Honda Bmw 5 Service Manual

							
Fuel Tank and Fuel Pump 
Fuel pressure gauge, installing 
(V-8 models) 
Remove  engine cover by pressing  down on  pins (arrows) to 
release  cover locks. 
4 Disconnect  and remove fuel supply  line from  lefl  side  of fuel 
rail  by sliding 
loclting collar  in (arrows) and pulling  lines 
apart. 
NOTE- 
* ME2 TU and MS43 vehicles (1999 and  later models) use a 
non-return fuel line with  only one line  to the  fuel 
rafl. 
BMW uses three styles  of fuellfne connections; a one-use 
clamp, a locking fitting that uses 
BMWspeclal tool 16 1 050 
to  release,  and a quick release sleeve (above) that discon- 
nects  the line when depressed. 
WARNING - 
* Fuel In fuel line  is under pressure  (approx. 3 - 5 bar  or 45 - 
75psi) and  may  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 
lealiing 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 workina on the  tank or lines. 
< Install inline fuel  pressure  gauge. 
WARNING - 
The fuel pressure  gauge must be securely connected  to pre- 
vent  it from  coming loose  underpressure. 
NOTE- 
The fuel pressure  gauge should  have a minimum range  of 0 
to 5 bar (0 to 75  psi).   
						

							
Fuel Tank and Fuel Pump 
Fuel delivery, 
testing 
Checitino fuel delive~ is a fundamental  oart of troubleshoot- .. ing and  diagnosing thk DME system. ~ukl pressure  directly 
influences 
fuel delivery. An accurate  fuel pressure gauge  will 
be  needed to make  the tests. 
There are  two significant fuel deliveryvalues  to be measured: 
* System pressure - created by  fuel pump  and maintained 
by pressure regulator 
Residual pressure 
- pressure maintained in closed sys- 
tem after engine and  fuel pump  are shut  off 
if  proper  system pressure  and residual pressure are present, 
also  check  for problems  in fuel  delivery  volume, which  can be 
affected by restrictions such as clogged  fuel filter or fuel  pick- 
up  port  in the  fuel tank. 
System  pressure,  testing 
1. Fuel pressure regulator  outer seal 
4 System pressure is created by the  fuel pump  and maintained 
2. Vacuum  line connection. 
3. Fuel pressure regulator Inner seal. 
4. Fuel flow back  to fuel tank. 
5. Fuel  flow from  fuel pump. 
Fuel pressure 
regulator 
Fuel pressure regulator locations 
M52 In fuel injector  rail, in engine 
compartment 
M52 TU In 312 way  valve,  below vehicle  under 
driver  seat 
by the pressure 
regulator. System pressure  is not  adjustable. 
M54 In fuel  filter 
M62 to 9/97 In fuel  injector rail,  in engine 
compartment 
M62 from 9/97 to 9/98 In 312 way  valve,  below  vehicle under 
driver  seat 
M62 TU from 9/98 In fuel  filter,  below  vehicle under  driver 
seat   
						

							
Fuel Tank and Fuel Pump 
4 Relieve  system pressure  and attach  a fuel pressure  gauge as 
described in  Fuel pressure  gauge, installing  (6-cylinder 
models)  or Fuel  pressure  gauge, installing 
(V-8 models). 
WARNING- 
Fuel in fuel line  is under pressure  (approx. 3 - 5 bar  or 45 - 
75psi) and  may  be expelled underpressure. Do  not smoke 
or 
worlc 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. 
- Operate fuel pump  as described  in Operating  fuel pump for 
tests.  Compare fuel pressure to specifications in  accompa- 
nying  table. 
Fuel  pressure  specification 
All E39 vehicles 3.5 +0.2 bar (50.76 i2.9 psi) 
- If pressure is  low, repeat test while  gradually pinching  off re- 
turn hose to fuel tank. Pressure should rise  rapidly. If not,  fuel 
pump is most  likely faulty. If  pressure rises, the fuel pressure 
regulator is  most 
likely faulty. 
- If pressure is too  high, checlc return line from pressure  regu- 
lator  to tank.  Check for 
ltinks in hose.  If  no faults  can be 
found,  pressure regulator is  most likely  faulty. 
CAUTION- 
The fuel pump  is capable  of developing  a higher pressure 
than  that regulated  by the  pressure  regulator.  In the  event the 
fuel pump  checlc valve is faulty  (stuck closed),  male sure the 
I fuel pressure  does not rise  above 6.0 bar (87psi). Damage 
to  the  fuel  lines  or fuel system  components  could result. 
- Reassemble  engine, noting the  following: 
Remove  fuel pressure gauge  and fittings. 
Replace schraeder  valve, if removed 
Replace fuel pump  relay. 
Replace fuel filler  cap. 
Residual pressure,  testing 
For quick restarts and  to avoid vapor lock when the engine is 
hot, the fuel injection system  retains fuel pressure  after the 
engine is shut  off. This residual pressure is  primarily 
rnain- 
tained by the fuel pressure regulator and  a checlc  valve at the 
fuel  pump 
outlet.   
						

							
. . 
I Fuel Tank and Fuel Pump I 
4 Relieve  system pressure and attach  afuel pressure gauge  as 
described in  Fuel pressure  gauge, installing  (6-cylinder 
models)  or Fuel pressure  gauge, installing 
(V-8 models). 
WARNING - 
Fuel in fuel line  is underpressure  (approx. 3 - 5 bar  or45 - 
75psi) and  may  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 
- Start  engine allow  it to  run for approximately  one minute. 
Note fuel pressure reading. 
- Observe fuel pressure reading  after approximately 20 mln- 
utes. The pressure should  not drop more than 0.5 bar from 
system pressure listed in fuel pressure specifications in ac- 
companying  table. 
Fuel  pressure  specification 
Ail 
E39 vehicles 3.5 i-0.2 bar (50.76 i2.9 psi) 
- When finished, disconnect pressure gauge  and fitting, and 
replace schraeder  valve, if removed. 
- If fuel system does not maintain  pressure: 
Visually  check for leaks  in fuel lines  and unions, 
Check  for leaking 
injector(s). 
Check  for faulty  fuel pump check valve. 
- To test fuel pump check  valve: 
Repeat  residual pressure  test. 
Immediately  aftershutting  off engine,  pinch off fuel  delivery 
line using a fuel hose pinch clamp (BMW 
13 3 010 or 
equivalent). 
If  pressure  is now  maintained,  fault is most  likely at fuel 
pump check  valve. 
If  pressure again drops below specifications,  fault is most 
likely in fuel pressure  regulator.   
						

							
.- 
err- .- Fuel Tank and Fuel Pump 
FUELPUMP AND FUELLEVELSENDER 
E39 models  use a two-lobed  fuel tank.  Each lobe  of the  tank 
has  its own  fuel level  sending  unit. Each sender  has a float 
connected  to a variable  resistance  wipercontact.  To equalize 
fuel  level  between the two 
tank lobes, a siphon pump is in- 
stalled  in the  left lobe. 
When  replacing  asender or fuel  pump, always  replace hose 
clamps, 
gasltets and  O-rings. 
WARNING 
- 
When  removing the fuel level sender  or the  fuel  pump, the 
fuel tank should be drained  to 
1/4 capacity or below  as de- 
scribed  later in this repair  group. 
NOTE- 
The compensating  siphon pump maintains the fuel  level be- 
tween the  right and left  tank lobes. If fuel  level  sender resis- 
tances are not approximately the  same on left  and right, 
remove  the senders  and visually inspect the  level in each 
lobe.  If  the levels  are different,  check the siphon  pump. 
Fuel  level  sender  resistances 
Float  position 
l~est results (Q 
Down (empty) 150- 70 
Up (full) 1401 -415 
Fuel level  sender  (right side) and fuel 
pump, removing 
and installing 
- Drain  fuel from  tank as described  later. 
- Disconnect  negative cable from battery. 
CAUTION- 
Prior  to disconnecting  the battery, read the battery discon- 
nection cautions  given in 
001 General  Cautions and 
Warnings. 
- To  access top  of fuel  tank,  remove  rear seat  lower  cushion  by 
lifting  front edge 
off catches.   
						

							
.- 
I Fuel Tank and Fuel 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. 
WARNING - 
Fuel  may be spilled.  Do not smolce or work  near heaters  or 
other  fire hazards. 
When  disconnecting  fuel hose,  wrap  shop rag around 
end  of hose  to prevent spray  of fuel under pressure. 
Remove 
tank sending unit: 
Release electrical harness  by sliding  lock back,  then lifting 
off  connector. 
a Disconnect hose  (arrow). 
Unscrew  threaded collar  from fuel 
pumpifuel level sender. 
NOTE- 
BMW special  spanner 16 1 020 should be used  to remove 
and  install  the threaded  collar. Damage  to the  collar  may re- 
sult  if the  special tool  is not  used. 
Slowly  withdraw  assembly  from tank, allowing  fuel to drain 
off.  If necessary, push level  sender arm toward sending 
unit  to facilitate  removal. 
CAUTION- 
Do not bend fuel level  sender arm. 
To  remove  fuel pump,  press locking tabs  (arrows) towards 
pump  body. 
Lifl out pump,  using care not to damage hoses.   
						

							
.- . 
Fuel Tank and  Fuel Pump 
- To reinstall: 
Use  new sealing  ring at tank  collar. 
* Align tab of sending unit  with matching  recess in opening 
of  tank. 
Be sure that fuel line connections point  in same direction 
as  they  came  out. 
Reconnect harness connector  and hose. 
Fill  tank  and check  for leaks by  running engine. 
Install access  cover and its mounting  fasteners. 
CAUTIOI\C 
After finishing  repairs but before  starting  engine, be sure 
there  is at least 
5 liters (1.5 gallons)  of fuel  in the  tank.  The 
NOTE- 
It is  common practice  to replace  the fuel  filter  when  the fuel 
pump 
unit is  replaced.  See 020 Maintenance. 
Tightening torque 
Tank collar  locking ring to tank 35 Nm (26 lb-ft) 
Fuel level  sender (left side), 
removing and installing 
The procedure for removing  and replacing  the left side fuel 
level sender is 
simllar to that  used for  the r~ght side. There  is 
no fuel  pump on the  left side. 
- Remove rear  seat lower  cushion  by lifting  off catches  at front. 
- Expose left side access cover: 
- Peel  forward lip  of carpet. 
Release rubber  grommet from center of access  cover 
insulation. 
Peel  back  insulation at 
perforations to expose fuel tank 
access  cover. 
Remove cover  to expose  electrical harness  connector. 
WARNING- 
Fuel may be spilled.  Do not  smoke  or work near heaters  or 
other  fire hazards. 
When  disconnecting  fuel hose,  wrap shop  rag around 
end  of hose  to prevent spray  of fuel under pressure.   
						

							
/ ~uel Tank and Fuel Pump 
4 Remove tank sending unit: 
Disconnect electrical harness  connector. 
Disconnect hose  (arrow). 
- Unscrew threaded collar  from fuel level  sender. 
NOTE- 
BMW special  spanner 16 1 020 should be used  to remove 
and  install  the threaded  collar. Damage  to the  collar  may 
result  if the  special  tool is not  used. 
Slowly  withdraw  assembly  from tank, allowing fuel  to drain 
off. If necessary,  push level sender arm toward sending 
unit  to facilitate  removal. 
CA UTIOW- 
Do not  bend  fuel level  sender arm. 
4 Once level sensor  unit  has been lifted partially  out of tank, 
disconnect  tank siphon hose  by pressing tabs  (arrows). 
- Installation is reverse of removal 
Attach tank siphon hose  to sender  unit firmly. 
Use  new sealing  ring at tank collar. 
. Be  sure  that fuel sender float points in same direction  as 
during  removal. 
- Reconnect harness  connector. 
Fill tank and 
check for  leaks  by running  engine. 
CAUTION- 
After finishing repairs  but before  starting  engine, be sure 
there  is at least 
5 liters (1.5gallons) of fuel  in tan/(. The  fuel 
pump will  be damaged  if run  without  fuel. 
Tightening 
torque 
Tank collar loclting rlng to tanlt 35 Nm (26 lb-ft) -   
						

							
7 .- A Fuel Tank and Fuel Pump 
Siphon pump, removing  and installing 
The fuel compensating siphon  pump equalizes fuel  level 
between the two fuel tank  lobes. 
- Drain fuel tank  as described later, 
WARNING - 
Fuel may be spilled.  Do not smoke or work  near heaters or 
other  fire hazards. 
- Remove  left and right fuel  level sensors  and fuel pump  as 
described  earlier. 
4 Once left side level  sensor unit has been lifted partially out 
of  tank, disconnect  tank siphon hose by pressing  tabs 
(arrows). 
- The tank lobe siphon pump is held to baffle in bottom  of right 
tank  lobe. Release retainer  and lift out  pump. 
- Installation is  reverse of removal. 
Attach siphon pump  to right side baffle. 
Attach  tank siphon hose  to left  sender  unit firmly. 
Use  new  sealing ring  at tank  collars 
Be sure  that fuel sender  floats point in same  direction as 
during  removal. 
Reconnect harness  connectors. 
. Before starting engine,  fill fuel  tank with  at least 5  liters 
(1.5  gallons) of  fuel. 
Check for 
leaks by  running  engine. 
Afler finishing repairs  but before  starting  engine, be sure   
						

							
-- 
I Fuel Tank and Fuel Pump 
The plastic fuel tank is mounted  underneath  the center  of the 
car  (underneath  the rear seat).  Mounted in the  fuel tank  are 
the  fuel pump  and fuel level  sending units. Connecting lines 
for  the  evaporative emission control  system and expansion 
tank are also attached  to the  tank. 
Fuel 
tank  capacity for E39 models 
Tank  capacity 
70 liters (18.5 gal) 
Reserve  capacity 
8 liters (2.1 gal) 
Fuel tank, draining 
Drain fuel tank into a safe storage  unit using an approved fuel 
pumping  device. 
WARNING- 
# Before  removing tank, be  sure  that  all hot  components, 
such  as the  exhaust  system, are completely cooled  down. 
Fuel  may be spilled.  Do not  smoke  or 
work near heat- 
ers or  other fire hazards. 
- Start engine  and allow  to run  10 - 15 seconds  to fill fuel com- 
pensating siphon  assembly. This will allow  both lobes  of fuel 
tank  to he  drawn off through fuel filler  pipe, 
- Disconnect  negative cable from  battery. 
CAUTION- 
Prior  to disconnecting  the batteg read the battery  discon- 
nection cautions given 
in 001 General  Warnings  and Cau- 
tions. 
- Remove fuel tank filler cap 
- Slide  suction hose into filler neck about  130 cm (51 in.), twist- 
ing  as  necessary. Withdraw fuel into storage  unit. 
- Monitor fuel level reduction  in both lobes: 
- Remove rear seat  cushion and access both  fuel tank send- 
er harness  connectors. 
Use  multimeter to measure  resistance  at both  senders, 
Resistance should drop as fuel level drops. 
- If siphoning  mechanism is  faulty, drain  left tank  lobe sepa- 
rately by removing sender cover and  pumping fuel directly 
out  of left  lobe.