frag

I might try that eventually. Thanks for the suggestion.

I dont have the answer to your question (sorry), but would like to know how you came to that conclusion. Thanks in advance.

Since, in your car, the temp gauge is conrolled via the ECU by the same coolant temp sensor that controls part of the fuel trim, I would replace the coolant temp sensor. It's due anyway if it has not been replaced yet and it's a relatively cheap part. Do a search on this board and you'll find info on how to locate it and replace it. It might be a problem with the gauge itself but it could also be the temp sensor. Have you had problems starting the car when the engine is hot?

The low fuel light is the only idiot light that does'nt light up when you turn the ignition to "On". It is lit so rarely that the chances of it being burnt are slim. If you want peace of mind, put a gas can in the car and drive til it lights or til the car stops. Dont do that on the highway . I tested mine a few years ago and it is working. Before that light comes on, your fuel gauge needle will be well under the E mark. If I remember well I had around 60 kilometers left after the light came on.

I use anti-seize. The torque value is 15 ft-lbs.

Thanks cookie. For the time being and for lack of a better method, I tried an oldie and connected a vacuum gauge to a vacuum port (intake runner for cyl no 3). I get 22 inches of mercury and absolutely steady. When I do the acceleration (2500 rpm) deceleration test the gauges jumps up 4 inches when I release the throttle and slowly gets back down. So everything seems perfect mechanically (rings, valves, vacuum system in general). I also sprayed WD40 around the intake manifold gasket with no effect. The last resort will be a thorough upper cylinder cleaning. Maybe it's just carbon in some of the cylinders.

A diagnostic machine would detect a small vac leak?

Maybe what he calls a "thermostat" is in fact a temperature sensor. Replacing the thermostat would only, by decresing the average coolant temp, decrease the number of times the fans would come on if the previous thermostat was "lazy", but it would not change the temperature at which the fan or fans would come on.

If I may chance a diagnostic, I think your problem is PCV related. When you drive downhill your engine is on "compression" and generates a lot of vacuum. Maybe that is sucking oil into the IAC, flooding it and temporarily disabling it. Check or replace the PCV and see if that cures the problem. It might not be necessary to clean the IAC. Just an idea. Edit: thinking about it still, it seems something like that would also generate a lot of grey smoke at the tail pipe when you drive down those hills. Just a tought...

My remarks, though exact for the 96, do not apply to mdwst car which is a 91 I think.

It all depends Cougar. On a 96 2.2L there is only one coolant temp sensor under the right side rear intake runner, under the IAC valve. There is no other sensor or thermo switch. This sensor sends its info to the ECU wich in turn uses it to trim fuel, activate the temp gauge, start the radiator fans, and maybe other things. I dunno when this new configuration began but I suspect it was already there in the 95 2.2 L. Not sure about that though.

Compared to what they were "before", they can now be called «benign" ? or "Buy baby" X 3 ?

I'll keep exploring but I suspect it might be a collection of small geriatric ailments, just like with my own body...

According to Haynes, the inner wire should have 3/8 to 1/2 inch of deflection near where it connects to the throttle plate. And that's the slack mine has.

I also took mine off with the engine cold and it did'nt seem to do any harm. You could have a look at my thread «IAC cleaning, asking for help» that is just below yours on the same page to get some more info. My opinion is that if the shutter cylinder moves freely, you dont have to clean it. Mine was more like between a third open. I cleaned mine anyway both with brake cleaner and throttle body cleaner. The results are described in the thread jus mentionned. There are two easily lost parts still in the throttle body opening where the IAC connects. A round rubberish ring and behind it a round metal disc with openings and a spherical cap soldered to it. Be sure they are still there when you replace the valve body. Did yours have three bolts holding it like mine or four?

A thermostat is a device that keeps a certain temperature constant. You have that connected to the lower rad hose on your car. The coolant temp sensor tells the ECU what the engine temperature is so it can trim fuel accordingly. With this info the ECU also activates the temp gauge ON A 96 2.2L. There is only one sensor on your model year engine. I think there are two on previous models. I dont know about turbo engines but if yours is normally aspirated, there is no need to remove the intake manifold. Just disconnect or push aside a few vac hoses and such and it's readily accessible with a 3/8 ratchet and a medium lenght extension. Only a few ounces of coolant will leak out but it could help to lower the coolant level in the rad first with a turky baster for example. Good luck!

Two good suggestions that make me notice I forgot to put in the «already taken measures» list that both O2 sensors habe been replaced recently and that the coolant temp sensor has been replaced a couple of years ago (around 40,000 kilometers ago). The strange thing is that when I relase the throttle the idle is smooth for the first 5-10 seconds and then slowly gets a little slower and rougher.

IAC cleaned and reinstalled with a new gasket. As far as I can tell, nothing as changed. That, of course, is almost good news: I was afraid to mess up things cleaning that valve. Lets recap the initial problem and measures taken. Maybe someone can help. > Problem: slight to moderate idle roughness. Idle is slightly lower than what it used to be at. Nothing like if the engine was running on three cylinder, rather 3 and 1/2 or 3 and 2/3 to use a comparison. 1) Plugs (NGK) and wires are new 2) Fuel and air filter have been replaced not long ago. 3) Throttle body and plate are clean. 4) IAC control module cheks out via Haynes method of testing it (9ohms between terminals 1 and 2 and terminals 2 and 3. 5) Coil tests OK. 6) MAF looks clean. 7) All vac tubes were inspected inch by inch and are like new. 8) I run injector cleaner (mild kind ) almost at evey other fill up. 9) I have checked all grounds and they are good. EDIT 10) Both O2 sensors are almost new 11) The coolant temp sensor is 40K kilometers old only (2 years). Revisiting the symptoms: When I start he car the idle goes to 1500 first like it always did. It then slowly decends to 1000. Up to that point idle is silky smooth (am I right in thinking that if I had valve problem, it would already show at that rpm?). This smoothness is still there until around 900 when a sligh roughness creeps in, when the idle settles around 680- 700 rpm, the moderate roughness I have previously described happens and stays. Maybe its the effect of the genreal aging of the car and I will have to live with it. WHAT HAVE i LEFT OUT? Would appreciate any opinion on this at this point. Thanks in advance.

V8volvo: that's where it is alright and like avk said, no need to remove the intake manifold. Setright, it's different on my 96 and I suspect it's the same on a 95. Also, for those model years there is only one sensor.

Two more questions Olnick if I may. 1) I can't find the torque value to replace the valve body to the throttle body in Haybes. Do you have it by any chance? 2) Did you simply replace the grey plastic control module exactly where it was in the first place or did you make some adjustments after having replaced the valve? About the wet oily gunk. Maybe you had a bad PCV valve or somehting. All I found in mine was a thin dry black coating that did'nt seem to interfere with the valve operation. At least my mind is at rest concerning this valve and I'll go on looking for something else if this cleaning does'nt cure the roughness in the idle. Next willl probalbly be the throttle position sensor.

One last note before I return to the car. This magnetic field between the top control module and the valve cylinder stem is so strong that when I went to replace it, it pulled the part right off my fingers ! Thanks again Olnick.

Well you saved my day Olnick. It was indeed a strong magnetic field that felt very much like a spring. So i'm finishing the valve cleanup, will replace and will report back on the results. Tonight or maybe tomorrow. Thanks again! Feels strange to be doing this with help from someone in Hawaii... Very small world in some respect.

Olnick, what year is your Legacy? Just to evaluate the chances my IAC being similar or different than yours. It really feels like a spring but I'll look, and feel, again. By the way, as far as I can tell right now the moving half cylinder (for lack of a better term to describe it) seems to moves very freely inspite of the fact that its covered with a thin and rather hard to remove coat of dried up oil and crap. I'm beginning to question the wisdom of going any farther but i'm afraid I might not be able to stop at this point.

One more info. Off the throttle body like it is right now, the valve is 1/3 open. Is this right?

HI! Im in the process of cleaning my IAC. Slight idle roughness that other measures did not get rid off. At this stage I have the whole body of the valve on the sink counter and have begun removing the top electric part (the one that controls the moving cylinger inside the valve) to get at the dirty cylinder and be able to clean it thoroughly. I removed the two philips screws holding the top grey plastic part. The problem is the plastic electric part on top of the valve is tied to the cylinder's axle with what seems to be a coil spring somewhere. When I pull on this grey plastic part it slides off the vertical axle a bit but the spring resits its being removed entirely. I'm afraid that I will mess up something if I plull any harder. Could someone that has done this on a similar model year car (95-96 2.2 L) give me some advice here please? Thanks in advance. By the way, I first did a search on this forum cause I knew IAC cleaning had been discussed here before, but found nothing pertaining to this problem.