1990 740 GLE 16 Valve_high_idle_thoughts??

smoky128 · Post by **smoky128** » 09 Feb 2008, 23:34

Hi everyone, im a new member, but this is my second volvo

Ok so i currently own a 740 GLE. bought it a few months ago. I had to replace the oxygen sensor and the in-tank pump which cost me like 600 from the dealer. Before i replaced the oxygen sensor the car was running horrible. but now the only problem that remains is that when the car iddles it does it so high like around 1400 1500 RPM's. Now when i first start the car it will idle fine and then as soon as it warms up all of a sudden it just starts reving higher, so it must be a censor but i have no idea which one. I recently tried replacing the MAF but it didnt do anything. I also tried to use a different ECM to see if that would do anything, but no luck there either. Please if anyone has had this problem its driving me nuts to figure out what it could possibly be. I think it has something to do with the car having a hard time starting in the morning after sitting over night, but i could be wrong. I looked around but couldnt find anything in the other posts yet.

Post by **sseir39** » 10 Feb 2008, 08:12

A high revving engine in those series Volvo's usually means there is an air leak somewhere in the intake system. Check all hoses for cracks and breaks. Also, the accordian type hose going to the intake manifold can crack. Anything plastic will break eventually. Also, the idle speed motor can be going or even the idle adjustment on the air intake manifold.

Chances are it is something simple. For a good series of information on the RWD Volvo go to brickboard.com, the RWD section, FAQ section.

Good luck!

smoky128 · Post by **smoky128** » 10 Feb 2008, 21:20

k but the thing is that when i turn the car on at first like after its been sitting for a while it idles normal, then after it warms up a bit, it just kicks in.. so you think its still what you said im youre previous post??

Post by **sseir39** » 12 Feb 2008, 18:08

Still would check out those things. Check out the website I suggested. They have far more info.

smoky128 · Post by **smoky128** » 12 Feb 2008, 18:10

ya i checked the hoses cant see anything, and the accordion hose thing seems okay, im gona have to buy one of those books to locate the idle speed motor, thanks again

Post by **sseir39** » 12 Feb 2008, 18:12

ISM should be under the intake manifold with two hoses and one electrical plug in.

smoky128 · Post by **smoky128** » 12 Feb 2008, 18:51

ok i located it, looks easy to get at, im going to go to that parts site i seen on here and order one and see what happens, the one thats on there looks like the original one that came with the car is still says BOSCH on it, lol. thanks again