Post VANOS Rebuild Issues: Rough Idle + Popping Sound

[danewilson77]

Not sure it's even possible with the length of the wires being what they are.

Echo...have you heard of someone doing this before?

[328ioc]

Not sure it's even possible with the length of the wires being what they are.

Echo...have you heard of someone doing this before?

This. I believe the wire runs make it nearly impossible to do this.


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[wertyu78]

I was thinking the same thing. The length of the wiring wouldn't allow such a thing.

[wertyu78]

Update:


After taking everything apart again, I verified that the timing was in fact correct. With the VANOS still attached to the head and spark plugs pulled, I manually cranked the motor clockwise to align the motor to TDC. I slid the crankshaft locking pin and after that the cam lock blocks sat evenly with the cylinder head without an issue. Both cams showed the dots facing upward and the cam lobes were facing each other as they should. I removed the VANOS and started the re-timing process once again, but ran into an issue. I broke a bolt(shitty Northern Tool torque wrench) that holds the secondary timing chain tensioner in place.




I've ordered the part from my local dealership but it wont be here until tuesday. All progress has been stopped. I'm running out of ideas. If the timing was correct, what is the problem?

[echo46]

I agree, I don't think the wire lengths would allow it. I remember when I replaced my upper and lower intake boots and cleaned the ICV that when I plugged all the sensors back in I had misfires and bad idle. I now remember when I went back in there I forgot to hook one of the sensors up causing the misfires.

[wsmeyer]

I don't think this is possible do to the wire lengths either but double check that the wires going to the ignition coils on each spark plug didn't get crossed. Particularly 2 & 3 that are now fouled.

[wertyu78]

I'll be sure to double and triple check everything once the new bolt comes in and everything gets out back together. If I'm still having issues, I'll tow it to the Indy.

[Dave_B]

Hey Wyatt, sorry hear about this buddy.

I personally don't think it's P2V contact or anything like that or the sound that is in that video would be constant.

Old trick to source a noise like that is to use a long instrument and put your ear to it. Carefully move the one end around the engine bay with the other next to your ear and use it like a stethoscope to find where that noise is coming from exactly. Long extensions work good for this.

[wertyu78]

The new bolt came in yesterday but I didn't get a chance to install it until today. I put everything back together with the old plugs and it still ran the same.

Popping sound only happened twice. I can now run the car and it not make the popping sound anymore. It seems as I'd cylinders 3,5, and 6 are not firing.

We checked the fuel rail for pressure and that checked out fine. All of the coils are working. Spark plugs new/old have no effect. Grounds for the coils are fine. The little OBD2 code reader pulled P2234: short in O2 sensor heater circuit.


I have a sneaky suspicion it's O2 sensor related. I'm hoping I can get access to a full diagnostics machine tomorrow. So close....

[Dave_B]

Wyatt, if things work out... I'll have access to GT1 with SSS and DIS on Sunday.

I'll keep you posted. I'm hoping we get that thing worked out. My step dad is in town who used to be a BMW Step Program instructor for UTI.