Daughters first car

[Esekstrom]

I have a 2008 X5 4.8i with issues, some known when we got it with the thought of her learning how to diagnose and fix issues.
What she has done:
Mounted and balanced new tires
Changed the alternator
Replaced the radiator
Replaced the valve cover gaskets and spark plug tubes
Replaced the plugs with oem plugs
Replaced the coil packs
Replaced both pcv valves
Cleaned VANOS solenoids using an ultrasonic cleaner
Changed engine oil
Cleaned all of the injectors

We are getting a code p0306
Coil is getting 30mm of spark
Switched injectors-misfire still present
Checked continuity back to the DME with good results
Sprayed either with no RPM increase
Car goes into limp mode when driving highway speeds and get code p0300

Any thoughts would be appreciated!

[White94RX]

You gave us the code, good. You didn't give us the description of the code, bad. You're using a generic P-code reader, also bad. p0306 and p0300 mean nothing to me. However, a proper BMW specific code, with the accompanying fault code description would go a long way.

A real BMW specific scan tool is an absolute must-have if you plan on working on, and diagnosing, your own BMW.

[ross1]

You mention new coils but I'd still swap a couple around to see if the misfire follows.
If not spark or fuel that leaves mechanical, a leaking valve can cause misfires.

[Esekstrom]

Thank you for the replies
P0300 random misfires
P0306 cylinder number 6 misfire
Swapped coils and injectors-still cylinder 6 misfire
Cylinder #6 is running at 122 psi, didn’t check the other cylinders

[bmwdirtracer]

122 psi isn't good. Check a few other cylinders to verify your gauge. That said, 122 psi shouldn't be enough leakage to cause a misfire, by itself. However, it is likely related.

For instance, IF you have a coil driver failing in the DME, the misfires will lead to unburned fuel in that cylinder....which will lead to the cylinder walls being washed with fuel, causing a loss of compression.

There are a dozen other possibilities, of course, so the place to start is gathering all the information possible. I'd recommend following White94rx's advice, and getting the car connected to a BMW diagnostic computer -- preferably ISTA, which is BMW's own diag machine, and can run a test plan for the BMW codes you can't read with a generic OBD2 device. With a good BMW diag computer, you'll also be able to see smooth running/cylinder balance, O2 sensor values, etc, to look for anomalies.

I'd also highly recommend doing a leak-down test, engine fully warm, to determine where your cylinder leakage is going.

Spraying flammables at the engine isn't a valid way to determine whether there's an intake leak; there are far too many places the chemical just can't reach. You need a smoke test with a professional smoke machine.

Not to throw water on the flames of your enthusiasm for teaching your daughter, but an N62 engine isn't a DIY kind of BMW motor. Wait 'til the coolant pipe in the middle of the "V" starts leaking.....

[Esekstrom]

Thank you to all,
I will have to use the proper diagnostic tool used to get more information and narrow down the problem. Scoping the cylinder did show unburned fuel on the piston head. I was planning on having her replace the head gaskets but want the engine running correctly first, maybe do the valley tube at the same time.

[White94RX]

Why replace the head gaskets? I've never seen a bad head gasket on an N62 in my 15 year career.

[Esekstrom]

Had a shop complete a diagnostic, bad DME. Number 6 injector would Fire a couple of times then quit causing the misfire. Used one found and ordered.
Great to hear you have not seen a bad head gasket. My concern for low compression may be misplaced.

[ross1]

Had a shop complete a diagnostic, bad DME. Number 6 injector would Fire a couple of times then quit causing the misfire. Used one found and ordered.
Great to hear you have not seen a bad head gasket. My concern for low compression may be misplaced.

When misfires are detected the DME is supposed to shut off fuel for the offending cyl. Sounds like it is working as intended.
Wet pistons don't always mean fuel, could be oil too.
A leak down test has been suggested already.
I hope the DME works for you, I believe it will need coding.

[moroza]

122 psi isn't good. Check a few other cylinders to verify your gauge. That said, 122 psi shouldn't be enough leakage to cause a misfire, by itself. However, it is likely related.

For instance, IF you have a coil driver failing in the DME, the misfires will lead to unburned fuel in that cylinder....which will lead to the cylinder walls being washed with fuel, causing a loss of compression.

There are a dozen other possibilities, of course, so the place to start is gathering all the information possible. I'd recommend following White94rx's advice, and getting the car connected to a BMW diagnostic computer -- preferably ISTA, which is BMW's own diag machine, and can run a test plan for the BMW codes you can't read with a generic OBD2 device. With a good BMW diag computer, you'll also be able to see smooth running/cylinder balance, O2 sensor values, etc, to look for anomalies.

I'd also highly recommend doing a leak-down test, engine fully warm, to determine where your cylinder leakage is going.

Spraying flammables at the engine isn't a valid way to determine whether there's an intake leak; there are far too many places the chemical just can't reach. You need a smoke test with a professional smoke machine.

Not to throw water on the flames of your enthusiasm for teaching your daughter, but an N62 engine isn't a DIY kind of BMW motor. Wait 'til the coolant pipe in the middle of the "V" starts leaking.....

+1 to every point here.

The 122psi number isn't good, but needs context. Was it done cold, dry, hot, wet...? Gauge verified?

I'm not a BMW certified tech, but have worked on a lot of them over ~10 years. I've never personally seen a BMW V8 with bad headgaskets, and heard of two - one heavily abused, the other unconfirmed. The L6 engines, on the other hand...

[bmwdirtracer]

That used DME is going to need more than just coding, it will need to be virginized and your old DME's brains will need to be cloned into the replacement. This requires specialized knowledge and computer programs not available to a shop -- even a BMW shop.

We are fortunate enough to have a regular on this forum who can do this. He has helped me with this sort of thing on many occasions, and you can trust him absolutely if he offers.

Send a PM to 328 Power 04.

[Esekstrom]

I would like to check the IVM but don’t see it in the controller housing, just the DME and VVT.
I was going to post a picture but don’t know how.
I would also like to PM 328 Power 04 to see if he is willing to program a DME (I bought one with the same part/model numbers), mirroring the original but don’t know how to do that either.

[MarcoZandrini]

You need 10 or 15 posts before you can post a picture. Alternatively, you can upload the pictures to a picture sharing website and post the link.

[Esekstrom]

Thanks for the information.

- - - Updated - - -

Thank you, does the same apply for PMing someone?

[bmwdirtracer]

Not as far as I'm aware. However, until you have 10+ posts, I think you are limited to a single PM -- in or out. Therefore you'd have to delete your "out" PM to receive an answer.

EDIT: I have PM'ed Abel for you. He may contact you, maybe not. He is in a field of work that is absolutely crazy busy during this crisis.

[Esekstrom]

How do you do a PM?

[bmwdirtracer]

At the very top right of this page, click on "Notifications".

Click on "unread private messages" (I am going to send you one to assist this)

Click on "Send new message".

Type the recipient's Bimmerforums name in the address slot, the subject, the message where indicated, then hit send.

You will need to delete your own message to receive an answer, until you have accrued 10 posts....which is not far away now, is it? (Delete my message too, you can only have a single message until you hit 10 posts)

[Esekstrom]

At a complete block. Had a replacement DME cloned by 328 Power 04 (many thanks!!); no changes. Traced both coil and injector leads from point of use to last contact (DME, ground point, all connections in between) making sure to flex all leads while testing - constant continuity with no opens at any time. The only item I did not test was the capacitor for the coils in the cylinder 5-8 wire housing “tray”.
Anything that I am missing??
Thanks.
Still misfire in cyl 6.
BMW Service diagnostic said cyl 6 misfire and to change the DME.

[MarcoZandrini]

Let’s get back to the cylinder with the low compression number. I think the first thing is to get that cylinder bone dry by removing the plug and allowing it air out. Also, remove the other 7 spark plugs. Next pull the fuel pump fuse and the fuse(s) for the DME. Check the compression in all cylinders. If cylinder 6 is still low put about 1/2 tablespoon of oil into the cylinder. Crank the engine for a few seconds so the oil gets distributed. Check compression again. Do you or the shop have a borescope? It might be a good idea to visually check the top of the piston and the combustion chamber.

[Esekstrom]

Update. Cylinder heads removed valve job completed, new valve stem seals, surfaced heads, installed new coolant crossover pipe. Head gasket blown in cyl 6. Heads installed and torqued. Note: my daughter suggested instead of dropping the engine to remove the left head why not take off the manifold to tailpipe coupling. We did this, removed the head bolts, put a wood block between the block and head, this gave us enough room to remove the exhaust manifold without dropping or lifting the engine (we got eight inches of clearance by doing this).
what are the torque values for the camshaft journals, and camshaft timing chain gears?
thanks! This has been a great learning experience for my 17 year old daughter.

[328 Power 04]

https://www.newtis.info/tisv2/a/en/e...1-31-camshaft/

and

https://www.newtis.info/tisv2/a/en/e...shaft-control/

I think

[Esekstrom]

Installing the heads and using a manometer to verify integrity of the coolant system prior to final assembly. Waiting on the elusive cam timing tool.

[ross1]

Update. Cylinder heads removed valve job completed, new valve stem seals, surfaced heads, installed new coolant crossover pipe. Head gasket blown in cyl 6. Heads installed and torqued. Note: my daughter suggested instead of dropping the engine to remove the left head why not take off the manifold to tailpipe coupling. We did this, removed the head bolts, put a wood block between the block and head, this gave us enough room to remove the exhaust manifold without dropping or lifting the engine (we got eight inches of clearance by doing this).
what are the torque values for the camshaft journals, and camshaft timing chain gears?
thanks! This has been a great learning experience for my 17 year old daughter.

I believe cam brg caps are 10#, cam gears 15#.
Perhaps your daughter could pass on her new knowledge to the pro that condemned your DME for doing what it was supposed to be doing. Who's idea to verify the cooling system? Brilliant!

[Esekstrom]

I wanted to show her how to make a simple manometer out of scraps and use it to detect leaks while the opportunity to fix any issues was still relatively simple.

[NeonStatus]

Impressive with the amount of work she is putting into this car. Interested in seeing how it turns out.