Terrh

iTrader: (7)

Ok, I'm having this weird power issue with my car.


If the engine is cool, like, if the car has been used but the engine has been off for 20-30 minutes, if I go drive it it will have TONS of power, and work right, etc.

BUT if it's hot or has been driven for more than 10-15 minutes or whatever, it feels gutless in the high end.. it just doesn't have that really strong pull above 4k that it will otherwise.

ALSO:

It didn't seem to do it very often (sometimes, but not NEARLY as much) when I had a bad exhaust leak just after the turbo. (eg, the exhuast was MUCH more open than it is now)



I'm running stock exhaust + gutted cats. Rest of the car is basically stock.

Could my twin scroll be siezing or something? I looked under the car, and the actuator rod is shiney, so clearly it's moving sometimes, but maybe it siezes at other times? if I were to remove the actuator and wire it open, would this tell me if it was the problem? how do I go about doing that? which way is "open"?



If you don't think this is the problem, what the heck could be causing it?

NZConvertible

I can't see how the twin-scroll system would be affected like you describe just because of temperature. However the twin-scroll system is pretty simple to test if you want to eliminate it as a suspect. Just follow the FSM's instructions.

Terrh

iTrader: (7)

any ideas, then? I need to figure this out...

TheBigOne

secondaries not kickin in?

HAILERS

Just idle the car. Have someone pull the plug off the twin scroll solenoid while watching the rod on the twin scroll actuator. It should move each and every time the plug on the solenoid is removed/reattached.

Retracts with the plug on, extends when the plug is off.

Or reach over and pull the vac hose off the feed pipe while you watch the actuators rod. Retracts with the hose on......extends with the hose off. We're talking taking ten minutes to check it out.

Or......the online factory service manual, located at http://www.iluvmyrx7.com in the FUEL section has a simple checkout

We're talking about a flapper valve that is spring loaded to the wide open position when there is no vacuum on the actuator( its condition when the rpm's are above 2700 rpm). Take the vacuum hose off and plug it and see what happens. Or take the electrical plug off the solenoid and the thing should go and stay at wide open(fully extended) Really no need to wire the thing open at all.

Terrh

iTrader: (7)

ok... I removed the actuator rod and left it wide open.. result: car boosts WAY quicker and easier now. Seems to boost more, too.. it will creep to boost cut in 3rd. However: car is still "slow"

so, I'll re-ask : what the hell could be causing this problem?

Fingers

hmmm... that's interesting... is it possible that your wastegate opens early? or is leaking?

Did you keep that little "pill" in the wg line?

Terrh

iTrader: (7)

only when the car is hot? and no, because it always boosts fine.. it just has less power sometimes.. its really weird.

bUmP

dr0x

There is supposed to be a pill in the WG line?

Terrh

iTrader: (7)

that's what I was wondering..

but I never messed with the wg line, so I'm assuming that it's' there.

what the heck could be causing this problem?

dr0x

Anyone want to confirm there is supposed to be a pill in there? Is it the same one as the boost sensor pill?

rx7_turbo2

I don't think there is a pill in the WG line.

Perhaps the lack of power is simply caused by heat soak. I know mine lost a ton of power once that top mount intercooler got hot.

dr0x

I noticed it a bit, but not too bad on mine. I even cut off that back plate (had plans to front mount the stocker, but ditched em). If I leave my car idle/drive around for like 45 minutes its still not too bad.

Boost Lee

iTrader: (3)

you know something stupid that happened... causing the same problem for me? My air filter had dirt caked all over it... I could throw it on the ground and dirt would come off. I cleaned the damn thing off and my smoof (smooth) idle returned as well as my high end power.

NZConvertible

There is no pill in the S4's wastegate line.

There is one in the S5's wastegate line for the electronic boost control.

Fingers

He has the S5 motor/turbo in his AE if i recall correctly.

NZConvertible

Not if he has the twin-scroll system.

Fingers

Ahh touché. But he does have the s5 motor, i know that for sure.

Terrh

iTrader: (7)

s5 block/s4 everything else.

and what's with the "pill" in the boost sensor line? I replaced that line, mine has no pill.

Fingers

Disregard that pill... i thought you had an s5 turbo/boost control for a minute

HAILERS

It's an orifice and it's found at : http://www.mazdaformance.com/rx7parts.htm and the part number has been posted on this site numerous times.

The lack of which will cause hesitation, jerking etc but not result in lack of power. It's meant to prevent *over shooting* of the boost/pressure gauge in a turbo or a non-tubo.

HAILERS

Maybe it's something to do with EGR??????Series four had the EGR. Series five did not. So it makes me wonder about the path to and from the EGR that is on the series four manifold on your car.

By the way, go to http://www.mazdatrix.com/ and view the *Front Page*. See the reference to the RX-8? Just FYI. Nothing to do with your problem. It's close to being a pig ugly car in my opinion. Maybe I need to see it close up. I could be wrong.

Terrh

iTrader: (7)

hmm.. I have some minor hesitation and jerking sometimes on light throttle.. but it's not major

like, low RPM in 1st or 2nd I can get some serious jerking if I'm trying to maintain a low speed (like 5-10km/h)

I just bolted up my s4 LIM to the s5 block... do you think that could be a problem?

Fingers

Series 5 intake manifold to block gasket

Series 4 intake manifold to block gasket


Short answer, yes. Yes I do.

Terrh

iTrader: (7)

I think I have the s4 gasket on there.. but to be honest, I don't remember if I saw that little port or not.

Anyways, how could this cause a problem? and what can I do about it?