A couple of months back I wrote up a quick posted stating a problem I had with my RX7. It has an APEXI ECU and all the usual bolt ons.
I took it to a car meet one night and as soon as I drove away from the meet something was instantly wrong. throughout the rev range on full chat boost would only hold and hold only at 4PSI through both turbos.
I checked pipework as best I could all round the engine bay, nothing snapped, hanging or cracked as far as I could tell. I removed the boost solenoids and hooked up a 12v to find they were both clicking away just fine upon contact.
The car is currently sat feeling sorry for itself as I wont drive it cos its not running to its full potential.
It dawned on me that on the very night it performed like a bag of poo... Just before leaving I helped jump start an old skool V12 jag running a very high end sound system... He was running multiple batteries. I left shortly after I jumped the jag off the rex to find the boost problems occuring...
What could have possibly happened? Have I blown a fuse or shorted or wrecked an electronic component?
Any help would be appreciated as I dont think this is a coincidence.
Thanks
You running on the power fc base map, or has the car been mapped?
Its currently running a base map fella. Ta
Well I would check all the basic things first.
- fuses
- vaccume pipes in rats nest
- Connections in and around primary turbo.
Are you still running a sequential setup? Can I ask if you are getting 4psi across te whole rev range or does boost completely die out during higher rev range?
Primary turbo is the one closest to me if I stand by the front yeah?... Checked that all seemed ok, rats nest from what I can see without lifting the inlet off looks ok. Fuses... By the footwell all ok... Any others I need to check and where? As above... Its 4psi right across the rev range, doesn\'t tail off at all. All sound fine, engine runs sweet, no grinds, bangs or whistles. Yes I\'m still running seq too. Thanks for your help so far. James
Hmm
Ok, So looking at this in a logical way (if that\'s possible with an rx7 lol), s sequential tt setup, the secondary turbo requires the primary turbo to generate 8psi min to activate the actuators for the secondary. The fact your reading 4psi across the whole rpm range suggests to me the secondary turbo is not even coming in. So if we forget about the secondary side of the system altogether for now, it seems there is a boost leak in the system somewhere.
The worst thing about this problem is its a hell of a lot of work searching for what could be a tiny split in a hose, but it\'s the only methodical way of troubleshooting this kind of problem when there\'s no obvious cause.
I don\'t see how jump starting a car could cause a problem, I would think ur ecu is ok since u say the car runs fine aside boost issue. So what I would do is grab a diagram of the twin turbo setup, can find a good one here
http://www.turborx7.com/rx7vacuum.htm
Manually check your hoses, it can be very difficult to just see a split hose, you have to feel them all the way round and make sure they haven\'t split on the underside.
I would say your primary turbo inlet is ok as boost doesn\'t fade at higher rpm, but due to the complexity of the system you have to eliminate things in a logical order and infortunatly the rats nest is must :(
Sorry I can\'t be more help, 90% of boost issues are normally problems with the control system so eliminating this will point you to the turbo unit it\'s self for removal and checking it over checking the waste gate actuator, charge control actuator etc.
While you delve into rats nest I would take the opportunity to replace all the hoses with stronger silicone ones, that way you know you have a fresh system and it also will give better knowledge of how the system is laid out and works. Could fix your problem too ;)
Many thanks mate your advice is much appreciated. Was gonna take it into a sspecialist aat some point (probably would have sat and rotten away bby that time) burnill find a day this week to have a thorough check and I\'ll remove as much as possible to try and see whats ggoing on... do i really need to remove the inlet?
Ta
To have access to the rats nest the inlet has to come off, it\'s a lot of taking parts off your engine but only way it\'s accessible. Have a search on google there\'s many forums that go through step by step how to access this :) good luck bud!
when you take the uim off please tape all of the holes into the engine and there are 2 very thin brittle pipes that run close to the lim DO NOT BREAK THEM.
matt
Mate, I did exactly the same as you have done and for months i tried to find out why my car dropped off boost. Eventually i conceded and drove the 200 mile to wgt to have a look.
He fixed it in 20mins
I was that impressed i got him to fit and map my pfc and a few other bits and set of home VERY happy. It went in, on his dyno at 240hp and left at 326 with nothing more than a decat and a safe map.
Hi guys. Im having issues too. Im bitting the bullet and taking it to wgt aswell. Only a 80mile trip thought. Are they really that good?
They are a specialist mate so see these engines regularly and these same symptoms.
For tuning and mapping my recommendation is powergains