Had trouble with my 2nd turbo not boosting up, found a vacum pipe off (the one thats zip tied on with the blue arrow pointing), took car out and it\'s now boosting too much. It feels like there is no wastegate control (opening) on 2nd turbo, on part throttle I\'ve had it to 1.15bar (recorded on defi boost gauge) and it feels like it\'d go as far as it could on WOT.
Is it right that the metal pipes in the picture (with the pink arrows) have no vacum pipes between them?, they appear corroded right to their ends which would indicate that they have been like this from the factory.
Everything seems in order with the vacum pipes to the manifold etc and they all seemed to go somewhere.
Has anyone experienced this problem of too much boost before?, I get circa 0.7bar on 1st turbo and it revs along then the 2nd turbo comes in hard all of a sudden (at circa 5krpm) and feels like it has no physical wastegate control. Is it possible that the wastegate actuator is seized in the closed position?. Reason I\'m wondering this is because the original pipe that was off (when I got the car) was giving no 2nd turbo performance at all. I would get 0.7bar at 2k rpm on WOT, then when the 2nd turbo should come in it was dropping to 0.2 bar (presuming just the 1st turbo\'s pressure addition to the twin turbo flow to the redline?). I\'m guessing there was no actuation of the 2nd turbo at all when this pipe was off and therefore the actuator for the 2nd turbo was not being used (as the 2nd turbo wasn\'t working) and has seized up in the time??
I\'m going to try and get under the car and have a feel of the actuator and also remove the actuator arm from the wastegate flapper arm to check there isn\'t stupid amounts of pre tension on the wastegate actuator or something too.
Any help/advice greatly appreciated:)
(http://homepage.ntlworld.com/james.greenfield/vacum24.jpg)
Also it\'s worth noting that the pipe I zip tied on (the one which wasn\'t on when I got the car) was perrished and I had to cut it back and put a plastic straight hose connector in line. It\'s very slightly (like 0.5mm or something) larger internal diameter than the standard rubber hose. Presuming this wouldn\'t effect anything?.
As far as I know there is only 1 wastegate and only one rod that controls it. And sice you get controlled 0.7bar on primary turbo that the wastegate is working fine but something is terribly wrong when 2nd turbo comes online.
Good source of turbo system troubleshooting:
RX7 Turbo System Troubleshooting (http://www.autosportracetech.com/RX-7/rx7stuff.htm)
Good luck and report back if you find the problem.
Hi, thanks for the help. I have looked through that site before, but nothing seems to be said about too much boost when 2nd turbo comes in.
I think that I\'m going to have to remove the intake pipework and check all hose connections to actuators again.
As far as the pipes with the pink arrows are concerned - they look correct. I\'ve attached a picture of my rats nest which has the same two pipes open. I think those two pipes are used on US cars for an extra emissions control system
I forgot to mention, don\'t be put off by the fact that one of my solenoids is missing (it\'s the double throttle solenoid nearest the front of the car) :o
Thanks, looks like everything is in order then. Next step is to remove the intake pipework to turbo\'s and have a look at the actuator pipewrok.
One more thing..
When I recconect the small water hose to the inlet manifold (some sort of throttle body warmer??) do I have to bleed any air out of the water system?
You\'ll probably not need to bleed it, the throttle body is one of the highest points in the cooling system. You might need to add a little coolant to top it up though.
hmm, any ideas on bleeding it then?, if it\'s the highest point it must need doing from there?, trouble is it just going to be sealed when the pipe is on. Also had the water pipe off at the bottom of the throttle body end.
Put the inlet back on and I\'ve now got the airbox out and all the inlet piping off, can\'t see anything strange..
Can\'t find anythin wrong around the turbos or actuators.
Was just wondering whether it\'s worth doing an ECU reset?. Maybe something has self learnt (if they do this) wrong whilst the 2nd turbo hasn\'t been working at all (from when the 1st pipe came off). Or am I really scraping the barrell now? lol
One good thing has come of this though..
When I removed the airbox I found an after market water temp sensor holder in the radiator hose. It has a Defi temp sensor screwed in and the associated wiring and plug. I bought a Defi boost gauge, water temp gauge and controller 2nd hand on ebay last year. The water temp gauge was missing the sensor and would also need the adaptor to fit. What a stroke of luck this car had defi\'s and has the parts I\'m missing allready installed!:rollin
As "fro" said, the 2 pipes are not needed, they are for the EGR valve (US only). Have you checked the 2no short hoses from the turbo housing to the Wastegate & Precontrol Actuators. If one of these is blocked (there are small pills inside them that can clog up) you will get a massive boost level.
Cheers
Jon
(p.s. no need to bleed top hose, it should sort itself out on its own, just dont leave it off like i did...:eek: )
Forgot to mention, try blowing through the (actuator) hoses, or replace them temporarily with empty ones to see if that makes a difference.
Jon
Thanks, sounds like some handy advice!
Will check it out when I can move (managed to put my back out just lifting my head off the pillow at 5 o clock this morning :reallymad )
Oh yes, nearly forgot, if you try empty pipes, the max boost level you will get should be 7psi.
Jon
Right removed both pipes from the actuators and the pills were as they should be (ie not turned in the pipes) :(
I\'ve replaced the pipes with some non restricted hose and reset the ECU, will hopefully take it out the weekend and see what it does but not hopeful after seeing the pills are straight :(
One other thing..
There are 2 hoses to each actuator, the ones I removed and checked go from the inlet compressor housing tee off on the front turbo. Where do the others go?. I tried to remove and check them for restriction but it was near impossible to get to the other ends of them (would have been very hard to get them back on)
The other hoses go to the Wastegate control & Turbo Precontrol solenoids. They are together at the front of the Rats nest. They can be got to by removing the pressure chamber.
Thanks for the help mate :)
Right, put the wastegate pre control hose (with restrictor) back in (as I read it has to be in there to keep transition spike low) and changed the actuator control hose with my own (without restrictor) and put a ball and spring boost controller inline in the same hose. Also reset the ECU (just in case).
Finally taken her out for a spin (in some scary ice, especially scary when I\'ve been driving a 1.8 mercedes for 2 weeks):eek:
It seems like it\'s ok on transition now, I don\'t have any preload on the boost controller (but they run a very tiny bit of preload but literally enough to seat the ball bearing) and boost is coming in at 0.6bar on 1st turbo and you can feel the transition but it\'s only spiking a tiny amount up to 0.7bar!.
I\'m a little bit cautious about being elated (as it\'s freckin dangerous out there) because I haven\'t done any long WOT at high revs runs to make sure it\'s 100% ok. Before it was coming in way too hard though on transition and it\'s not doing that now :) I managed to floor it briefly at 5,800rpm and it didn\'t spike beyond what I said.
If it is ok, it seems I\'ve been a bit over cautious (if the ecu reset hasn\'t done anything) as the last time I drove the car when it was seriously overboosting I would sware blind that a restrictor inline in the wastegate control would not have any effect (as I tried easy throttle runs and it still went mad when transition came in). It just seems the setup these cars run and the way they prespool is so different to anything I\'ve experienced (turbo\'wise) that the restrictor in the wastegate line was enough to make the prespool and 2nd turbo action behave like it did. Normally a restrictor in a single turbo watsegate line would have an overboost effect at WOT but on a slow build of revs it doesn\'t spike like it would on WOT. The setup these cars runs seems to spike however you throttle up because of the complexity. Feel a bit stoopid not trying this before but was blinded by previous experience.
Oh well I\'ve learnt a lot about my car (as I\'ve had it in bits a few times now lol) and I\'m pleased.
Thankyou to everyone who\'s offered help :cheers