Under load, 3krpm turn off. Vanos Discon, doesnt turn off.

[graphikg]

I have had a problem for a while that no one on the forums could solve. I took it to a shop and they're stumped. Had a BMW only shop assess the car, and they said they NEVER seen a problem like that before.

The car shuts off at 3k-3500rpm under load only. It has a grinding sound right before it turns off. The shop had the car timed to TDC - EXAXCTLY. The vanos has been rebuilt and the ECU has been changed. No codes are being summoned.

When the Vanos is disconnected, the car does not have the shutting off problem, but obviously has the lack of power. Crank pos sensor is good, MAF cleaned, and working fuel pump and fuel filter. All coil packs are also good, as well as there are new spark plugs.

What could it be?

[328ijunkie]

Does it completely shutoff? Gear dependent?

[samiam3356]

any codes? speed signal from the diff? check to see if its loose.

[graphikg]

zero codes. I didnt check the diff speed signal; the car doesnt turn off under load when the vanos solenoid is disconnected, so I dont see how the diff speed signal influences that.

And the car does completely turn off, as if someone just turned the ignition off - like a stall. It is not gear dependent either - just throttle and rpm dependent. For instance, I can get to 3700rpm maybe if I get on the throttle softly and gradually, but if I get on the throttle a little harder, the car shuts of even before 3k rpm. The auto shop cant figure it out so far, and they posted the problem in their forum board and have had no responses. Not even the BMW specialty shop knows what it is.

[samiam3356]

just throwing darts as it doesn't look like your getting anywhere right this second. Solenoid bad maybe?

[graphikg]

Honestly, thats what I kinda leaning at by this point, but the weird thing is why hasnt anyone "seen this before." Hasnt there been a bad solonoid in VANOS history? Also, would that explain the grinding noise that happens when the vanos starts initiating (right before the car turns off)?

[e46s54dr]

Has your car always had these symptoms prior to getting it re-timed? Or did your problem appear after the repairs? Have you checked your cam positioning sensor for the intake cam? Ohm it out and see if it's faulty or possibly short. Btw, how far off was your original timing for you to get it redone?

[e46s54dr]

have you extracted the cel codes? Of you haven't, go ahead and get them and it'll help point us in the right direction. Make sure you do an additional 5 stomps to get all the codes, otherwise the first code will keep repeating itself.

[graphikg]

I am borrowing a code reader/clearer from another nice fellow member, and all codes have been cleared. The problem seemed to start after an overrev, hence the reason for taking the head off to be checked. I havent checked the cam sensor yet, but I can have the shop check that since that is where the car is. The original timing could not have been too much off, since the shop said they set it EXACTLY, and it is stil acting the same. It is weird how whatever happened occured after an overrev.

[jrdeamicis]

Good day.

I have a spare vanos you can put it in. Just come grab it. And if you are obd1. If the codes can clear just use the pedal trick to retrieve the codes.

[hoveringuy]

I would separate VANOS from the ECU.

First, put a 100 Ohm load resistor in the connector to fool the ECU into thinking VANOS is still connected. It checks for it when you start the car, could be a problem with the VANOS map when it switches maps internally. When you just unplug the VANOS I don't think it still switches maps because it know it's disconnected. If you get problems with stalling using the load resistor it's an ECU issue.

I would then run wires to the VANOS to control it from the cabin. If advancing the VANOS under load causes the problem, it's a mechanical issue.

The most reasonable explanation is that the solenoid has an inernal short of some kind.

[dsobering47]

have you watched your fuel pressure when it happens? maybe even swap the coils with known good ones....

[graphikg]

^^^ Havent checked the fuel pressure, but I already did the coil swapping thing.

Good day.

I have a spare vanos you can put it in. Just come grab it. And if you are obd1. If the codes can clear just use the pedal trick to retrieve the codes.

AWWWW bad timing. Only if you messaged me a week earlier. If they dont fix my car by the first week of Jan, I will gladly drive their and borrow the unit. Such a nice gesture.

I would separate VANOS from the ECU.

First, put a 100 Ohm load resistor in the connector to fool the ECU into thinking VANOS is still connected. It checks for it when you start the car, could be a problem with the VANOS map when it switches maps internally. When you just unplug the VANOS I don't think it still switches maps because it know it's disconnected. If you get problems with stalling using the load resistor it's an ECU issue.

I would then run wires to the VANOS to control it from the cabin. If advancing the VANOS under load causes the problem, it's a mechanical issue.

The most reasonable explanation is that the solenoid has an inernal short of some kind.

This idea honestly makes so much sense. I am going to have them try this and see if they can do it.

[Schwarz325]

Take out and clean your vanos solenoid, possibly replace it. Check the ground on the solenoid/engine lifting part too.

[graphikg]

Small update - The VANOS solonoid should read at 28ohms, and the shop found it at 22ohms. Something is inconsistant there I guess, as if not enough current is going through.