lots of codes... advice on where to start.

[bcredliner]

Originally Posted by g300d

In general no change when you pull the MAF means it isnt related to the problem at hand.

Have you tried clearing all codes, attempting to start, then read again to see if anything gets stored that might point to what's preventing the engine from starting?

No change to the MAF means the MAF is bad. MAF is part of the determination of air/fuel ratio. When MAF is disconnected the computer sets the ratio to predetermined parameters.

[andrewwynn]

What he said. You can unplug MAF and the car will run.

My very first repair was cam shaft position sensor which caused the car to stall regularly at increasing frequency.

It's would be my first bet in your case. The engine will not run without CPS. If the CPS is just not reliable you'll get shut down and stall. I've never gotten a code for one of my two cars directly related to CPS when they have failed just odd codes that indicated chaotic readings from CPS were likely.

I have the "cheat" of two M54 engine cars and swap parts to diagnose problems. If your CPS is shot I would expect the engine computer to not even send gas to the cylinders. If you get random firing you maybe get a wayward signal occasionally.

My new reader can monitor the CPS real time and with 8 cylinder cars it's very easy to detect CPS problem by the differences but with a single bank car it can be very difficult. There was definite guesswork involved with my car and it was absolutely the CPS.

Both mine and wife's CPS failed about 130,000 miles for comparison.

Engine computer will shut off fuel flow if it can't tell where the cam is. When my CPS started to go, the signal wasn't strong and sometimes especially on throttle off going slow (say going 8 mph then coast) the car would stall. I would pull an error that would tell me cylinder 3 gas was shut off for example, nothing to do with CPS. The error code combo (there were two) led me to xoutpost and CPS being the likely cause.

Bought an OEM CPS via Amazon (none available prime) and in 4-5 days had a BMW stamped part with German directions car fired right up with new CPS no related problems in the next 30,000 miles.

[andrewwynn]

You mentioned the episode that got you here was freeway speed but did you have slow speed stalls before? If you had occasional stall at slow speed for example pull into intersection to turn left but have to wait for traffic or while putting through parking lot then throttle off to park but discover the RPM at zero when you pull the key those are classic CPS shot symptoms.

FYI my stall situations: I had maybe 4-5 episodes spread over 2 months. I had SES (MIL / CEL) light on when I bought the car clearly because of CPS. The code self cleared by the time the car was driven to me, but I had a stall with codes about a month in, about 2 months in about two weeks later then about a week after that. When they go they can go slow at first then die quickly. They are very very sensitive parts I would never use a non OEM part for CPS!

[Jaegze]

Ok. So here I am with this thing.

New crank sensor no change. Cam sensors all tested good. Cleaned old maf and vs new maf no change.

Took out disa valve and cleaned idle air control valve. No change.

Disa valve out of the car it starts right up. Major backfires but started right up.

Put disa valve back in. No start.

[bcredliner]

Originally Posted by andrewwynn

What he said. You can unplug MAF and the car will run.

My very first repair was cam shaft position sensor which caused the car to stall regularly at increasing frequency.

It's would be my first bet in your case. The engine will not run without CPS. If the CPS is just not reliable you'll get shut down and stall. I've never gotten a code for one of my two cars directly related to CPS when they have failed just odd codes that indicated chaotic readings from CPS were likely.

I have the "cheat" of two M54 engine cars and swap parts to diagnose problems. If your CPS is shot I would expect the engine computer to not even send gas to the cylinders. If you get random firing you maybe get a wayward signal occasionally.

My new reader can monitor the CPS real time and with 8 cylinder cars it's very easy to detect CPS problem by the differences but with a single bank car it can be very difficult. There was definite guesswork involved with my car and it was absolutely the CPS.

Both mine and wife's CPS failed about 130,000 miles for comparison.

Engine computer will shut off fuel flow if it can't tell where the cam is. When my CPS started to go, the signal wasn't strong and sometimes especially on throttle off going slow (say going 8 mph then coast) the car would stall. I would pull an error that would tell me cylinder 3 gas was shut off for example, nothing to do with CPS. The error code combo (there were two) led me to xoutpost and CPS being the likely cause.

Bought an OEM CPS via Amazon (none available prime) and in 4-5 days had a BMW stamped part with German directions car fired right up with new CPS no related problems in the next 30,000 miles.

What I was saying is if you unplug the MAF and the engine idle does not change the MAF is bad. The idle should change and the engine should still run. Assuming the MAF was cleaned with MAF cleaner and the wires kind of hidden were sprayed liberally, if the connector is removed the engine idle should change. If it does not the cleaning was not successful.

[andrewwynn]

Originally Posted by Jaegze

Ok. So here I am with this thing.

New crank sensor no change. Cam sensors all tested good. Cleaned old maf and vs new maf no change.

Took out disa valve and cleaned idle air control valve. No change.

Disa valve out of the car it starts right up. Major backfires but started right up.

Put disa valve back in. No start.

Major backfire means ignition with intake valve open.

If it starts with DISA not installed it's sucking air not through the MAF.

Pull the flap out of the disa and install so the intake air is going through the MAF. Also while DISA is off the car you can. Suck on the vacuum. It will open the valve. If disa valve stuck shut perhaps stopping the process but I think you have a bigger issue.

You can force the disa valve open with your finger: I think you need to remove a cover over the lever to do this but it pops off easy enough

You said the CPS "tested ok" the only way to test is to read the real-time difference between the intake and exhaust cam positions while running.


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[Jaegze]

Ok I’ll go play with it a little more and report back. Cam sensors were replaced that’s why I said they were ok. I tested as they showed online and they seemed to respond appropriately

[Jaegze]

Just to regroup I wanted to run through everything I have done with this.

Started off testing the fuel pump. I got the fuel pump test kit from parts place and hooked it up. The first time I didn't get a reading. I ended up leaving for a bit came back and read it at 55 psi. So I assumed the pump was good.

I checked spark with an inline tester and got a strong light.

I replaced the cam sensors, maf and CPS. I replaced each one one at a time with no change in the way the car acted. The intake cam sensor when I took it out, the outer casing was off the sensor and when I pulled that from the hole the outer casing was broken. Wondering if something could have happened inside of here?

I took out the ICV and cleaned it, it wasn't too bad when I took it out but cleaned it anyway and put it back in.

The car will crank but will not fire. When I push the throttle to the floor the car will sputter a little bit on and eventually may run a bit on its own but then backfires and shuts off.

Going through and randomly checking things I took the disa valve out. The car will start up with it out but will loudly backfire and shut off.

putting the disa valve back in returns the car to a no start with sporadic firing as described above.

The intake boot is in good condition and I check the vacuum lines around the car a couple of times and replaced things as needed.

I guess I'm kind of stuck moving forward as I don't know where to go from her with this thing. I may have to take it to a local garage. No BMW mechanics or shops within 90 minutes of me so it would be to an independent shop. Im not familiar with the vanos valves. Could this be an issue? Ill search a bit but I have never had to mess with them.
Thanks again for the help!

I do have to do the smoke test yet. Which will be my next step, unless theres a better idea.

[bcredliner]

Did you have a rough idle or was the engine cranking but not starting when you started troubleshooting by testing the fuel pump?

[andrewwynn]

Originally Posted by Jaegze

Ok I’ll go play with it a little more and report back. Cam sensors were replaced that’s why I said they were ok. I tested as they showed online and they seemed to respond appropriately

They are super sensitive you mentioned the old one being damaged. There is a plate inside that has notches that go past the sensor. If the old one was hit by the plate (disc) it could easily prevent proper reading and no way it will run. The spark timing is determined by the CPS.

It's a good sign you get any spark without that I'd be clueless. DISA out some success is a white rabbit not a solution path. I would bet on CPS related. Could have a defective part or as mentioned internal damage to the timing plate.