91 525i Wants to start but refuses too

This is a vehicle with the M50B25. So I parked the vehicle for about a week and when I went back to start the car, it refused to. Been working on the car via the Bentley Manual and checked everything. The car does backfire and pop while cranking but It will not fire up! It almost seems like it wants to start but it wont! Here is a list of components I've checked with the correct tools and are good:
Fuel pump, replaced fuel filter, air filter, all six coils work and throw a strong spark, all six injectors spray fuel. All six cylinders have compression, camshaft and crankshaft position sensors are good, MAF is good, ICV is good, no DME codes, occasionally I will get a "TRANSS PRGRM" but disappears after little time, battery and starter good is cranking at high enough speed, all fuses and relays swapped with a friends car and still nothing. Pump clicks on while cranking.

Please help!!!! If you need more info or a video posted to youtube.com to see the cars behavior please let me know!!!

You have a thread posted in late November into December about a no-start but it turned into a pissing match with other members. Did you ever find the solution? If so, what was it?

I assume you did as deductive reasoning would hold that the car was running a week ago.

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The car will start, but dies right away. It gets fuel, gets spark, and has compression. I'm not sure what the issue is now.

So you never found a fix from november?

Nope! Same thing! My plan is to get the car painted and restored by march, but this issue is pushing that date further and further.

making it run is a little more important than what color it is IMHO.

you never took that video, so lets try that. dont run it on carb cleaner, that solves nothing.

Did you check all vacuum lines? maybe a hose rotted away or popped off

Will fire on starter fluid or carb cleaner but thats because it does fire off of the fuel its getting a well. It just wont run or continue to run. I will take a video and put on youtube today.

Whole top end of motor rebuilt in summer 2012 all fuel and vaccuum lines replaced. No vaccuum leak detected when I checked.

I would check ICV real good and all lines to and from it. you have a gigantic vacuum leak somewhere.

Also, you're supposed to just run it on the carb cleaner without fuel to see if the fuel is the issue

Originally Posted by Monsignor

I would check ICV real good and all lines to and from it. you have a gigantic vacuum leak somewhere.

Also, you're supposed to just run it on the carb cleaner without fuel to see if the fuel is the issue

+1 have you thought of the possibility of water in the fuel , cause that would make it backfire to . Or one of the coils wiring has been switched ... Just going with the thought that you said top end was rebuilt last summer .. what do you think Joe ?

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I have tried that and it does the same thing on carb cleaner. ICV is good. Resistance on the ICV is within the threshold via the Bentley Manual specs. Hoses to and fro it are in great shape and clamped properly. Car was running on the top end rebuild for about 5 months before I had this issue. The only thing I could think of at this point is a DME failure but thats not possible because the engine throws spark and sprays fuel.

Noel, it'd be a magic trick to mix up the coil pack connectors on an M50 without realizing something is wrong haha. This top end rebuild is a bit suspicious...

E34 Obsession, when you did this top end rebuild, do you remove the cams or timing chain at all?

That's true with your theory on the spark and dme , but who knows what weird ghosts these cars produce and sometimes is a direct correlation to the dme !

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Originally Posted by supertech777

That's true with your theory on the spark and dme , but who knows what weird ghosts these cars produce and sometimes is a direct correlation to the dme !

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Gotta love those little boxes of nightmare... So happy mine is a factory 413 red label

Originally Posted by Monsignor

Noel, it'd be a magic trick to mix up the coil pack connectors on an M50 without realizing something is wrong haha. This top end rebuild is a bit suspicious...

E34 Obsession, when you did this top end rebuild, do you remove the cams or timing chain at all?

LOL but as you know Joe weirder things have happened in diy LOL wish we could help some of these people via Skype or facetime

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I had a friend of mine rebuild the top end and install a new head gasket. He is a BMW Mechanic.

answer this as honestly as you can because i take everything with a grain of salt here (nobody wants to seem like a noob or an idiot and they lie about the thing that will fix the car, to their own demise)

Did the car ever right after that head gasket job by your buddy?

Also, please define "BMW Mechanic." Certified? Works at a dealership? Or is he a lot jockey with a wrench...

Works at Laurel BMW of Westmont. Car ran beautifully after wards. Put a few hundred miles on it sinse the rebuild. This problem to my knowledge seem electrical, but im not sure.

My theory is that it wasnt timed properly or the cam sprokets werent torqued right which made it fall out of time over time.

I have checked the timing. Set to TDC and it looks to be correct. Looks same as

the picture in the manual

I feel like every suggestion we make you say "it looks fine. it works. i checked it."

TDC lines need to match up. Look at the back of the cams near the fire wall. They should be square, yes? With the Motor at TDC (the line on the vibration dampener matched up with the one on the block) there should be dots on the top of the squares at the rear of the cams

I will check today and let you guys know. I will also recheck the ICV as well as drain the tank and put some new premium in. I will then take a video and post on internet for everyone to see.

pick up another DME. they go for the price of a full tank of premium. Check which one you have. It'll be a color and number. I have a 413 Red Label.

He has non-vanos. He should have brown label 402 DME.