Please please need help

[Darrol]

Hello everyone
I am having major problems with my 1996 e38 750il
It has been off the road for one year now
Car will crank over but will not fire up
Once I turn the key to start it about 10 seconds later I get the engine failsafe program
Car is in complete shutdown
The fault codes I am getting a really as follows

P1543 throttle valve 1 potentiometer 1 voltage too low
P1543 throttle valve 1 potentiometer 2 voltage too low
P1544 throttle valve 1 potentiometer 2 voltage too high
P1590 throttle valve 2 potentiometer 2 voltage too low
P0601 potentiometer supply voltage 1 of throttle valves 1/2 deviates
P1545 throttle valve 1 potentiometer 1 voltage differs from speci value

Also these had no codes
External safety circuit to deml control unit (118)
Fault signal of pedal travel sensor 3 (28)
Fault signal of pedal travel sensor 2 (30)

Here is a list of what I have replaced
Spark plugs x12 plus 4s
Crankshaft sensors x2 ome new
Intake manifold gaskets
The two throttle bodies
The eml control module
The two dmel control module's

I live in new Zealand so parts for the e38 750il v12 are very rare and expensive Even if you can find them
The scanner I am using Isome the bmw icon a2
Hope someone out there can help me please
Thanking you

[Casey at Pelican Parts]

You will need to get a wiring diagram for your baby. This sounds like a wire harness issue. You will want to verify that the 5 volt reference voltage is present at both the throttle valves, as well and the pedal travel sensor. I will see if I can dig something up for you. In the mean time, follow the wiring that is visible and perform a good visual inspection. My thought is that the wiring is chafed somewhere and the 5volt reference (Vref) is not making it to the potentiometers, and this can be caused by a partial short to ground in the Vref circuit, or a bad ground connection somewhere that interferes with the Vref. Have you replaced the main DME relays? Checked the front eBox fuses and wiring for corrosion? Let me know... I love the e38!

[Darrol]

Hello thank you for your reply
My e38 750 has been driving me crazy
I checked out some of the wiring on the harness from the eml and found that some of the plastic coating on the shielded wires had broken down i tried to repair them but it made no difference
My cat is a right hand drive
I have found a engine loom but it is for a left hand drive
I was wondering if I could use the left hand loom and put it in to my right hand plastic casing
I can get the engine to start but have no throttle response engine will idle at 300rpm
But it takes a lot of cranking before it starts
But will only run for up to 2 minutes then dies
After that it is very hard to start again
Hopefully you can point me in the right direction
Thanking you
Darrol

[Casey at Pelican Parts]

Just know that the E38 is the last great 7 series so far, and your efforts are well worth it!! I had a 97 740il which was very good to me, sold it to a friend about 4 years ago and he still drives it with over 250k miles on it! Good cars...

Now...are the faults you're receiving any different after your car started to run a little bit??

Make sure that you allow the car to do it's throttle adaptation before starting it...just leave the key in the "ON" position without starting the car in about 30-60 seconds you should hear the throttle valves click, and clack. Then start the car...

Verify that the fuel pressure is approx. 3.5 bar while cranking and starting the car, watch to see if the pressure drops off before the car dies.

If the pressures look good, perform an intake leak check, either visually or with a smoke machine. It sounds like there is something basic that is missing from the equation at this point.

Just curious if you hold the rpm's up around 2000 while the car warms up does that allow a longer running time?

Have you replaced the crankcase breather valves on the back of the intake manifolds?

click here

CLICK HERE

Let me know how it goes!