1991 Volvo 240 Stalls Slowly & Dies In Hot Weather

[jepedoelph]

......aaaaaaaaaaand continuing where I left off in late July of this year because (((((crickets))))).....

Let us all give pause and say thanks as we continue to battle the insanity of this '91 240 stalling (you may recall from your reading that this whole thing began for us in early December of 2018, another lifetime ago).....

You may remember me from such educational films as:
Damn It, I've No Idea How To Drive This Thing
Start Me Up
One Broken Wreckord Follows Another
Lord of The Broken Wreckord (the entire trilogy)

and that all-time children's favorite.....
Save Me From Myself

Since July's Ozark Mtn debacle I have replaced:
distributor cap and rotor
spark plugs w/ correct gap spec on each - with dead nut accuracy
plug + coil wiring
(spoiler alert: none of the above matters)

and AGAIN cleaned the MAF (ooh-la la)
and tore down the alternator and had it professionally checked AGAIN by the amazing guy with the 50's sci fi film machine with belts.
and checked and cleaned all those ridic colored fuses at the driver's left leg by the door
Not sure if I mentioned it, but I replaced the starter with a Bosch reman from eff sea pea e/u/r/o in November 2022.

Car ran seemingly fine for a week in August of 2023 - that is, after replacing the above parts and cleaning the MAF.
Of course it did. Of course it would. Of course.

Has been sitting since August with a brand spankin new Optima yellow top.
I do have to remain gainfully employed after all.

Have also cleaned both battery terminal connectors, the grounds to engine + body, and the positive wire manifold just behind the battery with that little black slide off lid.

Car started up fine during that miraculous week in August (but then still stalling later at the worst possible time) and it actually seemed to have a lot more pick up, but now it plain doesn't start. Turns over. Doesn't start. Like it's not getting fuel or spark - like I've not already gone through THE ENTIRE THING. Which I have.

I checked the OBD codes - now getting a 2-3-4 throttle sensor blah blah. Anyone know if the throttle sensor could have been (all this time - hey it's been 5 years as of today!) producing hot stalls, cold weather stalls, and now no starts? Recall that I done torn down that darn entire intake....all of it full on down and cleaned ever-damn-thang meticulous-like 'clud'n that there rull purdy reinstallation of the throttle sensor (gives a perfect-like click right there after turn'n that there intake pulley).

On that note - I will say that I have been noticing a very slight pause on the engine (hiccup) when very slowly depressing the accelerator pedal while at idle - you know, like when a traffic light turns green? But that doesn't happen every single time. No no no. We're keep'n this thing real bro. It's like the tumblers on a bank vault - it feels like certain things have to "align" about the engine for that hiccup to occur - like which cylinder is firing and what time of day is it? This could be the throttle position sensor. Right? God knows. Right? Sure. Right?

If this was literally any other vehicle beyond a Duesenberg (which I'd sell) - I'd have run it straight off Mt Glory when we were in Idaho/Wyoming. What's absolutely nuts bag crazy.....is that this 240 literally drove from Victor, ID all the way to Northwest Arkansas in March of 2022 without one single stall or issue.

So now I'm heading out into the cold to check fuel delivery and spark. If anyone has any other ideas I'm all ears.

[Wilsemail1]

Ignition coil

[Vol240]

Hey man, was wondering if you figured out your HOT STALL issue. I’m having the same exact issues with my 1992 Volvo 240. It started happening to me about 5 months ago and now anytime the weather is over 85 degrees f it slowly dies out. I’ve don’t the head gasket and everything from the head gasket up. Everything from the head gasket up is brand new Bosch parts that I paid good money for lol. I’m gonna try the ignition coil but I have also replaced the ICM with a factory Bosch one as well. New fuel sender and fuel pump, new factory Bosch fuel injectors, new Bosch secondary pump, and a new fuel regulator.

I’ve been at kind of a loss with this thing and I don’t know what else it could be, I’m gonna try and clean my MAF next and replace that ignition coil. It almost seems like vapor lock or something, and I know that dosent happen on these 240s but that’s what it seems like.

Like you said after it stalls out, the longer you wait the further it will go after starting again. It’s like the Volvo gods are mocking me. I don’t know what else to try as I’ve replaced cap and rotor, spark plugs, plug wires, ICM, IAC, MAF, fuel injectors, fuel sender, fuel pump, secondary fuel pump, fuel pressure regulator, the entire PCV system, CPS, head gasket(and all gaskets up), and cleaned and set the throttle position sensor. The only things I have not replaced are the ignition coil, the fuel relay, and that’s about it.

Hopefully you see this I know it’s been over a year but anything will help, thank you

-JW

[volvolugnut]

Old coils seem to develop an air gap or crack, then get moisture inside and fail when hot. This has been an issue since flathead fords. To test a coil, use a timing light on the coil wire and crack the engine. If the timing light flashes but the engine will not run, the problem is likely not the coil.
If fails coil test, try a new Bosch coil.
volvolugnut