I am determined to find my boost problem ( low boost on second turbo). As part of my diagnostics I want to run the car non-sequential. According to Ashraf Farrag in the US and some other sites,
*Pull off the clips to the turbo control and pre control arms.
*Move Turbo control valve to the front of the car and wire it there.
*Move precontrol to the rear of the car and wire it there.
*disconnect lines going to charge control actuator and cap them.
*safety wire the charge control actuator open.
*tee charge relief valve vacuum line into blow off valve vaccum line, and plug the now loose line.
* disconnect the lines going to the Turbo Control Actuator and cap them off
*Disconnect the lines to the PRecontrol actuator and cap them off
This is the part I dont understand "* disconnect the lines going to the Turbo Control Actuator and cap them off
*Disconnect the lines to the PRecontrol actuator and cap them off "
I dont see the reason for capping off these lines since we already disconnect the actuators by removing the e clips. Anyone?????
I am hoping that if I get my 10+ PSI over 4k rpm, it will prove that:
I dont have a leaking pipe.
Wastgate good.
Blow off valve and charge relief valve hold pressure.
Turbos good.
If this test is good then I am going to put a boost gauge on the lines that actuate charge relief, and Trbo COntrol and see what I find.
Well, I did the nonsequential conversion, except, I left the vacuum and pressure lines connected to the Turbo Control. I also didnt bother removing the e clip from the precontrol arm, ( because my problem is AFTER transition).
I went for a drive and the boost builds really slowly until 4.5k, then the car just flew! In fact I came out of the throttle because the boost built so quickly I didnt want it to detonate. I reckon i pushed a good 12 or even 13 PSi. I have the standard ECu and i have no cat and a Racing Beat back box, so I was concerned I would hit fuel cut, or worse, detonation.
So I went back home and I connected up everything again. I "Teed" into the charge control actuator and went for a test drive.
Strong 10 PSi, good 8Psi on transition, then WHam! A 13Psi spike, but then it falls down to 8 PSi till the red line.
The charge control shows vacuum till 4.5, then switches to pressure, then if you let the revs drop back doen to 3K, it switches back to vacuum.
Ok, so the charge Control and its solenoid checks good. This also means my vacuum tank and check valve for vacuum are good.
Then I Teed into the Charge relief valve, and it checked good, too.
Then I teed into the Vacuum side of the Turbo Control. 0 till 4.5 k, then a good nearly 20 mm after 4.5. Then drop the revs to 3K and back to zero.
Then I teed into the pressure side of the Turbo Control. Nothing till 4.5 then a good 13/14PSI and it holds all the time until the revs drop below 3 k again.
So now I am really stuck. I have previously:
Replaced vacuum hoses.
Replaced 4 main check valves.
Replaced complete Turbo pack with NEW Mazda pack.
My next idea is to buy a std back box, put that on, and then do the non-sequential test again. I didnt keep my foot in it long enough to see if it will hold 10+ Psi or if it would have spiked and fallen back down to 8PSi again.
Question - When does fuel cut happen? I saw spikes of over 13 PSI during my testing and never experienced fuel cut.
ok..you have done all you can with it..next step in my opinion would be to get it onto a rolling road,someone like pip@wgt. I know its gonna cost a few quid(aint got a clue how much) but you have done the hose job,replaced check valves..maybe your ecu needs looking at just to see how its going all through the rev range
That seems a hell of a trip, why not just go and see Geff at RE:WORX and put it on his r/r and let Max do his thing. I have run up to 22 psi through stock twins and no fuel cut. I have 13oo sec inj and 044 fuel pump and water injection though. :yes
mmm I am beginning to agree that I need someone to at least check my a/f ratio.
Warthog, I did take it to Geff who diagnosed a bad secondary Turbo, and thats why I replaced the Turbo pack. But the symptom is exactly the same as before. So I am afraid I wont be going back there in a hurry.
Robbie I forgot to mention that I have swapped out the ecu before and it didnt help.
Pip is very far from me. I think I will either:
1) See if Carl has a wideband to put on it just to check the fuelling and determine whats a safe boost level. Then I could try the non-sequential test again.
2)Cough up and go to Rotechniks ££££££ !
By the way chaps, I found this table very handy, it tells us when the ECU decieds to switch solenoids on or off.
http://www.autosportracetech.com/RX-7/TurbochargerOverview.htm
Warthog, is that on the Standard ecu?
Carl can put it on a roller for you at TDI so not to far.
No mate, the HOG is on Apexiiiiiiiiiiiiiii...
Some diagrams of how the twin turbo system works...
http://web.newsguy.com/geesaman/TwinTurbo.PDF
Ah so that\'s your boost problem...
Doesn\'t the wastegate solenoid valve control boost by bleeding off air at a set rate, to give more boost at low rpms and prevent the wastegate control actuator opening the wastegate too much at 7psi and being unable to build boost. It would have to bleed off less at higher rpms to allow the wastegate to open more and hold at 10psi. I think it\'s controlled at a set rate by the ECU at certain rpms.
Could it be faulty and bleeding too little after the transition at high rpm.
How about pulling the vac pipe from wastegate actuator to solenoid valve, then taking it easy in 2nd or 3rd upto 5k rpm, then enough throttle to hold at 10 or 11 psi.
If it held the prob might be faulty solenoid valve?
Sorry Martiny missed your question.
Gary is spot on as usual, I\'m on a PFC.
The important mods that have made me the power are--1300 sec inj, 044 fuel pump, greddy boost controler, Pwr charge cooler ( big one ), water injection, uprated Pwr rad, same large electric water pumps on both engine and charge cooler. The rebuilt Re:worx engine is standard porting although the runners have been polished.
I\'m slightly mad when it comes to pushing things to the edge of the envelope, I would run more than the 1.2 bar I run at the moment( have been up to 1.5 bar ) but I would really need to change to 1600 sec inj to get the fuel in.
Anyway HTH all the best and I hope you solve the problem soon as I do know what it is like to have to go through every link in the chain to find the problem. :wave
TrevRX
We agree that it might be the wastegate solenoid. Its fine on Primary, and the primary\'s "wastegate" is the Precontrol.
I have now put a voltmeter on the O2 sensor, and I have been for a short drive. I will drive it to work and back and see what results I get.
My voltage readings when the Primary hits 10PSi are beteween 0.98 v and 0.90. And its the same when the Secondary hits 7 or 8 PSI. So thats pretty rich, eh?
So I think I am sort of safe to see if it holds boost above 10 PSI? I am going to try the non-sequential test again. Well, in fact what I will try is just wire the Turbo control fully open so I am getting the exhaust going to both Turbos. I want to see if it will hold 10+PSI in this mode. If it does, then I might start suspecting the turbo control actuator. Although I have tested it manually with my "home made" mityvac, it might not be strong enough to hold open, or its actuator rod might need adjusting.
If it cant hold 10 PSI during the non-sequential test, the next test I will do is a leak test. I will make some plugs for the turbo intakes, then pump up the system and see if I have leak.
Another thing I could do is swap the Charge relief valve and the blow-off valve and see the results. This will telll me that the charge relief valve is good/bad.
Question, (maybe for Warthog!)
If I am really rich at 10PSI on the Primary, is it likely to stay rich at 10PSI and above on the Secondary ( this obviously means higher rpm) ?
I am paranoid about detonation, but I really need to test in non-sequential mode again. But my results from the O2 voltage show a ver rich mixture, I think. So I should be OK if it goes to, say 11 or 12? ( Obviously not going to blame anyone here if it does go pop, just your opinion please)
Mate your knowledge is on another planet to mine. I would advise you direct that question to Max on here or by pm, he spends so much time now tuning on the r/r with his laptop/maps of FD runs, I\'m sure he could help answer some of your Q\'s. HTH.
Maybe, maybe not - sorry!
The only way to tell is to try. Many FD\'s have stock pumps which are past their best, and very often this only shows up when you ask the pump to work hard, such as high load and revs.
The best I can guess is to say if the fuel system is in A1 nick, then somewhere between \'maybe\' and \'probably\' !!!
Quote from: MartinyIf I am really rich at 10PSI on the Primary, is it likely to stay rich at 10PSI and above on the Secondary ( this obviously means higher rpm) ?
The point i\'d look out for when looking at possible lean peaks would be around peak engine torque at approx. 5200-5400rpm.
To be honest there may be nothing wrong with the hardware on your engine, it could just be an ecu that has gone bad. I know this as i have seen a few. Have you tried swapping the ecu over to a known good one?, maybe try attaching an apexi on base map to see if that sorts out the issue. Sorry if you have already tried this.
Good luck, you will definitely get there in the end.
Paul :)
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.
Quote from: TrevrxI 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... :-(
Quote from: TrevrxI 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... :-(
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!
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..
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.
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?
God I feel for you, I wish I knew the answer to put you out of your torment.
Lol !!!!!!!!!!
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
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.
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.
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.
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 :-((
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?
Yes I am going to swap it over with the PRecontrol and see what happens.