How can I make the turbo boost less/later?

JohnTurbo · Post by **JohnTurbo** » Mon Oct 29, 2007 1:14 pm

Thats right...

First up though, forget the standard length, as that clearly didn't work!...set the actuator so that you pull it out 2mm to fit the wastegate pin when its upright.

If that still overboosts then the solenoid/wiring/ecu must be off somewhere.

The other minute possibility is that someone has played with the ecu to deliberately alter the boost. You've had the car a while though haven't you? So i suppose it can't be that.

Christy · Post by **Christy** » Mon Oct 29, 2007 1:47 pm

Cheers John,

Will adjust the actuator rod to 2mm then.

The turbo has worked in the past 2 1/2 years, when I first got it. The garage changed a sensor (maybe temperature sensor) about a year or so ago to sort out the idle.

Maybe I will just have to bite the bullet and ask the guy at the garage. (they have serviced it for the last 10 years) Trouble is, he told me that the turbo was working when I got it serviced in July (it definitely was not working, as the actuator rod was not connected, and there was no boost). Got a feeling that he doesn't really want to fix it!

Christy · Post by **Christy** » Wed Oct 31, 2007 8:45 pm

Adjusted the actuator rod to 2 mm as suggested... Still can't put my foot to the floor without it throwing the power back at me and overboosting.

Seems that with the throttle going past 3000 rpm it just cuts and starts again.

Am stumped. Next step anyone? ECU check? Solenoid check? wiring check?

JohnTurbo · Post by **JohnTurbo** » Wed Oct 31, 2007 11:46 pm

I'd say most likely now is the solenoid.

Christy · Post by **Christy** » Thu Nov 01, 2007 10:05 am

Ok.

Is there a test for the solenoid? And where can I get a new one/how much would it cost?

Cheers for all your help John

martinholmesuk · Post by **martinholmesuk** » Thu Nov 01, 2007 10:17 am

Ã‚Â£70 volvo

or

Ã‚Â£20 from me.

If it don't fix the problem you can return it (long as you don't snap the ends off lol)

Test it? no idea.

Christy · Post by **Christy** » Fri Nov 02, 2007 11:05 am

Ok,

Have adjusted the actuator rod the other way, (lengthened it), and not much difference. (Slightly better but still the same overboost problem). The car boosts nicely, and then when the needle goes into the red, the car now sounds as if it has shifted down a gear, and the revs jump upfrom 3-4.5 in a split second.

I probably sound dense, but am now wondering exactly what the turbo boost should feel like. Its the thrust forward at about 3000 rpm isn't it?

And not the shift down feeling and the revs shooting up. That is simply overboost isnt it?

Still cannot put my foot to the floor without the ECU cutting in or a kick in the back feeling. Am getting hold of a replacement solenoid at anyrate. Replacing it might help...

Sorry for the dense question. This whole problem is driving me craaazy now!

480_rocket · Post by **480_rocket** » Fri Nov 02, 2007 11:10 am

If you connect the actuator pipe to the pipe coming out of the compressor side of the turbo (so it bypass's the solenoid) you should get about 2-3psi of boost. That would look like a touch into the yellow on the boost gauge. To do that I would carefully take the pipes off the solenoid and join them together with something like a biro tube. If it doesn't overboost then, then you need to look at the solenoid, or wiring or at worst case (unlikely) the EZK ECU.

You could also forget about allowing the ECU to control boost and buy a cheap manual boost controler (about 10-15 quid) and insert that to bring your boost up to any level below 13psi.

You car at the moment isn't giving pressure to the wastegate actuator, so your boost is climbing too much and the ECU shuts down to prevent damage to the engine.

Christy · Post by **Christy** » Fri Nov 02, 2007 11:21 am

Cheers. Beginning to make sense again. Am on the right track with this then.

Which two pipes to connect from the solenoid? Red actuator pipe to... black or white one? I.e looking towards the back of the car pipe leading to left of turbo, or pipe leading to right?

Also, what do I do with the pipes when I add a MBC? is it the same two pipes into the MBC unit, and just block off the otherone with a bolt and jubille clip? Again, need to know which pipes.

Will try the new solenoid anyway I suppose (after testing as you suggested), and then, if still a problem with boost, will get a MBC from ebay.

480_rocket · Post by **480_rocket** » Fri Nov 02, 2007 1:01 pm

Christy wrote: Which two pipes to connect from the solenoid? Red actuator pipe to... black or white one? I.e looking towards the back of the car pipe leading to left of turbo, or pipe leading to right?

I don't know colours, but the one that goes the acutator and the other pipe is the one that comes from the outlet of the turbo. The other pipe that you don't need to touch is the one from the inlet side of the turbo. The inlet side connects to the MAF, the outlet of the turbo runs to the front of the car for the intercooler.

Christy wrote: Also, what do I do with the pipes when I add a MBC? is it the same two pipes into the MBC unit, and just block off the otherone with a bolt and jubille clip? Again, need to know which pipes.

Yes

JohnTurbo · Post by **JohnTurbo** » Fri Nov 02, 2007 1:39 pm

Rocket is quite right. The spring on the wastegate is such that you get 2-3psi of boost connected like that.

I wouldn't recomment the mbc route though. When i've run an MBC i've found it wasn't capable of controlling boost as described above. I ran mine inline with the solenoid.
There are people who did remove the solenoid from the equation, but you can't easily be sure what types of mbs would and wouldn't cope.

I got rediculous boost spiking problems.

Christy · Post by **Christy** » Fri Nov 02, 2007 1:49 pm

Cheers John. Will try that at the weekend. Not too keen on the MBC anyway, as my aim is to simply return the car to its true glory, and not add bits here and there that it shouldn't need.

If there is not choice tho... lol

Christy · Post by **Christy** » Tue Nov 06, 2007 11:52 am

I think that it is all sorted now!

Just need to tweak the length of the actuator rod. No overboost, although the boost gauge needle still goes slightly into the red.

Drivable, and nippy as hell!

A big big big thankyou for everyones help... Couldn't have fixed it without you guys!

Cheers

Christy

Christy · Post by **Christy** » Tue Nov 06, 2007 11:53 am

(Oh yes... fixed it by changing the boost solenoid!!!)

pol · Post by **pol** » Thu Jun 04, 2009 6:17 am

Old thread dig up!

Unfortunately this was not really fixed. I now own this car and spotted a boost problem right away.

The lengthening of the actuator arm had lowered the boost but also caused it to come in at a later point, giving poor acceleration.

I swapped out the wastegate actuator last night and it now has the same overboosting problem.

I need to actually fix the problem and not improve the symptoms.

I'm going to look for holes in the solenoid hoses. Failing that, are there tests I can do on the solenoid wiring?

On a car which is working fine, if you were to unplug the solenoid, would it give the same overboosting? Is the solenoid always used to cut the boost?

I have an mbc but would like to know everything is working properly.

If the ecu isn't receiving the correct pressure, this could cause overboosting? So the hose that feeds the ecu could be damaged even though the gauge is accurate or are they on the same line?

Any ideas welcome. I'm going to investigate further tomorrow.

Thanks,

Pol

pol · Post by **pol** » Fri Jun 05, 2009 9:05 pm

I have the black (turbo side) pipe connected directly to the wastegate actuator and it is boosting a little, sometimes up to 3/4 into the yellow if I slip the clutch in 3rd but it drops and stays at around 1/5th into the yellow.

Can't see any holes in the pipes connected to the solenoid but will check more thoroughly tomorrow.

As the boost gauge seems to be reporting the correct boost, that would rule out a hole in the pipes leading to the ECU + boost gauge wouldn't it? Anyone?

pol

B18FT - LOVER · Post by **B18FT - LOVER** » Sat Jun 06, 2009 6:56 am

Yeah i'd say that it's not a hole in the pipe any where mate else that would cause a vacum leak and prob wont idle correct..

Have u checked the boost solinoid itself ? i have a spare if you want to try it ?

pol · Post by **pol** » Sat Jun 06, 2009 9:46 am

I haven't yet. Apparantly that was already swapped by the previous owner but i'll try it.

Thanks for the offer. I have a spare car so I can test with the other ones solenoid but if it turns out to be faulty then i'll need to find another and you'll probably get a PM!

Thanks,

pol

pol · Post by **pol** » Sat Jun 06, 2009 9:48 am

Is there anyway to test if the solenoid is receiving a signal from the ecu?

Maybe if I connect everything back together but leave the solenoid unplugged, and connect a multimeter up to it somehow?? I guess I need to trace it back to the ecu... Got to dig out some wiring diagrams

pol

B18FT - LOVER · Post by **B18FT - LOVER** » Sat Jun 06, 2009 4:27 pm

I also have spare ecu's if you wanted to try one of them in there bud