Hello,

For those contacts in the AMM/fuel injectors/ICV/ECT and in many more such plugs I don't recommend using wire brushes. You might spread open the contact points and they would fit in loose later. I did use fine grit sandpaper last time (cut into narrow flat strips to insert into those contacts) but that was a mistake.

I ended up replacing these contacts later on when I learned that these have special thin tin coatings on them. You might strip these coatings off with harsh tools.

But I did use the same sandpaper (rolled small enough to fit into) for those round bullet connectors found in the RSR, fuel pump and similar plugs. These are yellow coloured brass with no special coatings. This is when the connectors are full with whatever silicone/rubber crud from the harness wires.

For such fuel injector/AMM contacts it is suffice to just spray a little contact cleaner, wait for it to dry, put some dielectric grease and work those plugs in/out repeatedly into their electrical items. By doing this their mating surfaces evens out with each other and make good contact (no need wire brush/sandpaper).

The type of contacts used for example in the fuel injector/AMM plugs are called "junior timer contacts". Just in case you need to replace them by ordering from the electronics store (digikey/mouser/RS). Pick the one with 2.5mm mating surface and good quality ones such as from TE Connectivity.

For the brass bullet contacts unfortunately you have to order them from Volvo. No such size available anywhere I searched. Sorry don't have the part number.

Regards,
Amarin.

Okay. It is a cleaning question and a grounds question but here's the problem:

Check engine light that is going to keep it from passing smog check. OBD codes 1-1-3 & now it 2-3-2.

And here's some of what hasn't fixed it:

I am ready to put the original ECU 556 goldenrod back in; not sure which one I put in that tested okay and has been good for a couple years. I've troubleshooted my own, my wife's, and my 5 daughters various B230Fs and swapped loads of parts over the years and the original is a known good one that I want to clean-up before I install it because it's been unused for quite some time. Ditto for the AMM if necessary.

It has a brand new 02 sensor, flame trap & hose, air cleaner, irridium plugs, a hefty dose of Techron Fuel Injector cleaner; plus, fairly new cat converter & AMM accordian hose and, yes, I'm fairly focused on it being the ECU. I had to repair some wiring due to rodents. But just in case I've ordered a new ECT sensor. If I remove the battery cable and it is cold outside it has produced various patterns of idling symptoms; including, running strong & smooth and no check engine light for hours.

So... got any hot tips for cleaning vital contacts and locating the pertinent grounds?

Also, in line with Uncle Onkel Udo II's question, did you perform teh:

https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

See Bill's list, though the FAQ ECU list may be newer by now.
http://www.nuceng.ca/bill/volvo/database/ecu.htm

Though if you reside in a snow and salty, or always wet, or what have you climate, than that can cause corrosion in wire harness connectors where the little seals have failed.

As for grounds, well, you have wiring diagram resources in the big blue Bentley 240 manual (if yeh can read em), and in teh Haynes, and in teh:

http://www.volvowiringdiagrams.com/

As for grounds, well, visual inspection around the engine bay.

A Volvo TSB suggests treating the injector ground wires, secured to the top of intake port runner #2 and #3, should be treated by flowing solder into the crimps, replacing the ring terminals at teh end of the brown wires, and so forth. There a carbon steel hex head bolt (10 mm) that secure into the light aluminum alloy intake port, so aluminum being less noble, corrodes in contact with the more noble carbon steel alloy bolt.

Dialectric grease in the connectors. Yet you can use No-Ox or DeOX (a conductive, corrosion inhibiting grease treatment) on grounds and such.

The fuse box -- clip contact that hold the fuses in -- corrosion forms on the terminated wires that connect to the fuse box. (Disconnect the battery).

You have grounds under teh dash, secured to the body sheet metal, connected to the dash sheet metal, and more.

I dunno.

Hope that helps.

Happy Friday everybody!

And now, from Grumpy Cat!