Need 2nd Opinion on Fuel Pump Issue
Thread Starter
Rennlist Member
Joined: Jun 2004
Posts: 820
Likes: 2
From: SoCal
Need 2nd Opinion on Fuel Pump Issue
So I searched and found mostly DME relay threads so don't flame me yet (although I am sure one of you will find that thread describing my EXACT scenario
)
My car died while driving yesterday. I pulled the DME and made sure contacts were clean. It looks pretty new but I have not replaced it or gotten a spare yet (I know, I know...)
I checked the fuel pump fuse and it was blown. I put it in a spare and the car started and drove about 100ft. before dying again. I checked the fuse and it was blown again.
I suspect the fuel pump has gone bad and shorted out. It has been a little loud since I got the car and the PO records indicate small bits of metal in the fuel filter at 90K service - indicating that the pump was on it's way out. The car now has 106K miles.
So, everything lines up that it's the pump but thought I would run it by this group first before buying a new one.
Also, I haven't yet looked at any of my repair info but was wondering if the pump is underneath or inside the trunk area.
Thanks guys!
David
)My car died while driving yesterday. I pulled the DME and made sure contacts were clean. It looks pretty new but I have not replaced it or gotten a spare yet (I know, I know...)
I checked the fuel pump fuse and it was blown. I put it in a spare and the car started and drove about 100ft. before dying again. I checked the fuse and it was blown again.
I suspect the fuel pump has gone bad and shorted out. It has been a little loud since I got the car and the PO records indicate small bits of metal in the fuel filter at 90K service - indicating that the pump was on it's way out. The car now has 106K miles.
So, everything lines up that it's the pump but thought I would run it by this group first before buying a new one.
Also, I haven't yet looked at any of my repair info but was wondering if the pump is underneath or inside the trunk area.
Thanks guys!
David
Drifting
Joined: May 2006
Posts: 3,074
Likes: 205
From: Paris
Hello David,
The fuel pump's location is under the passenger footwell accessible from under the car.
There is a rectangular flap door held by several 10 mm nuts.
A reasonable price for the pump is on the auction site.
In the trap, there is the pump, a small hose, and the gas tank filter.
the fuel filter starts at a height of about 3 to 4 inches from the bottom low of the gas tank.
So if you think of any metal pieces left, you have to remove the gas tank for that.
Remember that you will have to empty the gas to replace pump.
The small rubber hose connecting the pump to the tank can be stuck from age, and is expensive to replace.
Put some grease on the electric connections after bolting the new pump.
The fuel pump's location is under the passenger footwell accessible from under the car.
There is a rectangular flap door held by several 10 mm nuts.
A reasonable price for the pump is on the auction site.
In the trap, there is the pump, a small hose, and the gas tank filter.
the fuel filter starts at a height of about 3 to 4 inches from the bottom low of the gas tank.
So if you think of any metal pieces left, you have to remove the gas tank for that.
Remember that you will have to empty the gas to replace pump.
The small rubber hose connecting the pump to the tank can be stuck from age, and is expensive to replace.
Put some grease on the electric connections after bolting the new pump.
Racer
Joined: Nov 2007
Posts: 296
Likes: 14
From: Berkshire UK
It is sort of under the tank, but not in the boot/trunk. It's mounted under the car in a recess covered by a metal plate just as Geo discribes. I guess you have to drain the tank as the pump is gravity fed. Once the hose is disconnected, I suppose you could stick a bolt in it or some other stopper, but it's probably safest to drain it.
Thread Starter
Rennlist Member
Joined: Jun 2004
Posts: 820
Likes: 2
From: SoCal
Thanks. I think I'll plan to drain the tank but prepare a stopper and see if it works. Good thing I did not fill it on Tuesday as I had planned. 
So, back to my original question... It seems as though you would all agree that the pump is bad.
I suppose if it sounds like a duck, looks like a duck, must be a duck (or pump), right?
So, back to my original question... It seems as though you would all agree that the pump is bad.
I suppose if it sounds like a duck, looks like a duck, must be a duck (or pump), right?
Rennlist
Lifetime Member
Lifetime Member
Joined: May 2001
Posts: 3,651
Likes: 8
From: Chino hills, CA
There is good write up posted in the DIY section of the http://p-car.com site from TJ90 from his evaporator core replacement which shows the removal of the fuel pump. The pics take sometime to load up.
Do you know if you always let the gas tank run low before you refuel it? Or has the car ever ran out of gas before? Fuel pumps were designed to pump liquid (gasoline), they could easily burn out if it was sucking air when the gas tank is almost empty.
http://p-car.com/diy/ac/
Do you know if you always let the gas tank run low before you refuel it? Or has the car ever ran out of gas before? Fuel pumps were designed to pump liquid (gasoline), they could easily burn out if it was sucking air when the gas tank is almost empty.
http://p-car.com/diy/ac/
Thread Starter
Rennlist Member
Joined: Jun 2004
Posts: 820
Likes: 2
From: SoCal
Thanks for the link to pictures Robin.
Yes, the fuel line comes on periodically so that could have accelerated the pump wear. Plus, according to the records (and noise), the pump has already been on it's way out for the entire 14K miles I've driven it so far!
Yes, the fuel line comes on periodically so that could have accelerated the pump wear. Plus, according to the records (and noise), the pump has already been on it's way out for the entire 14K miles I've driven it so far!
Trending Topics
Three Wheelin'
Joined: May 2001
Posts: 1,720
Likes: 7
From: Birmingham, AL
1 - I would tend to agree that your problem is the pump. I have no experience with the 993 fuel pump circuit, but a good bit with a '95 BMW circuit...can't imagine they would be THAT much different. There are many things that can cause the pump not to RUN, but really not that many things that will cause the fuse to keep blowing...at least not that many "likely" things...except the pump motor windings.
2 - On the BMW, the pump is actually submersed inside the gas tank. Cooling for the pump is provided by the gasoline. Many people suggest that by letting your tank get empty between fill-ups, you subject the pump to "lack of cooling" due to the lack of gas in the tank...thus causing premature pump failure. In the case of the BMW, I don't believe this to be true, as the pump is fitted into a "trough" at the bottom of the tank, and this trough always has gas in it...unless you are down to about the last cup or less of gas...otherwise, the pump is fully submersed in gas.
Item 2 probably doesn't apply to the 993, but item 1 probably does.
2 - On the BMW, the pump is actually submersed inside the gas tank. Cooling for the pump is provided by the gasoline. Many people suggest that by letting your tank get empty between fill-ups, you subject the pump to "lack of cooling" due to the lack of gas in the tank...thus causing premature pump failure. In the case of the BMW, I don't believe this to be true, as the pump is fitted into a "trough" at the bottom of the tank, and this trough always has gas in it...unless you are down to about the last cup or less of gas...otherwise, the pump is fully submersed in gas.
Item 2 probably doesn't apply to the 993, but item 1 probably does.
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Porsche's Top 5 Most Questionable Naming Decisions
Verdad Gallardo
Pogea Racing's 964 Porsche 911 Reimagination Stands Out in a Crowded Field
Verdad Gallardo
6 Convertible Top MYTHS Most People Don't Understand!
Michael S. Palmer
2026 Porsche 911 Club Coupe is Spectacular, And Everything Wrong with the Porsche Market
Joe Kucinski
Talos Takes Your 991 Porsche 911 GT3 to the Next Level for a Cool $1.13 Million
Verdad Gallardo
9 Vehicles Porsche Helped Engineer that Aren't Porsches
Verdad Gallardo
9 Features and Characteristics That Only Porsche People Understand
Verdad Gallardo
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way
Joe Kucinski