Car Only Starts After Third Attempt

Hello, all. I've got a problem that's got me stumped, and I can't find the answer through searching this forum. I've got a '96 328ic automatic. I recently had a trouble code come up, and it showed the problem as the cam position sensor. I replaced the sensor, and the car runs great except for one thing...it will not start until the third attempt. When the engine is cold and I crank it, for 5 seconds or so, it's just like it's not getting any spark. The second attempt yields a bit of a cough. On the third try, it fires right up, and idles and runs just like it did when I first bought it. What is happening that would require three start attempts? I'll need a new starter soon at this rate. Thanks for any help you can give me.

Maybe fuel pump or sending unit.

Will it still only start on the 3rd attempt even when the engine is already warm (say if you park the car for 15 minutes and then return to it)?

No, it will fire right up on the first try when the engine's warm.

If that's the case, it's possible that you have a slight pressure loss somewhere in your fuel system. My theory is that after the car has been sitting for a while, it loses all fuel pressure and needs to be cranked over for a bit to build it back up. If you are only away from the car for a short while, not enough pressure will escape to cause starting difficulty, and everything appears normal.

Just an idea.

Sounds like fuel pressure alright!

Check for leaks. Maybe replace fuel filter?

Getting a fuel line pressure gauge is only ~$20. Might as well know for sure.

Thanks, guys. I'll check into that. I hadn't really thought about that. I once let it crank for about 10 seconds, and still got nothing indicating it was about to fire. I can do really short bursts on the first two attempts, and then it will start on the third. I appreciate all the help I can get!

Bleeding injectors could be the cause. Check also for spark when your cranking, maybe you have a faulty cam position sensor, or maybe its just a bad connection to it.

What was the car doing before you replaced the cam sensor? Did this start immediatly after the install???

good question corey (you'll be on your way to top tech soon enough)

it could be fuel related, but if so, then an extended first crank (of the 10 seconds or so) would (at least in theory) circumvent the need for 2 additional attempts.

a fuel pressure test, as well as a fuel pressure leakdown test would be able to confirm this.

if it does this like clockwork when cold, then there is sufficient window of opportuity to verify the cam signal (with a power graphing meter) while looking at fuel pressure on initial cranking.


df

I know what the OP means, my 2002tii does exactly what he has described. I figured it was fuel pressure or something along these lines (no pun intended) but haven't had time to figure out for sure what's going on.

Try this. Turn ignition to on position and wait 60 seconds, then try starting. Fuel pump comes on when ignition is in on position and if pressure is slow to build it should do it even in 60 seconds and the engine should start the first time it's turning over.
If it doesn't start with this then it's probably not a fuel pressure issue.
You should still do a pressure test to confirm it, but it will put it as a less likely cause.

I was really hoping you guys had solved my problem, but to no avail. I went as long as a minute with the key in the RUN position, then turning it to START. It still does the same thing: a long crank with no hint of starting, and ending with an easy start on the third attempt. I'm stumped.

You never answered any of my questions...

Instead of turning the key on for 60 seconds, turn the key on for 4 seconds then off, then on for 4 seconds then off, then try to start it. If it starts its a fuel pressure problem. most fuel pumps are only energized by the ignition 2-3 seconds when the ignition turns on then the engine controller shuts it off until it detects an rpm signal from the crank sensor, then engine controller then turns the fuel pump back on.

If its not the fuel system then I would suggest answering what Corey asked because what your describing sounds like your not getting a cam signal. How long do you attempt spinning it over while its cold, have you tried spinning it on first attempt for 15-20 seconds?

^ Most pumps only run for 5 sec (prior to a running engine) to avoid extra heat and wear (and besides, a car that runs well DOES NOT need more than that as there is NO advantage). Cycle on for 5 sec... etc. as started above.

Have you pulled the plugs? Someone mentioned a bleeding injector (Leaking fuel; injector). It would bleed the fuel into a cyl, and can cause a 'pig rich' condition making starting difficult. You may have one plug with much more carbon build up than the others (but you may not. Plugs alone will not rule out a leaky injector).

How old are the plugs (for reference with the result of the plugs when you view them)
How does the car run once it is started?
How does it idle? How does it run at part throttle at various rpm, full throtle at various rpm?
How long has it been acting up for?

Originally Posted by Corey Milne

Bleeding injectors could be the cause. Check also for spark when your cranking, maybe you have a faulty cam position sensor, or maybe its just a bad connection to it.

What was the car doing before you replaced the cam sensor? Did this start immediatly after the install???

Sorry Corey. Before the code popped up from the "check engine" light saying the problem could be the cam position sensor, the car would fire right up. It then became sluggish to start, but would still start after 5 or 6 seconds. Also, the car was really down on power, but still ran with no engine miss. It was almost as if the timing was retarded 5 or 6 degrees. (I'm harking back to my mid '70's small block Ford days). After changing out the sensor, the car has really come to life, once it's running. I'm sure that was my problem, but that's not to say that I've not developed another one. I haven't checked for a spark when cranking, but the next time I've got a helper, I will. I'll try the 5 seconds on, then off, then on, etc. I really appreciate you guys' input on this. You've already given me ways to look at this that I hadn't thought of.

Originally Posted by Raw Steel

^ Most pumps only run for 5 sec (prior to a running engine) to avoid extra heat and wear (and besides, a car that runs well DOES NOT need more than that as there is NO advantage). Cycle on for 5 sec... etc. as started above.

Have you pulled the plugs? Someone mentioned a bleeding injector (Leaking fuel; injector). It would bleed the fuel into a cyl, and can cause a 'pig rich' condition making starting difficult. You may have one plug with much more carbon build up than the others (but you may not. Plugs alone will not rule out a leaky injector).

How old are the plugs (for reference with the result of the plugs when you view them)
How does the car run once it is started?
How does it idle? How does it run at part throttle at various rpm, full throtle at various rpm?
How long has it been acting up for?

I'll pull the plugs this weekend and see what they look like. I've got about 20,000 miles on them, so I would think they'd be OK, but I'll still check. The car runs great once it starts, idles as smooth as silk, and no issues at all at part throttle, all the way up to 6 grand or so. The hard start has only been since the cam position sensor was replaced.

Some cars need to "Re-Learn" when a new cam or crank sensor is installed. I am new to BMW. I have no idea if this car needs to re-learn. While many will run without learning they will not run correctly (rough / misfire / hard start), others may not be noticeable. Some cars will learn the sensor automatically. Many need to go through a specific re-learn procedure (sometimes with Dealer only scan tools).

Can anyone inform us further on how the above applied to the E36 and more importantly an ODBII version? (as all cars as of 96 SHOULD be ODBII). ODBII is FAR more likely to need to relearn a sensor.

the only time i have ever had to 'relearn' anything was when the battery was disconnected. if this was told to you by a technician i would ask to see written verification of this as this would be the first i have heard of it in relaton to a cam sensor replacement.

one could also argue that the vehicle is always 'relearning' as the parameters are constantly changing as one drives, but as i understand it, it is simply the long term and short term fuel trims. this also (iirc) gets reset when sing a non proprietary scan tool or code reader that has the ability to clear codes. they tend to clear all data to this effect.

if it were to be something like this, i would suggest disconnecting the battery, but my gut feeling is this may not do anything.

when you replaced the cam sensor, what did you wind up removing?? could you have happened to dislodge something along the way??


df

I did check the plugs today, and they were in great condition. I also tried the "turn the key on three times" bit. This morning, sitting in the garage at about 75 degrees all night, it still took two cranks to fire, but this afternoon, after sitting in 85 or so degrees for nine hours, it fired the first time. I'm still not sure what that means, but at least it seems like progress. Thanks for all the advice, gentlemen!

I would still check the fuel pressure. Maybe a long shot but you could have a vac leak?

Hi guys I'm new here I'm from south africa durban I bought
Myself a 98 318is with a m44 engin I had the engin done up
Now after a few weeks I picked up a misfire which isn't
Constant or isn't predictable I'm not sure were to start
1 thing for sure it looses all acceleration and it takes a few secs it misfires sumtimes on start up. Or while driving
Then a few times randomly any suggestions
Thanks

Originally Posted by beemer rookie

Hi guys I'm new here I'm from south africa durban I bought
Myself a 98 318is with a m44 engin I had the engin done up
Now after a few weeks I picked up a misfire which isn't
Constant or isn't predictable I'm not sure were to start
1 thing for sure it looses all acceleration and it takes a few secs it misfires sumtimes on start up. Or while driving
Then a few times randomly any suggestions
Thanks

You should your own thread so it doesn't get mixed up with helping the OP

So did you figure out what the problem was?

My '97 328is is doing the same exact thing.