Power loss + erratic fuel gauge -a warning and a fix!
04-21-2003, 03:11 AM
#1
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Power loss + erratic fuel gauge -a warning and a fix!
The culprit: A rubber sleeve slid downward to the bottom of
the fuel level sender tubular shaft causing fuel flow restriction...
The car is an '88 944 turbo with 27K actual miles....
...I was experiencing strange power losses upon acceleration.
This also was accompanied by the fuel gauge reading full
or empty regardless of how much fuel was in the tank.
The problem began when my wife ran out of fuel a few miles
from home -yet the tank indicated 1/2 full. After topping the
tank, the car ran O.K but it was not performing to its normal
power...
...I checked the suspected fuel level sender unit and measured
the output leads -it was near the proper value for 1/2 tank.
Upon starting the car the resistance dropped from 25 ohms to
6 ohms within seconds. This explained why the gauge climbed
higher. The fuel level was increasing inside the fuel lever sender
tubular housing.
Confused by this phenomena, I removed and
examined the bottom section of the sender unit and discovered
a black rubber outer sleeve had slid down to the very bottom
-covering the fuel inlet ports. This caused restriction of fuel flow
and caused the vacuum from the fuel pump to generate
fluctuations of fuel level.
The rubber sleeve appears to function as an adjustable air vent
limiter at the top section to dampen measured fuel level
response time. But this rubber part slid all the way down to the
bottom, due to aging, and blocked fuel flow. I secured this part to
the middle of the tube as it does more harm than good.
The car is running very well after this simple no cost fix.
( FYI, the fuel sender unit part # 94464103701 costs $304 retail.)
the fuel level sender tubular shaft causing fuel flow restriction...
The car is an '88 944 turbo with 27K actual miles....
...I was experiencing strange power losses upon acceleration.
This also was accompanied by the fuel gauge reading full
or empty regardless of how much fuel was in the tank.
The problem began when my wife ran out of fuel a few miles
from home -yet the tank indicated 1/2 full. After topping the
tank, the car ran O.K but it was not performing to its normal
power...
...I checked the suspected fuel level sender unit and measured
the output leads -it was near the proper value for 1/2 tank.
Upon starting the car the resistance dropped from 25 ohms to
6 ohms within seconds. This explained why the gauge climbed
higher. The fuel level was increasing inside the fuel lever sender
tubular housing.
Confused by this phenomena, I removed andexamined the bottom section of the sender unit and discovered
a black rubber outer sleeve had slid down to the very bottom
-covering the fuel inlet ports. This caused restriction of fuel flow
and caused the vacuum from the fuel pump to generate
fluctuations of fuel level.
The rubber sleeve appears to function as an adjustable air vent
limiter at the top section to dampen measured fuel level
response time. But this rubber part slid all the way down to the
bottom, due to aging, and blocked fuel flow. I secured this part to
the middle of the tube as it does more harm than good.
The car is running very well after this simple no cost fix.
( FYI, the fuel sender unit part # 94464103701 costs $304 retail.)
04-21-2003, 03:38 AM
#2
Race Car
How does the sender (top of the tank) restrict fuel flow at the fuel pump (at the bottom of the tank)? Did it fall to the bottom of the tank and block the fuel hose leading out of the tank? Maybe I am missing something.....
04-21-2003, 03:39 AM
#3
Race Car
Oh before anyone goes to buy a fuel sender at the dealer, I used to throw those things out along with the plastic gas tanks. I have a few spares if anyone needs one....just pay shipping.
