1992 Volvo 240 Idle

piv15 · Post by **piv15** » 24 Jul 2013, 23:31

This is my first post here. I'm not new to forums. I've used the Volvo Forum for some time now. I've posted about this issue there, and haven't come up with a good solution yet. So, I figured I'd post here!

Here's an in depth description of the problem. The car has an idling issue that I've been troubleshooting for some time now. When I start it when the engine is cold, like after it has sat over night, or for a few hours, it runs flawlessly. However, after driving it a while and the engine warms up, when I put it in park it idles at 1500 RPM. That's too high. It wastes gas and it's hard on the transmission shifting out of park. That's just one portion of the idling problem. The other portion is when it idles too low. If I turn it off for about 15 or so minutes, and try to drive it after that, it idles horrible. It idles less than 700 RPM and bounces, surges, and shutters. Eventually it will either die, or after a while, it will come out of it then go right back to 1500 RPM.

Here's what I've done.
Cleaned throttle body, cleaned the flame trap, switched Air Mass Meters (with the new one in, you'd have to force it to run once started, or it would die. However, once going it did fine. With the new air mass meter, it threw a plethora of codes. However, it's idle wasn't as high. I swapped back to the old one because it was less troublesome.), Cleaned and tested the Idle Air Control Valve, and that's about it. Just a side note, it runs quite nicely with the Air Mass Meter unplugged. However this is probably because it's stuck in open loop mode, and it ignores inputs from all the sensors.
As of now, I'm leaning towards replacing the o2 sensor. Before doing so, I figured I would get input from this forum.
Any advice would be appreciated.
Thanks!
Evan

e777 · Post by **e777** » 25 Jul 2013, 15:06

My wife's 240 had a very high idle problem and it turned out to be the idle motor.

Before replacing that, also check for a secure connection between the plug and the throttle position sensor. If that plug is loose, dmaged, or faulty (corroded) you can have idle problems.

Thanks and good luck!

piv15 · Post by **piv15** » 29 Jul 2013, 01:15

This car doesn't have an Idle Motor, unless you're talking about the Idle Air Control Valve? The idle problems only come after it's warmed up. I can't seem to iterate my self enough that the idle is fine when the car is cold started. Anywho, after it warms up, when I put the car in park, it idles at 1500 rpm. Now, when the car is shut off, and let it sit about 20 minutes, and re-start it, it surges around anywhere from 200-700 rpm. It sometimes dies. It'll either die, or after a few minutes, it'll go back to 1500 rpm. If I drive it, it seems bogged down. If let off of the accelerator, then push down on it, it'll go then bog. Eventually it does come out of it.

Post by **rgk** » 01 Aug 2013, 14:43

Make sure your MAF is the correct one for your model year. Test each MAF with a multimeter. Check for the proper resistance between the proper leads for a variety of functions. This resistance will vary, depending on your model. I can refer to my Haynes manual for the specifics when I get home. Test battery voltage to the MAF. Reset the computer by unplugging the battery for ten minutes before you put the new MAF in.

Also, check your throttle cable to make sure it's not holding the throttle open and check for vacuum leaks. Check fuel pressure.

Edit: if it runs nicely with the MAF unplugged, it's probably not a fuel pressure issue.