Weird problem
08-13-2004, 12:10 PM
#1
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Join Date: Aug 2004
Posts: 7
Weird problem
Help!!
I've got a '91 Firebird. 305 TBI/th700.
It has been losing power steadily over the last week. It's to the point now where it'll barely maintain highway speed.
It idles normally and has normal torque (for a 305
) below 2,000 RPM but develops no power above this.
It behaves as if it can't breathe, has a severe exhaust restriction, or severely retarded timing. Maybe insufficient fuel flow? I don't hear a knock, but the ALDL set a 43 fault code. All gauges register normal.
The exhaust is waay too quiet, the pulses feel weak and hot. When I push the accelerator at highway speed, the intake gets loud like it's lugging, but nothing from the exhaust (save a hissing noise I might just be imagining).
My first thought was that the cat disintegrated, but I don't hear any palladium rattling around in there.
So whaddya think? Plugged cat? Fuel filter? Something else?
I gotta get this pig back up to speed. Any help is appreciated!
-John
I've got a '91 Firebird. 305 TBI/th700.
It has been losing power steadily over the last week. It's to the point now where it'll barely maintain highway speed.
It idles normally and has normal torque (for a 305
) below 2,000 RPM but develops no power above this.It behaves as if it can't breathe, has a severe exhaust restriction, or severely retarded timing. Maybe insufficient fuel flow? I don't hear a knock, but the ALDL set a 43 fault code. All gauges register normal.
The exhaust is waay too quiet, the pulses feel weak and hot. When I push the accelerator at highway speed, the intake gets loud like it's lugging, but nothing from the exhaust (save a hissing noise I might just be imagining).
My first thought was that the cat disintegrated, but I don't hear any palladium rattling around in there.
So whaddya think? Plugged cat? Fuel filter? Something else?
I gotta get this pig back up to speed. Any help is appreciated!
-John
08-14-2004, 11:51 AM
#2
Registered User
Join Date: Dec 1999
Location: MD
Posts: 2,022
Re: Weird problem
I agree, most likely a cat. When the converter on my sisters Firebird plugged up, it made no audible sound. Once removed, a solid chunk nearly about the size of a orange broke off and turned 90*, blocking all flow.
It wouldn't hurt to replace the fuel filter either.
It wouldn't hurt to replace the fuel filter either.
08-15-2004, 10:33 AM
#3
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Join Date: Aug 2004
Posts: 7
Re: Weird problem
I decided to tackle the fuel filter first. Heckuva place to put it, btw (I'm shocked nobody ever came up with a relocation kit).
If that doesn't fix it, I'll try the cat next.
Thanks for the replies!
-John
If that doesn't fix it, I'll try the cat next.
Thanks for the replies!
-John
08-16-2004, 07:20 AM
#5
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Join Date: Aug 2004
Posts: 7
Re: Weird problem
The car seems to be running better now that I changed the filter, but it's not at full power. I reset the computer, but I don't know if the BLMs are stored in NVM. Does anybody know offhand?
If that's the case, I may just need to drive it awhile while it learns leaner settings.
If that's the case, I may just need to drive it awhile while it learns leaner settings.
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