Rallyssport

I have a 92 RS 305 TBI When I put an open element cleaner on it it seems doggy. When I have my stock air cleaner on and im drivin and give it about half throttle the rpms jump right up there but when i have the open element on the rpms are doggy and go up real slow? Whats the deal?

speedlvr

Injectors too lean for the greater airflow. Raise the fuel pressure (good tech article on this site) and that should help a lot.

Pukka

I never had a problem like that. Check to make sure the base is not interfering with your throttle assembly

------------------
92 Camaro RS, LO3, 5-spd, T-tops

Performance:
K&N Open Air Filter, Edelbrock performer TBI intake, Fastchip Prom, Timing +4 degrees, Centerforce clutch, Xact 8mm wires, SLP 1 3/4" Headers (coated), Flowmaster Catback Exhaust, Z28 Grille w/aftmkt fog lamps
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers.
NEXT UP: TBI mods, 3.42 gears w/Torsen posi

snflupigus

both posted assumptions have been looked at i assume, since i responded with the same concerns.

have you checked out all my suggestions yet rallyssport?

let us know what the problem was when you do find out.

greearhr

Did you relocate the inlet air temp sensor?

Bear Tracks

chevyboy07 91

make sure any and all hoses are connected to the TB...(PCV,etc). Plus, there's a vaccuum hose in the back of the actual TB plus a couple more in the front. Maybee you pulled it out on accident. That will make the car run like ****. You didn't lean out the friggin injectors and all that non-sense

Andy89RS

Despite the greater intake airflow of the air filter, the engine still won't be drawing enough air to lean you out. Like chevyboy said, check all your connections. Did you make sure to plug the port that the thermac control hose was plugged into?

Rallyssport

Ya I double checked everything. I made sure i pluged the vaccuum port. I have had the air intake sensor in 2 places. I put it back in the open element just like stock. The other i just hooked it up and put it outside of the air cleaner. Yes it does clear everything. The throtle cable, coil. Fits real good. The only thing i didnt do was reset the computer. I wouldnt think reseting the computer would be a big deal in this case. Let me know if it is. Thanks

Rallyssport

Oh by the way i still cant figure it out. I think i will just make me a dual snorkle air cleaner. That will give it more air then its gettin now! Hopefully that works!

speedlvr

Injectors may be lean since you have all the friggin hoses connected and all that nonsense done.

My305camaro

Rallyssport,
I have done the open-air-mod, and you must be running lean. If you know a guy in your local performance shop, go in and have him hook up a scanner to your OBD-II port and read your O-2 sensor readings. If they are lean, which they will be, you need to follow the instructions on this site to up fuel pressure. I have done all the mods in the "Ultimate TBI" and am happy with the outcome. The only thing I didn't do was to hook up a volt meter to my O-2s, I had that professionally done. I have had no problems like your having, and am runnin 10.5 psi normally, and 13 psi with the 0-2 sensor disconected at the 1/4 mile track. Hope this helps!

------------------
1991 Chevy Camaro RS TBI

Jza

OBD-I...

RGZWS6

Same problems here!! I installed the 14x3 open air element and my car seems weaker than before. I had the stock setup but with the "ram air" set up from the front end. I plugged a 4.7K ohm resistor into the IAT sensor to make up for that. No clearance problems anywhere and the thermac vaccum was plugged as well. (Low end feels stout but up top seems weaker than stock)

I was all pumped to do this since so many people have had good results. Now all I have are looks. I guess I'll have to do the U.TBI mods next to bump up the fuel pressure.

------------------
89 Formula 305 TBI
160* stat, 200* fan switch, K&N, Headers, 3in Flowmaster (hollow cat) back, pullies, 1.6 full roller rockers, B&M trans cooler, home-made ram-air
3.73 Richmond gears and SLP Zexel Torsen Posi (MAY 01), Wonder Bar

[This message has been edited by RGZWS6 (edited May 14, 2001).]

89IROCZ28

iTrader: (14)

Try locating the IAT sensor(s) to a cooler location, away from any heat generated by the engine. This will still allow the ECM to compensate for warmer/cooler temps, but use a richer mixture than when in the stock housing or just lying in the hot engine bay.

Also, are you running a dropped open element less than 3"? If so, you might be restricting the airflow into the top of the throttle body.

Try a test run w/o an air cleaner - make sure you're not going to suck the hood insulation in the TBI, and don't run where there's a lot of dust being kicked up!

If it still runs bad, it sounds like you're running lean. It could be the IAT is located in a bad spot when its not mounted in the stock air cleaner housing; or you have a vacuum leak somewhere when the stock air cleaner isn't being used; or your fuel pump/pressure isn't keeping up (changed the fuel filter lately?).

If it runs decent, the open element housing is restricting airflow in some way.

In the tech article posted on this site related to installing an open element air filter, it suggests disconnecting the battery for a couple of minutes to 'reset' the ECM. Otherwise, you may have to drive it until the ECM figures out it's running too lean

Rallyssport

89IrocZ28...So your saying if I unhook the battery for 30 sec. That might make it work? Ya i tried it with no air cleaner and it did the same thing. Ill try that and see what it does. Hopefully it works cause i dont really want to mess with my fuel press. Thanks

JPrevost

I don't know what the problem is because this is making NO sense to me. Let me try and relate. First let me recall 2 years ago when I was doing little things to me car. I had SLP headers and a hypertech that's IT!!! I did a few of the u.tbi mods like remove that heat riser crap and silincer ring. I was at work and glass beed cleaned my air cleaner, I had to get paint for it so during lunch I drove off. I came to the SAME place in the road that I always did before pulling out onto the highway. From a slow roll I tried to accelorate into traffic and the "wheel" ( ) just spun and I hit me like a lightning bolt....DUH....I had forgoten that I didn't have my air cleaner on. I was really a newbie and I was kind of scared about getting something sucked in so I made my trip to the store as FAST as possible. This car moved, I was so impressed with it that I got a dual snorkel setup a few weeks later. There was really a noticable difference, maybe the no air cleaner and headers worked great, I don't know. Still...you should feel a difference, there is no reason for it to feel any slower than before. If you're around Columbus Ohio anytime make sure to stop in or let me know, I'd like to figure this one out hands on.

------------------
, Jon (350 TBI!)
91 Red My website

Rocky

would putting on a throttle body from a bigger motor help?
mine motor is doing the same thing after i put in a open element air cleaner.

snflupigus

anybody having problems with no power after an open element, first check your wot air fuel ratio with a volt ohm meter.

then maybe boost your fuel pressure, like the article says, i wouldnt go more than 4 full turns on the screw.

just keep playing with fuel. you want MORE air, just because you give your engine more air and its not faster doesnt mean you want to restrict your air intake again. you want to compensate somehow for that increase in air. most likely a small fuel boost. check your plugs. do a tuneup. runs some of that 2$ a gallon gas with some injector cleaner in it. buy a free flow muffler. you will eventually notice the gains from flowing more air than the stock peice. but like any modification you are going to do for performance enhancement. you will ALWAYS have something else to do after you do it. if you dont plan on doing any other mods besides the open el. dont bother even doing that. seriously. there is just no point.

RGZWS6

Well here is a big DUH but maybe not:

Since the screw down bolt was too short to accomidate the taller filter, I flipped the lid over so the dome was facing downward. I wonder if this could be killing the flow at full throttle. Don't hurt me poppa!!

I went and bought the correct size bolt last night and will see if it makes a differance later today.

Think that 4.7K ohm resistor has anything to do with it????

------------------
89 Formula 305 TBI
160* stat, 200* fan switch, K&N, Headers, 3in Flowmaster (hollow cat) back, pullies, 1.6 full roller rockers, B&M trans cooler, home-made ram-air
3.73 Richmond gears and SLP Zexel Torsen Posi (MAY 01), Wonder Bar

RGZWS6

Well I may see another error in my ways. Looking at the tech article (couldn't see the next button) I see that a 7.5k resistor was used. Not a 4.7k. My ecm must think its winter!! I got my hands on a 6.8 and a 8.2. I'll try these out tonight.

NOTE: The capped flipped over does not hinder air flow on my set up.

Rallyssport

I unhooked the battery today to reset the computer. It seems a little better. Im going to time myself with the open air cleaner and the factory cleaner and see which one does better. Why can i hear more of the engine sound with the open one on than the factory?

RGZWS6

UPDATE:

I got rid of the 4.7 and hooked up the 8.2K ohm resistor. BIG DIFFERENCE!!! Next I'll reset the ECM, but wow, the open element works great. Not to mention it really cleand things up under the hood!!

snflupigus

my opinion.

I think the resistor is not the best way to go for everyday driving. your ecm tunes your car automatically with a lot of sensors. by forcing the ecm to beleive that the air coming into your engine is a certain temp. i think the farther the actual temperature is away from the forced temp, you could be running worse than if you had the actual iat mounted at least somewhere under the hood.

the only side effect is the usual that you are going for by using it, running rich because the computer thinks you are getting dense air into the engine, but you arent, so your air fuel ratio is going to be off.

the more i think about it. the more i think that its a good idea to leave the iat connected, and maybe put the resistor in when at the strip.

just my opinion.

89RS355

Everybody here brought up great suggestions, and nobody was wrong. I think this is a great reminder of how important it is to look at your engine as a "system" rather than a few seperate components. Even simple mods can effect alot of other things down the line. This is a great thread, textbook.



------------------
Jerry

-------------------------
89 RS Lt Blue T-Tops T5
355 Crate, Compucam 2040
Pst Front Hotchkis Rear
Edle. TES 3" Flowmaster
Harwood hood, bla, bla, bla...
94 Z28, LT1 6M, Black
Most of the bolt-ons
-------------------------

buddman91rs

when i took my 91 rs(below) to the dealer to have the brakes redone, they took a look at the air cleaner and said that it was too thin, i've got a 14" round by about 1 1/2" thick paper OE cleaner.....they told me to go buy a 3 or 4" thick k&n they said that the engine pulls more air in than what my air cleaner allows.....try a larger air cleaner......

------------------
1991 RS LO3
mods: 14" chrome air cleaner, straight-piped after cat exhaust with one chrome dual tip on the left side.
future mods: headers, removing smog equipment, and as many cheap mods as i can find
aol s/n: budman8503

GONE MUSTANG HUNTING.......
BACK IN 10 SECONDS

AJ_92RS

Rallyssport,
To answer your question about the louness of the engine with the open element. Now you can hear the air being sucked in by the TB. With the stock air cleaner, all of the suction is being done in that little bitty seam between the hood and fascia. Hard to hear. That's all.

All I did on my air cleaner (I'm a cheap *** ) was go and buy the K&N Filter #1500 for fullsize trucks, I think it's a 3" or 3 1/2" tall filter, and put it in with the lid flipped over so it would reach the stock stud. It is just a touch to high though. Later I am gonna cut off the excess diameter of the lid that doesn't cover the filter. That will lower the overall height. Then I'm gonna drill holes around the bottom outside edge of the lower part so that it gets even more air flowing in. That way I can still put in the old filter when it gets cold here. I don't see any reason to waste a K&N in sub-30 degree weather, do you?

I have had no problems with my car acting like it's running too lean since I've done my mods. However, I do wanna adjust the fuel pressure just to make sure that I am getting full pressure & power. I left my IAT alone so that it does get "true" readings of the air temp under the hood. I guess if I go with a cowl induction hood, then I will relocate it to the cowl. Part of what you may be experiencing is with such an improvement on your lower RPM's, it may just "feel" like the top end has suffered. Best of luck.

------------------
92 RS w/t-tops 305 TBI Auto.
170K miles and don't burn a drop o'oil
-K&N Truck filter #1500 w, open ele.
air cleaner
-Dynomax 2 1/2" cat-back
-B&M TransPak
-Jet Stage2 Chip
-180* T-Stat w/ 185* Fan Switch
-JVC CD--Alpine speakers & 4ch. amp
Rockford 2ch. to 2 MTX 12" subs

Rallyssport

This sucks...I keep hearing about how good an open element air cleaner is. How much hp gain is it suppose to be? I timed my self and its a couple sec faster off the line but same speed in the long run as the stock air cleaner.

AJ_92RS

I don't know how much HP it help with. I see K&N Filters ads that say "As much as 20HP!" Well that's probably on a +400hp motor. Who knows. A free flowing air cleaner does help the engine run more efficient. Maybe not a lot, but every little bit helps stuff like gas milage, engine wear, power output, etc.

About the biggest crutch on GM engines has always been exhaust. From the valves to the tailpipe. That's what caused cam companies to develope dual pattern cams for GM engines. That way the ex. valves open more and for a longer amount of time, trying to work around the flaws of the head design. Do you have any exhaust mods done? It's just like 89RS355 said, the entire system has to work together. You can't put more air/fuel into an engine until you get the spent gases out.

snflupigus

anybody that said they gained tons of power from the open element swap was judging off of sound of the engine crossed with the little increase in power. the sound multiplies what people think their engine just gained. its a trick we play on ourselves since we have crappy engines. every little increase and our brain gets sensory overload. LOL

gain is minimal, however happyness level from the new roar of your engine at wot, priceless.

anybody really expect to gain 20hp by installing an airfilter. nice try.

Macgyver

I gained a noticeable amount of top end with my 14x3, even more when I finally broke down and bought a K&N.

Not 20 hp of course, but It was noticeable.

Eggplant Jeff

Yeah, I gained 20 HP from my open element. But that was because my stock setup had the opening welded shut, and all the air for the engine was leaking in around the stud that holds the lid on. (kidding)

The problem with the open element mod is that you then need to get more fuel in too. Some people force this by increasing fuel pressure or putting in that resistor (incidentally the HIGHER the resistor, the COLDER the computer thinks it is. So putting in an 8K instead of a 4.7K makes it run richer). The computer should compensate also, but it takes it a little while (a few days or a week). Resetting it probably won't make it happen a whole lot faster because it starts with the stock fuel tables and begins working from there.

Basically the computer will compensate either way. Even if you make it run rich now, it will watch the O2 sensor, see it's running rich, and correct that. Of course there are limits to how much it can correct, which is why you often need a chip if you get a new cam or something. But from the open element and/or fuel pressure, it should be able to get everything balanced back out in a little while.

The problem with this is that it means you don't put the air cleaner on and see the power. It happens slower, so you need patience and you need to write down a metric ahead of time (say, time or speed over some fixed course, I used to use this long access road near where I worked). Then, a week after you've put on the air cleaner, run that same course and see if your times/speeds are improved.

JPrevost

Open element is GREAT for top end. You will notice a difference. If you want to see what a difference it will make, install your stock air cleaner on a 300+hp engine then go to open element. That is an even bigger difference. Basically there is air coming in and air going out. The air cleaner is like a cat-back system, intake manifold like headers, they both end at the valves. I see the open element as being one of the best mods to do for our cars. The next step is usually more expensive: headers, gears/posi, heads, intake etc.

------------------
, Jon (350 TBI!)
91 Red My website

Rallyssport

Ya im startin to feel a little difference. Its nothing really big but the only way I can tell is if i put my old stock air cleaner on. I think its faster off the line but i dont think theres a diff in top end. Thanks guys.