Hard Cold Start and VANOS Error Codes

[sapote]

I’m surprised nobody has tried to make a better solenoid pack from the ground up with better serviceability and durability. The circuit seems extremely simple and the solenoids are fairly straight forward

So far all I have heard the weak link is the solder joints. The head temperature is close to 90C to 100C and went through many heat cycles, leading to solder crack. Using lead-free solder can lead to solder joint crack easier than the old lead solder, as the former is more rigid and fragile than the old softer solder.
I would think adding 8 wires from the solenoid solder joints to the connector pins solder joints will take care the cracked joint, as the wires bypass the pcb traces with the cracked solder.

[eacmen]

I’m surprised nobody has tried to make a better solenoid pack from the ground up with better serviceability and durability. The circuit seems extremely simple and the solenoids are fairly straight forward

[heinzboehmer]

What did you do to cause the intermittent open circuit (just want to pin point the bad connection)?

Accidentally used low temp solder when reflowing the solder joints. Then took it to an autox and melted/cracked the solder. Reflowed with higher temp solder and no more issue.

[sapote]

The tricky thing about the solenoid is that the failure can be intermittent. I had mine fail (after I messed with it, 100% my fault) only when it got hot.

This sounds more like having cracked solder joints on the pcb than the solenoid coil wiring. What did you do to cause the intermittent open circuit (just want to pin point the bad connection)?
The 6pin connector soldered to the pcb, and the 4 solenoid coils. So there are 6 copper traces on the pcb that maybe cracked in addition to the 8+6 = 14 solder joints.

[heinzboehmer]

I think you left the solenoid unplugged when you shot that video

But yeah, that's what mine sounded like when the solenoid failed. Same failure mode to leaving it unplugged, DME asks for cam timing to change and nothing happens mechanically. Mine would smooth out above 2.5k rpm, as the cam timing was stuck in a position that worked well for that rpm.

[eacmen]

The tricky thing about the solenoid is that the failure can be intermittent. I had mine fail (after I messed with it, 100% my fault) only when it got hot. Could only reproduce it after sticking it in the oven for a bit.

Pressure test and timing check are a good idea, but unless the resistance readings are repeatable in multiple scenarios (hot, cold, upside down, etc.), I wouldn't fully rule the solenoid out yet.

Thanks. I put the VANOS back together and now the engine is running like total dogshit. Now in addition to inlet codes im getting exhaust codes. It was running so bad I didn't feel comfortable running the tool32 script to test VANOS. According to data both the exhaust and intake cams are at 0 degrees. The idle sounds like nascar V8 with giant cams in it and a bad tune.

Looks like solenoids are in my future.

I recorded a video of the engine at idle. I didn't hear anything abnormal but sometimes my ears are optimistic.

https://www.youtube.com/shorts/Q3AR5VcPmZs

[heinzboehmer]

The tricky thing about the solenoid is that the failure can be intermittent. I had mine fail (after I messed with it, 100% my fault) only when it got hot. Could only reproduce it after sticking it in the oven for a bit.

Pressure test and timing check are a good idea, but unless the resistance readings are repeatable in multiple scenarios (hot, cold, upside down, etc.), I wouldn't fully rule the solenoid out yet.

[sapote]

Before dropping a cool $1k on new solenoids I ordered the pressure gauge and going to pressure test the VANOS.

If all solenoids pin to GND pin were measured within 7.5 Ohms, then there is no reason to blame the solenoid module.
Instead of spending $1k on the solenoid, I would check the vanos timing with VC removed.

[eacmen]

Thanks everyone. Took the solenoid pack off. All solenoids measured between 7.2 and 7.4 ohms. I measured resistance from both pin 2 and pin 5 as GND. I was not able to do a VANOS test before pulling it off since I couldn't get DIS to start up. I might try the tool32 method tomorrow.

The sealing plate looks good, all the o-rings are soft and seem to be sealing well. The codes I gave before were from the Schwaben tool. I also grabbed codes from INPA, screenshots attached (annoying you can't copy-paste from INPA!). I cleared the codes and the VANOS codes didn't immediately return but the oil level sensor definitely needs to be replaced.

Before dropping a cool $1k on new solenoids I ordered the pressure gauge and going to pressure test the VANOS.

[jet_dogg]

No. Beisan rebuilt unit. Approx 3yrs but only on track. Maybe 30 track hours

This is a good data point if the solenoid is to blame.

Subbed for the resolution, hope you get it fixed soon.

[eacmen]

Are you on your original factory solenoid?

No. Beisan rebuilt unit. Approx 3yrs but only on track. Maybe 30 track hours

[jet_dogg]

Are you on your original factory solenoid?

[sapote]

Went out to move the car today. The last few cold starts it was hard to start, would have to crank it twice. Today the SES light came on and it had the following codes:

[CODE]
0x43: DME: Inlet VANOS, advance valve
0xB8: DME: Function, inlet VANOS
0x2C: DME: Signal, thermal oil-level sensor

It says advance value; does this mean too advance or not enough? If too advanced then solenoid must had activated to let pressurized oil moves the cam. A lots of guessing here as the code description is not clear.
Check solenoid pack:
pin2 and 5: GND
pin1, 3, 4, 6 are the power input to each solenoid coil. There is a flywheel diode across each solenoid, so when checking the coil resistance, use red lead on power pin and black on the GND pin; the other way could cause a short reading valve due to the diode.

[heinzboehmer]

You could run a VANOS test to rule out internal pressure leaks.

You could also measure the resistance between pins on the solenoid connector. I got 6.8 Ω for all four. If any circuit is open, then it's definitely the solenoid. I can't remember exactly what pin goes to what, but TIS should have the info. More solenoid stuff here: https://nam3forum.com/forums/forum/m...-solenoid-pack

But yeah sound like solenoids to me.

[eacmen]

UPDATE: Fixed the issue. It was loose ground connector in the e-box. If you experience sudden VANOS codes along with oil level sensor failure check your grounds! Specifically X6053.



Went out to move the car today. The last few cold starts it was hard to start, would have to crank it twice. Today the SES light came on and it had the following codes:

0x43: DME: Inlet VANOS, advance valve
0xB8: DME: Function, inlet VANOS

Sounds like solenoids to me?

What was weird was I also got the following code:

0x2C: DME: Signal, thermal oil-level sensor

My oil temp gauge did not move when I started the car.

I am assuming the two errors are not related. But weird for them both to pop up at once.

Any diagnostic steps to try before buying new solenoid pack?