Just my luck (a small rant)

[tice23]

So I have been rebuilding a near scrap 330xi over the past year and was finally getting some good road time with it when the starter motor failed. I know how much of a pain it was to do on my other car so I put it off for a while and let the car sit. I got the parts ordered and a few weeks later once the weather was nice again I decided to pull it apart and get it done. I should mention at this time I had experienced on two occasions prior to the starter failing some random misfires and an intake temp sensor error that would clear and go away for several hundred km's so I wasn't too worried about them and I was preoccupied with this issue and we just sold our house that week so it was on the back burner.

All the moving was now done, and I got the car back together again with the new starter and intake manifold temp sensor and tried to fire it up. It cranks! hooray! problem solved!...but now it wont turn over. I double check all my connections, hoses test for fuel pressure. everything seems fine and it almost wants to start but just wont. maybe the engine flooded? (it did that to me in the winter after a long time sitting) I took out the fuel pump fuse and ran it dry, put it back in and it did the same. It's cranking fine just wont turn over, and now that I notice it the engine feels a bit shaky when cranking. It already has a CEL from an O2 sensor that's failing but better hook it up and scan the codes anyway. At first nothing else popped up, but after the third scan and a few more attempts to crank it over 53[083] crank position sensor pops up which is right under the starter I just replaced, awesome! That explains the few random misfires from a while ago.

Parts ordered and I am without a car for at least a week now. Well see what comes first: my parts or the other shop working on the rear suspension of my e36 that is horribly overbooked right now and failed to tell me. I am in a mood today.

[jclausen]

It's cranking fine it just won't turn over, it can't be both of those, is the engine turning over when your trying to start it?

[tice23]

Sorry if my terminology was a bit off. The starter is cranking the motor but the engine won't run. I have fuel pressure, all the air hoses were double checked, all of the the electrical connections were checked. Just feels like all the cylinders are missing and the crank sensor code came up after a couple scans.

[MarcoZandrini]

Does the the tachometer needle move when you crank it?

[tice23]

It did a little, like nothing over 500rpm. it was a bit jerky though. I also checked the reading on the computer and it was about 250rpm when cranking and would occasionally spike to 500 when one of the cylinders would fire.

[tice23]

So I installed a new CPS and the intermittent no signal persists. I think it's down to the wiring harness (it has a few cracks and exposed sections on the CPS pigtail) or there's an issue with the computer. The pigtail is easy enough to replace and should be done anyway with its condition so I'm starting there. Hopefully I don't need to get a new ECU or have to send it out for repair.

[harrier]

Did you test the fuel pressure with a gauge?

[tice23]

Update: Haven't had a lot of time lately but I took this evening to do a few things.

I don't have a fuel gauge. The car has a brand new fuel pump and filter less than 500km's earlier. There is enough fuel at the rail to spray out when the valve is pushed in. The EWS is showing no issues causing the pump not run and there are no blown fuses. Because the crank sensor code was detected that's my primary focus right now.

Before I go and rip everything apart again I thought I would try something out. I bought a simple single channel lab scope on amazon for $60. I decided to hook it up and see what kind of signal if any is coming directly off the sensor. I discovered the old crank sensor had failed enough to allow oil to get sucked up into the harness. I cleaned out as much of it as I could. Then I found the wiring diagram: https://www.newtis.info/tisv2/a/en/e...it-dme/hCVEZvo

I hooked up the scope across #27 and #37 and with the cleaned up connectors reinstalled I turned the key. At first it wasn't doing much different and I would get a brief spike of signal every few seconds that corresponded with the engine rumbling a bit (one or two cylinders getting the signal to fire) and I kept trying until it finally turned over for about 5 seconds. It felt smooth and showed a pretty strong consistent signal from the sensor until suddenly it disappeared and the engine sputtered out. Something is causing the signal to drop. I repeated trying to start it and got similar results: when it wasn't turning over the signal was sparse or non-existant and when it got signal again it fired up and ran briefly until another drop of signal.

From what I gather here:

-The signal measured from the sensor before it reaches the computer has issues with it dropping. This confirms what the DME was reporting with intermittent no signal code 53[083]

-When the signal was finally consistent for a moment the engine ran fine. Therefore the DME is not the source of my issue.

So the issue has to be along the harness (as suspected) or I was unlucky and I got a junk sensor (unlikely but not impossible).

Have to pull the airbox off again and get to the harness to check continuity in the harness, try to remove all of this oil residue, and check the resistance across the poles of my new sensor. For now I have to wait for another free day with some decent weather again. I miss my garage

[tice23]

Well the big issue is solved. The cam position sensor is now being recognized by the DME and no longer presents the intermittent issues.

The final cause of the error was a damaged cable and connector. I bought a new connector from FCP euro. When I had it back apart I tested the sensor just to be sure and it read open resistance across all three pins as its supposed to. I tested the harness for continuity and 2 wires had definite breaks near the connector. I soldered in new wires and rebuilt the connector using the old pins and a new clip (the old ones tabs were not holding it tight anymore). Put it all back together and it runs again! scanned the computer and the intermittent signal is gone!

[harrier]

Nice work