WOT Huge Power Loss :: Can The Catalytic Converter Cause This?

[lbwd]

My catalytic converter is some cheap aftermarket piece of shit that some exhaust shop put on. My mechanics tell me you can't do that to a Cadillac and that it's causing back pressure problems (and setting off the SES light.)

Could this be a Fuel Pump or MAF, or do you think it's all related to the catalytic converter?

The problem is when I give my '96 STS WOT, It hits around 4500 RPM and looses power instantly. Can't reach redline. Like a shut down. On the floor and nothing. No codes other than Catalyst Low Efficiency.

Input is appreciated.

[Krashed989]

It's either that or an ailing fuel pump. I would check the fuel pressure to be sure before spending money on the cat. converter. It does sound like it's most likely the cat. converter though.

[lbwd]

Thanks, Allen. I see your PIMP LEVEL is maintaining a healthy percentile.

One question remains: I have never checked the fuel pressure; can this be done through the FPR or is that totally unrelated?

Thanks again.

[Krashed989]

LOL yeah, I think right now my pimp level isn't very high... The car needs a good washing. lol... and also my radio isn't working propery. lol

If you follow the fuel line going to the fuel rail you should find a shraeder valve (like the ones on your tires but a little bigger). The FPR is on the fuel rail, but you can't check the pressure using it.... To check the fuel pressure you would have to get a fuel pressure gauge with the right fitting and attach it it to the shraeder valve, then tape the gauge to the window and go for a drive. If it's the fuel pump, you should see a big fuel pressure drop when you go WOT... There is a certain range that the pressure should be at all times... I don't know that range offhand though... Something like 50-60psi... but that's just a guess. Maybe someone will chime in with more solid figures. It should be in the FSM.

[Ranger]

Cat sounds highly suspicious. Fuel pressure should be 45-50 psi if I remember correctly.

[lbwd]

That's good to hear.
I'll be replacing it along with the struts and tires. Tires are cupped with like 97% tread.

[thu]

I had the exact same problem last month. SES came on and sometimes it would flash. Fulll throttle gave me nothing much. Couldn't make it up some hills. Dealer says 'plugged cat'. So he replaced under warranty. Suddenly, it's a whole different car.

[CadillacSTS2003]

yup
cat can kill power

[chubbyranger]

Originally Posted by thu

Dealer says 'plugged cat'. So he replaced under warranty.

Back in the day I recall getting something replaced under a federal mandatory 5-year or 100,000 mile warranty on all automotive emissions components. Don't know if that's still the case but it seemed to be one of those secret things the dealer didn't want to own up to.

[CadillacSTS2003]

def not
most are 5 50
i know caddy has 80k

[I~LUV~Caddys8792]

Sounds like the Catalytic Converter. The Federal govt puts out a warranty on all cars, atleast the domestic made ones for the Catalytic Converter....8 years/80k miles. Replaced at no charge if there is a problem. Now I'm not totally positive if this is on the aftermarket ones too....maybe just OEM.