I'm still having problems with cold start I havent checked operation of cold start injector yet. Wondering if it might be the ecu is bad I have a 561 and have heard here they go bad on 89's. How would you check? Or do you need to get a replacement and just try it out. What is the bosch number for the better replacement and do you simply remove the old ecu and plug in the new or is it more complicated than that. Is a boneyard ecu worth trying. I dont want to put a ton of money into my beater (as if I havent already spent a ton). How much should I expect to pay for a used ecu? Thanks Phil
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89 240 wagon (oxidized)

If you don't want to replace the whole ECU, you can get a replacement chip ( eprom ) for the 561 from volvo for between about $68-$120 depending on the dealer.
Takes about ten minuits to swap it out
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '82 Mercedes 300SD

561 failure is typically no-start. Loss of fuel pump ground.

My car starts but after alot of cranking and waiting and trying again Once it starts, and warms up very slowly, w/o hitting the gas it runs fine. Once it's warm it will restart easily. Is this a plugged fuel filter, defective check valve or something else. Why does it start right up once it's warm? I tried to start car cold w/o AMM attached and it would not start so probably not that. My check engine light wont go off even if I pull battery cable for 10 min. I'm showing 1-1-1 on the OBD. Help!!!
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89 240 wagon (oxidized)

If your boneyard is not yet a supplier to ebay entrepreneurs, you might get a 951 cheap, or else you'll just have to get there first. A 561 at pick'n'pull prices is not a bad risk, especially if you can determine a different reason for the car's being there.

Failing that, I'd look to the auctions before buying new or rebuilt.
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Art Benstein near Baltimore Crrrrazy Ray's!

I had a cold start problem that was caused by an incorrect base idle adjustment. It was at 650 rpm and should have been 700 rpm. After correcting it and adjusting the idle mixture, it started much easier.
-bill

Information I've seen indicates that the cold start injector only squirts when its -20F. There is a check valve that keeps residual fuel pressure in the system when not running. If bad you might not be getting good fuel atomization when starting. Did you check the temperature sender?

where is the ck valve and how do you ck it. What temp sensor? can you tell me where it is and how to check. Do you mean cool temp sensor- I changed that last week Thanks for helping
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89 240 wagon (oxidized)

I believe the check valve is part of the main fuel pump under the car, if not inside, it is right next to it. But I don't think that would explain a no-start, only a slow start. If it were bad, it might take your pumps a moment to get the pressure up. but they would.

There are two temp sensors under your fuel injectors. The forward one is for the temp gauge only and so would not affect starting. The one further back (toward the seats, under injector 3) is for the ECU, so that would be the one to check. See the FAQ for how to do that. It is a bitch to get to with the intake manifold on, but you can do it with socket extensions.

Do you hear the fuel pumps run when you turn the key to position 2? If not, I would be checking out all of the electrical items that might behave differently (open a gap) when cold. Fuses, fuel pump relay, etc.
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Andy in St. Paul, '91 745 Regina 198K mi, '89 244 142K, '87 245 RIP

I don't think it's your ECU. The classic failure of the 561 causes the fuel pumps not to run at all. The 951 is the better replacement.

Hopefully, Art Benstein will chime in, but I think he has said here in the past that LH 2.4, which our 89s have, does not use the cold start injector at all. I clamped mine off trying to diagnose something last Summer, split that fuel line and have just left it clamped off since. No problems starting here when it's been below zero.

I have a spare, good, 561 ECU that I am planning to put on eBay when I get around to it. A search of completed auctions there should show you what they have been going for.

Do you get any codes from your OBD box?
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Andy in St. Paul, '91 745 Regina 198K mi, '89 244 142K, '87 245 RIP

1-1-1 on the codes. Ck engine light is on but I think because I changed cool temp sensor. Thanks for the ecu info and yes hope to hear from Art Thanks
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89 240 wagon (oxidized)

It doesn't sound like the usual trouble with the -561 ecu, which is failure to provide fuel pumps. But there's lots more to an ecu, and reliability of any part is just a probability game.

I found the -561 drives the cold start injector -- that is it has the circuitry for it -- but I don't know what temperature or conditions are needed. However, I suspect a lot colder than Maine is right now. It is the -951, that holy grail replacement ecu that lacks the circuit to fire the cold start valve. No matter, though, I'm sure it makes up somehow with the timing of the other four injectors.

First thing, I'd deal with the check engine light. At least pull the 25 A fuse or neg. lead on the battery to reset the computer completely. Make sure that wire is in great shape like it would be in sunny (not) California. Loosen and retighten the two ground wires attached where the fuel rail is mounted to the intake manifold. Look at the crimps while you're at it.

Also, like Andy says, look for things electrical that shrink in the cold - contacts, terminals. Nothing Seinfeldian.

For yours, I'd try without the AMM connected. But try it from stone cold, not as, like a fourth attempt. You should get enough enrichment from the limp home setting you'll know if lean mixture is the likely problem. If it starts easily with the AMM disconnected, well, you know the next trick. Swap in another AMM.

Or if swap parts are a real problem where you are there are some meaningful voltage readings you can make. Pull plugs to see how dry. Have you anything to measure fuel pressure?
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Art Benstein near Baltimore Crrrrazy Ray's!