Boost issue

Took the black car out today for it's first blast following it's 6mths winter hibernation.

All seemed fine and both turbos come online fine but when I changed the boost controller to it's high setting of 1.2 bar I noticed that despite how hard the acceleration the boost would not go above 1 bar?

I had a quick look and there were no loose hoses anywhere?

All the setting on the controller seen correct....any ideas folks?

IACV VSV is the usual suspect...

Check the hoses to the valve as well..

Hoses seem fine mate.

I take it it's a pull out and replace job or is it a repairable part?

Check IanC's FAQ on the sequential system, has some good info for trouble shooting..

I used it to diagnose my issues, waiting for parts to arrive...

In the meantime, running in TTC..

TTC is a good starting point rule out pressure tank and most of the vac hoses...

Hoses seem fine mate.

 

I take it it's a pull out and replace job or is it a repairable part?

Follow the repair manual for testing, if its a dud then you need to replace it..

http://www.mkivsupra.net/vbb/showthread.php?35926-The-sequential-system

http://www.mkivsupra.net/vbb/showthread.php?35924-Sequential-turbo-hoses

I found this on my car, plus the IACV VSV was a dud..

The was the short hose leading to the IACV.. Very difficult to see the hole.. (Sorry for the grubby fingers)

Appreciate the reply. Thanks mate

Appreciate the reply. Thanks mate

Good luck, these can be a pain to diagnose....

Is the IACV VSV the same on both non VVTi and VVTi cars?

Is the IACV VSV the same on both non VVTi and VVTi cars?

According to Toyodiy, they are the same..

1bar is quick enough for you Daisy.

If both turbos are coming online, it sounds more to do with the boost controller. Could be the solenoid.

According to Toyodiy, they are the same..

1bar is quick enough for you Daisy.

Not quite. Supra as a daily has taken away all sensation of speed.

If both turbos are coming online, it sounds more to do with the boost controller. Could be the solenoid.

I thought this mate. Second turbo definitely comes online but the boost seems restricted

 

Not quite. Supra as a daily has taken away all sensation of speed.

When I had my car I felt similar....replace the word speed with acceleration though

Mine did the same last year after removing the entire turbo vac system and using silicon it never drove and boosted right and struggled hitting 1bar but both turbos were working as they should..

I removed it all and used genuine Toyota ones and it was back to 100%

Not sure if your using silicone but If I were you I would just pull the lot apart and check the hoses you cant see anyway its only a few hours to do.

Have you taken your turbo link pipes off and had look at them as well mate?

All hoses are original factory. Car has only covered 47k miles.

Car boosted fine before it's winter hibernation. Could the link pipes degrade that much over winter?

Next day off is thurs....looks like I may have to pull it apart.

All hoses are original factory. Car has only covered 47k miles.

 

Car boosted fine before it's winter hibernation. Could the link pipes degrade that much over winter?

 

Next day off is thurs....looks like I may have to pull it apart.

I would start with the VSV's first before pulling it apart...

Try TTC first. If it makes 1.2bar then its most likely one of the VSV's or actual air valves (IACV or EGCV).

If it doesnt make 1.2bar then it it could be the link pipes or more likely a vac hose leak, or the pressure tank..

Are you sure your settings are ok on your boost controler as I thought I had problems last year but for some reason the boost duty had reset itself

I'll try TTC prior to pulling it apart.

I flicked through the settings and they looked the same as before. Does anyone have a link to the correct settings so I can check that also?

Thought it would be easier to pull the IACV VSV off the bronze and swap it onto the black car....no change though...still only boosting to 1bar.

Booked the car in to have a leak down test to see if there is a slight boost leak somewhere but failing that it looks like it may be the solenoid for the boost controller?

I'll pull the turbo link pipes to see what kind of restriction they are putting on the airflow but doubt they are the issue tbh

- - - Updated - - -

Thought it would be easier to pull the IACV VSV off the bronze and swap it onto the black car....no change though...still only boosting to 1bar.

Booked the car in to have a leak down test to see if there is a slight boost leak somewhere but failing that it looks like it may be the solenoid for the boost controller?

I'll pull the turbo link pipes to see what kind of restriction they are putting on the airflow but doubt they are the issue tbh

Did you try TTC?

Make sure its booked in for a boost leak check and not a leak down check matey.

For what its worth, a little bit of fairy liquid in some water and a spray bottle could save you some money diagnosing.

Any other boost leak symptoms? rich? Revs drop below 800rpm when coming off the throttle at junctions, etc?

I'm still betting on the solenoid, but definitely worth eliminating a boost leak.

Car has always idled low...sits around 700rpm once warmed up.

It's a smoke test they are using to establish any leaks.

Not tried TTC yet but I thought that was to eliminate the IACV VSV?