Honda Bmw 5 Service Manual

							
160 Fuel Tank and Fuel Pump 
General ........................... .I6 0.2 
Special tools ........................ .I6 0.2 
Fuel pump ......................... .I6 0.3 
Fuel tank  evaporative  control system ..... .I6 0.3 
Evaporative  system troubleshooting ..... .I6 0.4 
Warnings and cautions ................ .I6 0.5 
Fuel System Troubleshooting ...... .I6 0.6 
Fuel pump fuse and  relay .............. .I6 0.6 
Operating fuel pump  for tests ........... .I6 0.6 
Fuel pump electrical  circuit, testing ...... .I6 0.7 
Fuel pump power  consumption, testing ... .I6 0.9 
Fuel pressure gauge, installing 
(6-cylinder  models) 
................. .I6 0.1 0 
Fuel pressure  gauge, installing 
(V-8 models) ....................... .I6 0.1 1 
Fuel delivery, testing ................ .I6 0.12 
Fuel  Pump  and Fuel Level  Sender . . 160-15 
Fuel level sender (right side)  and 
fuel  pump.  removing  and installing 
...... 160-15 
Fuel level  sender (left side). 
removing and  installing 
............... 160-17 
Siphon pump. removing  and installing .... 160-1  9 
Fuel  Tank  and Fuel  Lines .......... 160-20 
Fuel tank.  draining ................... 160-20 
Fuel tank. removing  and installing ....... 160-21 
Fuel  expansion  tank. removing 
and installing 
....................... 160-23 
Activated  carbon canister I fuel tank 
leak detection unit 
(LDP or DMTL). 
removing and  installing ............... 160-24 
Running losses  (312-way) valve. 
removing and installing 
............... 160-24   
						

							
This repair group covers service information specifically for the fuel supply  system. Information on the fuel injection  sys- 
tem  is covered  in 
130 Fuel Injection. 
In  the  descriptions  and procedures given below,  engine and 
engine management (DME) systems are referred to  by man- 
ufacturer  code. If necessary,  see 
100 Engine-General  for 
model year, engine code,  and DME applications. 
NOTE- 
Fuel  filter replacement is covered  in 020 Maintenance, 
Special tools 
Some of the procedures  in this  group require the use  of 
special tools. 
I( Fuel line clamp 13 3 010 (Tool No. BMW 13 3 01 0) 
4 Fuel pressure  gauge T-fitting  with shut-off valve 
(Tool  No. BMW 13 
5 220)   
						

							
Fuel Tank and Fuel Pump 
Fuel pump 
The electric  fuel pump  is mounted  in the fuel tank  in tandem 
with  the right  side fuel level  sender.  The fuel pump delivers 
pressurized  fuel to the  fuel injection system. 
A pressure  regu- 
lator  maintains system pressure.  The quantity  of fuel supplied 
exceeds  demand,  so excess fuel returns to  the fuel  tank  via a 
return line.  See 
130 Fuel Injection  for more information. 
NOTE- 
Fuel pump  removal procedures  are given under Fuel  level 
sender  (right side) and  fuel pump,  removing and install- 
ing. 
Fuel tank evaporative control system 
Evaporative control,  also referred to as running losses  con- 
trol,  is designed  to prevent fuel system evaporative losses 
from venting into  the atmosphere. 
The  components  of this system allow  control and monitoring 
of  evaporative losses by the  on-board diagnostic 
(OED II) 
software incorporated  into the engine control module  (ECM). 
NOTE- 
1997 V-8 models (540i) with Bosch  DME M5.2 are not 
equipped  with an 
OBD I1 running losses monitoring  system. 
Fuel  tank evaporative 
control  system 
(models  with 
DME MS42.0) 
4 The main  components  of the  evaporative  control system  and 
their functions: 
Fuel  overflow 
tank acts as a liquidlvapor separator 
Carbon canister  stores evaporated  fuel. 
Plumbing  ducts vapors from  fuel tank to canister and from 
canister to  intake 
manifold. 
- Carbon  canister purge  valve is controlled by  enginecontrol 
module  (ECM). 
Running losses  or 312-way  valve (not shown) shunts  ex- 
cess fuel  volume directly 
back to fuel tank before  it circu- 
lates through injector fuel rail (models with Siemens  MS42 
or  Bosch  M5.2.1 engine management only). 
Leak detection  unit (LDP  or DMTL) pressurizes fuel 
tank 
and  evaporative system to monitor system leaks (models 
with Siemens  MS42 or Bosch  M5.2.1 and later). 
Leak detection systems vary among models  and years,  and 
are further described  in 
130 Fuel Injection. 
NOTE - 
3/2-way valve, tunning losses valve and fuel changeover 
valve  are used  interchangeably 
in BMW technical  literature.   
						

							
Fuel Tank and Fuel Pump 
Evaporative system troubleshooting 
- Start by accessing  diagnostic trouble  codes (DTCs) using a 
BMW  or BMW compatible aftermarket scan  tool. 
For  purposes  of OBD 
II emissions compliance, the DME 
system sets a  diagnostic trouble  code (DTC) when it de- 
tects a leak that  is equal  or larger than minimum 
lealc 
sensed  by system. 
Malfunction Indicator Light (MIL) is illuminated  upon sec- 
ond recurrence  of fault.  See OBD  On-Board  Diagnostics. 
- When leak testing, observe  following conditions to obtain 
plausible results: 
Fuel  tank 
1, to I., full. 
0 Vehicle  parked for at least 2 hours to  allow fuel to reach 
room  temperature. 
Ideal fuel temperature is  10- 20°C 
(50 
- 68 F). 
Do not  refuel immediately before 
lealc test. 
- If a leak  is detected, check the  following areas: 
* Fuel filter cap (leaking  or off). 
Fuel  tank ventilation lines leaking at fuel 
tank or activated 
carbon  canister. 
i 
Tank ventilation  valve leaking (in engine compartment). 
Fuel  level 
sensorlfuel pump cap  leaking. 
Evaporative system component replacement  is covered later 
in 
th~s group in Fuel Tank and  Fuel Lines.   
						

							
Fuel Tank and Fuel Pump 
Warnings and cautions 
Observe the following  warnings and cautions when servicing 
the  fuel  system. 
WARNING- 
* The fuel system  is designed  to retain  pressure  even when 
the  ignition  is off. When working with the  fuelsystem, loos- 
en  the  fuel  lines slowly  to allow  residual 
fuel pressure  to 
dissipate.  Avoid  spraying  fuel.  Use  shop rags to capture 
leaking  fuel. 
Before  beginning  any work  on the fuel system,  place a 
fire  extinguisher in the vicinity  of the  work  area. 
Fuel  is highly flammable. When working  around fuel, do 
not  disconnect  any wires  that could cause electrical 
sparks. Do not smoke or worknearheaters  or other  fire 
hazards. 
* Always  unscrew the  fuel tank  cap to release pressure 
in the 
tanlc before working  on the  tank  or lines. 
When  disconnecting a  fuel hose, wrap shop rag around 
end  of hose  to prevent  spray  of fuel under pressure. 
Do not  use a work light with an incandescent bulb  near 
any  fuel.  Fuel may spray  on the hot bulb causing  a fire. 
0 Make sure  the  worlc area is properly  ventilated. 
CAUTION- 
- Prior  to disconnecting the battery, read the battery discon- 
nection  cautions  given  in 
001 General Cautions an4 
Warnings. 
Before 
making any electrical tests with the ignition 
turned on,  disable the ignition system as described in 
120 Ignition  System.  Be sure the battery is discon- 
nected  when replacing components. 
To  prevent  damage  to the ignition system  or other  DME 
components,  including the engine  control  module 
(ECM), always connect and disconnect  wires and test 
equipment  with the ignition off. 
Cleanliness  is essential when 
worl~ing with the fuel sys- 
tem.  Thoroughly  clean the fuel  line unions before  dis- 
connecting  any of the  lines. 
Use only clean tools.  Keep removed  parts clean and 
sealed  or covered with  a clean,  lint-free cloth,  especial- 
ly  if completion  of the repair  is delayed. 
Do not move  the car while the fuel  system is open. 
Avoid  using high pressure compressed air to  blow out 
lines  and components.  High pressure  can rupture  inter- 
nal  seals and  gaskets. 
Always  replace seals,  O-rings and hose  clamps.   
						

							
.-- - 
/ Fuel Tank and Fuel Pump - .. -. -- 1 
Fuel pump fuse and relay 
Troubleshooting  of any  fuel pump  fault should begin with 
checking  the fuel pump fuse  and the fuel pump  relay. The 
DME main relay should also be  checked. The fuel pump relay 
is located behind right side luggage compartment interior 
panel. 
I Fuel  pump relay 
BLU =blue ERN = blo$,m GRN =groan GRY = grsy ORG =orange PNI< =pink RED =red VIO =violel WHT = wlilte 
rk-; I I 1 ECM 
I I I 31 8 ,._--___.I 
NOTE- 
Special  tools are  required for some  of the tests  described 
here. 
4 Fuel pump circu~t is  fuse-protected. 
0 6-cylinder  models with Siemens DME MS41 .I, MS42, V-8 
models with Bosch DME  M5.2,  M5.2.1 englne manage- 
ment:  Fuse 
F54,15A (luggage compartment fuse panel) 
6-cylinder  models with Siemens DME MS43  engine man- 
agement: Fuse 
F22,25A (glove  compartment fuse panel) 
V-8 models with Bosch  DME M7.2: Fuse F54,25A (lug- 
gage  compartment  fuse  panel) 
- Fuse 31 in glove  compartment fuse panel supplies  power to 
coil side  of fuel  pump  relay. Engine  control module (ECM) 
supplies switched ground to  relay. During starting, fuel pump 
runs  as long  as ignition  switch is in START  position  and con- 
tinues to  run once  engine starts. If electrical system  fault in- 
terrupts power to fuel  pump, engine  will not run. 
. . 
Operating fuel  pump for tests 
- To operate fuel pump  for testing purposes without  having to 
run  engine,  bypass fuel pump  relay to power  pump directly. 
< To run fuel  pump, open luggage compartment  and release 
right side trim  panel.   
						

							
- Fuel Tank and Fuel pump] 
Remove  fuel pump 
relay (arrow). 
4 Connect  relay socitet  terminal 6 (redlviolet  wire) to relay 
socket  terminal 
2 (whitelblue  wire) with a fused  jumper  wire. 
After  completing  tests, remove  jumper harness. 
CA 
UTIOG 
Relay  locations  may vary  Use care  when  identifying  relays 
and  making electrical  checks at 
the fuse/relay panel. See 
610 Electrical Component Locations  for additional  re- 
lay  information. 
The fuel  pump relay has  a 1.5 
md red/violet wire  at 
terminal 
6 in the relay  socket. Terminal2  has a 2.5md 
white/blue wire.  See ELE  Electrical  Wiring Diagrams 
for  additional wiring  information. 
NOTE- 
* The fuel  pump will run  as soon as  the jumper  wire Is at- 
tached. 
The jumper  wire should be 1.5 
md (14  ga.)  and include 
an  in-line fuse holder with  a 15A fuse.  To avoid 
fuse/relay 
panel damage  from repeated connecting and  disconnect- 
ing, also  include a toggle switch in  the jumper  harness. 
- If pump does not  run  with jumper  installed, fault  could be in 
fuel  pump,  fuses 
F31 or F22 1 F54, or wiring to  pump. Check 
pump,  fuses and its wiring  as described  below. 
Fuel pump electrical circuit, testing 
- The  test given below assumes  that the fuel pump  relay circuit 
is  functioning correctly  as described  earlier. Access  to the 
pump  is from  below  the rear  seat  bottom cushion. 
- Remove  rear seat  lower  cushion  by lifting  front  edge off left 
and  right  catches.   
						

							
160-8 
I Fuel Tank and Fuel Pump 
4 Disconnect  harness connector  from tank sending  unit by 
sliding  connection  lock to  release connector. 
Connect  voltmeter  between fuel  pump terminals  on 
connector. 
NOTE- 
Fuel pump  power (+) is supplied  through the white/blue wire 
Ground 
(-) is  supplied  by the  brown  wire. 
With jumper  wire  connected in place of fuel pump  relay as 
described  above, check for battery voltage  at fuel pump 
harness  connector  terminals. 
If  voltage  and ground are  present, fuel pump is probably 
faulty. If  there is no  voltage,  check wiring between fuel  pump 
and  relay.   
						

							
.- - 
Fuel Tank and Fuel purnpl 
Fuel pump power consumption, testing 
To achieve  accurate  test results,  the battery voltage  at the 
fuel pump connector  should be 
12.6 volts. Charge the  battery 
as necessary. 
A higher  than normal power  consumption may indicate a 
worn fuel pump, which  may cause intermittent fuel starvation 
due to  pump overheating  and seizure.  The only  remedy  is 
pump  replacement. 
A lower than normal power consumption 
may  indicate a blockage.  Be sure  to check that  the return  line 
and  the pump pickup are not  obstructed before replacing  the 
pump. 
- Expose right  side access cover: 
Peel forward lip  of carpet. 
Release rubber grommet from center  of access  cover insu- 
lation. 
Peel back insulation  at perforations to expose fuel  tank ac- 
cess  cover. 
Remove right  side cover to expose electrical  harness  con- 
nector. 
Disconnect harness connector from tank sending unit  by slid- 
ing  lock back. Lift off connector. 
Test  fuel pump  for current  draw by attaching digital ammeter 
between  pump and harness (terminal 
2, whitelblue wire)  and 
connect a jumper wire between pump and harness (terminal 
1, brown  wire) as shown. 
CAUTION- 
Do not  allow  the test leads to  short to ground. 
NOTE- 
See 600 Electrical Systern-General for  information  on elec- 
trical  tests 
using a digital multirneter. 
Run  pump  as described in Operating fuel  pump for tests. 
- Compare  ammeter reading with specification listed  in ac- 
companying  table. 
Fuel 
pump current 
Current consumption  (average) 9.5 amps   
						

							
I Fuel Tank and Fuel Pump -- 
Fuel pressure gauge, installing 
(6-cylinder  models) 
4 Remove fuel  rail cover  by prying  off trim covers  (arrows) and 
removing nuts. 
4 If equipped,  remove schraeder valve  cap (arrow).  Blow fuel 
back  through  feed line using  a brief  burst  of compressed air 
(maximum 
3 bar  or 43.5 psi). 
WARNING - 
Fuel  in fuel  line is underpressure  (approx. 3 - 5 bar or 45 - 
75psi) andmay be expelled  underpressure. Do not smoke 
or  work  near heaters  or other fire hazards.  Keep a fire ex- 
tinguisher  handy Before disconnecting fuel hoses, wrap a 
cloth around fuel  hoses to absorb any  leaking fuel. Catch 
and dispose  of escaped  fuel. Plug  all open  fuel lines. 
Always  unscrew the fuel tank  cap to release pressure 
in  the  tank before  working  on the tank  or lines. 
4 Attach fuel pressure  gauge to BMW special  tool 13 5 220 
(T-fittlng) or equivalent  and attach to schraeder valve. 
WARNING - 
The fuel pressure gauge must be  securely connected  to pre- 
vent it from 
coming loose underpressure. 
CAUTION- 
When  using the BMWspecial tool, use care when turning  the 
T-handle in to open  the schraeder  valve. Screw the handle  in 
just until the schraeder valve opens.  Turning the handle  in too 
far  will  damage the  schraeder valve. 
NOTE- 
* The schraeder  valve must  be opened to  the fuel  pressure 
gauge  connection.  Either remove  the valve using  a stan- 
dard tire  valve removal tool  or use the BMW special tool 
15 5 220. 
* The fuel pressure gauge  should have a minimum range of 
0 to 5 bar (0 to 75 psi). 
- For  vehicles without  the schraeder valve  on the fuel rail, at- 
tach  the fuel  pressure gauge  in line  with  the fuel  supply  line 
to  the  fuel  rail.