Loss of Power

[MTV]

Alright, very weird problem.

I gunned it in first gear this morning and at around 5500 RPM, there was a sudden loss of power as if I had hit the brakes for a second.

So I hit it again later on and it did the same thing. Then a little while later I floored in first, all the way to redline without any problems. Pulled hard the whole way. I did this a few times and the problem went away...

What the hell happened?

Thanks,
Matt

 

[MTV]

bump. Any ideas?

 

[MTV]

Only happens in first gear BTW.

 

[MTV]

Wow, no answer...

But it hasn't happened since this morning so it shouldn't matter.

 

[Qcpro5]

I used to have the same problem on my old 94 protege dx.

It would loose power during acceleration in first. It did this when I started the car in the morning to go to work. Never could tell what it was.

A mechanic told me once it had something to do with the fuel lines.

 

[Demoniam]

might be dirty injectors, buy some techron, or Lucas brand, and add it to a full tank. might be your plugs, too.

 

[FastMSP]

Max power is at 5700rpm and power goes down afterward. Also, the protege gauge is 200rpm less than actual rpm.

 

[MTV]

Max power is at 5700rpm and power goes down afterward. Also, the protege gauge is 200rpm less than actual rpm.

Nah man, not even close.

It surely wouldn't feel like I'd be hitting the brakes if it was because I passes peak HP...

 

[MTV]

might be dirty injectors, buy some techron, or Lucas brand, and add it to a full tank. might be your plugs, too.

Plugs were changed 10 000KM ago.

If it happens again, I'll slap some additive in there.

Thanks man.

 

[Mike R]

Were the 2 times it acted up while the engine temp was still pretty low? The VTCS being closed in cold temps might do it.

 

[MTV]

Were the 2 times it acted up while the engine temp was still pretty low? The VTCS being closed in cold temps might do it.

It's never happened before and I floor the s*** out of it all the time when cold. The car was warm though.

I was maybe thinking it was my drive belts, cause they need replacing. Could a slipping drive belt cause loss of power?

 

[808MP5]

very interesting problem. I got the exact opposite. When I hit 5500rpms my car pulls harder. Sorry no help.

 

[MTV]

very interesting problem. I got the exact opposite. When I hit 5500rpms my car pulls harder. Sorry no help.

Ya that's what mine normally does. Just for some reason decided to lose power for a little while today.

 

[niky]

VICS not opening. VICS is triggered at 5000 rpm and opens fully at 5250 (which would be at around 5500 on your tach). It should probably feel like your car is running out of air, but the "brick wall" feeling might just be your AFRs and ignition not being optimized for the amount of air coming in.

Check your vacuum lines. I'd have said solenoid, but if that were malfunctioning, you would be having the VICS open all the time, which would lead to low rpm bogging. Or it could be some gunk on the VICS butterflies that was holding them closed and your full-throttle run dislodged it (and sent it into your engine... oops...) ?

 

[MTV]

VICS not opening. VICS is triggered at 5000 rpm and opens fully at 5250 (which would be at around 5500 on your tach). It should probably feel like your car is running out of air, but the "brick wall" feeling might just be your AFRs and ignition not being optimized for the amount of air coming in.

Check your vacuum lines. I'd have said solenoid, but if that were malfunctioning, you would be having the VICS open all the time, which would lead to low rpm bogging. Or it could be some gunk on the VICS butterflies that was holding them closed and your full-throttle run dislodged it (and sent it into your engine... oops...) ?

Ya that's pretty much what it was like. As if the car was running out of air, not so much of a "brick wall" feeling.

So when the car warms up, the VICS is always fully open? And how come this only happened yesterday and no other time before that?

Matt

 

[P-Funk!]

Me? I would suspecta bad plug, wire or coil. No CEL i assume.

HHHmmmh. It may just been gunky gas...

For reliability - let her warm up (all clearences) so you don't cause undue wear on the engine.

 

[MTV]

Me? I would suspecta bad plug, wire or coil. No CEL i assume.

HHHmmmh. It may just been gunky gas...

For reliability - let her warm up (all clearences) so you don't cause undue wear on the engine.

You're right man, probably just bad gas. I'm just gonna fill up with Shell from now on, no more Esso.

 

[niky]

Ya that's pretty much what it was like. As if the car was running out of air, not so much of a "brick wall" feeling.

So when the car warms up, the VICS is always fully open? And how come this only happened yesterday and no other time before that?

Matt

I don't think it's bad gas. You'd feel that at low rpm and idle, in the adaptive portion of the powerband (been there, seen that). A dramatic cut over 5000 indicates VICS.

What I mean is that it's not opening. It can't be that it's always open, because that'll feel like the thing is bogging at low rpms (been there, seen that, too...). Without an electrical signal, VICS is open. With a signal, it's closed.

Thus, it can't be the signal itself. The VICS shutters simply weren't opening. Your primary runners aren't designed to flow enough for high rpm work, so yeah, that's the feeling you get... like running a racecar with a restrictor plate..

If it doesn't happen again, probably means that whatever it was is gone. But you should look at your vacuum lines and see if there's a kink in the line going to the VICS that might have caused this (it's on the left side if you're standing in front of the car looking in, beside the canister, halfway down the intake manifold).

Me? I'd open up the manifold, too, and take a look at the butterflies and spritz them with carb or throttle cleaner. Loctite the screws in, while you're at it... it's paranoid, yes, but paranoia is useful in staving off bigger issues... a buddy's engine ate a VICS screw just months out of warranty.

 

[MTV]

Thanks for the heads up. If it happens again, I'll get it looked at. For now I'll just inspect my vacuum hoses.