Here we go again. Former post was "Internal Fuel Pump Right". So was having issues with the car acting like it was out of gas below 1/2 tank. Replace internal fuel pump, sock, filter, and relay. Today is the first time I have been below 1/2 tank since and my issues have returned. Exact same thing, acting like it is running out of gas. I checked the hose on the internal fuel pump when I changed it and it did not have a whole in it. Isnt there 2 fuel line check valves running down the driverside? Could they be bad? I am really tired of messing with this thing.

 

My experience with 240 series, In tank fuel pump = Hi flow, Low pressure, Main fuel pump, Low flow, High pressure. Regarding check valves failing, they normally fail open, hence not blocking pressures back to the tank and resulting starving fuel upon starting the vehicle, i.e. both pumps have to start from scratch. You may want to look into the fuel safety relay. The one that functions in case of an accident. On the 240, it is built into the FPR. Always at a 1/2 tank is a puzzle. Is it just the second time at 1/2 tank or is it every 1/2 tank since your post. Can you suck the tank down manually to say 1/4 tank and test?

regards

- rev -

 

Rev, pretty sure he's tried the lower gas levels...this has been going on a bit. The 91 940 and 740's are essentially the same car. As I recently dissected a 91 740T I'm quite familiar with 'em. One check valve between the inline and fuel filter. And, I've never had one fail and restrict fuel flow. Basically, it just means it takes 4-5 seconds to start versus 2-3. Your 91 doesn't have a schraeder valve on the fuel rail, does it? I don't think that came until near the end. I have a fuel rail adapter for my fuel pressure gauge but other than that, sort of tough to check your FP. Did you ever pull the fuel hose off of the inlet to the inline pump and just visually inspect the fuel flow pumped out by the tank pump? If the tank pump is working as it should, there will be a Vesuvious of gas in no time.

 

I am swapping a '00 Ford engine into an '82 245. Just discovered that this particular year has 65 psi injectors. What pressure is the Volvo fuel pump capable of producing?

 

swift I had the battery disconnected when i worked on it, thought I might blowmyself up. Is it safe to work on the pump with the battery connected?

 

Well, BD, I would never tell anyone to even change the spark plugs with the battery connrcted. This country is way too litigious! All I can do is mention how I and all the techs in my shop do it. I've seen people crawl under a car with a cigarette in their mouth looking for a gas tank leak! True story. When I check fuel flow on the intank pump, I have an oil catch tray under the predicted path of said gasoline. I have the car on a lift, about a foot off the ground. Could be done on jack stands. I sit in the driver's seat, lean out so I can see the end of the fuel line removed from the inlet of the inline (under car) pump. I turn the key to KOEO (key on, engine off...the run position). There should be a healthy shot of gasoline hopefully landing in the catch tray. In my opinion (worth nothing!) it is no more dangerous than gassing a lawn mower. Obviously, working with gasoline is an issue that involves common sense; no open sources of ignition, pilot lights, smokes, etc. I do this on every intank pump I swap to make sure a. the new pump is not wired backwards b. that the small connecting hoses are sealed. Furthermore, I always check the new pump out of the car before installation. Today's parts all together often begin their life in Communist China and their quality control leaves a lot to be desired.

 

Thanks again Swift! I was trying the turn the key, listen down the fuel inlet method to try to hear the pump running and did not hear anything. I think I will be in it all day tomorrow trying to figure something out.

One really strange thing today. I was leaving a client and when I started the car I immediatly reached for the gear selector and and looked in the side mirror to back out. When I looked in the mirror I saw gas fumes, you know like you see when you are putting gas in the car, come up in the air. I looked twice and the got out of the car and looked under and around and saw nothing. Got back in the car and looked in the mirror again and nothing. May be random, I dont know but thought I would mention it.

 

Ok pulled everything apart. Checked internal pump and it was fine. Chased all lines, all fine. Put pressure on the small hose off the internal pump, fine. Got sending unit moving thought it was going to be ok, still off. Replaced big fuel filter by external pump, had to replace feed line of course. Twisted fuel line up cause fittings were so tight. Ended up replacing entire fuel line from intake to pump. Time will only tell but everything seems to be working. would the fuel pressure regulator make this happen? Could the main pump be getting weak and when the static pressure is low it lowers the pressure? Guess I need to put guage on it. Forgot to look for the schrader valve on the intake.
BTW the battery **** out on me in this process, thank goodness for strong alternators. Ended up driving aboout 40 miles with a dead battery. Replace it tomorrow, go on a drive and see what happens when the tank gets low.

 

Fuel pressure gauge my man or else you're just shooting in the dark

 

Well VG, tell the man how to hook up a fuel pressure gauge to a 91 fuel rail, ok? There's no schraeder valve. The only way is to cut the female end off a donor car's rubber inlet line and the male end off of a fuel rail, which of course ruins the fuel rail and build an adapter. Most folks don't have access to these parts so often

 

Just gonna have to see what happens, can a fuel pressure guage be put inline on a rubber hose? I messed up the fuel lines, cut the fittings off the old line and used rubber fuel lines and clamps to put it back together.

 

Yeah, in theory. Most pressure gauge sets have a set of ****** end adapters you could use.

 

All fixed. see thread "Well it just completely died crap" for final prognosis.