Spluttering when turning over

[Maxxxer]

I'm having a bit of an issue with the above - essentially my battery went flat a couple of weeks ago - went to start, nothing at all. So, charged the battery up overnight and it starts, albeit with a bit of effort and on the second turn of the key.

Prior to it going flat it started on the button with no issues, so i initially put it down to a combination of the cold weather and having stood for a while (only 6 weeks or so, but i had been mucking about changing the seat bushes and suchlike, so I'm not surprised the battery was flat).

I took it for a spin yesterday to put some fuel in, it struggled with coughing and almost turning over the first time, then second time it started. Its a bit lumpy on idle when cold, but once warmed up its seems to be fine (runs well enough without issues).

Earlier today I've taken it out on a run of mixed roads over around 27 miles, and just took it out for a spin to see if started any better - still the same.

Any ideas? I've not changed anything since the battery died (other than the aerial base grommet and removed the headlights to fit halo's (which aren't yet wired in)) so I'm at a bit of a loss.

It's a '98 2.8 Auto if that helps....

 

[colb]

Get a code reader on it and see if its set any codes that may point you in the right direction.

 

[mrscalex]

Get a code reader on it and see if its set any codes that may point you in the right direction.

The point being the battery may be a red herring.

 

[NZ00Z3]

Bad idle when cold but OK when warm tends to be a vacuum leak.

Check the rubber boots between the MAF and throttle body for cracks and breaks. Similarly any rubber hoses and the CCV system.

If you have a scanner, look for lean codes. Also check the short term fuel trims when the engine is hot. If they are >8% you are likely to have a vacuum leak. Rev the car to around 3,000 rpm for approx 30 sec. If the short term fuel trims drops, then it confirms that you have a vacuum leak.

 

[Maxxxer]

Ah OK i can look into that then. I need to get myself a code reader (could borrow one but for £30-40 its worth owning one i think!). Will report back once I have both bought one and hooked it up to read the codes. I suspect I've nicked something when refitting the lights somehow, but where I have no clue...!

 

[mrscalex]

Ah OK i can look into that then. I need to get myself a code reader (could borrow one but for £30-40 its worth owning one i think!). Will report back once I have both bought one and hooked it up to read the codes. I suspect I've nicked something when refitting the lights somehow, but where I have no clue...!

Well now you mention that I would start in the area of the MAF and work back from there. You could have opened up some rotted bellows. The MAF connects in around the headlight.

 

[Maxxxer]

So an update on this - after realising the rubber pipe behind the MAF was a cheap (possible) fix i replaced it along with cleaning the inlet butterfly to see if that would help. No change.

So, I decided to break out the code reader I bought recently - impressed with how easy it is to use, and after initially getting the MAF, camshaft and crankshaft sensor codes (makes sense as I'd had the MAF disconnected to swap the pipe out), I cleared them and started the engine, let it tick over then turned off.

The only one remaining was 53 Crankshaft sensor, which, looking at the numerous threads on here associated with that error, it seems about right - same symptoms of being down on power, struggling to start and being lumpy at cold.

So - I need to get a price from Sopers for a replacement (as I understand pattern part copies of this is a waste of time) then figure out if i can tackle it myself or get it done at a garage.....

 

[colb]

Item 17 in the diagram here
http://www.realoem.com/bmw/enUS/showparts?id=CJ33-USA-06-1998-Z3-BMW-Z3_28&diagId=11_6172

OEM part is the way to go either Bosch or Seimens, don't buy cheap pattern parts you will end up pqaying twice, been there done that!!

Should be doable may need to strip down the intake manifold to get at it or find a child with small hands!!

 

[Maxxxer]

Cool - it looks easy enough according to the Pelican Parts guide (although 3 hours and 4 spanners doesn't sound that easy );
https://www.pelicanparts.com/BMW/te...ent/37-FUEL-Crankshaft_Sensor_Replacement.htm

If it can be done on the drive in a couple of hours I'll give it a go (got axle stands and a decent jack so no worries getting the car in the air). Otherwise I'll send it off to my local (to work) garage and let them deal with it....

 

[Eddie Zedder]

removed the headlights to fit halo's

Going off topic here, but just interested to know whether you have fitted ccfl or led halo rings and where you got them. One of mine has given up the ghost .

 

[Maxxxer]

I followed this guide
https://zroadster.org/threads/fitting-angel-eyes.25021/

Although I've not yet got round to wiring them in - all in place ready to go, but not had chance to splice them in yet (not least due to other things taking priority).

 

[Eddie Zedder]

I followed this guide
https://zroadster.org/threads/fitting-angel-eyes.25021/

Although I've not yet got round to wiring them in - all in place ready to go, but not had chance to splice them in yet (not least due to other things taking priority).

Thanks, they're the same one's I have fitted. I was hoping that you had come across some LED ones specifically for the Z3.

 

[Maxxxer]

@colb Isn't that item the camshaft sensor and not the crankshaft sensor?

Happy to be corrected if that's the part i need (and not the crankshaft sensor) just that i want to make sure I'm ordering the correct part....

 

[Maxxxer]

Just to double check (if anyone can clarify) I believe its part number 9 in the link below;

http://www.realoem.com/bmw/enUS/showparts?id=CJ32-EUR-02-1998-Z3-BMW-Z3_28&diagId=11_6173

???

 

[colb]

Sorry pointed you to the Camshaft sensor, Crankshaft sensor is item 18 in this diagram
http://www.realoem.com/bmw/enUS/showparts?id=CJ33-USA-06-1998-Z3-BMW-Z3_28&diagId=11_1651
Should be able to get to it from underneath the car by the look of its position on the side of the block.

If the Camshaft sensor code has not returned and the crankshaft sensor code is the only one setting then more than likely the sensor is duff and may have contributed to setting the other codes which so far have not returned. Most common of the sensors to go bad are the camshaft sensors.

I just saw you posted with a link to another diagram showing crankshaft sensor mounted on timing case. I checked oem agains a 1998 2.8 built June 1998 which showed it on the side of the engine block. Make sure you enter your last 6 digits of your Vin number on the oem site to make sure you are seeing the correct parts listing for your actual car. Seems to me there are differences in engines on the 2.8 having come up with two diagrams showing crankshaft sensors. The June 98 build I checked had the sensor greyed out on the timing case one idicating it was not fitted there on a June 98 car. Double check what you have using your Vin number.

 

[Maxxxer]

Cheers for that @colb - just noticed in the diagram I posted its for up to 03/1998 (mine was made in Jan '98) and yours states from 03/1998, so I think we do have different models.

I've inputted my VIN on RealOEM, so I'm reassured its the right part (plus its the same diagram as the chap at Sopers sent me, so i just wanted to check I was talking about the right part!).

So my next question is - being as all the videos and guides I've seen suggest it is located on the right side of the engine below the starter motor - is it there on mine, or is that from June 98 onwards....?

If anyone has done it on a 2.8 up to a March 98 model, please do let me know...

 

[colb]

I would go with the position shown on the diagram against your Vin number, to be certain make a visual check to locate it, preety sure Sopers would have checked against the year of build, did they check against your Vin number?
I reckon yours will be on the side of the engine block under the starter motor accessible from underneath the car, use axle stands when you have it jacked up and get under there.

 

[Maxxxer]

Thankfully they did - sent them the reg and VIN, and he came back with the diagram copied in the reply as per the one i posted above.

If its under the starter motor then I'm happy with that, as long as I'm going in to the right place to begin with - last thing i want to do is go in to take it out and find its somewhere else...!