Going non-sequential - why disconnect Turbo Control lines?

[Martiny]

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.

[Martiny]

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.

[RobbieRX-7]

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

[Warthog]

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

[Martiny]

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   ££££££ !

[Martiny]

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?

[g11ary]

Carl can put it on a roller for you at TDI so not to far.

[g11ary]

No mate, the HOG is on Apexiiiiiiiiiiiiiii...

[Martiny]

Some diagrams of how the twin turbo system works...

http://web.newsguy.com/geesaman/TwinTurbo.PDF

[Trevrx]

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?

[Warthog]

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

[Martiny]

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)

[Warthog]

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.

[maximtaylor]

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\' !!!

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) ?

[Wav]

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