need help 86es fuel pump

[unkown]

i thought my fuel pump was out. so i bought another one.it dose not come on. what i have checked so far, fuse 15amp #11 (or 10) relay... pump runs when i jump #87 &#30, injectors (new ford 19lb) they work when i turn key to start. the car turns over, but dose not start. the fusible link in truck rings out like it works fine.it has 13 button computer, i replaced the relay for that (black box above abs), ive disconnected the battery for 24 hours. my questions i need help with, if the sender in the tank dosnt work dose it stop the pump from working? and will the sensors on the bell housing and afm shut it off if they are broke? or is it my dme? or did i not check something that i should have?

[DÌEGØ]

you replaced your in-tank pump? is the external working?

[jlevie]

The fuel pump relay is controlled by the DME and engages when the DME sees timing data from a rotating engine. If the relay isn't closing when cranking the engine the DME may not be powered up, the CPS could be bad, there could be a wiring fault, the fuel pump relay could be bad, or the DME could have failed. If you have spark when cranking the engine the DME and CPS aren't the problem.

[unkown]

i replaced external pump, i get no spark (new plugs cap rotor)old coil, but its got power.and the fuel pump relay is also new.

[unkown]

how do find out if im getting power to the dme?

[unkown]

dose it mean that i have power going to the dme if my check engine light comes on when i turn my key to the start position?

[unkown]

i traded my cps for one that came out of my old car that worked before i scraped it....nothing...so dose any one have anyother suggestions before i go and by a new cpu?

[Alpinweiße30]

learn how to spell the four letter word "DOES" that is all the help i have to offer. you tried 4 times and failed

[unkown]

i dont use spellcheck... i say fuck spellcheck, but really anything left to try before i buy a dme?

[Imagine_M]

yes inline fuse about 6 in from battery on small positive wire

[unkown]

checked... 50amp fusible link in perfect working order, one of the things ive already checked

[unkown]

nobody has anymore ideas?

[jlevie]

Have you solved the spark problem? While it is possible that the lack of spark and fuel pump operation are related, the odds are that there is a single cause for both. If this is an M20B25 engine, run through the checks below to narrow the search space.

For the engine to run the following conditions must be met:

Power on DME pins:
27 Start Input
18 Un-switched Power input
37 Power Input from Main Relay

Ground on DME pins 2, 14, 19, 24

Timing data from the CPS on DME pins 47 & 48 from a rotating engine

To have spark power must be present at the coil positive and ground pulses
from the DME's pin 1 must reach the coil negative. Power to the coil is
controlled by the ignition switch via C101. When checking for spark, use the
output lead from the coil to eliminate the distributor, rotor and plug wires.

To have injector firing power must be present at each injector and ground
pulses from the DME's pin 16 (Bank1) and pin 17 (Bank2) must reach the
respective injector bank. Note that the injectors are wired as two banks of
three. With cylinder 1,3,5 being bank 1 and 2,4,6 being bank 2. Power to the
injectors is controlled by the main relay.

The fuel pump relay must have power on pin 86 (relay coil) from the main relay
output (pin 87) and power on pin 30. The DME will ground pin 85 to turn on the
relay and power the pump(s) via pin 87. Of the above, only the fuel pump power
is fused. So if the there's power at pin 87, but not at the pump, check fuse
11.

The main relay and DME pin 18 receive power from the smaller of the to wires
that connect to the battery's positive terminal. That wire incorporates an
in-line fuse. When the DME is presented with a start signal, it grounds the
main relay pin 85 and furnishes power to the fuel pump relay, injectors, and
DME.

Troubleshooting:

Disconnect the battery and the DME cable. Then:

1) Disconnect the coil negative and check continuity from that connector to
DME pin 1. Also verify that from DME pin 1 to ground is an open circuit.

2) Check the resistance across DME 47 & 48, which should be 500-560
ohms. If the CPS is dismounted, the resistance can be seen to change
from about 500 to 540-540 when a ferrous object is brought to the face of the
sensor. Neither pin should be grounded.

3) Check for continuity from DME 36 to main relay 85 and from DME 3 to fuel
pump relay 85.

Reconnect the coil, remount the CPS (air gap should be 0.040"), plug the
relays back in, reconnect the DME, and connect the battery. Then do the
following checks:

1) With the key off, verify that power is present at DME pin 18 and main relay
86 & 30.

2) With the key on, verify that power is present at DME pin 27 and pin
18. Power to pin 18 is from the main relay and there should be power to the
injectors and fuel pump relay.

3) With the key on, verify that no voltage is present at the DME grounds (2,
14, 19, 24).

4) Verify that power is present at the coil positive and at fuel pump relay
pin 30. Those get switched power from the ignition switch via C101.

The engine will start and run (if poorly) with only those connections to the
DME in place. The other signals from Cylinder ID, AFM, temp sensor, etc., are
necessary for proper operation. But they won't prevent the engine from firing.

IMPORTANT:

A power check means seeing a voltage within about a tenth of a volt of what
you measure across the batter terminals, which should be at least 12.6v on a
charged battery.

A continuity check means seeing less that 1 ohm of resistance.

An open circuit means seeing a resistance of at least 100k ohms.

A good quality auto-ranging Digital Multimeter will make these tests much
easier.

[unkown]

its a 86es (old dme) i found this already,you told this to someone else doing a swap. i figured that when i was test the pin 37, its only has 36 slots. it would be awesome if i new which pins to check for the 1.0 dme
thanks for the help!

[jlevie]

You can use the wiring diagrams at http://wedophones.com/BMWManualsLead.htm to cross-refence to your car.