My 1993 240 wagon has had a cold starting issue for about 6 months now, but it's actually getting bad enough that I'm trying to solve it now... any ideas would very welcome.

On cold start (cold engine, not weather-related. it's been doing this every day since July) it seems to run fine for a second, then immediately gets REALLY rough, missing, etc. If it can maintain idle, it usually will clear up in 30 sec - 1 minute or so... but sometimes, it dies and needs to be cranked for quite a while. Definitely flooding, the plugs are wet...
If it does clear up and start, it then runs completely fine. No issues with idle at lights, etc. It also is fine with hot starts (if it's been running recently).

I haven't been paying close attention to mileage, but I think it's worse than it used to be, probably always running somewhat rich.

FPR and FI relay seem fine, but I don't think that those would cause it to run rich.
I gave it a tuneup a while back - new plugs, cap/rotor, wires - with no effect.
No check engine light, but when I checked the OBD, got a code saying O2 sensor is faulty/missing. Am I correct in thinking that the O2 sensor should have absolutely no effect on cold start issues?

I just swapped in a spare AMM to see if that has any effect, should know if it does tomorrow AM.

My next plans are to test coolant temp sensor or cold start injector - any suggestions for quick testing of these? is there anything else that I should be thinking of?

Thanks for any assistance!

Okay, thanks for the responses! Last weekend, I cleaned the IAC valve and throttle body (they were pretty awful), then raided my parts bin and swapped in a spare AMM. After that, it might have run a little better but not much.

Then, I put a new set of NGK copper plugs in, and ran through all of the LH 2.4 green book tests at various sensors & at the ECU. Everything checked out, but the TPS test values were a little off (point to Onkel Udo), so I swapped in a spare clean throttle body/TPS from the parts bin, which checked out okay. While doing the tests, I also found that the O2 sensor had been purposefully disconnected (wires carefully taped to keep out water & tucked away). Hmmm. I reconnected that, it seemed to test okay, so I called it "good enough".

It was starting somewhat better - at least it didn't miss quite as much and never came close to stalling any more. A few days later, though, I noticed that the idle was a bit uneven - a little bit of hunting and vibration - and then it started intermittently bogging down, almost to the point of stalling, upon acceleration after being stopped (making a turn at a stop sign, etc).

So, this weekend, I checked the ODB and got a 2-3-2: "system adjusting for rich or lean mix" or something along those lines. Real helpful, right? I did a thorough check of all the vacuum hoses & the FPR - all was good. I cleaned the AMM connector really well, and also cleaned off the battery connections, which were a bit gunked up with corrosion. I also pulled the old O2 sensor, which looked pretty toasty, and put in a Bosch universal replacement... and everything is good again. After clearing the old codes, the ODB is now reading 1-1-1. Gave it a real test today (weatherman promised a high of 16°), it started right up with no misfiring or hesitation, and ran with a smooth idle.

To sum up: who knows what the real issue was - my best guess is a combination of kind of bad AMM connection, really dirty throttle body and/or weird TPS, and a missing/dead O2 sensor - but doing a bunch of stuff seems to have fixed it. Thanks again for the input, everyone!

I have had an '87 and have a '92 240 that flood when started in cold weather. The '87 had trouble at -15°F, the '92 seems to flood when it is just below zero.

On the first start the car tries to start, fires once and no more. Turning the car off, pressing the accelerator to the floor (shuts off the fuel) and trying again gets the car to start. Depending on how cold it is the '92 may need a little throttle until it settles down. Then it runs fine. You might try that with yours and see if it helps.

I suspect that the problem is the fuel injection temperature sensor. This car is new to me and I have not tried a new sensor yet as it just got cold enough to act up (and I can get it to start).

Greg

I am having this problem in my car (1991, LH3.1) lately when the weather is very damp. It's been going for a few years but until last week with a long cranking session it would eventually start. But before xmas after days of rain she finally caught but ran very rough with a miss, then died about a minute later. I checked for water in the distributor cap and sprayed some WD40 in it but it still would not start again with lots of wild bucking and snorting. I left town for a couple of days and after everything had dried out she started up right away and ran fine.

I'll check for any OBD codes this weekend if the weather is good.

Yours SCREAMS plug wires in the loudest voice ever ever conceived. Make sure the coil to distributor wire is included or buy it seperately. I may be wrong but there has NEVER been an easier internet redblock diagnosis than this.

Huh, who knew? I didn't! The plug and coil wires are IPD house brand (blue) and are oh about five years old. I have a new set in my parts crate minus the wire for #4. The first set they sent had a #4 wire that was too short, so they sent me an entire new set. I'll check it out! Might as well throw a new cap & rotor on her while I'm in the engine room.

One word...bougicord. OE and lasted more than 15 years from the factory in I think every 240 I ever owned. I would replace them at that point just because.

Noted. I did have a look while it was running in near-dark tonight and did not see any arcing, but I will replace them all with Bougicord.

One other new-ish symptom: idle drifting from 750 or so, up to about 1200, then back. TPS maybe?

...or dirty TB or failing O2 sensor or vac leak after the AMM. If after driving i a bit is continues, start with looking for big vac leaks then clean the TB.

Yes maybe it does need new leads. Bite the bullet and buy quality leads from Volvo if you have to. First though check for sparking on the leads when running in the dark. A WD wipe round inside the cap is fine but spray down the outside of the cap and wipe down all of the leads with a WD soaked cloth. If your wires are clipped up properly they do run very close together and will be prone to cross sparking. A general spray down with WD of the cap and leads will often get you going straight away in damp conditions. This is what it was first marketed for WD = Water Dispersant.
Yes I know, Granny/suck eggs etc, but there you go.....

Check the vacuum hose on the fuel pressure regulator to see if it's dry, or wet with fuel. My 88 brick was starting very hard, cranking forever, and once started ran stincky flooded. FPR was shot. Two sense FWIW.

It would check the TPS first.

I had this exact problem but it was intermittent. Start up fine then run rough. Almost stalls out but not quite. Then after a few minutes runs fine.

I changed the AMM sensor. (Ebay) non Bosch part

I changed the Idle Air Controller (IAC)

I cleaned the throttle body and installed new tb gasket.

I installed a new air filter it was dirty.

I cleaned the PCV flametrap.

It runs fine now.

Ordered an intake manifold gasket- just in case I can't get to them. Going to replace coolant temperature sender ( CTS) and the water temerature gauge sender. CTS under cylinder 3 and temp gauge sensor under cylinder 2 under intake manifold.

Hope this helps- 250k plus miles on 93-240dl

Also-I forgot- I noticed the coil wire arcing against the power steering metal hose connector. I readjusted the wire away from metal. No more arcing. Look at engine in dark and see if you have arcing anywhere. It ran rough when the wire was touching.