trouble starting

[rh71]

I'm confused.
If it cranks, then its turning over. It can crank and turn over, but not fire or start. A car can fire, but not start, but has to be cranking and/or turning over to do so.

then i used "turning over" incorrectly. Looong crank and never start.

Stop giving advice. Fuel injected cars do not depressurize by just sitting there. And gravity? WTF.. Do you really think that your fuel system will depressurize because of gravity?

fyi they did do a smoke test for leaks and fuel pressure test as well... both ok.

 

[rh71]

oh forgot to ask, are fuel injector cleaners you throw in with gas every now and then a gimmick or what? I'll say that I run it near empty more often than not and the bottom of the tank gunk "myth" comes to mind.

 

[SSSnail]

Stop giving advice. Fuel injected cars do not depressurize by just sitting there. And gravity? WTF.. Do you really think that your fuel system will depressurize because of gravity?

So you're telling me if I turn my car off, and the fuel pump is not pumping, there's NO CHANCE that any leaks in any seals in the entire fuel system would preventing me from losing that pressure? Perhaps it's one of the seal that is on the pump that is known to leak a little every now and then? No?

Sorry, I was wrong, learn something new every day.

 

[bruceb]

I will say it is your fuel pressure regulator. They can cause a no start condition or long cranking time on a fuel injected motor. On most cars, it is under the hood on the end of the fuel rail and usually has a vacuum hose attached to it.

 

[Zenmervolt]

says intake vanos solenoid, both replaced. They found a bulletin on it too.

That'd do it. Since VANOS is BMW's variable valve timing setup, it makes sense that a borked VANOS actuator could muck with valve timing enough to cause a hard start.

ZV

 

[SSSnail]

That'd do it. Since VANOS is BMW's variable valve timing setup, it makes sense that a borked VANOS actuator could muck with valve timing enough to cause a hard start.

ZV

If I'm not mistaken, solenoids either work or not, that wouldn't explain the hard starts in the morning, where the car has had a long standing period where more pressure was lost vs during the day, hence he doesn't have that problem at lunch. And yes, messed up timing would not start a car, at all.

All I'm saying is, this is the exact symptom on my car, and the fix was just wait a few seconds.

 

[SSSnail]

then i used "turning over" incorrectly. Looong crank and never start.



fyi they did do a smoke test for leaks and fuel pressure test as well... both ok.

This is not an external leak (else you'd smell the fume), nor a pressure issue. It's the immediate availability of fuel right when you start up.

 

[Eli]

If I'm not mistaken, solenoids either work or not, that wouldn't explain the hard starts in the morning, where the car has had a long standing period where more pressure was lost vs during the day, hence he doesn't have that problem at lunch. And yes, messed up timing would not start a car, at all.

All I'm saying is, this is the exact symptom on my car, and the fix was just wait a few seconds.

And what car do you drive? You make it sound like it's the same as the OPs?

Also, valve timing is different from just timing, which generally refers to ignition timing.

Have you ever been around an engine with a high performance cam? They don't like to start/idle.

This is not an external leak (else you'd smell the fume), nor a pressure issue. It's the immediate availability of fuel right when you start up.

If there's no leak, how does the fuel system depressurize?

If there's no pressure issue, why is there a fuel availability problem?

 

[SSSnail]

And what car do you drive? You make it sound like it's the same as the OPs?

Also, valve timing is different from just timing, which generally refers to ignition timing.

Have you ever been around an engine with a high performance cam? They don't like to start/idle.



If there's no leak, how does the fuel system depressurize?

If there's no pressure issue, why is there a fuel availability problem?

One that has VANOS (which I have actually disassembled). And, the leaks are not EXTERNAL leaks, but internal leaks. (think of it as fuel going back in the tank instead of staying in the fuel line) I'm sure you can differentiate between the two, right?

Once the pump gets going, there are not any problems with fuel delivery, just at the very start because all the fuel has drained back into the tank.

What is it about what I've written that got you guys panties in a bunch?

 

[Zenmervolt]

If I'm not mistaken, solenoids either work or not, that wouldn't explain the hard starts in the morning, where the car has had a long standing period where more pressure was lost vs during the day, hence he doesn't have that problem at lunch. And yes, messed up timing would not start a car, at all.

All I'm saying is, this is the exact symptom on my car, and the fix was just wait a few seconds.

The VANOS solenoid allows oil into the VANOS system. If it fails, the VANOS system will not operate properly (insufficient oil pressure) and the valve timing will be borked. If the failure causes the VANOS system to be "stuck" at some setting other than "start", the engine will experience hard starting. If the VANOS solenoid fails mechanically and "sticks" only partially open, it may take longer than normal for the oil pressure in the VANOS system to build to acceptable levels and cause hard starting until the oil pump has re-pressurized the system.

Look, I've had cars where the FPR got weak and the rail would de-pressurize if the car sat for a few days. I understand that this could cause the same symptoms. What you are missing, however, is that the dealership fixed the problem and that they did so by replacing the intake VANOS solenoids on the double-VANOS system in the OP's X5. The dealer replaced the two VANOS intake solenoids, and it solved the problem. What you described could have been a cause, but investigation by the dealer ruled it out.

If the OP posts that the problem persists, then your hypothesis will be something to follow up on. But if the problem is indeed gone, then the culprit was the VANOS system because that's what the dealership fixed to eliminate the problem.

ZV

 

[SSSnail]

Hey Zemmervolt, you've always been a voice of reason and that is appreciated.

I'm not saying the OP's car won't be fixed by changing the VANOS solenoid, but considering all the other factors (mileage, car age, etc...) VANOS solenoid failure, though not out of the equation, is somewhat improbable.

Fearing the same issue with the VANOS issue, I rebuilt mine at ~55K miles (myself) last year (since then I've put roughly 45K miles on it) even though nothing was wrong with it. The common problems with BMW's VANOS assembly is that they use inferior material on the O-ring and teflon rings in the assembly, causing them to fail prematurely due to plasticize of the seals.Half a year after my VANOS was rebuilt the hard to start problem in the morning commence.

At first, I thought it was the fuel pump, but then after a bit of research, I found out that there's a seal in the fuel pump that use pretty much the same inferior material (call it planned obsolescence) which would drains the lines of pressure. So after the problem started, I tried to troubleshoot and couldn't figure out why, was very close to replacing my pump (but alas, I didn't). So now, I'm content with waiting until the fuel light goes out then crank my engine.

I'm not saying that it's 100% certain that's what's wrong with the OP's car, but I have a very good feeling that it might be the same, all things considered.

 

[Eli]

What is it about what I've written that got you guys panties in a bunch?

Because you're saying things that don't make any sense, like:

And yes, messed up timing would not start a car, at all.

..When someone was talking about valve timing.

That leads us to believe you don't have any idea what you're talking about. lol

And, the leaks are not EXTERNAL leaks, but internal leaks. (think of it as fuel going back in the tank instead of staying in the fuel line) I'm sure you can differentiate between the two, right?

Of course. But fair enough, I didn't really catch the external leak part.

 

[SSSnail]

Because you're saying things that don't make any sense, like:

..When someone was talking about valve timing.

That leads us to believe you don't have any idea what you're talking about. lol



Of course. But fair enough, I didn't really catch the external leak part.

There's other type of timing on a car? Do YOU know what you're talking about?

 

[Eli]

There's other type of timing on a car? Do YOU know what you're talking about?

Also, valve timing is different from just timing, which generally refers to ignition timing.

 

[SSSnail]

Hmm... I thought they all have to work on the same timing? You know, part of the whole ignition cycle? Of course, I could be wrong.

 

[Eli]

Hmm... I thought they all have to work on the same timing? You know, part of the whole ignition cycle? Of course, I could be wrong.

Aww.. That's cute. *ruffles your hair*

The reason "timing" almost universally refers to ignition timing is because.. being able to adjust valve timing is a relatively new technology. It's also limited to a few set points, while ignition timing can range from something like 60 degrees BTDC to 12 degrees ATDC, depending on the engine and the conditions being experienced by that engine at any given moment.

Anyway, the point is that the valve timing being wrong in this case could indeed cause a hard start. This is because it could only be "wrong" in the sense that it isn't optimal for starting; the engine is obviously capable of running in any state the VANOS system is capable of.

That's also why I asked if you had ever been around an engine with a high performance cam. A cam that is designed for high performance can be very difficult to start, and gives a very "lopey, barely running" idle.

 

[SSSnail]

So if the valve timing is off, wouldn't the car run like shit? Even if it starts?

 

[Zenmervolt]

So if the valve timing is off, wouldn't the car run like shit? Even if it starts?

Rough idle, etc, yes.

Though if the VANOS system was just bleeding down and had to re-pressurize after sitting too long it could cause difficulty until things pumped back up (analogous to a noisy lifter that quiets down after a few seconds). And I'm just theorizing based on an assumption that the dealership's work did fix the issue.

ZV

 

[Eli]

More or less, I guess? Some people consider a lopey idle to be glorious.

It's also possible there's way more to it than that. Like you said, solenoids either work or they don't. Maybe it was just sticky, and the ECU won't allow a start under those conditions? I'm not really sure.

But like ZV said, they found the problem and fixed it. Your diagnosis is indeed good and valid, it just seems it was the wrong one in this specific case. Nothing wrong with that.

 

[Zenmervolt]

It's also possible there's way more to it than that. Like you said, solenoids either work or they don't. Maybe it was just sticky, and the ECU won't allow a start under those conditions? I'm not really sure.

A lot of times if the ECU doesn't get the signals it expects, it won't tell the plugs to fire.

As for an idle with wicked cams...

http://www.youtube.com/watch?v=RAxVlBWFmew

And just for fun:

http://www.youtube.com/watch?v=KygxhiTQvYc

ZV

 

[rh71]

so I now notice right at the point the engine starts, it sounds & feels "rougher" for a split second. Almost like a very brief shake, as if it was done stronger to make sure it starts. Is there something they could've "overdone"? Is this just a symptom of a new part?

I hate when it doesn't come back the way I left it cause I know of every little quirk and now it's different. Just want to be sure I'm good before warranty runs out.

 

[Zenmervolt]

so I now notice right at the point the engine starts, it sounds & feels "rougher" for a split second. Almost like a very brief shake, as if it was done stronger to make sure it starts. Is there something they could've "overdone"? Is this just a symptom of a new part?

I hate when it doesn't come back the way I left it cause I know of every little quirk and now it's different. Just want to be sure I'm good before warranty runs out.

Nothing that I can immediately think of just from replacing VANOS solenoids. Most EFI systems do "surge" a very little bit on a cold start as the ECU feeds in extra fuel to start (like a choke on a carburetor) and then backs off once the engine fires. Probably just a consequence of the VANOS system working fully now, but just to be safe check to make sure that it doesn't get worse.

ZV

 

[SSSnail]

More or less, I guess? Some people consider a lopey idle to be glorious.

It's also possible there's way more to it than that. Like you said, solenoids either work or they don't. Maybe it was just sticky, and the ECU won't allow a start under those conditions? I'm not really sure.

But like ZV said, they found the problem and fixed it. Your diagnosis is indeed good and valid, it just seems it was the wrong one in this specific case. Nothing wrong with that.

Ah, must be the way I interpret things. I didn't know that changing cams is considered adjusting valve timing, I always thought that had more to do with duration rather than timing; since cams pretty much have to operate in sync with ignition timing. I know of the timing advance and retardation on cars with distributor caps, but that's not valve adjustment timing, right?

V-TECH just kicked in, yo.

 

[PricklyPete]

Hey Zemmervolt, you've always been a voice of reason and that is appreciated.

I'm not saying the OP's car won't be fixed by changing the VANOS solenoid, but considering all the other factors (mileage, car age, etc...) VANOS solenoid failure, though not out of the equation, is somewhat improbable.

Fearing the same issue with the VANOS issue, I rebuilt mine at ~55K miles (myself) last year (since then I've put roughly 45K miles on it) even though nothing was wrong with it. The common problems with BMW's VANOS assembly is that they use inferior material on the O-ring and teflon rings in the assembly, causing them to fail prematurely due to plasticize of the seals.Half a year after my VANOS was rebuilt the hard to start problem in the morning commence.

At first, I thought it was the fuel pump, but then after a bit of research, I found out that there's a seal in the fuel pump that use pretty much the same inferior material (call it planned obsolescence) which would drains the lines of pressure. So after the problem started, I tried to troubleshoot and couldn't figure out why, was very close to replacing my pump (but alas, I didn't). So now, I'm content with waiting until the fuel light goes out then crank my engine.

I'm not saying that it's 100% certain that's what's wrong with the OP's car, but I have a very good feeling that it might be the same, all things considered.

Sounds like you should have bought an Audi.

 

[SSSnail]

Sounds like you should have bought an Audi.

Lol, you made a funny. But nah, I'm an obsessive preventative maintenance kinda guy. OCD, really. 100k in and she purrs like a kitten. Of some of the things I've done, I know I'd have had to drop the engine a few times if it was an Audi.