my car is idleing lower than normal is there any way to adjust or what would be casuing this ?

it's a 96 cavalier 2.2l OHV Automatic

what is a z22?

theres a sensor on the throttle, could be dirty. also you can adjust the idle i think on the throttle

Jake wrote:what is a z22?

dealer rice

What does it idle at? It should be about 600rpm. Much lower than that and you should see the low oil presssure light come on.

I can't remember, but to adjust idle, don't you need to short out one of the pins in the diagnostic port with the key on, then start the car and adjust the idle screw, then shut it off and remove the short?

^^^that doesnt sound right at all. atleast not obdII. i would get injector cleaner

Machzel08 wrote:^^^that doesnt sound right at all. atleast not obdII. i would get injector cleaner

He has a 96 OHV 2.2. I believe that's still OBD I

i thought the idle on our cars was computer controlled and there was no way to adjust the idle, plus if it idles below like a certain point wouldn't the comp go into limp mode or something and the engine would stall out. I know mine idles right around 500,550 600 somewhere in there about 12 or 1300 when the engines cold but mine is an 04 with the ecotec so it might be entirely different

You can adjust the idle on a computer controlled car, but it needs to be done in a certain way. If you just adjust the set screw, the computer will compensate for it. On almost every computer controlled engine, there is a mode to set the idle, so that the computer has the baseline to go by. You can do this with a diagnostic unit, but in many cases on OBD I vehicles, you can do it by shortin out a pin in the diagnostic port before turning on the car. This causes the IAC to close completely, then you start the car, adjust your idle, shut the car back off, and remove the jumper. The ECM will then have the baseline idle to adjust to.

As far as what the computer does if your car idles below a certain point, it opens the IAC to try to bring it back up to the set idle, and if it can not do so, it will give you a check engine light. Limp mode does not cause the engine to stall, it actually tries to keep the engine running, but in a safer mode.

So where is this so called set screw, is it like cars of the 80's and early 90's where you can pretty much just stick a screwdriver anywhere and wham it's set or do you really need all the tools and stuff. Plus unless you keep the idle right in the middle, like if you go too far one way or too far the other your pretty much just wasting gas aren't you .

The screw is on the throttle body. It's the stop for the closed position. As you tighten it, it keeps the throttle open just a little more to let a little more air in, hence increasing idle speed.

Yes, you can waste gas by setting your idle too high, and you can get deposit build up if you set it too low.

The idle on our car (either OBD I or II) are computer controlled and even if you set the screw, the ecm will compensate with the IAC and if you ever go high enough to make the idle higher, you'll get a CEL for high idle and you will get an hesitation when you push on the gas and the car may stall when you let go the gas.

Also, the way you said is NOT the way to set it on our cars. It is burn in the Eprom and cannot be changed unless you modify it with a programmer.

The 96+ 2.2 were OBD II and 1.5 in some case.



Gilles
2.3 Ho

i'm gonna switch out the the iac and the tps and see if that does it

it idles like around 500 or lower sometimes and the car stutters and sometimes stalls out on me.

Well if it idles any lower than 500 it probably would stall out on you either that or you would get a cel or possibly even carbon build up after some point because of your idle being too low

Ok well my car is still idleing low but it seems she got a miss in her and the engine like cuts out for like a split second and the idle hits below 500 when idleing and comes back on, driving is fine just when idleing it does this and it's sounds like a little backfire is coming out of the tail pipe not lound just a real quiet one that you can only hear when standing behind the car.

i checked the plug gap and it's got all new plugs and wires so what would be causing this ?

Hey J body if you can find out what's causing it let me know because mine backfires on occasion when the engine is cold mostly when i first start it in the morning, i'm fairly sure the timing on our cars is computerized or i would suggest you check that. Being as you said there is an apparent miss somewhere in the engine. If you let your engine continue to run with a miss even if it's just at idle your gas mileage will probably sooner or later drop, i think an engine miss would probably again even cause a cel light. I know a car we had years ago not a J but a blazer it backfired one time and it managed to blow a hole right through the muffler it was loud from then on lol .

Quiklilcav wrote:

Machzel08 wrote:^^^that doesnt sound right at all. atleast not obdII. i would get injector cleaner

He has a 96 OHV 2.2. I believe that's still OBD I

sorry man i gotta correct you on that gm has been experimenting with obd2 since 1994 thats why you see those connectors on older cars like grand ams sometimes, in 1996 all gm's used obd2

even the now defunct oldsmobiles.

Does you engine light come on? does it come on when you first turn the key on?
Look to see what your throttle body looks like inside, sludge in the bore and back side of the butterfly is common. (no codes will set)
Check for carbon chunks wedging the EGR valve open. most of the time causing an emissions code. This will cause intermittent severe idle issues and will clear up if you press on the gas. Most people say they have to drive with both feet to keep it running at a stop. Just pulling the valve off to see if the valve is open doesnt cost anything as long as you have a 10 mm socket handy. after you take out the bolts slowly pull it off making sure that the gasket doesnt get distroyed. As long as you dont pick at the gasket you can re-use it. oh yeah, EGR is the exhaust recirculation valve, it is located next to the master cylinder , is vacuum controlled on earlier models, and elecrically on newer. Some dont have them. This is a common problem that I have with several GM vehicles not just the cavs. Hope this helps.

Oh one more thing, You shouldnt have to go through an idle relearn procedure if you didnt change any parts ( ie, ignition module) or clean the throttle body out. I wouldnt turn the idle screw either. clean the throttle body first.

01 cav w/01 3400 gam gt 4t45e

Did you figure it out?


01 cav w/01 3400 gam gt 4t45e

Wow!.. this is exactly the problem that initially led me here. I've set aside some time tomorrow to take it on, along with some other projects I need to do (including changing the spark plugs and doing a compression check while I'm in there, just because...) I was worried about the IAC O-ring, but I'll just be careful like the advice above and hope to re-use it. Got my carb cleaner handy for the throttle body, too. Just for grins I'll try one suggestion at a time and note what happens, starting with the easiest and least invasive (which would be to clean the friggin' throttle body). I'll post back with my results (and hopefully a solution).

Question: Anyone know what the part number is for that IAC valve O-ring, or where I can get it? I can't find it at Advance Auto, NAPA or AutoZone, and I'm thinking there's a chance I'll have to replace it.

BTW, mine's a 2000 Sunfire 2.2L OHV, for the record.

- Steve



Remember, the main thing is to keep the main thing the main thing...

Well, it turns out that I had a number of things going on, not just one problem. I just got this car, bought it used with 105,000 miles on it but in (mostly) really good shape. Basically, some regular tune-up type stuff made a HUGE difference, and I didn't even touch the IAC valve. Here's what I did:

- Degreased the engine (just because it needed a good cleaning). Was careful to not get the distributor or other important bits wet...

- Replaced all 4 spark plugs with new, properly gapped plugs. The old ones were worn, although not extremely. They DID look like they were the original plugs, though. BTW, the Haynes manual for my car (2000 Sunfire 2.2 OHV, Automatic) is wrong about the gap for plugs on this model. They say it is 0.050, but that's not true. It is 0.040... The 0.050 gapping came along in 2001, NOT 2000...

- Replaced all 4 spark plug wires with new ones. The old ones had a good bit of corrosion inside the caps.

- Cleaned out the throttle body with carb cleaner. It was pretty gummy in there, now it's clean and shiny Checked the throttle action, confirmed that it was operating correctly and ranging from fully closed to fully open.

- Replaced the air filter. The old one was dirty and BENT. It had been jammed into place incorrectly, and unfiltered air was bypassing it in the intake.

- Verified that all 4 fuel injectors were connected and seated properly.

- Ran a full compression test on each cylinder while I had the plugs out. All 4 plugs were out during the testing, and I found a problem that is probably a BIG factor causing the rough idle. Cylinder #3 has low compression compared to the other cylinders.. Low enough that it is out of spec according to the Haynes book. The other three cylinders were reading 175 (give or take a little) on the compression gauge. #3 was only hitting 120, which is below the spec of "within 75% of the other cylinders" set by Haynes. Low enough to cause a rough idle... So, I added a little 5W30 through the spark plug hole, and ran a wet compression test on #3. It DID increase compression, but not by much... Only up to 130. So, I'm losing compression in that cylinder, and it's probably a valve leak rather than a piston seal (whew! MUCH easier to take on when I have the money and time). The good thing is that I'm not losing ALL compression; it will hold at 120 for quite a while, so it's not dead yet.

- Meant to change out the fuel filter, but ran out of time. Will do that tomorrow.

- Didn't change the oil because the current oil and filter only has 1500 miles on it.

The end result??? Well, I'm thrilled, actually! It's purring like a big kitten when idling in park or neutral, which it wasn't doing before. The idle is no longer rough when the car is not in gear, and the in-gear idle is much improved, although not 100% smooth. A passenger didn't notice idle vibration at all, actually, until I pointed it out. I also got a BIG boost in performance and throttle responsiveness. It jumps like it should when I get on the gas, which it also was not doing before. Acceleration is greatly improved, especially when I'm at higher speeds on the highway. Engine noise is reduced as well; it's a much quieter ride.

So, it seems that doing normal tune-up things worked wonders in this case, and I have an explanation for the remaining slightly-rough idle which I'll take on very soon (the leaky valve in cyl 3). Give the motor some clean, regulated air with no leaks in the intake, a clean throttle and some good plugs and wires providing solid fire and voila! It's a happy camper without the shakes. That, and the compression testing was worth the effort because I now know where to focus on next, and am aware of a problem long before it became destructive (or so I hope). I'd strongly suggest getting out the compression gauge.

- Steve

P.S. - You think the Armor-All on all the black plastic under the hood made a difference? Maybe the car FEELS pretty, so it's ACTING that way, too...?





Remember, the main thing is to keep the main thing the main thing...