Started loosing power. Help pinpoint the cause.

[Newlogics]

Something unusual is happening to my 1G lately.
First and formost, my timing belt tensioner is failing (makes squeaking noise). *About* the time it started failing, the car started to loose loads of power throughout whole lower rpm range.
IF I slowly bring it up to about 3500rpm and the gun it, it's *usually* launches very nice, but got forbid I give it some throttle when i'm below 3K. (All this assuming I'm already in gear and rolling)
Car just doesn't pull at all. Turbo builds boost earlier then usual, EGTs fly high (I'm talking past 1600F unless I let off) and I get NO pull whatsoever. That little acceleration that I do get feels jerky a bit, but doesn't backfire.

All this I'm describing does not involve full throttle. It does that at virtually any attemt to accelerate.

I tried adjusting fuel delivery with SAFC, but it seems to have little of no effect at all. Since it's not doing 100% of time, It's hard for me to even pinpoint specific rpm range that has mixture problems (if that indeed is the problem)

Here's the summary:
If I give it throttle when I'm below 3000K, I don't get any pull, my EGTs rise and boost biulds up quicker then normal.
When it gets to about 4500, there is a 50% chance I get all my power back all of a sudden. Otherwise I'm still crawling untill my EGTs are so high that I have to let off.

Could this be detonation ? -- Why at partial throttle ?

Oh yeah, i'm also showing knock of up to 43 when it happens.



Help Help Help.

P.S. My timing belt is geting fixed tomorrow

 

[Phoenyx]

Ouch! There could be a number of things wrong. Can you do a shake-down of your car and check the basics (spark wires, plugs, O2 sensor, etc..)?

At this point, it could be anything. It sounds like you aren't getting enough fuel down low.

-M

 

[Newlogics]

Originally posted by Phoenyx
Ouch! There could be a number of things wrong. Can you do a shake-down of your car and check the basics (spark wires, plugs, O2 sensor, etc..)?

At this point, it could be anything. It sounds like you aren't getting enough fuel down low.

-M

I run Walboro 255 through stock injectors.
I run 57 trim Mutt. I know my injectors are stressed, but according to my calculations, they should've handled 17 psi. (I was waiting for them to fail anyway to finally get 660s)
However, sonemthing leads me to believe that injector failure won't act like that. As I said, sometimes it acts normally. Even more so at higher rpms (more fuel required).
It's lower range that give me all this trouble and triggers the knock.....


edit
I tried adding fuel with SAFC, but saw no response at all. I can't trust my A/F gauge either.

 

[nine5raptor]

mine will do this when it is cold. timing goes to -5deg.

 

[Newlogics]

Originally posted by nine5raptor
mine will do this when it is cold. timing goes to -5deg.

Mine used to to it when cold, but now does is most of the time

 

[AWDGSX415]

Hmmm Mine used to have almost the same symptoms untill I upgraded my MAF to a 2g. Also I would check plugs, 02 sensor, etc...

R.

 

[Newlogics]

Originally posted by AWDGSX415
Hmmm Mine used to have almost the same symptoms untill I upgraded my MAF to a 2g. Also I would check plugs, 02 sensor, etc...

R.

I already have 2G MAF, ready to be installed, however, it used to run fine up untill a week ago. I can' think of anything I've done to make the effect ...

 

[Phoenyx]

Originally posted by Newlogics


I run Walboro 255 through stock injectors.
I run 57 trim Mutt. I know my injectors are stressed, but according to my calculations, they should've handled 17 psi. (I was waiting for them to fail anyway to finally get 660s)
However, sonemthing leads me to believe that injector failure won't act like that. As I said, sometimes it acts normally. Even more so at higher rpms (more fuel required).
It's lower range that give me all this trouble and triggers the knock.....


edit
I tried adding fuel with SAFC, but saw no response at all. I can't trust my A/F gauge either.

Well, I know you are definitely stressing the injectors! Perhaps they aren't working very well at low rpm? Perhaps your timing is being pulled hard?

Do you have a datalogger?


-M

 

[blackvr4]

check your cam timing make sure dots line up pefectly.

 

[LandoAWD]

Since you are doing the t-belt soon...wait and see if that is the prob. I had CRAZY p-knock before my swap..now its all gone.

 

[Enraged78]

It is also possible that the failing tensioner is setting of your knock sensor. If that happens, the computer will pull back timing and also change your long term trims. Reset your computer and go for a ride. If the performance improves, you've found your culprit. Better yet, get a datalogger and see what your computer is doing for timing. If your injectors are stressed, you may be running lean, and the computer will pull back timing even more, because a lean condition will induce even more knock (real knock, not phantom). The combination of real and phantom knock will cause a huge power loss, even though you are still making full boost. Also, get that tensioner fixed before it breaks and you lose the motor.

Later,
Matt.

 

[Defiant]

Originally posted by Newlogics
First and formost, my timing belt tensioner is failing (makes squeaking noise).

Gaah! And you're still driving it? Gaaah!

 

[Newlogics]

Well, looks like the problem has been taken care of.
The culprit was the t-belt tensioner. Also, while at it, found out that my water pump was leaking. (I was loosing coolant, but couldn't find the spot for a long time)

I'm back to full power.
Thanks guys.
Just got my 2G MASS, next step - Injectors.