Intermittent Starting

[BFEINZIMER]

From my other thread, no responces:

So sometimes, randomly mind you, the car will not start, it will just crank and do nothing, or if I hold it long enough, it MIGHT BARLEY come to life, or seem like it and die. So I usually just trun it off for a second or two, retry and it fires to life. Now, recently, sometimes it will start without me even hearing it crank. I turn and it comes right to life like everything is on steorids. I can't figure out why its doing either of these things. Anyone?

[31Hertz]

Crank Position Sensor?

[we_call_him_doher]

I think I have the exact same problem, with both the hard starting and "very fast starting". Hope someone can shine a light on what the problem is.

[BFEINZIMER]

From other thread:


When was the last time your fuel filter was changed?
-ashley

My autoshop teacher suggestuded that also...so I guess I'll replace it and see what happens...

[we_call_him_doher]

That might fix yours but just fyi, I changed my filter, still have the same issues.

[BFEINZIMER]

Really, **** well changing the filter can't hurt right? ANy other ideas?

[barry 90 525i]

i also have this problem, most of the time fires right up, but about every 10th time it wont start, have to keep trying and finally starts

[we_call_him_doher]

Well it definitely wouldn't hurt to change the filter, it just didn't fix mine. The weird starting doesnt happen very often, just every once and awhile.

[mamilapon]

Get an inline fuel check valve part # 16 14 9 068988 from BMA and look up the fitting procedure on the troubleshooting section of this site un M30 3.5 hot start pb. I just did mine and now it starts first time.

[BFEINZIMER]

I don't think its hot start problem its think its allthe time but I'll look into this. Thanks.

[we_call_him_doher]

Would the fuel check valve cause the weird "instant start"?

[mamilapon]

For some reason, if you try to start first thing in the morning, it'll start first go.(may be due to cappilliary action). But subsequently during that same day, you'll need a few cranks to get it going specially if you leave half hour between starts.Reason being after shutting down the engine the fuel slowly drains back to the tank through the faulty check valve. So you need a few cranks to bring the fuel all the way back to the rail before it starts.

[Felixdacat]

Replace the CPS. I had the same prob, and mine finally took a crap. I found mine for $84.00 from a place in florida. Plmmotors? I think they are vendor on this site, or Bimmer forums. Can't remember

[BFEINZIMER]

Replace the CPS. I had the same prob, and mine finally took a crap. I found mine for $84.00 from a place in florida. Plmmotors? I think they are vendor on this site, or Bimmer forums. Can't remember

As an update:

The car did the bad start issue sevral times today, I replaced my fuel filter a couple weeks ago which seemed to solve the issue.

2 questions:

What is the CPS?

And is this the correct fuel check valve?

http://www.bmaparts.com/item.wws?mfr=BOSCH&sku=BSH040188&price=250.78&orpartno=1106257&cookieID=1Y213SX3P1ZS1753FF&drillid=9&image=http%3A%2F%2Fcatimages2%2Esophio%2Ecom%2Fweb app%2Fwcs%2Fstores%2Fservlet%2Fimc%2Fimages%2Ftn%2 F0580464995%2Ejpg

And dam...$250 for that litte guy

[BillionPa]

thats the entire pump not the check valve. the valve itself goes inline with the fuel hose coming out of the sending unit.

the CPS is the crank position sensor, it determines ignition timing based on crank position. it is a little hall effect sensor at the front of the engine.

[BFEINZIMER]

o ok, i coudlent find the check valve on bma, ill just call tomorrow, but to my stupidity and lazyness, where is all this located? trunk area?

[RussC]

Intersting thread. Mine is a little hard starting when cold. I usally give it half throttle, and it starts after about 4sec of cranking. W/O the throttle input, it seems to take forever.

The E28 with M30b35 conversion starts up instantly all the time! I wonder if its the CPS? Ill have to look at that, and the check valve.

RussC

[Dave M]

o ok, i coudlent find the check valve on bma, ill just call tomorrow, but to my stupidity and lazyness, where is all this located? trunk area?

The dealer should sell you this for ~$10-15 if you have one handy. Again, its in-line on the suppy fuel hose.

Dave M