Injectors have no power
 

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.

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 ?

check the fuses in the E-Box

Thanks for your response. This is an ongoing problem right now.
Latest: I just measured the voltage on the injector wiring harness with a multimeter. Negative on the car body, positive on each prong of the connector. I do have 12 volts on one prong and about 4 volts or the prong. This is the same for all six connectors. The problem now is instead of 4 volts, I should have zero volts. Does this mean a short somewhere?

Fuel pump fuse in the glove box is fine.

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.

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.

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.)

Different scanners give different info. If you can say what type of scanner and what codes if any you are getting, that would help.

Also, in case you are not familiar with a "noid light", google that - it is a special tool for measuring fuel injector control pulses. Many parts store chains will rent those for free as part of their tool loaner program. The main challenge with those is often just physically fitting them where they need to go.

Simple test to try whenever weird engine control things happening = unplug the MAF sensor. With no sensor, a code will be thrown, and the engine will try to run in a safe mode, which is simpler, less likely to be broken by faults outside the MAF. Easy to do, might give clues.

More random ideas:
- could it be your car's immobilizer that is killing the injectors (if they are actually not working)?
- I believe (from memory, which could be confused and wrong or both) one of the wires on the starter is a ground for the starter control, which is disabled by the car's immobilizer. Could it be that was touched when you were down there? (although, I think the immobilizer is supposed to kill the starter as well, but yours is cranking ...)
- Second on the fuse checking suggestion above - not just the fuel pump, other things, which may have been blown while doing all the work.
- Do you hear the fuel pump prime (run for two seconds) when the key first goes to on, before starting?

but did you check the E-box Fuses???