Fuel pump
11-21-2006, 11:43 PM
#1
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Fuel pump
How much noise should a fuel pump make?
I can hear my fuel pump when my engine is
at idle....a slight whine. Should these things
be basically silent?
Darren
'87 944S
I can hear my fuel pump when my engine is
at idle....a slight whine. Should these things
be basically silent?
Darren
'87 944S
11-21-2006, 11:50 PM
#3
Burning Brakes
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I don't think noise necessarily means something is wrong. Mine has whined since I bought the car (12/2001). At first I was worried about it and sourced replacements, but I've never had a problem with fuel delivery, so I left it alone. It gets louder the hotter the weather is.
11-22-2006, 12:20 AM
#4
Rennlist Member
could be that the rubber dampner that it sits in is worn out or missing. Ive never heard my fuel pump running- one of the few cars ive had that i couldnt- but the good thing is that its running.
11-22-2006, 01:55 AM
#5
Drifting
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Sometimes on these cars, when the filter starts to get dirty, it will make the pump whine some. I had this happen on a couple of my cars. Got quite after replacing the filter
11-22-2006, 02:04 AM
#7
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The reason I ask is that I'm trying to track down uneven,
erratic idle. I have replaced just about every ignition/fuel
related component I can think of...AFM,FPR,ISV,ICM,TPS,temp
sensor. The last things I replaced were the two hoses that
connect to the ISV. That made a BIG difference. Not as smooth
as I would like but I nice steady idle that didnt fluctuate much
at all. I thought, problem solved, yeah! NOT! Fast forward
2 weeks later...sitting at a red light, idle surges, then drops
and engine dies. Restarts fine, but wont maintain idle. The only
difference was that I was about out of gas. I fill up with
gas...which is where I was headed anyways and 19.5 gallons.
No idle problems. Now I'm wondering if it's related to my fuel
pump. I'm going to see what happens when I get low on gas again.
Darren
'87 944S
P.S. - I dont believe the engine dying was related to being out of gas.
On restart, it idled rough, but drove well, with good acceleration.
erratic idle. I have replaced just about every ignition/fuel
related component I can think of...AFM,FPR,ISV,ICM,TPS,temp
sensor. The last things I replaced were the two hoses that
connect to the ISV. That made a BIG difference. Not as smooth
as I would like but I nice steady idle that didnt fluctuate much
at all. I thought, problem solved, yeah! NOT! Fast forward
2 weeks later...sitting at a red light, idle surges, then drops
and engine dies. Restarts fine, but wont maintain idle. The only
difference was that I was about out of gas. I fill up with
gas...which is where I was headed anyways and 19.5 gallons.
No idle problems. Now I'm wondering if it's related to my fuel
pump. I'm going to see what happens when I get low on gas again.
Darren
'87 944S
P.S. - I dont believe the engine dying was related to being out of gas.
On restart, it idled rough, but drove well, with good acceleration.
Trending Topics
11-22-2006, 02:07 AM
#8
Drifting
There is a strainer in the fuel tank. It is that silver "cap" looking thing that the fuel line connects to. If you ran a 20 year old car close to empty, there could be lots of crud lurking near the bottom, kinda like the last cup of coffee in a day old pot.
11-22-2006, 11:43 AM
#9
Instructor
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Hey, Darren. It's worth looking at the strainer (I just checked mine last week, by coincidence; I've got similar problems with my car). It's a PITA draining the tank, though. Personally, I hate working with gas like that. It seems like it always gets splashed around no matter how careful I am.
I assume you've changed the filter and had the injectors cleaned and tested. Also, you've replaced/checked all the vacuum lines and connections?
As I understand it, if you've got good, steady fuel pressure and you get a good volume test, it SHOULDN'T be the pump. Of course, that doesn't mean that you're not getting some sort of electrical glitch with the engine running/vibrating, etc., with the pump after it's been running for a while, and so on. It's an expensive shot in the dark to just replace the pump. It COULD just have been coincidence that you saw improvement after a refill. The car had been given a chance to cool down a little, for instance.
Have you checked to be sure that the AFM isn't way out of adjustment?
Kurt
'87 944S
I assume you've changed the filter and had the injectors cleaned and tested. Also, you've replaced/checked all the vacuum lines and connections?
As I understand it, if you've got good, steady fuel pressure and you get a good volume test, it SHOULDN'T be the pump. Of course, that doesn't mean that you're not getting some sort of electrical glitch with the engine running/vibrating, etc., with the pump after it's been running for a while, and so on. It's an expensive shot in the dark to just replace the pump. It COULD just have been coincidence that you saw improvement after a refill. The car had been given a chance to cool down a little, for instance.
Have you checked to be sure that the AFM isn't way out of adjustment?
Kurt
'87 944S
11-22-2006, 12:38 PM
#11
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Haven't change the filter yet. I'll wait until this tank runs down. How does this strainer come out?
All vacuum lines in the engine compartment have been replaced with silicone lines.
BTW, I have been getting parts for my VW bus and my 944S at http://www.autohausaz.com.
They have pretty good prices and I've been very satisfied. They show a Bosch fuel pump for $194.
Other places show $222,$225,$209. I just found a rebuilt Bosch pump for $110 ($70 core) at Vertex.
I'm tempted to replace things when I can before they fail and leave me stranded. These parts ARE 20 years old.
Darren
'87 944S
All vacuum lines in the engine compartment have been replaced with silicone lines.
BTW, I have been getting parts for my VW bus and my 944S at http://www.autohausaz.com.
They have pretty good prices and I've been very satisfied. They show a Bosch fuel pump for $194.
Other places show $222,$225,$209. I just found a rebuilt Bosch pump for $110 ($70 core) at Vertex.
I'm tempted to replace things when I can before they fail and leave me stranded. These parts ARE 20 years old.
Darren
'87 944S
11-23-2006, 11:05 AM
#12
Drifting
It is threaded onto the fuel tank. Just take a pair of channel locks and twist. Of course that is after the fuel is drained and the fuel line is removed from the nipple.