingition. (or under fueling, but the engine would be toast by now)
If the turbo is spooling even quicker, then that's also a sign of retarded ignition.

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If at first you don't suck seed, try drier grain.

or is the exhaust possibly blocked, cat buggered if fitted?

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1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
Nitrous Oxide Steroids for Cars!

Im getting the same with mine. Im wondering if, now that I have increased the boost, the CAT is restricting flow.

Im just wondering whether to take it off and put a screwdriver through the element

Well the problem I was experianceing was solved. It was quite easy to be honest. I just messed around with the setting on the boost controller and all of a sudden the car was back to its old self.

In the past I've experianced another issue where the car does not give me the boost that is set on the boost controller. If I change settings say 15psi down to 14 then it's a mission to get my boost to 14psi. What will happen is that the boost will go down to 8 pr 10 psi max. The only way to get it back is ragg the car. I mean highest revs possible in 4th gear. This normally after a couple of attempts gives me the correct boost all the time. As you can imagine this isn't very practicle.

I thought I had a sticky solenoid on my boost controller. I removed the solenoid and gave it a good clean. This was approx 2 months back.
Now this seemed to help but the problem was still there. It just felt like I didn't need to ragg it so hard to get the required boost.

I've not had the issue of recent as I turned the boost and gain down as the wether has been cold. Always hitting boost and the gain was good.

I took the car out this am and I thought I'll turn the boost up a bit as its a nice day. BIG Mistake.
All I can get is 7 or 8 psi its also very slow spooling up to this. I'm probably only getting about 4 psi at 4k rpm. My dirty diesel has more poke.
I tried going back to previous settings etc and still low boost. There are no ecu error codes.

Now I'm wondering is this the boost controller solenoid or waste gate? How is the best way to check this out.

Sounds to me like the wastegate sticking open.
It's quite common on some downpipes for the wastegate to catch on the pipe. If you loosen the nuts holding the downpipe to the turbo you'll probably hear a clang as the wastegate snaps shut. The cure is to fit 2 gaskets to space the downpipe further away or modify the downpipe with a hammer at the point it's sticking. (You should see the mark on the inside of the pipe).

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If at first you don't suck seed, try drier grain.

Thanks Chris,

We will probably have the the charge cooler off tomorrow so I'll have a look then.

I have an Aussie down pipe. Is it common with these?

My waste gate stuck open on mine, but has never done it since its abit strange

What I don't understand is why it only does it when I change boost settings.
Why does it not do it all the time if it's getting stuck?