'84 volvo 240

This car would not start, and then I Changed the main fuel pump (the old one was dry (no fuel in it)) and it started up, but then began to idle very rough, sputter and cough, with virtually no gas pedal responce, and then it died. I cannot restart it since.

I am guessing that it will not start due to timing (timing belt replaced 30k ago)
poor compression (I need to pick up a gauge)
poor fuel pressure (The hose to the fuel rail is pushing fuel in vapor, not liquid form (is this normal))

Do any of my three assesments sound likely?

And what can you do if your car has poor compression?

Thanks
vincent

If both fuel pumps are running, it has fuel in the tank, and the regulator is operating it should produce (liquid) pressure on the fuel rail. Try jumpering from the primary (left) side of fuse #7 to fuse #5. Both pumps should run as long as this jumper is installed. Remove the fuel cap and listen at the opening for the in-tank pump. You should hear it. A few problem areas such as a ruptured hose at the in-tank pump, a clogged fuel filter, a malfunctioning fuel pressure regulator, a clogged fuel line all come to mind if the pumps run and you still don't have fuel pressure. How much fuel is in the tank?
steve

I am guessing that it will not start due to timing (timing belt replaced 30k ago)
poor compression (I need to pick up a gauge)
poor fuel pressure (The hose to the fuel rail is pushing fuel in vapor, not liquid form (is this normal))

Do any of my three assesments sound likely?

They sound vaguely possible, but not likely to me. More like "last resort". But without some background info, it's hard to tell where to begin with suggestions.

Did it suddenly quit on the road while running? How long since it last ran? Do you have any manuals (Haynes or Bentley)? Do you have a digital volt meter (DVM) or a 12 volt test light. Do you know where the 2 Fuel Injection relays are?

Here are a few ideas to try:

Go to the fuse panel and connect a jumper wire from the fuse 7 LEFT side contact to the fuse 5 LEFT side contact. Both pumps should run immediately. If you hear them (or at least the Main pump), try starting. If it fires, the ignition is probably OK.
Let us know what happens.

If doesn't even try to run, see if the timing belt is OK -- look thru the oil fill hole to see if the camshaft turns while someone else cranks it over.

If it runs only with the fuses jumpered, suspect the 25 amp blade fuse (and the fuse holder wires) up near the battery and coil. (this is the main fuel injection fuse)

Also check fuse 13 for being blown or having loose/corroded contacts. (this fuse powers the Fuel pump relay)

I'll check for your reply later.

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

I have a haynes manuel. I checked the fuel relays (good) replaced main fuel pump (it was bad). Car died while driving, before it ran fine it only has 125,000 on it. In tank fuel pump (unchecked, maybe bad, and leading to low fuel pressure)

I guess this because I did something that you are not supossed to do. I disconnected the fuel rail hose, and jumped the 5and 7 fuses for the fuel pump. The main pump is running, but only fuel vapor is coming out the hose


The car has a stong spark, and just because I have an extra that I know is good I replaced the air mass meter. It turns over just like it should, but doesn't catch


I have seem simlar symtomes with a bad timinmg belt, and bad fuel pump, so that is where I stand.

thanks

The main pump is running, but only fuel vapor is coming out the hose

Maybe when the pump was switched the wires got reversed and it's running backwards?

Or, if the gas is real low in the tank and the tank pump is dead, plus the short hose inside the tank is shot, then maybe the main pump just can't suck fuel.

Normally, just a dead tank pump won't cause a no-start if the main pump is OK.

You can test the tank pump for running by pulling fuse 5 and jumping +12V to the RIGHT side fuse contact.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.