96 328i hard start part 2 "now with video."

[DotBeta]

So I made a thread a couple weeks ago regarding my issue but it wasn't very well put together and ended up going nowhere so I decided to make one more with a more comprehensive OP and a video in hopes it helps you guys help me diag this drama.





Here is the video I made this morning showing the hard start with a description of the symptoms, unfortunately it fired up quicker than usual so it doesn't show the full extent of how long it cranks at times. On the other end I was fortunate enough to catch the semi long crank and stumble before actually firing up. Sometimes it will just crank the whole 10 seconds and start right up, sometimes it will stumble as if it's trying to start but not fully turning over. It'll usually hard start more often once the car has been warmed up. Either way the end result is no code and the car runs perfect the rest of the time. Normally it literally takes one crank to start like a new car, instant start.

so far I've replaced the crank sensor 3 TIMES in the past 2 weeks, The first 2 being import direct crank sensors that I ended up returning and the one currently in the car Which is an OEM BMW Seimens crank sensor, the results haven't changed a bit between the 3 sensors so I can say with confidence it's not the CPS.

I pulled the fuel rail and primed it but saw no fuel leaks of any kind, replaced injector filters, pintle caps, O-rings and spacers for good measure. I also replaced the fuel pressure regulator in the slight hope it was related and to get better gas mileage if the diaphragm was busted but no change whatsoever.

On the ignition side of things I've replaced the plugs with stocker copper NGKs and the coil boots, coils are still the original ones but I haven't noticed them misfire or run odd in any way once it's fully up and running.


p.s. the check control light is telling me my washer fluid is low and my tail light is out, but they're both fine :/.

[DotBeta]

First and last bump.

Unsure if yall hate my threads or if you're all truly stumped lol.

[Eric93se]

so you say you replaced the crank sensor 3 times? why did you need to do it 3 times? Also not sure if your may confuse the crank and cam sensor, the cam is the one that very typically fails, its located up top while crank sensor is located below the starter.

So you need to scan for codes with an OBD2 code reader or better yet get an old windows XP 32bit laptop and put INPA on it. You have to buy an INPA cable off ebay for less than $20.

Common no starts (or intermittent) are bad fuel pump, cam sensor, bad relay (fuel), clogged fuel filter. You replaced the spark plugs, be sure to inspect the air filter.

The cam sensor is for fuel at the injector, the crank sensor is for spark, so if you can determine which one your not getting.

- - - Updated - - -

Also, do not crank your engine for long periods, you will ruin the starter and the battery. The starter is not fun to replace.

[DotBeta]

so you say you replaced the crank sensor 3 times? why did you need to do it 3 times? Also not sure if your may confuse the crank and cam sensor, the cam is the one that very typically fails, its located up top while crank sensor is located below the starter.

So you need to scan for codes with an OBD2 code reader or better yet get an old windows XP 32bit laptop and put INPA on it. You have to buy an INPA cable off ebay for less than $20.

Common no starts (or intermittent) are bad fuel pump, cam sensor, bad relay (fuel), clogged fuel filter. You replaced the spark plugs, be sure to inspect the air filter.

The cam sensor is for fuel at the injector, the crank sensor is for spark, so if you can determine which one your not getting.

- - - Updated - - -

Also, do not crank your engine for long periods, you will ruin the starter and the battery. The starter is not fun to replace.

I replaced the crank sensor 3 time because after replacing it the first time people on and off the forum said OE sensors commonly fail or are bad from the get go so I warranty exchanged it to make sure, after the second one didn't change anything I just said screw it, returned that one and bought one from the dealer so there is no doubt. The cam sensor is also new and when is bad causes the injectors to batch fire which has a very distinct sound, it had a bad cam sensor when I bought it so I replaced it, works fine now.

I've scanned it several times with an OBD2 scanner but no codes are logged or pending. I'm gonna be getting the INPA cable very soon.

I'll have to keep an eye on the fuel pressure on start up but I am almost positive it's ignition related at this point.

[Eric93se]

What do you mean, keep an eye on fuel pressure? Have you hooked up a gauge?

With the car off (don't try to start it), remove the fuel pump relay and jumper it to start it, try it a few times to make sure it runs each time, you should hear it run. Do it correctly, don't jumper the wrong pins, check old posts from flyfishvt.

You can also test the relay, remove it, get a12v power source, energize the coil with the +/- 12v, while energized use a multimeter to measure the resistance across the other set of contract that are the switch. But your problem is probably not the relay since the car does start.

[RobinME28]

This is exactly how my car starts: hold the key, it will crank for some seconds (sometimes 5 sec, sometimes longer) and then it will start but very hesitant and almost like each cylinder "wakes up" on each own...

Tomorrow I will film this whole event and I will make my own thread so I don't spam your post

[JDStrickland]

267,000 miles on a 20+ year old car. Me thinks you protest too much.

[jc43089]

Mine starts like a new car and it has 273k on it. It did start somewhat lazily before I replaced the fuel injectors. I swapped to Bosch EV6 injectors too.

[bluptgm3]

I've taken to turning key to "On" position, pausing, then energizing the starter. Fires right up now at 260k miles. If I insert key and immediately twist to energize starter it will crank a bit before starting.


Sent from my iPhone using Tapatalk

[DotBeta]

267,000 miles on a 20+ year old car. Me thinks you protest too much.

If it was a couple cranks I wouldn't worry about it so much and blame it on age, but it can sometimes take several turn over cycles to start so I don't burn out the starter. Before the issue started it would take 1-2 cranks before starting without a hiccup. The symptom started right after a drive up and down the mountain but it was under normal driving condition I wasn't pushing it at all.

I still have no idea what it can be.

[JDStrickland]

Well, you have a fuel pressure regulator that ought to act like a check valve. If it was leaking down, then you have a situation where you are waiting for the fuel pressure to rise. BMW says that if the car starts in 20 seconds then it is okay. I get that it has never taken so long until recently, but you are at a cross road where what's wrong and why do not intersect.

If you could test the static fuel pressure, you might be on the road to figuring this out. You would need to put a pressure gauge on the shrader valve and see what the pressure is when you park the car, then in the morning before you start it, see if the pressure is the same.

[DotBeta]

UPDATE:

Well I figured it out the hard way lol. Was doing the deposit for my job earlier today and when hopping back in to get back the car was hard starting, this time it would chug and struggle to start but wouldn't turn over as usual, but this time it wouldn't start at all. Spent sometime diagnosing spark and ignition and everything looked good. Used a little ether to try and start it and it fired up in one crank then died shortly after.

Fuel pump is bad, replacing it as we speak, pressure tests never showed signs of pressure dropping on cranks so in all honesty maybe it's just coincidence and the problem will persist after I replace it, just crossing my fingers and hoping for the best.