Injectors have no power

2004bmwx53i · #1 07-22-2022, 11:04 PM

2004 X5, 3.0i
Hi Everyone,
I removed the airintake manifold and all the attached components, to gain access to the starter. The nut was loose. I tightened the nut, while in there, replaced CCV and all the temperature sensors, 3 in total. Put everything back together. Now the car cranks but won't start. Tried a few times. Tested the injectors by a scanner, turns out they receive no power. I cleaned every connector with connector cleaner and made sure they are all properly firmly connected. Also made sure the injector harness is properly connected to the injectors.
There is fuel in the rail.
Do I have to remove the airintake again to check all the connections?
Thanks for any guidance.

Edit: Just measured voltage at the injector wire harness for each injector: there's some micro voltage across each terminal with the ignition on at position 2. So there is power, but maybe not enough. This added to my misery.

80stech · #2 07-23-2022, 12:58 AM

Did you replace the starter? What nut?? How do you test the injectors by scanner ?? How much fuel pressure in rail? Did you have battery disconnected when doing the work? I think the crankshaft sensor is in that area, did you disconnect that maybe ?

2004bmwx53i · #3 07-23-2022, 10:01 AM

Quote:

Originally Posted by 80stech

Did you replace the starter? What nut?? How do you test the injectors by scanner ?? How much fuel pressure in rail? Did you have battery disconnected when doing the work? I think the crankshaft sensor is in that area, did you disconnect that maybe ?

Only the nut connecting the main power line was loose. I tightened that nut. No need to replace the starter. The engine has a strong crank now.
I have a scanner that does testing of a lot of components.
I do have fuel in the rail, but I haven't measured the pressure. I'm sure this a power issue.
I did disconnect the battery during the work.
I did not touch the crankshaft sensors.

Henn28 · #4 07-23-2022, 10:13 AM

Maybe pull the harness plug from the DME and see if it needs to be cleaned. I just added a subwoofer and when I pulled the plug from the OE amp to splice into the trigger wire I found lots of corrosion at the harness plug-amp connection. Perhaps if there is corrosion when doing the work the harness moved enough to break the connection in spots. I got a small amount of oil in my engine harness plug which migrated to the DME connectors and were causing some very odd problems after my motor swap. Not my finest hour.

Be careful if you do need to clean it though, I bent a couple pins on the amp when he were painful to straighten out again.

2004bmwx53i · #5 07-23-2022, 11:16 PM

Quote:

Originally Posted by Henn28

Maybe pull the harness plug from the DME and see if it needs to be cleaned. I just added a subwoofer and when I pulled the plug from the OE amp to splice into the trigger wire I found lots of corrosion at the harness plug-amp connection. Perhaps if there is corrosion when doing the work the harness moved enough to break the connection in spots. I got a small amount of oil in my engine harness plug which migrated to the DME connectors and were causing some very odd problems after my motor swap. Not my finest hour.

Be careful if you do need to clean it though, I bent a couple pins on the amp when he were painful to straighten out again.

Can't locate the DME. Is it under the filter housing on the passenger side?

80stech · #6 07-23-2022, 10:36 AM

Quote:

Originally Posted by 2004bmwx53i

Only the nut connecting the main power line was loose. I tightened that nut. No need to replace the starter. The engine has a strong crank now.
I have a scanner that does testing of a lot of components.
I do have fuel in the rail, but I haven't measured the pressure. I'm sure this a power issue.
I did disconnect the battery during the work.
I did not touch the crankshaft sensors.

Good catch on the starter solenoid nut. I actually did a post about that issue and you can tighten that nut from the bottom without doing all the work you went through.

If you want to measure voltage to the injectors then a multimeter would be a better way.

"Fuel in the rail" doesn't tell you much if you don't know the pressure.

If you disconnected the battery then there is a lot less chance that the issue is a fuse and more so that you forgot or disturbed a connection while you where doing the work.

You could try disconnecting the battery leave it for 20 mins. or so and
reconnect again.

(I didn't see your post about checking the voltage at the injectors with the DVM. You have 12v so the the problem is not that. The neg side is controlled by the DME.)

2004bmwx53i · #7 07-23-2022, 11:08 PM

Quote:

Originally Posted by 80stech

Good catch on the starter solenoid nut. I actually did a post about that issue and you can tighten that nut from the bottom without doing all the work you went through.

If you want to measure voltage to the injectors then a multimeter would be a better way.

"Fuel in the rail" doesn't tell you much if you don't know the pressure.

If you disconnected the battery then there is a lot less chance that the issue is a fuse and more so that you forgot or disturbed a connection while you where doing the work.

You could try disconnecting the battery leave it for 20 mins. or so and
reconnect again.

(I didn't see your post about checking the voltage at the injectors with the DVM. You have 12v so the the problem is not that. The neg side is controlled by the DME.)

-----

That is good to know for the negative side. BTW, I did use a multimeter to test the voltage causing the engine not starting. I even tested all injectors by giving them a 12 volt and hearing a tick sound. All six are good. The fuel pressure shouldn't be an issue because the car ran perfectly prior to this event.
So why do the injectors show "off" when tested by the scanner if there is voltage. My scanner is Foxwell NT530, it's not the greatest but does have capability of testing a lot of components. It reaches the component and activates it. It can even move the seats. I didn't get the print of the test at the time, but showed "off" for all six injectors.