fuel pressure

58pv · Post by **58pv** » 16 Dec 2007, 17:16

i have a 58 544 and the fuel pump is no good i replaced it with a holley elecric blue pump wat is the fuel pressure supposed to be on the factory pump thanx matt

sdewolfe · Post by **sdewolfe** » 28 Dec 2008, 08:13

Dual HS6 carbs? No more than 3psi. Some folks have reported problems even at that pressure. Start there and dial it down as necessary to stop flooding. The SU carbs are very sensitive to inlet pressure.

intelmujib · Post by **intelmujib** » 05 Nov 2009, 03:39

Need the year , make , and model to tell you what the pressure SHOULD be. Most cars/trucks now a days run on about 60 PSI, and can be no-start with as little as a 5 lb drop. Unfortunately, a Gage is the only way to tell (Hint-Advance/discount auto part stores have a policy that they will refund money on ANY thing they sell-theoretically you could buy the tools to rebuild an engine and they will buy them back when you are done!)
If you are no sure if its fuel or not, spray a LITTLE carb cleaner into the intake and see if it runs. If so, then its a fuel delivery problem, but still not necessarily a pump issue-the cam or crank sensor could be out, not giving the PCM the signal it needs to fire the injectors. Time for some professional diagnostics.

Post by **billofdurham** » 05 Nov 2009, 12:15

Your advice is sound in respect of a modern fuel injected engine. This thread relates to a 1958 Volvo 544, a true classic car, with dual SU HS6 carburettors. A fuel pressure of 60 psi would wreck the system.

Bill.

Klausc · Post by **Klausc** » 09 Jan 2010, 13:05

There are rebiuld kits for the mechanical fuel pump, please use google to find some. The 'pressure' varies with rpm and at idle is around 2psi. Much too weak for any electrical fuel pump to handle.
So long as you are using carbs, you need a very weak pump.

virg · Post by **virg** » 29 Apr 2010, 11:47

speaking of mechanical fuel pumps.............
Disassemble a failed fuel pump, down to the valves. Likely to find a droplet of gray jelly-like substance, which I think is a mixture of water and dust. Remove the stuff and you're back in business. A few years down the road, when there's another failure
skip the dis-assembly and just force (with rubber syringe) a little alcohol or through the exit and entry hoses.

Rejuvenated a few that way.