4.8is Cranks over but engine won't start

[tonycajjo]

If the crank sensor is bad the computer won't turn on fuel pump or spark cause in its eyes the motor's not turning so there's no need. Find the sensor, remove and clean to see if you can get it to work one last time. They work on voltage and are very sensitive so fussing with it might get it to work again. You'd still have to replace cause its worn out.

[crystalworks]

Crank sensor seems like a possibility...

Still scratching my head on the EWS, now that I think about it Upallnight is right. My memory is not the best and we saw many cars with EWS errors but I think they were in fact no crank situations...

He suggested good "no start" general practice diagnosis... engine only needs three things to fire. Spark, fuel, and air. Find out what's missing and go from there.

Edit: After looking at another thread, I think my first check would be the fuel pump. Ridiculously common failure... really easy to check usually, though not sure how easy on the e53. On e30, e28, e39, e36, and e46 it's right under the rear seat. Pull up and listen for pump.

[X5Ghost]

Ok, based on earlier suggestion, I took the key apart to check the battery which was soldered in and a PITA to remove but this didn't turn out to be the issue. If it was that, the engine shouldn't crank. Now the key buttons are inoperable so I will need to replace the damn key.
I checked the fuel line during a crank and there is plenty of fuel flow. Not a fuel pump issue.
Next need to check the crank sensor, I think that might be the issue.

What's the way to check the operation of the crank sensor? Is it to check for spark with the ign coil out or is there a better way?

[crystalworks]

^Did you ever get the codes read? Upallnight dispelled my original thought of the EWS (key) being an issue almost immediately.

You can ohm out the crank sensor with a multimeter... but I'd get the codes read and see what pops up before going any further.

[upallnight]

Originally Posted by X5Ghost

Ok, based on earlier suggestion, I took the key apart to check the battery which was soldered in and a PITA to remove but this didn't turn out to be the issue. If it was that, the engine shouldn't crank. Now the key buttons are inoperable so I will need to replace the damn key.
I checked the fuel line during a crank and there is plenty of fuel flow. Not a fuel pump issue.
Next need to check the crank sensor, I think that might be the issue.

What's the way to check the operation of the crank sensor? Is it to check for spark with the ign coil out or is there a better way?

Get the car scan and if the CPS is the problem you should have an error code.

Wow that's an expensive mistake. There are people on this board and on eBay that can repair your key.

Watch out for the Cliff Clavins on this board.

[upallnight]

If you have the App Torque or any other type of diagnostic software, that allows you to view the engine rpm when the engine is cranking. If you don't see any rpm count on the app, your CPS is not sending a signal to the DME that the engine is turning so the DME is not sending a signal to the coils to fire.

[X5Ghost]

Originally Posted by crystalworks

^Did you ever get the codes read? Upallnight dispelled my original thought of the EWS (key) being an issue almost immediately.

You can ohm out the crank sensor with a multimeter... but I'd get the codes read and see what pops up before going any further.

Ya but I didn't see that before going to town tearing up the key. I was too eager to get going on A fix. No worry, it's my mistake. I hope to somehow get the key fixed otherwise, it looks like $280 key with programming. Outch!

My OBD2 shows no codes, I don't have access to a better reader unless I get the car towed to the dealer which about another $250 including towing and dealer diagnosis. Trying to avoid that if I can and do some diagnosis in my driveway, otherwise this is going to be an expensive repair when all said and done. Sucks!

[Joshdub]

Fwiw a Bluetooth obd dongle that'll work with the torque app is ~$10

[upallnight]

You should tell us where you are located. There are many X5 members throughout the world and someone may be able to help you. I helped a fellow X5 owner this past summer. He was having problems with his ac and I told him that I can scan his car if he wanted to drop by since we both lived in Crook County.

Scan his X and told him he needed a new aux fan. He had the aux fan replaced and his ac was blowing ice cold air again.

[upallnight]

When the engine is cranking does the tach bounce a little? If there's a little bounce the CPS may be okay. This is not a definitive test, it just a cheap ass check to see if the DME is getting a signal.