No extra power with the power-key / secondaries on

[c4koh]

Does anybody have any experience / help for the following?

• Engine seems to run / sound the same with power key on or off
• Lack of 'breathing' it seems >6000rpm
• >6500rpm, engine is rough
• Power light is 'ON', all fuses OK
• No codes set
• Vacuum [connecting to vacuum line on right-hand side of plenum] is OK, pump it up and it stays, suggesting no leaks there.

I suspect it could be sticking / inoperative secondary actuators, but before I pull the plenum I'm just looking for any advice if anyone's had the same type of problem before.

Thanks in advance,

Steve

1991 ZR1
Stock except headers + No Catalysts, Marc Haibeck chip, Corsa Exhaust

[zr-1assassin]

hi, i had the exact same thing!! mine was the little black hose that goes into the drivers side of the plentum, was cracked in half. i just taped it back together until i can find another and..... problem solved. hope this helps!

[zr-1assassin]

speaking of that... where can i get another line for the drivers side. its the one that crosses over to the front right (pass.) side and goes to the pump.

[GrayZ]

Originally Posted by zr-1assassin

speaking of that... where can i get another line for the drivers side. its the one that crosses over to the front right (pass.) side and goes to the pump.

Our president Ron ..had a set of vacuum lines...check with him
or phrogs.

[Z Factor]

Glad to see you posting Steve.

Have you checked you air duct to see if it is soft or collapsing under demand? If it is it will rob you of air when you get on it. There can be other causes, but rule that out.

I'd check the accordian as well. It can starve a motor for air at higher RPM's. but it should not make the car run rough. You can use a sturdy wire coat hanger to hold the duct open. Just do some gently bends on it to fit the duct.

Drive again and see.

Plus when the car is in normal power it should take it a different amount of time to go from 3K-5K, and 5k up to 6k is a crawl. Full power you should be able to feel the difference in the initial 3-5 range.

[c4koh]

Folks - thanks for the tips so far.

The accordian - air duct - is fine: it has a nice bit of curved Aluminium sheet to prevent in collapsing.

zr1-assasin: did you mean the hose at the rear of the plenum (to the MAF / MAP [cannot remember which] sensor?) - if so this is fine. Another hose - also at the rear of the plenum and looks like a fuel-pressure regulator - is also fine...

But if it was a different hose - let me know so I can check!

The engine response is the same regardless of the power key, but with the possibility - I don't know if I'm just imagining it though - that there is a little bit more growl with the secondaries on... hence, I do wonder if all is OK apart from the secondary actuators sticking or similar...

Looks like I'll have to get that plenum off... again (last time was 3 years ago so not too bad!!) ...

[zr-1assassin]

hi, the line im talking about is the vacuum line that goes into the side of the plenum, the drivers side, and runs under the plenum and up to the vacuum motor in the front headlight compartment(pass. side). mine was doing exactly!!! the same thing as you described and that was it. it may even be the vacuum pump motor, feel it and see if its hot from constantly running, mine was. and i taped the hose together as a quick fix to see if that was it..... presto! the pump was no longer hot either. give it a good looking over because i think it probably has something to do with your illness. let me know