Hi BrickBoarders.
I keep having a stalling issue with the stalwart and recently rebuilt B230FT at idle, either while in Park or Drive. Car acts as though someone just turned off the ignition key. No warning or stumbling whatsoever prior to the stalling event. No OBD I codes stored.
Then my 945T will not restart. I have a VERY strong charging and starting system, and the engine turns over with aplomb, but will not restart.
If I wait a couple of minutes, easy restart and no further problems.
I have switched out the Power Stage (Ignition Module) with 2 new and 1 known good ignition modules, and a new crank sensor. Both of these items have not stopped the random stalling.
FAQ's point to both these items as potential trouble sources, and their replacement has not cured the issue.
Stalled out last night in freeway stopped traffic, then restarted with no further issues 3 minutes later.
The fuel system primes and the no-start issue does not (In my opinion) seem to be fuel related.

What in the world can I check next???
-Heat Sink Tubes?
-ECU?
-Air Mass?
-Coil?
-Distributor Cap/Wires?

Looking for a solid diagnostic procedure to pin this problem down.
An early "Thank You!" to all who respond with sage technical prowess.
John

I did have an intermittent snag on my 240 several years ago. The car would run fine and then suddenly not start. Leave it for a half hour and all would be fine. It would run along and then all power seemed to disappear and it would come to a stop. This went on for a while, resulting in some tow charges.

It turned out to be the coil in the distributor. It would break contact with heat and then remake it again when cold. I can't think of the technical name of the coil at the moment but it is the one that replaced the old points from the earlier cars.

Mechanic found it by replacing the whole distributor when the car did one of its sudden stops nearby his shop.

If everything else has failed, try changing the distributor.

Bob

maybe there is a broken ground wire some where??

After reading your new thread https://www.brickboard.com/RWD/volvo/1661665/940/960/980/V90/S90/heres_one_record_book.html I think you're not done quite yet.

Though a rear main seal leak is messy, the oil won't keep your crank sensor from working in the short term. The 214 on ignition side is lucky for you, though, and knowing you changed the sensor in a recent maintenance routine.

Yes, new parts are not to be trusted just because they're new. I went round and round with a new Bougicord sensor for months after just such a proactive replacement.

However, there's a more common fault associated with this maintenance, and that is the female pins in the sensor's electrical cable socket (on the harness side) can retract while making the connection, pushing back away from the male pins inside the socket.

Roll the boot back from the socket and examine the wires, to make sure they are fully engaged. Try tugging on them individually with needle nosed pliers to make sure the locking tabs are engaged. If all is tight, then replace the suspect CPS and see if your intermittent trouble is changed.
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Art Benstein near Baltimore

Sometimes I wonder if our lives are all about the challenge of keeping gases and liquids where they belong.

this sounds like a classic ignition switch starting to fail

turn the key to the start position and as soon as it just starts to crank but before it actually does start let go so the key moves backward to run since its spring loaded

pay careful attention to the dash warning lights for the various components at the bottom of the cluster

if they go out as the key springs backward the switch is going bad

this is not a definitive test but short of really pulling things apart to get to the switch it will get you started

Great idea and test Ted. I'll check it and advise.

this sounds like a classic ignition switch starting to fail

turn the key to the start position and as soon as it just starts to crank but before it actually does start let go so the key moves backward to run since its spring loaded

pay careful attention to the dash warning lights for the various components at the bottom of the cluster

if they go out as the key springs backward the switch is going bad

this is not a definitive test but short of really pulling things apart to get to the switch it will get you started

I’ll second that. Carry a spare spark plug with you so you can check for spark the next time it konks out. If you can narrow it down to either no fuel or no spark you will have reduced the troubleshooting task by one half.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)

The engine dies but no OBD codes usually means basic things. Air, spark and fuel.

Air - Check the air filter box for any foreign object.
Spark - Ignition module usually stops working when its unduly hot. Check if its still comfortable to the touch when engine dies. Similar check for ignition coil too.
Fuel - The B230T uses a set of resistors wired to the injectors. Check that too. Its located behind the driver's side headlight. Centre console - Check fuse#1 for ECU/injection relay and fuse#11 for fuel pumps - any sign of melting? Check the white fuel injection relay (located deeper behind the fuse cluster) replace with a known good part. Lastly check electrical connections at main fuel pump underneath car.

Good luck,
Amarin.

Disclaiming any 900T experience beyond reading the forum, I noticed you didn't have "radio suppression relay" on your list of usual suspects. And just to leave it at that, you might say it has been replaced, but then I'd wonder about its socket.

Wish you well. Fighting intermittent problems without wholesale part swaps is truly a daunting task.
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Art Benstein near Baltimore

Reassembly is the reverse of disassembly. Except the profanity. You don't take that back; you just keep adding to it.

I'm rather intrigued by your thought.

I just can't figure if your suggestion is tongue in cheek or serious. But I'm going to run with it.

Now I just have to find out where the radio suppression relay is located......

Thanks Art.

Dear Townshend Act,

Hope you're well. On 940s, the radio interference suppression relay (RISR, aka fuel injection relay) is affixed to the inner fender wall, behind the headlamp.

The relay's case, rectangular in cross-section, is very dark brown (almost black). The relay will be partly hidden behind a thick wiring harness.

On cars sold in the U.S., without a turbo, the RISR is on the passenger-side of the engine bay. On turbo-equipped cars sold in the U.S. the RISR is on the driver-side of the engine bay.

The relay has two lugs, which engage catches on the wiring harness connector. It may take some effort to separate the relay from the connector. Hold the connector firmly, and press on the catches, while pulling on the relay with the other hand.

Hope this helps.

Yours faithfully,

SPook

I've been in more 940s in the pick'n'pull than in real life, my MIL's 92 Rex/Regina 944 being my only hands-on experience, long gone. Its RSR only gated current to the injectors. In the pnp, the 7/9 cars mostly had the guts behind the ashtray removed, showing burned areas under the fuse panel.

The only tongue in cheek I offer is below my sig. Sorry, I figure loads of 900 owners would create an immediate consensus on the RSR suspect, since the turbo version has both fuel injection and ignition power dependent on it, and its location under the hood is considered the reason its socket is vulnerable to the weather. Perhaps the others responding assume this as a given and move on to offer you new ideas. Have a look at the FAQ, or if you already have, say so.

Serious suggestion: Do a search in the search panel above on RSR. Here's an example post: https://www.brickboard.com/RWD/volvo/742155/940/960/980/V90/S90/radio_suppression_relay.html

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Art Benstein near Baltimore

"Sometimes I think the greatest talent of all is perseverance. But only sometimes." -Mitch Albom