Hi Guys,

I'm working on a 1990 240 for a friend and we've got the following problem...the car will start but won't run. Here's what I've tried:

1. Replaced the fuel filter.
2. Cleaned new MAF.
3. Cleaned injectors.
4. Cleaned throttle body.
5. Verified function of TPS.
6. Checked for vac leaks - non found.
7. FPR has been changed.
8. New plugs/plug wires/cap/rotor.
9. Checked and taped up some small holes down stream of the MAF.
10. Verified function of main injectors (changed out for known good set - verified both sets working (hear click when cranking)).
11. Cleaned IAC and verified operation.

So here's what I know - the engine seems to be running on the cold start injector only. When I pulled the fuel rail, didn't appear to be 43 psi of fuel pressure in the line. I don't have the T I'd need to verify the rail pressure (no Schroeder valve). So I'm guessing that the main fuel pump is not working properly. We've got it moving volume (it does move fuel) but apparently doesn't build pressure.

Is it possible that this is the problem?

I just had a similar experience on my 960.

My research tells me the following:
- Fuel pump relay is a likely culprit
- Fuel pump could also be bad (check relay first)

Have a look at Dave Barton's site for more info on weird Volvo relay issues and stalls.

RT

Ya - done all this stuff - really. I've even cleaned all the grounds and battery terminals etc. I'm not trying to rebuild the f'ing thing, just get it drivable. I've got the activity at the main pump - which means the relay is fine. What I don't have is pressure in the line.

Is the fuel pressure regulator holding pressure? Disconnect the fuel supply line to the rail and try to pump up the rail to 45 psi with a bicycle pump or carefully with a compressed air line.

If the FPR holds, then it points to the fuel pump (or blockage at pump).

RT

I probably have a used fuel pump in my stash you could try, might even have a new one. I was going to mention the fuel pump check valve as it's not on your list, not sure if it would contribute to the extent of your issues right now though.

Verify three injectors are or are not firing by pulling them and cranking.

There's a really good trouble shooting guide Google Volvo 740 faq. Crank position sensor is another possible culprit though first off would be to verify crank and cam timing.

Have you checked for stored codes?

Just found out about the code voodoo. I was under the impression (from all the reading that I've done on EFI) that if the CPS isn't working then you'd get a no-fire situation. Without a functioning CPS, the engine can't tell what stroke it's on, so the initial idle isn't possible (correct me if I'm FUBAR'd). There is a new pump on the way - could it be the intank pump isn't supplying fuel to the main pump?

Um, yeah... Duh! Why didn't I think of that? I bet the tank is in the bottom third, isn't it? Pour 5 gallons in and try that.

Shoot.

If you're pressed for time I have a new NA fuel pump and check valve as well as an in-tank pump & filter in my stash. You know I have the bung tool if it's the in-tank pump, let me know if you need any of this to get going sooner.

We got it running...the following is the list of what was wrong with the car.

1. IAC stuck - cleaned and now working.
2. Main fuel pump was not putting out any pressure.
3. Recently changed MAF was faulty - installed fresh JY unit and we're done.

Used the code reader for the first time. It's pretty addictive actually. Waiting patiently for the little blinking light to tell you if it's happy.

Car has reasonable power - but boy it sure is different from driving my 242. It wallows through the corners, is supper cushy and the gear shift (while vague) is not as crunchy as mine (making me want to change the M46 to an M47).

Still lots of repairs to do on this car - it's unbelievably dirty (even the hippies would find it toxic), but is remarkably complete. Windows won't go up if they go down, passenger seat was repaired by a "mechanic" and they didn't install the bolts for the adjustable mount, there's 50 lbs of subwoofer just floating around in the trunk! She needs some love.

Good work!

RT