Anyone know what could cause a sudden overboosting on a stock twin turbo, no boost controller or anything. Car felt significantly more powerful than nornal, checked boost fauge, needle is sitting just over the 3rd notch on the boost side. Quick calculation puts that at around 11psi. Any ideas? The power is nice, and I'm not concerned with the boost level itself so much as WHY its doing it.
I love how it's one actual suggestion, 2 borderline congratulations It's definitely not safety boost as it never went into safety boost in the first place and afaik it won't exit safety boost of it's own accord. Car now chirps the wheels into 3rd at 100km/h so I'm not complaining, but obviously something is wrong and I don't want it to one day unlimited boost into oblivion. Will check the vaccuum lines when I get a chance.
The ECU will apparently reset an error code after 50 no error starts, so if something caused the car to go into safety boost like bad fuel or high temps or whatever, after 50 starts without the same problem it would reset, ECU reset can be done by a number of ways a lot easier than starting the car 50 times. Did you notice the gauge go to a higher point ? It seems to be reading about right, considering stock boost is about 9 PSI, as you can see by the gauge design it is not intended to be a precise thing. Going from safety boost to normal means improved timing and fuel as well as a 50% increase in boost from 6-9 PSI. My best guess is this is what has happened, but I can understand your concerns if it not the case, a damaged engine is not a good way to find out. Only way would be to use an accurate gauge to test.
It's definitely not a safety boost thing, it started happening whilst car was running and the gauge has always sat lower previously at the same point since I bought it. Was definitely NOT in safety boost then and has never overheated or detonated or anything else to cause safety boost.
Maybe not but it seems to be around the right mark on the gauge now, if we can assume some sort of basic accuracy, the only way you are going to know if you are over boosting is to work out a way of measuring it, not the only way of resolving the issue, but a quick way of seeing IF there is a problem and saving a lot of time chasing something that may not be even there. Just been looking over system diagrams and descriptions in the manual and I can not see how it could over boost unless there was a problem with the actuator itself. So either something came good and there is no problem or a waste gate actuator problem. Testing actual boost pressure and or waste gate actuators as per page EM-43 of the manual is probably the first 2 places to start. A bit of a sticky situation, one of the pro's might have some better ideas.
What Kakaboy/Karl said in the first reply is probably high on the list, checking the hoses going to the actuators for issues, kinks, splits etc.
The one suggestion is questionable because the hose he's talking about also feeds boost to one of the stock boost solenoids which is the only thing stopping you running at safety boost pressure or wastegate pressure. Without this you're at about 4-5psi. So yes CONGRATULATIONS your Z now runs correctly.
Had it checked out quickly, it's definitely overboosting Haven't had it looked into as to WHY as it's still within safe limits and it's getting written off in a week or 2 anyway so not about to sink too much money into fixing it, just keeping an eye on the boost gauge for any spikes beyond where it's at. I do pizza delivery in it so even if it WAS in safety boost it would have cleared a looooong time ago from all the start/stop I do (assuming the x amount of starts and it clears is true). That and it started doing this suddenly whilst driving, not after an engine start. Edit: Maybe a small leak is causing the actuators to see slightly less boost than it should and therefore acting the same as a different boost jet? (Clutching at straws here, obviously).
Error codes don't clear if the error continues to be. boost jets don't work that way, the stock boost solenoids do work that way tho. A welding tip (boost jet) is just a restriction in the hose and needs the stock boost solenoids to bleed off air for them to work. So unless your boost solenoids were fubar and you have welding tips in the line and now suddenly you have a hole in the hose after it or your stock solenoids are now working then... this is just getting nuts.
No 225 MA-V1's Prior to this I couldn't chirp third at all with them and second was only a chirp. Now second is a reasonable wheelspin and third a chirp.
Your actuators could be stuffed. Happened to me a few years back. They can be tested by simply disconnecting the hoses and blowing air thru them but not sure on the finer points of doing that. Is a big job to replace them with the motor in.
