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240 '85 B230F fuel cut in 1st gear

Going off memory, IAC pin 2 is power (12v I think) and pins 1/3 are connected to ground by the ECU to pull it towards open or close. If you haven't already, put the meter on resistance and see if the 3 IAC wires have any connection to each other with the IAC and ECU disconnected. I think you should only be seeing voltage on the middle pin.
 
Diagnosing & Replacing Idle Air Control Valve Volvo 240

https://www.youtube.com/watch?v=M_KwUo4Q0LQ

Read his comments...there are some manual to download

Looking at the wiring diagram he linked, it looks like I had the connector for the TPS and IAC swapped. When I plug them in correctly the car starts idles up to 2k rpm cuts out and then revs up to about 3k rpm idles there. If I blip the throttle it will drop down to about 1k rpm for a quick second then rev back up again. If I unplug the IAC and blip the throttle the idle will drop immediately to about 1k rpm and stays there. I tried grounding out the IAC using the blue/white wire and connecting it to the battery but it will not lower.

I am referencing the green book he linked for the wiring.
http://www.240.se/litteratur/tp30427.pdf

Here is a picture of the voltages and ohms I get when going through the testing in the video and the forum link from the video.
 
When incorrect or defective parts exist, and when OEM specs are exceeded, stuff happens.

Video showed base idle being set....ECU "assumes" OEM specs exist, and ECU may not be able to over-ride "Joe Fixer's" fiddling. If too much air is flowing across throttle plate (intake manifold), the ECU can't fix it. Amount of air passing into intake manifold controls RPM...more air, higher RPM...lower airflow, lower RPM. Base idle must be set, according to Volvo's specs, not Joe Fixer's.

I never had to trouble shoot IAC...I'm under the weather currently, but later, I'll take a look at Volvo's wiring diagram to see if any relay might cause an issue.
 
High Idle on LH2.2

Looking at the wiring diagram he linked, it looks like I had the connector for the TPS and IAC swapped. When I plug them in correctly the car starts idles up to 2k rpm cuts out and then revs up to about 3k rpm idles there. ...

Seems a shame it took this long to get here, but that's an error you're not the first to make.

Depending on whether you envision yourself replacing a transistor in the ECU or not you have two options.

http://forums.turbobricks.com/showthread.php?t=199170
http://forums.turbobricks.com/showthread.php?t=322155
http://forums.turbobricks.com/showthread.php?t=332250

PS - that video was excruciating even at 1.5 speed. How can someone sound so authoritative and be so wrong about so much?
 
Depending on...

Not having test equipment limits what can be evaluated. But, having a wiring diagram and test equipment is priceless; page 36 in that Green Manual.

On a different note, earlier on, I would have supplied external power to pin 87 on relay #15's plug....since it powers up injectors, IAC, and fuel pumps. I would have also measured duty cycle (or Hz) of IAC.

His base idle appears too high, and when this thread started, he had timing not set to OEM spec. I don't recall if ECU's temp sender is correct one or not
 
Depending on

hiperfauto - Grounding the test point puts the idle motor in it's base position. When the throttle switch is open, the idle motor goes fully open to prevent stalling on decel. It sounds like the throttle switch isn't working. Just because you can hear it click doesn't mean it's making contact. Also, check the connector for any pins that may have pushed back in the insulator.
http://forums.turbobricks.com/showpost.php?p=5603010&postcount=3

Hence, if throttle switch is not set correctly, and working...yeah, stuff happens!
 
40% off weekend at Pick n' Pull so I grabbed an ECU, TPS, and IAC. Put them in the car and it idles properly with everything plugged in and no more fuel cut! I need to slow down and label connectors when I disassemble stuff... lesson learned!

The tachometer still seems to stick at a random RPM with the key on as well as when the motor is running. I believe my roommate just found a spare one in a box so I will give that a shot to see if it resolves the issue.

Thank you guys very much for your help, I really appreciate it!
 
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