Daytime sluggishness

[RedDragonGSX97]

I am having a wierd issue and im stumped. I have a 96 gsx automatic. During hot muggy days it seems slow as hell.But at night when it is cool it is dramaticly quicker.At first Ithought i was crazy but i let my fiance drive and she thought the same thing.

Now i know i have at least 2 boost leaks. The throttle body shaft seals and the biss o ring are leaking and im going to have my TB rebuilt next week. But that doesnt explain the performance differences from day to night.

I have a guess at what it is. The previous owner wrecked this car and totalled the front end. I did the body work myself and it looks pretty good on the outside. Behind the front bumper however the plastic vent cover thing stock SMIC doesnt line up with the bumper. This is causing about half of the SMIC to be covered up by the bumper. Could the lack of cool air hitting it in the daytime be causing the sluggishnes.Here is a pic.

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I have 4 CELs

rear 02 sensor and heater circuit (im straight piped)
p1105 fuel pressure solenoid. (changed it twice wont go away)
and p0443 EVAP emissions system PCV circuit ( just came on yesterday and i dont know why yet)

If it indeed is the SMIC being blocked then i guess I need to go ahead and save up for a FMIC.

Any help is appreciated.

 

[AngelOfPassion]

If your intercooler is getting heat soaked because of a lack of air flow you would notice a difference. I don't know how much but it would be noticable. So that could be your problem right there. The boost leaks won't help either.

The p0443 is a really annoying code, I have it on mine as well. But I was just told in another thread that it is excluded from emissions testing in the United States. So if you have ECMlink you can tell it to not check for that code and it will not pop up again. It is a code that has to do with the readiness monitors for emissions not being set to complete. '96 and '97 cars have a really hard time getting them to come back on so they make a rule that it doesn't apply to us.

The rear o2 is normal with a straight pipe. You can cover the sensor to get it to not throw a CEL... I can't remember what thread explains it but it's something you can get at an auto parts store. Basically tricks the sensor into not reading... Something to do with a spark plug non-fouler, you screw the o2 sensor into it...

I've never had the p1105 so I'm sorry but I can't help you with that one.

EDIT: Here is a link to the epa rule that exludes our cars from that test. It's on page 5. Keep this in your glove box and you should be good when you have an emissions test done. http://www.epa.gov/otaq/regs/im/obd/.../420f08009.pdf

 

[zcoh2gdsm]

the rear o2 sensor you can put a spark plug non fouler on and make the code go away. it pretty much just removes the o2 sensor out of the exhaust stream.

 

[fourgsixthree33]

This is a normal problem. Not saying you don't have other issues because you have clearly state your problems.

But, temperature always takes affect. Colder the air going into the intake, the more power. The warmer the air, the less power. Which is what the turbo's job is- to condense and cool the air entering the intake so you can make more power.

Find someone who can log from a hot day compared to a cool day. It's amazing how much a difference temperature can make. That's why so many people are crazy about lowering their IAT's.

 

[turboglenn]

that';s just turbo cars hating the heat.. You may have leaks and sucj to deal with but I have a full stand alone that puts the same exact timing and fuel numbers down everytime no matter the outside temp (disabled IAT correction with 1600's) adn the difference between a cool night and the middle of the day is an easy 15hp at minimum i'd say (that's at the level of 26-27psi and arund 480hp when the temp is about 80* F

The air charge is less dense when it's warmer and since the turbo is compressing the air charge to begine with there's less volume of oxygen per cubic foot of air that's compresses so that's less of the stuff you need for an explosion in the engine that makes it run (hope that makes sense)

 

[RedDragonGSX97]

Yeah I had a feeling it was. I may get a better air filter (I have a cheapo ) and make a heat shield for it. As far as the intercooler goes I will go ahead and get a FMIC. I will need it later anyway .well thank u guys for the info. I learn something new every day

 

[fourgsixthree33]

that';s just turbo cars hating the heat.. You may have leaks and sucj to deal with but I have a full stand alone that puts the same exact timing and fuel numbers down everytime no matter the outside temp (disabled IAT correction with 1600's) adn the difference between a cool night and the middle of the day is an easy 15hp at minimum i'd say (that's at the level of 26-27psi and arund 480hp when the temp is about 80* F

The air charge is less dense when it's warmer and since the turbo is compressing the air charge to begine with there's less volume of oxygen per cubic foot of air that's compresses so that's less of the stuff you need for an explosion in the engine that makes it run (hope that makes sense)

I agree. Well written.