So once again I am bringing up my hot restart issue.
Volvo 240 sedan B230F 1989 150K miles.

Recap: Warm up to operating temperature. Let stand anywhere between 10 minutes and 45 minutes (depending on outside temperature). To restart, the car need a good 8-10 cranks (engine rotations) to startup.

Replaced: Fuel pump relay; 25A ignition fuse & holder; fuel pressure regulator; complete in-tank assembly; crank position (RPM) sensor. No improvement.

I can now confirm that the issue lies in the fact that there is a lack of either residual line pressure or lack of fuel in the line... I confirm this by 'manually' turning o nthe fuel pumps (via their relay) for around 2-3 seconds before cranking the engine. After doing this the car starts up right away as if it were cold (2-3 cranks).

Question: Should my ECU 'prime' the fuel as I manually do above as I turn the key to ON before cranking? It does not. Please confirm.

Any other info or suggestions are welcome. Remaining is to replace the fuel check valve and filter.

Regards,
Greg Mustang
1989 240 DL sedan B230F 150K miles
1992 940 GLE (16v) B234F 50K miles

On my 93 245 with LH 2.4, the fuel pump will run for a few seconds with the key on, engine not running. I think your's should do the same, since I believe you also have a LH 2.4 system.

ok thanks. Which ECU do you have? I think mine is the 'apparent' problamatic one (xxxxxxx561?)...

Let me know. If our ECU is the same then likely mine should prime since yours does.

Thanks again.

Greg

Mine is a 951. The problem I have heard w/ the 561 relates to its losing the ability to come on at all, not just when the key is on and the engine is off. The ground from the relay runs into the ECU. When the ECU detects a signal from the coil, it completes the ground and the fuel pump runs. The common (but dangerous) work around to this failure of the 561 is to tap into the ground from the relay to the ECU and ground it to the body so that the fuel pump runs whenever the key is on. If you ever get into a wreck and the engine shuts off, the fuel pump will go on pumping fuel - not a good thing if your fuel line gets cut.
This is not your problem, since your pump obviously runs when the ECU gets a coil signal. I think you have another failure in the ECU, but I'd have to look at the pin out to be sure. I suggest you get ahold of a good pin out diagram.

Hi Greg,

I believe the first activation of the fuel pump occurs after the first spark of ignition. What I find interesting about your hot restart symptom being caused by the check valve is it does not also occur cold. But maybe it has something to do with how much residual pressure is lost and what amount the 5th injector dumps in.

If you find it is the check valve, would you open it and see if the spring has rusted in two?
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Art Benstein near Baltimore

I had a serious hot start problem on my '80 240, and it was caused by the check valve. I am told that the check valve affects hot start and not cold start because the fuel boils when it is hot. The rest pressure in the system is what keeps it from boiling.

Phil
'80 244 DL

Now that you mention the reason, I remember a discussion of this vapor lock. But unlike you I hadn't discovered this for myself so I suppose it went in one ear and out the other. Thanks, Phil.

Maybe I can apply this to my 79. I've been thinking about checking my rest pressure when it gets warm again, because it seems to crank too long after sitting awhile. Not real bad, but at least twice it felt like it wasn't going to start again just after refueling immediately after running at 4000 rpm for 50 miles. But most times it starts fine, so I haven't had the motivation to pursue this in the snow.
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Art Benstein near Baltimore

If the check valve fixes it, I'll definately let you know!

IF not, not sure where else to look... this thing has puzzled me for months...

I ask the question about the 'priming' because I once say an EU on ebay (like mine (561 or somthing) that worked OK except for this fuel priming not working... but everyime I have asked I have been told that there is no priming until cranking and the RPM sensor snds the signal...

Strange... hope it is the check valve.

Greg

I've heard this too, about the ECU priming. I know none of my Volvos do this, but I've heard many domestic FI cars buzz a second when you turn on the key. It does wonders for the starter's longevity, I think. Sounds like it might be a good mod too if done correctly and safely.

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Art Benstein near Baltimore

yah, if need be I will just jump the appropriate terminals at the fuel pump relay and run through a high current push ON switch and just mount it on the center console in one of the empty slots (lots of space!)

ciao,
Greg