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The solution to this problem is eluding me.
For anyone reading this for the first time I put my original text at the bottom of the page.
My main fuel pump is still making a growling noise.
-the prepump has been replaced with a new one, it is working at 7psi(lots)
-I looked inside the tank and it was spotless, no dirt or grunge
-after the new prepump was installed, the main fuel pump started to make
growling noises,(it had run quietly before the prepump was replaced)
-we replaced the main pump with a new one(bosch), it made a growling noise too
-the supplier replaced the first new main pump with another one which we installed, it growls also.
We started looking else where.
-a multimeter on the fuse contacts for the main pump shows about 16 amps draw
-the fuel pressure taken at the cold start injector is 70 pounds
-I tested the pressure regulator by disconnecting the return line near the
fuel filter on the firewall and connected a rubber hose, there is lots of
flow, about a gallon a minute
-While doing this test the main pump was quite(the first time since this ordeal
started
-so I blew down the return line to the tank to make sure it was clear, it was,
I could hear it bubbling in the tank
-I started the car again and checked the fuel return flow again, still lots
of flow but this time the main pump was starting to make noise again
-I re-connected the fuel return pipes to each other again, and now things are just the same with the growling fuel pump
-The engine was starting to warm up at this point, also on hot days sometimes
when I press the gas pedal the car will buck and lurch a few times (this
didn't happen before).
-The tailpipe seems to be blacker that it should be
-Also on hot days sometimes when I press the gas pedal the car will buck and lurch a few time(this didn't happen before).
-is the pressure regulator electricaly our vaccuum activated?
Does anyone have any ideas as to what might be going on.
Thanks
Doug Roberts
Volvo owner, Kaslo, BC, Canada
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ORIGINAL POSTING ON JUNE 27
My main fuel pump is making a horrendous growling noise. This all started with my belief that my in tank pre-pump had failed. I had my mechanic replace the pre-pump with a replacement from IPD. Unfortunately he didn't replace the rubber connecting hose, he said the original one seemed fine(he should have just replaced it anyway). He installed a new fuel filter as well as the pre-pump sock.
On my way home my main pump started to make an intermittent growling noise so I returned to the mechanics shop. He identified the main pump as the source and we could feel intermittent vibration in relation to the sound. We figured the main pump must be worn. I had to leave for the Vancouver the next day and decided to chance it and get a new pump there. (I live at 1700 ft altitude, Vancouver at sea level) At sea level the pump didn't seem as noisy but I had a Volvo shop replace the main pump with a new Bosch. For the month that I spent in Vancouver the pump was nice and quiet and the car ran well.
On my way back home the main pump started to growl more and more as my altitude increased. My mechanic here took the pump off and I shipped it back to the shop in Vancouver and they replaced it with another brand new one. When the new one was installed it made the exact same sound.
Also on hot days sometimes when I press the gas pedal the car will buck and lurch a few times then run fine after that(this didn't happen before).
In doing some tests this morning;
-we can here that the in-tank pump is running and a pressure gauge put on the line that supplies the main pump shows about 7 pounds pressure
-a multimeter on the contacts for the main pump at the fuse strip shows about 16 amps draw(it sometimes blows the fuse)
-the fuel pressure taken at the cold start injector is 70 pounds
Any suggestions?
Thanks.
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