Going non-sequential - why disconnect Turbo Control lines?

[Trevrx]

12psi is only about 8% leaner than 10psi, so 10/1 afr would become 10.8/1 at 12psi.

You\'ll be fine, it\'s not like you\'re gonna be ragging it at 8k rpm.

I didn\'t think you could read afr\'s without a wideband sensor, aren\'t your readings just confirming thet you\'re on the rich side of stoich?  The o2 sensor gets ignored by the ECU at WOT when it goes into open loop, and reads TPS, MAP, rpm.

[Martiny]

I didn\'t think you could read afr\'s without a wideband sensor, aren\'t your readings just confirming thet you\'re on the rich side of stoich?  The o2 sensor gets ignored by the ECU at WOT when it goes into open loop, and reads TPS, MAP, rpm.

Yes trev thats correct, I am not tuning the car here, i just wanted to confirm it was rich, before I test. And when I test I may go over 11 or 12. I am not going to drive the car like this or take it up the strip or anything.

I will give it a go tonight then !

yes, I have replaced the ecu before... :-(

[Martiny]

I didn\'t think you could read afr\'s without a wideband sensor, aren\'t your readings just confirming thet you\'re on the rich side of stoich?  The o2 sensor gets ignored by the ECU at WOT when it goes into open loop, and reads TPS, MAP, rpm.

Yes trev thats correct, I am not tuning the car here, i just wanted to confirm it was rich, before I test. And when I test I may go over 11 or 12. I am not going to drive the car like this or take it up the strip or anything. And I definitely wont be going near 8K !

I will give it a go tonight then !

WAV< yes, I have replaced the ecu before... :-(

[Martiny]

Ok, I wired the Turbo control open, wired the Charge Control open, and connected the charge relief valve with the bolw off valve.

Slow build of boost at low revs,  then I saw a massive spike to 14 PSi around 4.5 K, but then it still dropped to 7psi after that.

Someone here suggested the wastegate solenoid may be faulty. I will make sure that I have the pills ( I have been working on this so long that I cant remember what I have/havent checked!).

How can I test the wastegate solenoid?  Are the Pre-control solenoid and the wastegate solenoid interchangeable? I will check the part number and see if they are the same.

I am beggining to get desperate enough to :

1) put a bleeder/restrictor in the wastegate pipe  and just turn up the boost. Ok, someone said that if I do this I will overevving the 2nd Turbo. But the 2nd Turbo works a lot less than the primary, eh? Besides, I have a spare Turbo pack anyway.

2) take it to Rotechniks!

[Martiny]

Just checked the Mazda parts list ,and the 2 solenoids are sold as a unit.

I will have a look tonight for the pill/s and if I have them, then I will try and swap these solenoids over nad see what results I get next..

[Trevrx]

Symptoms are as if WG actuator to solenoid has been capped off.
Can you try simply pulling the vac pipe off from wastegate actuator to solenoid,
that should give you way too much boost on secondry turbo I think, so take it easy.

[Martiny]

Ok, let me see if I understand this correctly.

The Pressure side of the primary turbo has a rubber hose that goes to the Wastegate actuator. This hose (Is supposed to have) has the restrictor in it.

Then there is another hose that goes from the actuator to the wastegate solenoid valve. On the other side of the solenoid valve another hose goes to what looks like a little "air collector box".

From here it vents (to the intake side of the Primary Turbo.)

Now when the solenoid is off, the flow through the solenoid is stopped/blocked.

There is a spring that holds the wastegate closed in this state (Part of the waste gate actuator?).

When boost builds, pressure is applied to the actuator and forces the actuator to move against the spring, thus opening the wastegate. The solenoid switches quickly on and off, and allows some of this pressure to escape, and therefore the wastegate closes again.

Thus, if I remove the pipe that comes from the actuator and allow it to vent, I will only be using the spring to hold the wastegate closed?

If I were to cap this pipe, I would see less boost, because now the pressure is going to actuator?  ( actually, this sounds like exactly what my car is doing ! If the solenoid were to not work at all, wouldnt I see a Secondary boost of about 7 or 8 psi?)  

What is the rating of that spring? Should I see well over 10 Psi with the wastegate actuator vented?

[Warthog]

God I feel for you, I wish I knew the answer to put you out of your torment.

[Martiny]

Lol !!!!!!!!!!

[John Yorke]

Hi Martin

What I dont understand about your problem is that no one else has had this missfortune, real sorry for you mate, most 2nd turbo problems seem to be about solunoids or split pipes, all seems a bit extream what you are going through........... hope you get it sorted sooner rather than later :guinness

[Trevrx]

I think you\'re gonna be sorted soon Martin lol.  Yes the spring is 7psi, that\'s why it clicked with me when you said your boost holds at 7psi.

If you cap it off you will hold at 7psi.  I\'ve never tried it, but I would think if you let it vent, the wastegate wont open and you\'ll be able to see that the secondry turbo boosts fine, taking it cautiously obviously! Just enough throttle to hold 10 psi will do.

When an electronic boost controller is fitted between pr turbo and actuator, the WG to solenoid hose gets capped off permanently.

[Martiny]

John it may still turn out to be the Wastegate solenoid. I have replaced just about every one of the little hoses.

Trev, I feel like I am close to it now, Wastegate solenoid, wiring to the wastegate solenoid, ar a leaking charge relief valve.

I havent checked for the pills, but my replacement turbo pack was new with everything connected, so I am sure the pills are there, and I am pretty sure the wastegate arm is adjusted correctly. Besides, the symptoms never changed after I replaced the turbo pack.

[Martiny]

Ok, so tonight i got under the car, and I disconnected the pressure line at the wastegate actuator.

I could not go for a test drive, as my wife was out and I have a 1 year old at home sleeping.


I have been thinking about it, and I have been reading about guys hitting fuel cut and blowing the rear rotor. So, what I am going to do instead is:

instead of leave the line loose and risk fuel cut, i am going to plug it. But I am going to connect an adjustable air valve (for a fish tank pump!) and then go for a drive and between drives I will open the valve little by little and see what happens.

I am hoping I see 7/8 pSi with the line completely closed, and see if it increases as I open up the valve.

Plus I think I will throw in a whole lot of octane booster first, even though I am on a fresh tank of Optimax.

[Martiny]

Ok I really really thought I would find a problem with the wastegate today.

So I pulled off the pipe between the solenoid and the wastegate actuator, and plugged it - bear in mind i am running it non sequential -

So I go for a drive, 6 PSI, even after 4.5 k - Damn, that means that the wastegate solenoid IS doing something. Then I remove the plug, and another drive. SH1T - it zoomed up to 14 PSi and I let go the throttle immediately !!!   Damn, so the wastegate system is working, what the hell else can be wrong??

Then I had to baby sit my little boy today, so tonight...

I connected everything up to be sequential again. I am now nearly at the end, I cant think what else to try, except...

1) Swap over the blow off valve and the charge relief. If it still holds 10PSI on the primary, then I know the charge relief is good. ( are they the same part number anyone?)

2) Then i will swap the electrical plug, AND the vaccum pipes on the precontrol and the wastegate. This means the wastegate solenoid is the precontrol solenoid, and the precontrol solenoid is now the wastegate solenoid. Except the car wont know the difference, and the ECU wont know the difference.

If the boost pattern is the same, then I know the solenoids are good?

I cant spend more time on the car right now, have some DIY projects looming.

If these 2 tests dont take me any nearer, I will simply put  a bleed valve into the Wastegate to solenoid pipe and start opening it up slowly slowly till I get my 10 Psi boost.

Other than that....... Rotechniks :-((

[Trevrx]

I think it proves the problem is the W/G solenoid (or thereafter) not operating correctly.

The bleed valve idea is ok, but it wont vary the bleeding like the solenoid does, so when you set 10psi at 5k rpm you\'ll over boost from there onwards unless you keep closing the valve more and more.

Can\'t you just replace the solenoid valve and try that?