no boost after 5000rpm

[rx7aberdeen]

Picked up my rx7 on wednesday drove it for a while and found it was only boosting to 0.4 bar, and after about 5000rpm the doost was dropping off to 0 does anyone have any ideas as to what the problem may be?  I let my mechanic drive it he reckoned it was pushing 200 brake, it should be round the 350 mark!!!

[eatmyrx7dust]

Seems to be a lot of Boost problems at the moment.

Check lrge dia. hoses from turbo to intercooler and 1" hoses from turbo to BOV.

[Steve Burnett]

Is it a silver \'97 RX7 by any chance???

[rx7aberdeen]

certainly is how did you know that

[richrx]

steve\'s from aberdeen too, so i\'d guess he\'s seen it around

welcome to mrc its goos to see another Scottish FD.

As for your problem, 0.4 bar sounds like the first turbo isnt getting full boost, AFAIK if thats the case the second wont come in at all!! As for the cause probably a vac hose leak or solenoid fault. Neither anything serious.



rik

[rx7aberdeen]

THE GARAGE RECKONS THAT THE CAT HAS COLLAPSED MEANING THE PRESSURE WAS BUILDING UP IN THE TURBOS, THE GARAGE THREW IN A NEW CAT AND IT IS HOLDING 0.7 BAR BUT THIS IS LESS THAN IT WAS BEFORE THE CAR WAS DE-TUNED FOR THE SVA! THE CAR HAS AN FC BUT THE GARAGE SAY THERE IS NO ADJUSTMENT ON THE BOOST WITH AN FC SO WHO KNOWS!  THE NEXT THING THEY ARE GOING TO DO IS THROW IN A CDE-CAT AND SEE WHAT THE BOOST GAGUE SHOWS ONLY HAD THE CAR FOR A DAY!!!  OPE THIS IS JUST TEETHING!

[rx7aberdeen]

HERE IS A PIC

[Steve Burnett]

F**k me, you\'ve been busy, I love the spoiler! and I see you got the 19\'s on then. It\'s looking good.
Im just begining to walk just now after my broken ankle so I\'ll be in soon enough to get my back box fitted.

No idea about the problem you are having other than what Rich has said. Check Vac hoses, they can become brittle and split.
If no luck with that you could try giving a guy called Pip a call. He owns a place called WGT. Very good reputation for RX7\'s.
http://www.wgtautodevelopments.co.uk/
Also he is the closest RX7 specialist, if you ever have a problem you will need to go see him if you can\'t get it fixed locally. Angus (also from Aberdeen) is doing just that next week I think. He has a boost problem too.

[bnaellis]

Apparently your car had some broken solenoids that were replaced or repaired I can\'t quite remember. There may be more solenoids that are sticking. A vacuum hose may not have been plugged back on. Also the pipe that runs from the manifold to the blow off valve make sure it\'s not loose on the blow off valve i.e you should not be able turn the pip on the nipple of the blow off valve. My money is on a solenoid though. Also the pfc can have boost adjusted but that will not be the problem. Also make sure the power fc is not still on it\'s detuned map. With engine running Click on etc then select init data then select yes  switch engine off and back on and it will be on it\'s normal map again.

[bobster]

If you are Initialising the PFC don\'t forget to let it do through it\'s self learning process.  

Also you never said the new cat fixed your secondary problem or not.

Do you know what sort of boost the car was running at?

[rxangus]

Welcome! Nice car!!

No doubt will see you round Aberdeen!

My car had similar boost probs when I got it. Turned out to be a knackered cat so not enough back pressure to drive the turbos. Was fine for several months after it was removed although I now have a new boost problem which is 0.7bar to 4500rpm then 0.2 bar after the transition. Off to see Pip the guru in Northwich in 2 weeks (he\'s on hols just now)

Cheers

Angus

red \'96 RB

[Gman]

The part in the pic that is usally black plastic - what is it called as i need one.

[bobster]

The whole thing is an Efini Y-Pipe. It was the replacement on the 99 onwards cars.

It comes in 2 parts. There is a Y-Pipe that comes off of the turbo pack and brings the 2 airflows together. Then the metal Crossover Pipe which bolts down onto the Y-Pipe. You need the whole thing you can\'t just have the metal crossover pipe. AFAIK

I don\'t know if you need to remove the turbo\'s to fit it.

[Gman]

I just need a replacment stock black plastic one.

[Phil Bateman]

Don\'t know if this is any use, found it an article:

No boost above 4500 RPM

This is usually caused by a vacuum line coming off the Charge Control Solenoid. The lines sometimes pop off while under boost. The solenoid in question is positioned under the upper intake plenum. Look in page F10 of the manual, the solenoid is item F. If a vacuum line has come off here, trim off the end and re-attach to the solenoid possibly using sealant and wire ties or wire clamps from motorcycle shops.

Good luck
Phil