sudden engine power loss

[steevo]

hi everybody my name is steve and ive just joined the club last week.Im still a bit unsure how to use this website properly as im quite new to the internet.
Can anybody help me with a problem i have with my 98 model type r.The car has been running trouble free until today when i noticed that it was reluctant to produce any more than a couple of pounds of boost from the small turbo.the secondary turbo was boosting correctly.I parked the car up for about an hour then went back out in it.The car then drove really hesitantly and i was only able to drive it on part throttle as soon as i opened the throttle it would die as if i was applying the brake.even revving it up out of gear it seemed very lethargic.
If anybodys got any idea what could be the problem id be really grateful,cheers.

[Robertio]

Welcome Steve

I\'m sure someone will be able to give you some hints as to what could be up.  Do you have a boost gauge?  if so is it holding a few psi then dropping off? or holding the same boost all through the first turbo?
Any mods on the car?

[steevo]

thanks for replying robertio.My car is completely standard apart from boost gauge fitted.Went back out in it couple of hours ago and it ran a lot better than earlier allowing me to use full throttle without missing and hesitating.Thing is it was only boosting 3 psi on first turbo(11 psi big one).Then i let it cool down completely went out in it again and it ran much better boosting 12-5-11.
  It seems as though ive got an intermitant  problem with boost control on small turbo when it gets hot which remidies itself when cooled down.anyone got any ideas !  CHEERS !

[Fish]

Steve, when the engine bay is hot, check the bottom big hose coming out of the air box.

It has been known to collapse when hot.

Dan

[steevo]

Intake pipe seems to be ok with no restriction to airflow when hot.

I,m going to try and have a look at actuators,solenoids and sensors to see if theres anything obvious.

Anyone got any tech info on how these work together.

          CHEERS ! !

[JayDee]

When you next drive it, put your foot down from low revs, let the turbo spool, lift off the throttle, then reapply the thottle and see if the boost is higher.
Let me know how it goes.
Did you squeeze the bottom hose when it is hot to see if it is soft?
Jason

[steevo]

Bottom hose definately seems good when things heat up guys

Just taken it out again from cold and it ran superbly for about 10 mins. After about half a dozen full boost spurts dropping a gear and flooring it causing sudden big increases in boost the small turbo refused to boost more than 3psi.

I tried spooling the turbo,lifting off then re-applying but it did\'nt seem to make any difference,still gradually boosting to 3psi max.

What appears to happen next after driving like that for a while is the car refuses to boost at all and will only drive with the boost gauge in the vaccum range,any positive boost at all and it tries to cut out as though i had just driven through a puddle drowning the electrics.

Once it\'s fully cooled down (next day) it\'s fine again.

I was going to treat her to a nice stainless exhaust if she behaved herself.....Think i\'ll hold off..... bad girl...!!!

[JayDee]

It seems like it is a solenoid either turbo/pre control or wastegate control and charge contol not working properly when hot.
Check all your connections from the turbo to thottle body esp the Y-pipe.
go here

http://www.autosportracetech.com/RX-7/rx7stuff.htm

[maximtaylor]

One more thing to check!

The two black ribbed hoses in and out of the intercooler can also soften with age and heat. Result is they sometimes suck in on themselves and boost vanishes

Top one is easy to check, but the bottom one is a bit more fiddly to check.

Mine did this and it was the bottom hose.

Regards

Max

[JayDee]

Hi Max
Wouldn\'t these expand under boost?
Max have you got that single on yet with your ported motor?

Jason

[maximtaylor]

Jason

I know, it sounds odd as in theory they should be under pressure.

Mine would collapse in the transitional state between vacumn and boost, where I would assume you floor the throttle, engine demands air, turbo\'s aint cooking yet, and in that split second, you have vacumn in the pipe. Also did it between 1st and second turbo..

The turbos then cut, because the exhaust gas slows from air starvation caused by the blocked pipe and your stuck!

Single turbo is in Jason and looking good! Loaded new single turbo map onto the apexi, electric water pump is nearly there, water injection is ready to go, heat wrap is on, still having the ancillary stuff sorted at the moment but it\'s looking hopeful for later this week.

I must thank Chris down in Portsmouth for all the hard work he has put in on my car while Geff has been away. I\'m very impressed with his standard of work so far and his regular updates on his progress

Looking forward to Pod next month Even if I\'m going to be running 1.0 bar boost tops. There should be some real whoop ass FD\'s there!

Regards

Max

[steevo]

Cheers for the info guys,gonna have a good read up see if i can sus it.

If not anyone know a decent garage in the south east who can sort it.

STEVE.

[Kennington_Rick]

I had pretty much the same problem with my 98 RB - took it to Rotechnics (Reading) and they tested everything inside out.

They found that the charge control solenoid had died a death.  Got the car back this morning and everything seems fine - and it\'s not popping and banging nearly as much as before.  Seems a little quicker as well which is nice !

Rotechnics is a pretty cool operation - they must have had 8 FD\'s there, several having engine-out type mods.  They also have an open rotor case with moving parts - now I finally understand how it is the crank rotates three times faster than the rotor....

R