idle control valve fail

[pong]

my idle control valve ifailed already

so i decided to get a surplus one first,
however, this only lasted a year or so.
it still runs and idles ok, however, sometimes
it cuts off and my car does not run

this time, i bought a brand new one.

my main problem now is when i attached the
bnew one, idle is so different, very high for that
matter, then when u unplug the wire there,
supposedly idle will change, but it does not
then when i turn on the aircon. boom, engine
dies

so what is wrong? what should i do now?

thanks!

[Tiger]

Sounds like it is not the idle control valve problem... did you check for voltage at the ICV plug?

[pong]

actually, what makes me wonder is the fact that i just plugged in the old one and the idle is ok. 800rpm when i plug in the new one, 1200rpm

the surplus one that i got is the L type, the original one for my car is the T-type. now i have the T-type and its giving me a headache. could it be that the hose is a bit bigger now?

[pong]

btw, with the old one, when i remove the plug, the engine dies out
so i guess, it provides current to run the icv.

[pong]

anyone?

also, do i have to adjust the tps or is there anything else that i should adjust?
to make this thing run properly?

thanks!

[myles]

your can can only use the t type of icv

[pong]

your can can only use the t type of icv

yes, its supposed to be the T-type only,

however, desperation kicked in and the only icv that we could find it the L-type
my mechanic was able to make my car run well after that. however, my mechanic is not here anymore and i do not know which parts he adjusted.

i have a t-type now

[billkirk]

Check out the crankshaft position sensor cable, a problem there can have similar symptoms to your description. My '89 525 would starting momentarily then die. I thought it was the ICV and gave it a good soak with carb cleaner and WD40. No change. I checked the resistance on the connector for the position sensor (under the intake manifold, buried generally below the ICV but impossible to see from above without a mirror) and found no resistance (should be 54 ohms, from memory). My problem was a cut in the cable near the water pump, cut half-way through it worked OK until the fan kicked in and the stronger airflow pushed the cable enough to break the connection at the cut. That may explain why your problem happens when the a/c is started, because that can trigger the fan to engage and start blowing stronger. Then again, maybe not.

Over the 10 years that I've had my 525 I've learned that when I can't find an obvious answer to starting problems the place to check is the page in the Bentley manual that covers the various sensors; water temp, and the position sensor; as the ECU won't let the engine run if it doesn't sense that the engine is running once it has started. The ECU immediately shuts off the engine. Others have mentioned that the ECU does the same thing if it can't sense anything from the water temp unit.

Good luck...

[citti2004]

I got the parts that I need off of eBay. Well, I have the idle control valve (http://www.carpartswholesale.com/cpw/idle_control_valve.html) and the fast idle valve. If I am somewhat mechanically inclined, could I replace these parts by myself? I don't want to pay a mechanic for it for i know that i can make it, right?anyway, My idle is messed up and it is doing the bouncing idle thing. I mean when it is idling, its very annoying. So i think that replacing it would be okay. And also how it should be clean?Thanks in advance.