Tricky crank no-start problem

[BimmerBreaker]

It sounds to me in the video like it is not getting fuel. Either that or the compression is very low, lower than the values you posted earlier. Or way mistimed engine. It's hard to say for sure but doesn't sound like a very happy M54.

[DonaldFoss]

I agree with the beer break or asking the Captain to come by for a visit...

I installed an analog fuel gauge inline under the hood and have a pressure tester that connects to the Schrader valve on the fuel rail. My fuel pressure is 51 PSI on both gauges when cranking, 40 PSI in the line before the fuel rail when not cranking, 45 PSI on the Schrader valve on the fuel rail when not cranking, and 30 PSI in the line the next morning the couple of times I looked. It takes several days for the fuel pressure to go to near 0 by itself.

Since these are NGK 4-strap spark plugs for BMW, they're supposed to be pre-gapped. I haven't measured them, but I have feeler gauges, so that's not hard to do. What should the gap be? I can easily measure the voltage going into the coil, but isn't the voltage at the plug really high? My O-scope only goes to 475 volts, but a regular multimeter goes to 1,000, I think; I will have to look. I've never tried to measure the voltage at the end of a spark plug before. I have been using a recessed inline spark plug tester, basically, a light that goes in line with the spark plug. I've also taken a video of the spark plug out of the engine and grounded while cranking to ensure it lit since I can't see that from inside the car. (The wife is ok with me working on it but wants nothing to do with it, and the kids all have their own places now. Have a Son-in-law who is a Toyota mechanic but hates German cars...)

I can certainly check compression again. I normally do 10 seconds with the check, throttle open, fuel off, etc. When you say 4 strokes, do you mean listening for 4 repeats of the sound? It's cranking at 140 RPM, so 4 strokes or 8 RPM a little more than 1/20th of a second, kinda hard to hit--or am I overthinking this, i.e. need some Captain, and you mean something completely different?

On the valve timing, I can check the timing mark on the crank and timing cover when cylinder 1 is at TDC. It was correct before I installed the engine; something could have happened during installation, which took 4 tries to get right. Timing would certainly explain a few things, including why I got fire out the intake with starter fluid. On the flip side, it can't be that far off or it would be kissing the piston heads and making all kinds of terrible noise, bending valves, etc.

Once I understand your compression check test, I'll do that and check the timing mark, then report back.

[DonaldFoss]

Originally Posted by BimmerBreaker

It sounds to me in the video like it is not getting fuel. Either that or the compression is very low, lower than the values you posted earlier. Or way mistimed engine. It's hard to say for sure but doesn't sound like a very happy M54.

Neither of us is happy...

The spark plugs smell strongly of fuel, and the wideband O2 says 7.89 AFR, so I think it's getting fuel. The thing is, the engine sounds mostly the same whether I have the fuel turned on or off. The only difference is the smell of the exhaust. That's confusing.

The timing was correct before I put the engine back in the car. I followed the re-timing procedure, and it was spot on. I'm going to double-check that by manually moving cylinder 1 to TDC and checking the timing mark on the timing case.

I'm going to recheck the compression. When I do it, I typically do a 10 count when cranking before taking the reading. I may try a lower number. I have a nagging feeling it is compression since that will take the most work to resolve.

[DonaldFoss]

Originally Posted by andrewwynn

Pics didn't load but I was able to listen to the video.

I used the image tags from the editor, sorry about the pics now showing up; at least the video link worked. The pics were just from the Foxwell, showing that there isn't anything reporting I feel would stop the engine from starting. If I'm wrong, please let me know. Here are the direct links:

https://imgur.com/gkVwq11
https://imgur.com/MbYEVgI
https://imgur.com/9H3qUkM
https://imgur.com/yemnInf
https://imgur.com/a4KJ43l
https://imgur.com/3JhFfSP

[andrewwynn]

I use Tapatalk for positing photos. No comparison to other ways

[DonaldFoss]

Originally Posted by andrewwynn

I use Tapatalk for positing photos. No comparison to other ways

But there ads.... Ugh. Tapatalk used to be there fun easy way.


Sent from my iPhone using Tapatalk

[80stech]

The needle on the compression tester should jump and hold at each compression stroke so do that for 4 strokes, not more, not less. You need someone on the key or a remote starter button. Doing these kind of tests for the first time when you are having a problem like this is a problem in itself. I checked my spark gap tester from when I last checked some M54 coils to compare them and it was pretty close to 30,000 volts.
You can pretty much hear puffing back from the intake valves on the video so you better look into that again.

[DonaldFoss]

Originally Posted by 80stech

The needle on the compression tester should jump and hold at each compression stroke so do that for 4 strokes, not more, not less. You need someone on the key or a remote starter button. Doing these kind of tests for the first time when you are having a problem like this is a problem in itself. I checked my spark gap tester from when I last checked some M54 coils to compare them and it was pretty close to 30,000 volts.
You can pretty much hear puffing back from the intake valves on the video so you better look into that again.

When you said spark gap earlier I was thinking gapping the plug like I used to do on small block Chevies. I think you mean measuring the spark length with something like https://a.co/d/2LiOaHi. I don't have one so I will in the morning, thank you Prime.

Even with my electronics background I I wasn't Anker to trigger the starter remotely without the wires and momentary switch getting really hot-which they should not have. I use an IP camera system with an old phone to watch under the hood while I'm in the seat. I see the needle bump, so I can count 4 of them. Wish I'd done that last year so I had a baseline with that method.

The intake is indeed puffing. It was worse with my N55 intake. That built pressure in the intake, the intake temp went over 150F, then would blow out my catch can relief valve. What you saw/heard was there stock intake.

Thank you everyone for your input. I'm accustomed to helping other people with anything/everything, not asking for help, and you've all been great.

[DonaldFoss]

Originally Posted by BimmerBreaker

It sounds to me in the video like it is not getting fuel. Either that or the compression is very low, lower than the values you posted earlier. Or way mistimed engine. It's hard to say for sure but doesn't sound like a very happy M54.

All of those involve opening up the head, so another question: which do you think is easier, removing the head while still in the car, or yanking the engine?

I'm leaning towards just pulling the engine but I don't relish dealing with the power steering, transmission cooler, etc. Fortunately I didn't reconnect the compressor, not until everything else works. I had to reroute the low and high pressure refrigerant lines, ended up making my own, plus I might mount the compressor somewhere else, like near the power steering fluid reservoir. I like to take the torque converter off/on while the engine is hanging in the bay, before I put it on the motor mounts, so I'm not worried about that.

What would you do?

[andrewwynn]

Originally Posted by DonaldFoss

But there ads.... Ugh. Tapatalk used to be there fun easy way.


Sent from my iPhone using Tapatalk

I pay the $1. It's worth it. No ads


Sent from my iPhone using Tapatalk Pro