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| 88 fiero formula awful gas milage (Page 1/2) |
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Kyle88formula
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MAY 05, 03:06 PM
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Hey all, my 88 formula is currently getting around 11mpg without ac running. It used to get around 19 but after I let the car sit for 2 months it dropped down to 11. The only thing that changed was my exhaust blew out more on both sides of the catalytic converter, would this cause such a large loss of fuel economy? Car idles around 900 rpms, no SEL or decrease in power. Any ideas? Of course I plan on replacing the exhaust but I’m tight for money and time currently so if that won’t fix my issues I’ll have to find something else to drive. Thanks
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Patrick
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MAY 05, 03:24 PM
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| quote | Originally posted by Kyle88formula:
The only thing that changed was my exhaust blew out more on both sides of the catalytic converter...
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Blew out more what?
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olejoedad
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MAY 05, 03:46 PM
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Gall757
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MAY 05, 04:01 PM
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The 02 sensor can be reading a false lean condition because of holes in the exhaust. The computer adjusts by adding more fuel...and more fuel...but it's never enough.
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theogre
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MAY 05, 06:00 PM
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| quote | Originally posted by Gall757:
The 02 sensor can be reading a false lean condition because of holes in the exhaust. The computer adjusts by adding more fuel...and more fuel...but it's never enough. |
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Yup, any exhaust leak can cause between head and O2 and down to the cat can cause very rich engine getting crap MPG.
ECM only sets codes 44 or 45 when both BLM and Integrator are Pegged and stay there for some time.
BLM can stay Pegged for days w/o setting codes when Integrator can move even 1 number off of pegged.
More See my Cave, Scan Tool Help
That's assuming you don't have fuel leaks, injector problems, etc.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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phonedawgz
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MAY 05, 06:12 PM
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Unplug your o2 sensor and disconnect the battery. Tie up the o2 sensor wire so it doesn't burn on the exhaust. Reconnect the battery. See if that brings your mileage back. If so, yes your o2 sensor is driving the loss in MPG. If not, time to look elsewhere.
Ignore the CEL light during this test.
Cheap and easy.
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Kyle88formula
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MAY 05, 07:15 PM
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| quote | Originally posted by Patrick:
Blew out more what?
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Sorry for the confusion, It was leaking before and was patched but after it sat the exhaust rotted out more and the leak got worse.
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Kyle88formula
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MAY 05, 07:20 PM
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Appreciate the help, I’ll put a exhaust on it next. Do you guys recommend the ocelot exhaust from the fiero store? Thanks
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Patrick
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MAY 05, 10:05 PM
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| quote | Originally posted by Kyle88formula:
I’ll put a exhaust on it next.
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Is the entire stainless steel factory exhaust rotten (very doubtful), or is it just the short mild-steel lengths of pipe on either end of an aftermarket cat that have rotted?[This message has been edited by Patrick (edited 05-05-2022).]
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John W. Tilford
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MAY 06, 10:45 AM
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I'm well pleased with the Ocelot exhaust, which is good because I couldn't find any other!
88 GT with 3.4 pushrod and 4T60.
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