I am a new to me Volvo owner. Year and model in the title of course.

First the cars history on how I got it. A co worker took the car to a mechanic to fix something minor and the idiot removed the ECU and ECM and left them at the junkyard months before I got the car from him.

So over the last few months I found some same year and same model volvos in the boneyard and got two ECU's and a ECM.

Now I get it to start and run with one ECU but not the other, makes sense in my mind as the volvos I pulled them from were not wrecked.

Now my issue is it won't idle without feathering the pedal and it misses bad when you step on the throttle.

So I go to the volvo ecu repair site and the 280 000 510 I have is listed as turbo ecu which is weird as both ECU's came from non turbo 84 manual transmission 240's.

So two questions I guess are how do I find a right part number so I can get it rebuilt? And should I find a new ECM also?

Thank you for any help.

 

The part number is 0 280 000 510 for the ECU on your car. That is the correct one for your car. Rebuild site=wrong.

Check for vacuum leaks, including on the bottom side of the accordion hose going to your throttle body and all lines, injector o- rings etc. Some people spray carb cleaner at the various hoses, some leak propane at them. If your idle increases while your doing this, you found a leak. Make sure all ignition components are good plugs, wires, etc.

 

Awesome, so I got two ECU's from a boneyard that are correct for my car awesome. I think other than the coil all the ignition components are new. But can't hurt to replace. I will get the ecu that won't start the car at all rebuilt as well. Is there a way to test the ECM? Or do I just need to have it rebuilt also?

 

what ECM ? do you mean the ignition control unit aka ICU ? which ignition system does the 84 have, anyways? I've tinkered some with the Chrysler ignition on my daughter's 87 240.

 

Everything I have looked up for the unit under the hood that has vacuum line to it and is wired throughout to the ECU and distributor shows up as the ECM (electronic control module).

I don't know what the name of the ignition system is. I plan on getting the ECU repaired so I can rule that out, I just want to make sure the ECM not being redone won't hurt the repair. Just in case.

 

Sometimes Volvo stuff gets called different names. As far as I know, what you are describing is the Ignition Control Unit. It's actually very easy to test using a decent digital multimeter. The plug looks like this:

1o 10o
2o 9o
3o 8o
4o 7o
5o 6o

With the unit plugged in, use the probe from the multimeter and slide it alongside the wire at the appropriate number.

A- check for continuity between #10 and ground
B- switch the ignition on and check for battery voltage between #2 and ground.

The little o's represent the plug prongs.

Or, you could have it rebuilt. Saying that, these units are very robust.

My advice? Get a manual or utilize:

K-Jet.org | 200 Series

And keep posting here.

Get a decent multimeter and test your car systems as you need. Learn how now, and save yourself endless frustrations later.

(for whatever reason, I cannot get the plug diagram to line up.)

 

Thank you.

 

note the CONNECTOR on those ICU's is quite fragile. do NOT rock it if you unplug it, pull it straight out. on our 87 with a similar chrylser ICU, we had to use a little probe to 'tighten' up the pin sleeves to make good contact.

 

So the ignition module I had under the hood was the culprit. A lot of people said they were robust and should be ok, finally found a donor out of a wrecked wagon and runs first turn over. Thanks all for the help. Now just need to dial it in and I'll be good to go.