my car runs really fast when it is cold. I'm talking at least 30 horsepower more than when hot. I hooked the fan up full time. This has made a small difference, maybe 10 horsies. Isn't the car running in "open loop" or something when it is cold? Is there a way to keep it running like that? maybe a computer chip? If so, will this kill my gas milage? Also I believe my oxygen sensor is bad. I get a ses light on hot days on the freeway. If I change the oxygen sensor can I expect any hosepower gains? one more thing. can you adjust the timing on a tbi car? or is that controled by the computer? any info would be great. I don't have alot of cash for big mods, so I'm trying to get the most out of what I have. thanks

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92 firebird. tbi. flowmaster muffler with no cat. open element air cleaner. more to come when funds allow.

http://www.geocities.com/joecarrr1/SLAPPY.html

www.geocities.com/joecarrr1/joecarrr.html

 

I'm in the same boat as you .... My car screams in Open Loop; it still runs great in closed, but there is a noticable HP loss.

I've changed my chip and O2 sensor, but the problem remains. I bought a Knock Sensor, but haven't had the time to climb underneath and swap it out yet.

If anyone can shed light on this, that would be great!

Thomas.

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1992 RS Camaro - Red
305-TBI/5 Speed Manual- 3.08 geared rear
1.6 Roller Rockers / Adjustable Fuel Regulator with high flow pump / Open Air K&N Filter / TBI Spacer / ADS Super Chip & custom burned Off-Road Only chip / MSD ignition
Headers - 3" Cat'Back - Flow Master - dual chrome tips
Adjustable Coni shocks & struts & 16" factory wheels

 

anybody???????????????????

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92 firebird. tbi. flowmaster muffler with no cat. open element air cleaner. more to come when funds allow.

http://www.geocities.com/joecarrr1/SLAPPY.html

www.geocities.com/joecarrr1/joecarrr.html

 

You need to get into eprom burning if you want to make your car behave consistently.

My car currently performs virtually identically whether a "cold start" or "hot restart".

Different engines/ECMs require different things; keeping the engine at a constant operating temperature and having all the "correction" tables in the eprom "tweaked" assist greatly in maintaining constant performance in ALL driving conditions.

There will ALWAYS be some "power loss" encountered with higher elevation and higher ambient air temperatures just because you have "less air", but you can minimize it's affect. But, there should be minimal difference between "cold start" and "hot re-start" when you get your eprom properly "tweaked". Some ECMs pull spark out when the engine is hot and this tends to be a major "culprit" in the "Cold vs Hot" difference. Others have a "Low Octane Retard Routine" that will pull timing out if any knock is encountered and it will remain that way until the engine is restarted. When engines are "hot" they are more prone to knock and you may "encounter" some knock if you booted it when the engine was hot and just restarted, causing your ECM to permanently pull timing out.

This is just a sample of some of the "little things" that all work against you in trying to maintain "constistent performance".

 

The reason you have more HP when the engine is cold is because the under hood temp. is lower thus causing colder air into the intake, but when your car heats up so does the surrounding air.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER, NO CAT
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat
2:73 GEARS
Rebuilt 700R4, with manual valve body
B&M Megashifter, 5" Autometer Tach w/shift lite
Soon to be installed
3:73 Richmond Gears and 3" Hooker Aero Chamber
Corvette Servo & .500 boost valve
15.61@ 95.2mph G-Teched, 1-2 shift slippage, and just replaced a burnt plug wire
"There is nothing more addicting than speed"

 

I understand the underhood temp thing but I have never driven a car that the difference was so drastic. It feels like a totally different car. I'd like to get into burning chips. How much does it cost? where do you get the stuff? Where do you learn how to do it? Is it hard to figure out?


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92 firebird. tbi. flowmaster muffler with no cat. open element air cleaner. more to come when funds allow.

http://www.geocities.com/joecarrr1/SLAPPY.html

www.geocities.com/joecarrr1/joecarrr.html

 

Read TRAXION's PROM burning article in the Tech Section. Then go to the DIY-PROM board. You'll have all the info you could want.

 

Cold air is more dense so effectively "more" air gets into the cylinders on a given combusion cycle when it's cold out, or before the engine gets hot. Prom burning is certainly a great thing to get into, but a cold air intake of some sort will also help a lot. You have an open element, which in general will flow more air that a closed off intake (like stock) but the air will also be hotter. The cooler you can keep the air coming in the better. This does NOT mean you fool the ecm into thinking there's colder air, because all it will do is dump in more fuel while the actual air temperature remains the same. Hope all that helped.