Pulled fuse 165

locum · 09-09-2021, 09:10 AM

Can someone please help me understand what I did wrong?

I did some engine work that required a full oil drain. Before doing anything, I pulled fuse 165 and kept running the engine until it stopped to ensure gas lines were empty. After the work was complete and the oil refilled (car was on jack stands for about a week) I started the SIB priming procedure to crank the engine with fuse 165 still removed.

I was never able to crank the engine even for 10 seconds. Instead, after about 3 seconds of cranking the engine started!! With fuse 165 in my hand, I sat their listening to the engine run. This was not supposed to happen. How could gas possibly reach the engine if i ran it dry after removing fuse 165 to begin with??

I really really need to find an answer to this to know how to avoid this situation again in the future. Any other method to fully disconnect gas supply to the engine to complete the SIB procedure next time I do this?

Thank you for any words of wisdom you can spare!

Billfitz · 09-09-2021, 01:49 PM

I'm curious why you needed to drain the fuel line. Draining the oil doesn't require anything special, you do that every time you do an oil change. If you're concerned about the fuel pump starting up disconnect the battery negative lead. As for fuse 165 it's associated with the fuel supply, but so are 149,150 and 151. As best as I can tell 165 is the low pressure pump. Perhaps just the high pressure pump alone was enough to start the car?

locum · 09-09-2021, 04:14 PM

Quote:

Originally Posted by Billfitz

I'm curious why you needed to drain the fuel line. Draining the oil doesn't require anything special, you do that every time you do an oil change. If you're concerned about the fuel pump starting up disconnect the battery negative lead. As for fuse 165 it's associated with the fuel supply, but so are 149,150 and 151. As best as I can tell 165 is the low pressure pump. Perhaps just the high pressure pump alone was enough to start the car?

I had to drain it to install a Mosselman oil thermostat and also OFHG / vanos solenoids replaced. I do need battery connected to crank the engine when all was done.

There was zero gas in the lines before this job and it "miraculously" appeared after even with fuse 165 removed.

What gives?

paimon.soror · 09-09-2021, 05:13 PM

Lol i had the same issue.

I removed that fuse so i could "prime" my oil pump after the ofhg change last weekend. Car started anyway * shrugs*.

Fwiw, 70 miles after ofhg change and no priming... Car hasn't blown up (I'm still skeptical as to why it would)

locum · 09-10-2021, 10:39 AM

What I did was to pour four quarts of oil through the OFH opening, and the rest through the oil filler. Perhaps that's what saved the engine from seizing?

123Britt · 09-10-2021, 12:14 PM

Absolutely - oil priming is a good thing.

Although, how to accomplish correctly is the issue.

I tried to follow a YouTube Guide and disconnect the (2) main disconnects
at the battery -- it did not work.

I know the best way or per BMW instruction is to disconnect the small connectors at each individual injector (not hard except for the back aft connector)
which I just could not do .

So - Like a dumb ass - I decided to just disconnect the ignition coils -- which does let you prime but the fuel pump was still active spraying fuel into each cylinder. I also poured oil through the OFH (only about 1 qt).

I am thinking this is absolutely NOT what you want. I have seen no issues but I do think disconnecting the fuse for the HPFP and the Ignition Coils in combination would accomplish the same goal.

In my mind: There is a possibility that an air entrapment within the complexity of oil lines to oil coolers can create a situation for oil starvation post removal of the OFHG and other work that makes oil priming needed on theses N55 engines.

THe preferred method -- just not sure.

drdino · 09-10-2021, 01:34 PM

Perhaps the HPFP has enough head to pull fuel even with the LPFP inop?

thejeremyman9 · 09-10-2021, 03:16 PM

Quote:

Originally Posted by drdino

Perhaps the HPFP has enough head to pull fuel even with the LPFP inop?

This is what i was thinking. A buddy of mine with a 228i got a "drive moderately" drivetrain malfunction while on the freeway, he drove to the nearest BMW dealer, and they said the LPFP failed and had to replace it. But OP said he ran the fuel lines dry... so would be surprising if the HPFP could still pull fuel, but possible.

locum · 09-11-2021, 10:32 AM

If so, the only correct way to disable fuel supply to do priming correctly is to disconnect the injectors. Removing 165 did nothing in my case.

09-09-2021, 09:10 AM	#1
locum New Member 2 Rep 16 Posts Drives: BMW 335xi Join Date: Sep 2021 Location: Canada iTrader: (0)	Pulled fuse 165 - engine still started… Can someone please help me understand what I did wrong? I did some engine work that required a full oil drain. Before doing anything, I pulled fuse 165 and kept running the engine until it stopped to ensure gas lines were empty. After the work was complete and the oil refilled (car was on jack stands for about a week) I started the SIB priming procedure to crank the engine with fuse 165 still removed. I was never able to crank the engine even for 10 seconds. Instead, after about 3 seconds of cranking the engine started!! With fuse 165 in my hand, I sat their listening to the engine run. This was not supposed to happen. How could gas possibly reach the engine if i ran it dry after removing fuse 165 to begin with?? I really really need to find an answer to this to know how to avoid this situation again in the future. Any other method to fully disconnect gas supply to the engine to complete the SIB procedure next time I do this? Thank you for any words of wisdom you can spare!
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09-09-2021, 01:49 PM	#2
Billfitz Lieutenant General 8243 Rep 16,079 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	I'm curious why you needed to drain the fuel line. Draining the oil doesn't require anything special, you do that every time you do an oil change. If you're concerned about the fuel pump starting up disconnect the battery negative lead. As for fuse 165 it's associated with the fuel supply, but so are 149,150 and 151. As best as I can tell 165 is the low pressure pump. Perhaps just the high pressure pump alone was enough to start the car?
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09-09-2021, 05:13 PM	#4
paimon.soror Captain 629 Rep 965 Posts Drives: 2016 F36 435x MSport Join Date: Oct 2017 Location: Hartford, CT iTrader: (3) Garage List 2016 BMW 435xi GC [6.00]	Lol i had the same issue. I removed that fuse so i could "prime" my oil pump after the ofhg change last weekend. Car started anyway * shrugs*. Fwiw, 70 miles after ofhg change and no priming... Car hasn't blown up (I'm still skeptical as to why it would)
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09-10-2021, 10:39 AM	#5
locum New Member 2 Rep 16 Posts Drives: BMW 335xi Join Date: Sep 2021 Location: Canada iTrader: (0)	What I did was to pour four quarts of oil through the OFH opening, and the rest through the oil filler. Perhaps that's what saved the engine from seizing?
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09-10-2021, 12:14 PM	#6
123Britt Captain 289 Rep 864 Posts Drives: 15 M235i AT Join Date: May 2008 Location: Madison, Alabama iTrader: (0)	Oil Priming Absolutely - oil priming is a good thing. Although, how to accomplish correctly is the issue. I tried to follow a YouTube Guide and disconnect the (2) main disconnects at the battery -- it did not work. I know the best way or per BMW instruction is to disconnect the small connectors at each individual injector (not hard except for the back aft connector) which I just could not do . So - Like a dumb ass - I decided to just disconnect the ignition coils -- which does let you prime but the fuel pump was still active spraying fuel into each cylinder. I also poured oil through the OFH (only about 1 qt). I am thinking this is absolutely NOT what you want. I have seen no issues but I do think disconnecting the fuse for the HPFP and the Ignition Coils in combination would accomplish the same goal. In my mind: There is a possibility that an air entrapment within the complexity of oil lines to oil coolers can create a situation for oil starvation post removal of the OFHG and other work that makes oil priming needed on theses N55 engines. THe preferred method -- just not sure.
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09-10-2021, 01:34 PM	#7
drdino Lieutenant 135 Rep 457 Posts Drives: BMW 330i Join Date: Feb 2019 Location: UK iTrader: (0) Garage List 2019 BMW 330i [0.00]	Perhaps the HPFP has enough head to pull fuel even with the LPFP inop?
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09-11-2021, 10:32 AM	#9
locum New Member 2 Rep 16 Posts Drives: BMW 335xi Join Date: Sep 2021 Location: Canada iTrader: (0)	If so, the only correct way to disable fuel supply to do priming correctly is to disconnect the injectors. Removing 165 did nothing in my case.
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