hey guys,im new posting on the forums,but ive been reading them since i bought my 84 c4 about 4 months ago.you guys have helped me alot.i've been wanting a corvette since i was 16,im 52 now lol.i need to know about the flaps on my crossfire air cleaner.are they both supose to stay closed? i changed the air cleaner temp sensor because only the passenger side stayed closed.if i turn it around they both stay closed.they do open a little when i give it gas.i would think that they should both open when the engine warms up.any help? thks for all the help in the past 4 months the car has a bunch of little stuff wrong with it but its a CORVETTE

 

Welcome aboard. I've owned my 84 for 10 years now and still love it. They're great cars, and with basic maintenance, will run forever.

The flaps are both closed on cold start. The engine has a pipe that runs from the left exhaust manifold up to the Thermal Air Cleaner (Thermac). When the flap is closed, it draws warm air from the heated exhaust manifold in to help atomize fuel and prevent throttle plate icing in cold conditions.

Once the engine warms, the left side should open and remain open until the car cools off after shutdown.

The right side opens only under full throttle to allow more air into the engine. It responds to low vacuum conditions produced by full throttle appliacations. Those of us who live in hot climates sometimes just disconnect the flappers and plug off the vacuum openings so they're both open all the time. Cold start conditions are seldom an issue here.

Again, welcome aboard and feel free to ask anything about the car. Anything that can pop up has probably already been dealt with by at least one of us.

 

thks for the fast reply friz.from what i see the left one don't close at all even when cold.it don't idle to good when i plug the vacum,about 600 rpm after it warms up,and it acts like it wants to stall after i first start it,hot or cold.it really runs good for a car with 115,000.some friends told me to go with a carb,but i want to keep the crossfire.LUVMYC4

 

Sounds like it just needs some tuning and basic diagnostics. Start with plugs, wires, cap & rotor, and set the timing. Change the fuel filter and air filter, and then every vacuum line on the car. After 23 years, everything made out of rubber has turned to mush and is leaking.

Next thing I would do is check the fuel pressure. Not easy to do on a crossfire, as there is no schrader valve.....you have to run a T fitting to a low pressure fuel gauge. It should have between 9-13 lbs of fuel pressure according to the factory service manual. In my experience, however, they don't run correctly below 10. It also would be a good idea to balance the throttle bodies and reset the TPS too. The procedure is outlined in both the Haynes and the Helm Factory Service Manual.

Down the road you might also consider changing the timing chain. After 100K, it's stretched out. I changed mine at 135K at it made a HUGE difference in how the car runs....smoother idle, better vacuum signal, and much better low end torque. A stretched out timing chain retards timing and costs power and fuel economy.

Above all, DON'T change to a carb. You will gain nothing, and will lose fuel economy, driveability, and you won't be able to pass emissions if you live in an area that tests. EFI is a very good thing, and if tuned correctly, the crossfire is as reliable as any other EFI system.

If you haven't already done so, check out the Crossfire Injection Vault. These guys are the CFI experts and know these cars inside and out. They are very friendly and helpful.

Crossfire Injection Forum.

Enjoy that first 'Vette.

 

thks again friz.i hope its nothing that big.i changed the plugs and wires,the timing was set 12 degrees btdc i set it at 6,i think thats where it should be,it made it run better,could you tell me what yours idles at?i think im going to put a roller timing chain in anyway.i dont care if it takes ten years i'll have this babby better than new,i love the way it runs and takes the turns,with the z51 suspension.1 more thing plz,how can i get the rpo numbers if they are not on the console lid,or the storage compartment like they say????thks again friz your tops

 

My car didn't come with the option label or service parts identification label either. The only way I know to get that information is from the Corvette Museum. For enough money you can order a build sheet or window sticker. They wanted more that I thought is was worth.

Keep the car as is. Get new friends.

RACE ON!!!

 

thks for the info.i dont want to pay it either,thats more money i can spend on stuff i really need

 

My 84 idles at around 800 in park, around 600 in drive. Something else you might do to improve your idle is clean the IAC (Idle Air Control). These allow air to bypass the throttle plates and control idle speed. The procedure is spelled out in the Factory Service Manual

The absolute best money you can spend for this car is to get the Factory Service Manual


The Haynes manuals you can buy at Pep Boys are only slightly better than nothing in my opinion. The factory manual tells you how to fix the car the way the pros do.

 

yea i have a haynes,dont tell you alot about the crossfire.im going to order a fsm asap thx again for the help.LUVMYC4

 

The FSM is a godsend. Sometimes I read it just for the hell of it....or I get curious about how something on the car works. Although after 10 years of ownership, I've had it apart 10 ways from Sunday, so there's little mystery left.

When you get a chance, post some pics of your new ride.

 

I unpluged my flaps ( ) and did this --



and yes I did finish the pop-rivets and foam around da edges .
I do feel a difference on top end.

 

roger on the pics,as soon as i get a good camera,the inside is really sweet all i need is some red carpet for the doors,the seats look like new,i don't know if they have been covered or not,the carpet and mats are in great shape,as are the door panels.its white,but needs painted,and new weather seals all around.i cant wait to post some pics of the engine.i painted the air cleaner red{someone painted it white lol,and i painted the valve covers red,and dress it up with some red wireloom,and polished all the control arms and put new shocks on the front.dang just like a noob to rattle on LUVMYC4