Bad Idle air control valve = no start?

[kraia]

I'm trying to find out if a bad idle air controll valve can cause a no start. I have a '89 325i and when I turn the key to the on position the valve makes a quick grinding noise like it's working and then stops. I thought that it always ran with the key on engine off.

 

[Rukus]

try taking your idle air control valve off and plugging both ends of the hoses (mind you don't run your car like that!!! just test it like that) and see if your car runs.

 

[ldzpstnr]

You can eliminate the Idle control system on the 318i's, I did on mine. Might be able to also do the same on the 325's. On the 318 throttle body there is an adjustabe stop screw, you can turn this to crack open the butterfly in the throttle body and let a little bit of air in, just enough to make the car idle. If you look RUKUS you will find it. It is of course on the underside of the throttle body.

I do not think a bad idle control valve will keep the car from starting. If you have to give the car a little bit of gas while you are cranking it over. All the idle valve does is monitor the engine rpm and increase or decrease how much air is let in through the valve to control the idle. My idle system was not working right and pissing me off so I just ripped it out, plugged the holes and adjusted that little bump stock screw on the throttle body tell I got the car to idle around 900 rpm.

This is just what I did with my car, not saying everyone should eliminate there idle system. I just didnt want to spend $200 on a new idle valve and control module.

Later.

 

[Rukus]

i wouldn't do that.

If i wanted to "fix" my idle control valve, i would either kludge it, or install a deadset idle valve.

to idle at the proper speed and proper air/fuel ratio.

 

[AutoXfreak]

If you take 5/8" heater hose and run it in place of the Idle Control Valve, If you need to run the car for a few days you can drill a 1/4 inch hole in a penny and place it in the hose and this will meter a small amount of air into the intake and give a resonable dle speed.

 

[Rukus]

actually,
thats called deadsetting your idle. its perfectly fine. except that you lose that extra idle speed that you might want for when your car is cold.

 

[bluebimmer]

When the car idles up and down in by itself in any gear, is this the IAC valve? When I bought mine last year, I bought a new IAC valve for it and it still does this on occasion. What' causing this?