|
|
|
I wanted to change my fuel filter. Manual says "depressurize" the system before doing so. Okay. I pulled the fuel pump fuse, cranked the car, and waited for the motor to quit. The manual says it will quit. The motor didn't quit. Garage filled with Carbon Monoxide. Waited and waited. Eight minutes later, me and the dog are nearly dead. Motor still didn't die. Finally I shut it down. Then I noticed a second fuse, I think this was for fuel injection. Pulled that. Motor didn't start at all. So the question is this:
1. Why am I not dead?
2. Should I bother de-pressurizing the line at all? If so, how to do it.
2. Should I change the fuel pump while I'm down there? I can hear something buzzing from the trunk of the car when the motor's running. I'm told that's normal. Is it? This thing is a pain to get to because that platform that the fuel filter and pump live on, the back bolt of that platform is fastened to a long arm that needs to be held steady with vise grips or something to keep it from twisting off due to age as I loosen the bottom bolt.
Thanks for your help.
Cuddy
|
|
-
|
|
|
Thank you Brick Brothers. I will, as they say, take your counsel into advisement etc, etc, and in exchange pray for you all, etc, etc, and in the meantime pull that damn thing out, put it on the bench and eat it. I did not realize that a falling wrench on a garage floor could create a spark. My dog thanks you. He'd prefer not to die because of my foolery. Anyway, if the whole thing goes to hell, maybe you'll read about it in the National Enquirer. I've actually considered just running the car till it's out of gas, and then doing the job, but they say the gunk at the bottom of the tank will ruin your fuel injectors. It's a gas bath no matter what. At least my fingernails will be clean.
Thanks again.
cuddy
|
|
-
|
|
That was a good one, I can just see the dog looking at you with that "is this how it is supposed to end" look in his eyes.
But not so fast on the fingernails there, Depends on how much of that aged leaked oil has settled in around all that stuff that gas bath may not cut all of it. You want to check that out before the fumes make you light headed, trip over your dog who is stoned from the benzine fumes, drop the filter, which will create the spark, and causes a fireball of not soon to be forgotten glory and you with dirty finger nails. At least the casket will be closed and only the dog would know.
Good Luck and If you live let us know how it went.
Regards,
Paul
|
|
-
|
|
|
>1. Why am I not dead?
Because God needs more work done on his Volvos.
|
|
-
|
|
This "depressurizing" myth bites us all eventually, and comes up here fairly often. It doesn't work because there is no specific Pump or Relay fuse. And pulling any fuel-related fuse (more below) results in an immediate stall—with no appreciable depressurizing.
I know this is a published thing, but it gets worse on U.S. 240s '86-'90, where the fuse cover label says Fuse #6 is for the Main Fuel Pump. That's only true for some foreign markets where K-Jet FI was used in 240s of that period. (I know of one from Kuala Lampur who posts here.)
On our LH FI cars, Fuse # 6 is essentially a spare. A close look at the wiring will show that it has a Red input wire (the common feed to fuses 6 thru 10) but no output wire(s).
NOTE: Fuse #6 isn't "dead". Fuses 6 thru 10 are all "live" from the battery on the LEFT (input) contact.
Tank pump fuse aside (the car will run without it), the only LH FI fuse is the 25 AMP blade fuse (or Fuse 6 for '91-'93), and pulling that will either cause an instant stall or no start at all, because it feeds everything in the FI system, including Tank fuse #4.
So wrapping a rag around a fitting and carefully loosening it is the only way I know to depressurize.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
|
|
-
|
|
|
Clamp the hose coming from fuel tank to pump - you can wrap a rag around it then use Vice-grips, or a c-clamp, or whatever works for you. Just be careful not to damage it. Then remove the whole fuel pump platform and change the filter on the bench. You will spill some gasoline. It is not a big deal unless you are smoking a cigarette at the time, just try to keep it out of your eyes.
I have gotten away without clamping the hose on an old leaky system, just caught the pint or so of gas that spilled out in a coffee can, but on my '93 it just kept siphoning gas out. Clamp the feed hose, mop up the little bit of gas that hits the floor, call it a day.
--
'93 244: 'A' cam 4 deg. advanced, 25/22 sways, custom heim endlinks, poly bushings, and a lot more styling customization than I care to recount.
|
|
-
|
|
|
With the car idling, or preferably with it in park at around 1000 RPM (throttle slightly cracked open), pull the fuel pump relay. This approach guarantees the fuel system is depressurized. Be slow and careful about cracking the lines loose from the filter, the rigid plastic hoses get brittle over time. Make certain that you replace the copper washers with new ones... fuel leaks can be a very bad thing.
jorrell
--
92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
|
|
-
|
|
|
"With the car idling, or preferably with it in park at around 1000 RPM (throttle slightly cracked open), pull the fuel pump relay."
Easier than pulling the relay is pulling the main FI/Ignition fuse (25Amp Blade fuse—replaced by Fuse 6 in'91 up 240s).
However none of these methods will depressurized the fuel lines. They all result in an instantaneous shut-down. This leaves pressure retained by the FPR and check valve.
To my knowledge there is no way to depressurize the lines that will eliminate some expulsion of fuel when the line is opened.
I just barely crack the fitting loose, then wrap it with a rag to catch the inevitable surge when loosening it the rest of the way.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
|
|
-
|
|
Hi Bruce,
Maybe you recall that experiment I did pulling the main fuel pump connector under the back seat. The car idled on (rather leanly) on just the tank pump. End result, no matter how you try to let the motor use up the fuel, is it dies of a lean mixture long before the lines are emptied of pressure. Just use a rag. No more than a teaspoon comes out anyway, in LH cars with no accumulator.
--
Art Benstein near Baltimore
Nobody cares if you can't dance well. Just get up and dance.
|
|
-
|
|
|
Someone more articulate than me can explain, but they are all asleep. Basically removing those fuses to depressurize only works on European Volvos.
They won't stop American Volvos. (or something like that!) Lots of people don't bother with depressurizing. I think most just open the gas cap, clamp the line to the tank with vice grips and try to stem the initial gas flow with a rag. Disconnect your battery. Have a fire extinguisher handy.
Changing a fuel filter on a 240 (or 740) is a disgusting ugly job full of trials turmoils and cursing. I'd rather put on a head gasket. It's easier. If you have a mechanic that you trust, this one is worth paying someone else to do it.
Wiglaf
|
|
-
|
|
|
If you have ever been shot in the face with a gallon of carcinogenic gasoline (according to California) from a pressurized fuel system, you just might change your mind about that approach.
Note that a stream of liquid gasoline isn't flammable on its own, heck, it can even put out a lit cigarette (DAMHIK), what you have to worry about are the tiny leaks that atomize the fuel like an injector... accidentally create one of those and the static that builds up in your clothes could easily set it off! If there is no pressure in the system, this scenario can't happen!
Fire extinguisher is a must in any case, but please respect fuel vapor it can burn you alive before you reach that extinguisher!
jorrell
Sorry to sound so "safety cop", but I have been burned before....
--
92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
|
|
-
|
|
|
You could be dead and someone else could have typed your post. :-)
If you have a new pump laying around then go ahead and change it, but you will be looking at least $150 if you have to buy one new. If you dont get the pressure out of the system, you will get a decent spray of fuel providing that your fuel pressure check valve is working properly. Its almost faster to unhook the line going to the filter and the fuel line going to the pump, unhooking the + and- wires, unscrewing the 3 bolts and taking the unit off. Then you can change the filter and pump on a bench and reinstall. Its a 5 minute job taking the unit down after you have seen it or done it once.
|
|
-
|
|
|
I found none of the tricks work. Let the car sit over night. While the system is designed to hold pressure after shut down, our cars are old, and not perfect by any standard, so you will leak some of the pressure. I cracked the hose going to the tank first, plugged it with a 3 inch ratchet extension. Then I cracked the banjo fitting bolt. Boy was that hard and nerve wrecking, but the amount of gas that shot out wasn't as bad as I thought. But, prepare to catch fuel, disposable baking pan on a rubber dish drainer mat to ensure no sparks on the cement, lots of towels and wear gloves. Its easy if you remove the whole platform. You will need ventilation, a garage might not be suited, driveway works though! Air tools make this soooo much easier. Buy a new line, the one that goes from the filter to the pump, incase you destroy it wrenching with all of your might. Be careful, and patient. Good luck!
Oh, you can thank your catalytic converter for scrubbing most of the CO, its not really scrubbing so much as it is giving it an extra oxygen, or so I have been lead to believe. And the pumps can be loud, both of them, but overly loud pumps are usually attributed to a rotting rubber line in the tank starving the in tank pump and making the main pump work harder. Or it could be the pressure build up of the fuel filter, in tank sock filter, so on and so forth. Loud pumps are part of RWD Volvo, but the sound should be constant not swishing, gushing, surging, or gurgling.
|
|
|
|
|
