My trusty 240is no longer starting, and after replacing the main fuel pump, it got proper fuel pressure (25 cold) readings (I did not check it before.) It has proper compression 195, and has a strong spark, I even swapped out the air mass meter, because I had a working spare. I'm out of ideas? could it be the timing?
thanks

Yes, the pump could still be bad. Fuel pressure is regulated be the fuel pressure regulator, and that pressure relates to the fuel intake system - rail, injectors, etc.
Check the fuses...a good little trick is to simply turn them all in their holders. There's a separate fuse in its own holder under the hood (one of those horseshoe type which is 25 or 30 amp) which is located just behind the battery. I've seen them attached to a bracket there or sometimes just flopping around. That fuse is for the fuel pumps. You can usually hear the fuel pumps activate when you turn the ignition on. Of course that doesn't mean there functioning properly, but at least you'd know they were getting the required juice. You can take about a 10 ft. length of garden hose, put one end into the gas tank inlet and bring the other end into the cab and listen, a la stethescope, for the gurgling when you turn on the ignition.
Could also be the ignition computer, which is very expensive to replace. I'm not sure how to diagnose that. A shop replaced mine a while back when it had the same symptom.
Then of course there was the time when my gas guage was misreading and the car wouldn't start because it was out of gas, and I didn't know it!!!

If you want to know if the prepump is working take the inlet hose off of the back of the main pump, pull a wire off of the coil so there is no chance of it starting, and then have someone crank it over while you see what comes out of the feed line. If the pump is working it should gush pretty good out of that line, if not then it is dead. If it is dead now go check and see that you are getting current to it. If you are getting current to it then plug the coil back in and replace the pump, sock, and hose.

The official Volvo way to do it is to measure the amount of amperage draw threw the fuse with a multimeter. I have done it both ways but I like the way that I outlined better because it is much more definitive.

Mark

Mark - no argument, but I check at the fuel rail, with an adapter hose leading to a jug. On the 240 anyway—where it's easy to pull the Tank pump fuse. I jump +12V from fuse 6 to the Tank pump fuse (4 or 5) output contact.

That will power just the tank pump, which should push a good solid stream thru the (unpowered) Main pump and out into the jug. The advantage is you don't have to crawl under the car, and except for crouching to diddle the fuses, it's a stand-up job.

In any case, with a "strong spark", I think it should fire even without a tank pump. Knowing the YEAR of the car might be helpful too.

P.S. Isn't Marshy's fuel pressure ("25 cold") on the low side for a new pump?

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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

Bruce, that would be a good way to test for sure. If the pre-pump can push all that way and through a dead main pump you can rest assured that it is a good one. Being as I have always had an entire shop at my disposal the thought of "getting under the car" never even crosses my mind. But, should I be in a parking lot somewhere that is a good trick to know, thanks.

I have seen plenty of cars with strong spark that would not run with a dead pre-pump. In fact I've seen 2 in as many weeks.

I like to see 2.5 BAR at rest, 36 PSI

Mark

Sounds pretty low to me but I am not expert in 240s.
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George Downs Bartlesville, Heart of the USA!