[avery0829]

I recently bought a 2006 325Xi. The last few days I noticed the idle would fluctuate a couple hundred RPM. Wasn't sure if this was normal as I just bought the car.

I started the car this morning and backed out 10 feet then it died. Tried starting it again and it just cranked. Then I cranked it a few more times and it ran for a moment to repark. The odd part is once I was able to get it started, if I stayed on the gas around 1500 RPM or higher it would continue to run smoothly.

Today I borrowed a scanner to check for codes. I didn't have a check engine light on the dash, but thought I would see if anything was saved. No codes.

After a bit of research, I started to think it could be the fuel pump as they usually don't throw any codes. So I followed the Pelican parts "Fuel Pump Testing DIY"

https://www.pelicanparts.com/BMW/tec...mp_Testing.htm

I tested the connector to the fuel pump on a multimeter and got a reading of 10.5v when trying to start. I rented a fuel pressure tester and once I was able to get it started after 3 or so tries. The pressure was around 72 PSI. I held the RPM and it continued to stay there. Once I let off the gas it died.

I'm at a loss for what else it could be. I checked over the intake system for any leaks and nothing. When I was able to get it running for a moment, went to listen to engine for any abnormal sounds. Nothing.

Here are a few videos of what I am working with.
Fuel pressure test

Thanks for any help

[avery0829]

Ended up taking it to a shop. Had pending code for TPS sensor. Had it replaced and still doesn't start. Anyone?

[tlow98]

You check it with a BMW specific scanner?

And I take it the shop gave it back to you not running?

[bkwld]

Any follow ups?
Could be the eccentric shaft sensor...
Vanos solenoid for rough idle...

[avery0829]

Originally Posted by tlow98

You check it with a BMW specific scanner?

And I take it the shop gave it back to you not running?

The shop I took it to has a BMW specific scanner. They are going to give me the car back tomorrow. No charge on diag.

[avery0829]

Originally Posted by bkwld

Any follow ups?
Could be the eccentric shaft sensor...
Vanos solenoid for rough idle...

Sensors were checked by the shop it was at.

[avery0829]

Took it to another independent shop before being succumbed by the dealer.

Findings are:

Eccentric cam sensor is bad, oil leaked through the harness and got to the ECU. Recommend replaceing sensor and ECU.

[PhaseP]

Try this, disconnect your MAF sensor connector. Then try to start the engine. If engine starts and idles well, your problem is likely a somewhat big vacuum leak throwing off the computer to calculate correct air fuel ratio for idling. If MAF disconnect doesn't change anything then you can check the ECC connector if it has oil that is at the valve cover. If it does have valve cover it is very likely toast. The ECU not likely toast though, unless the oil travelled down the wires of ECC all the way down to ECU.
First replace the ECC, then if you still have problems then consider ECU replacement. Your 325Xi's ECU is easy to be cloned on a used ECU from ebay or salvage yard.

If MAF disconnect is causing good idle, then most likely vacuum leak is the broken/cracked breather hose from valve cover to oil separator inside the folds of the manifold. Other likely vacuum leak is torn diaphragm inside the oil separator valve. You can test this by removing its vent nipple covering piece and then close it with your thumb and see if this changes engine idle issue. Another way to test this is when engine is off put a small hose on that vent nipple, blow gently to the oil separator valve. You should be able to only blow air into it for a very short time, that would make it move down a bit to close the valve. But not anymore. If you could blow air for more than a split second, the diaphragm is torn which will leak air vacuum in.
There is possibility but less likely unless some work was done that meant removing and putting them back, the oil return hose from oil separator valve into the oil pan could have cracked and leaking vacuum. You can test this also, assuming oil separator valve is fine, its diaphragm is not torn. But will need another person to keep the RPM's up for engine not to die. Put a small enough hose at the oil separator vent nipple again. Blow on it that will cause the diaphragm to close the valve and keep pressure to keep the valve closed. If there was a vacuum leak going down to oil pan, this will close that section and leak will stop. You don't want to hold that valve closed to long, because if there is no leak, the crank case pressure will rise and will want to go out from somewhere.

If you end up with vacuum leak and fixed your issue, but if you did have oil at the ECC connector, consider changing it sometime soon.

[Volasko]

Originally Posted by PhaseP

Try this, disconnect your MAF sensor connector. Then try to start the engine. If engine starts and idles well, your problem is likely a somewhat big vacuum leak throwing off the computer to calculate correct air fuel ratio for idling. If MAF disconnect doesn't change anything then you can check the ECC connector if it has oil that is at the valve cover. If it does have valve cover it is very likely toast. The ECU not likely toast though, unless the oil travelled down the wires of ECC all the way down to ECU.
First replace the ECC, then if you still have problems then consider ECU replacement. Your 325Xi's ECU is easy to be cloned on a used ECU from ebay or salvage yard.

If MAF disconnect is causing good idle, then most likely vacuum leak is the broken/cracked breather hose from valve cover to oil separator inside the folds of the manifold. Other likely vacuum leak is torn diaphragm inside the oil separator valve. You can test this by removing its vent nipple covering piece and then close it with your thumb and see if this changes engine idle issue. Another way to test this is when engine is off put a small hose on that vent nipple, blow gently to the oil separator valve. You should be able to only blow air into it for a very short time, that would make it move down a bit to close the valve. But not anymore. If you could blow air for more than a split second, the diaphragm is torn which will leak air vacuum in.
There is possibility but less likely unless some work was done that meant removing and putting them back, the oil return hose from oil separator valve into the oil pan could have cracked and leaking vacuum. You can test this also, assuming oil separator valve is fine, its diaphragm is not torn. But will need another person to keep the RPM's up for engine not to die. Put a small enough hose at the oil separator vent nipple again. Blow on it that will cause the diaphragm to close the valve and keep pressure to keep the valve closed. If there was a vacuum leak going down to oil pan, this will close that section and leak will stop. You don't want to hold that valve closed to long, because if there is no leak, the crank case pressure will rise and will want to go out from somewhere.

If you end up with vacuum leak and fixed your issue, but if you did have oil at the ECC connector, consider changing it sometime soon.

God damn this man knows... +1 for you

[avery0829]

Thanks for the reply. I have since sold the car. The buyer simply replaced the eccentric shaft sensor and the car runs... The shop I'm assuming, wanted nothing to do with it and wanted to replace everything to cover themselves...

[Fritzer]

What's the mileage like and how much did you pay, if you don't mind me asking.

[avery0829]

Originally Posted by Fritzer

What's the mileage like and how much did you pay, if you don't mind me asking.

I believe around 180k or 190k. I paid very little for the car. The previous owner wanted it gone that day. I just had some bad luck with it a couple months down the road.