starter and ignition question

[nextelbuddy]

my new to me 4.8is had the fuel pump replaced 2 years ago for $650ish dollars...it died on me a few days after taking ownership. I removed it and found that they did not use an OEM fuel pump, it was a generic 3rd party pump that had no markings on the pump itself. literally a no name brand pump and sending unit for $600+ dollars what? lol

ordered a replacement pump and sending unit for $305 from fcp euro but now the car has an issue where on cold starts it starts up perfectly and of the engine is warm/hot then it takes a LONG time to start.

my issue also is i dont have to hold the key in ignition III to keep the starter going, the starter seems to run on its own until the engine finally starts or it gives up after X amount of tries until i try again.

i will be addressing the fuel filter soon (waiting on the part from FCP Euro) and that should resolve the long start issue

but is the starter supposed to keep running on its own until it detects the engine has caught and started?

none of my e46 ever did this so if its normal then its new to me lol

[andrewwynn]

I think the e53 with the high cluster runs the starter for xx seconds. Mine does not but I did a side by side test with a buddy with the 4.4 and high cluster and it will hold the starter running for a bit. It's not fully automatic I think it just runs for a bit of time.

If it's taking longer to crank usually one of three things: starter wearing out and pulling too much current, battery worn out and can't deliver full current or a loose connection is dropping voltage.

If you have a peak reading DMM you can measure the voltage drop from cig lighter to the B+ jump under the hood. Multiply by 185 and you'll get a fair appropriate current draw of the starter.

It should be about 225-250A max I believe on the V8. I have the 6 and pulls less than 225.

[andrewwynn]

FPR is very very rarely at fault in these situations.

Do you wait for the fuel pump to charge before turning to start? Eg. Click the key to the on position and wait for the him to stop under the back seat. Then turn the key to start.

If your warm start is within 30 minutes the fuel pressure should hold at 50 psi. You can check with an tire pressure gauge as long as you have one you aren't too concerned about being perfectly accurate for tires. I'm not sure what gas will do to the internals but my spare digital gauge read 49.5 on my fuel rail when I checked it.

Not sure why cold start is more reliable unless the auto start runs longer on a cold start.

My first suspect is the one way valve on the pump is not holding pressure when not running. If you wait for pump to charge before starting and it starts more reliably then even more likely.

Check the fuel rail pressure while idle should be 50psi. Then check after it's been sitting 30 then 60 minutes.

Get the battery tested for CCA and try to get a current reading on the starter.

About 20-25% of the threads that start like yours it's the starter. I've seen at least five cases where somebody replaced the battery the alternator and the fuel filter / FPR before they finally discover it was the starter the whole time.

When the starter soft fails it will slowly take more and more current to operate. It loses more voltage on the wire and internal battery resistance so less voltage so slower crank.


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[nextelbuddy]

Originally Posted by andrewwynn

FPR is very very rarely at fault in these situations.

Do you wait for the fuel pump to charge before turning to start? Eg. Click the key to the on position and wait for the him to stop under the back seat. Then turn the key to start.

If your warm start is within 30 minutes the fuel pressure should hold at 50 psi. You can check with an tire pressure gauge as long as you have one you aren't too concerned about being perfectly accurate for tires. I'm not sure what gas will do to the internals but my spare digital gauge read 49.5 on my fuel rail when I checked it.

Not sure why cold start is more reliable unless the auto start runs longer on a cold start.

My first suspect is the one way valve on the pump is not holding pressure when not running. If you wait for pump to charge before starting and it starts more reliably then even more likely.

Check the fuel rail pressure while idle should be 50psi. Then check after it's been sitting 30 then 60 minutes.

Get the battery tested for CCA and try to get a current reading on the starter.

About 20-25% of the threads that start like yours it's the starter. I've seen at least five cases where somebody replaced the battery the alternator and the fuel filter / FPR before they finally discover it was the starter the whole time.

When the starter soft fails it will slowly take more and more current to operate. It loses more voltage on the wire and internal battery resistance so less voltage so slower crank.


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i was going off of this thread for my long start issue.

https://xoutpost.com/bmw-sav-forums/...el-filter.html

the issues in that thread are exactly like mine where every morning Cold start is perfect, engine fires right up when i turn the key. if i turn the engine off after its up to temp and try to start it again it will take a long time to start unless i let the engine get cold again.

thats when i noticed I did not have to hold the key to keep the starter going but instead the starter just continued on its own until the engine started finally on hot starts.

[andrewwynn]

As upallnight mentioned in that thread and I mentioned, its symptomatic of the check valve in the pump failing. Even though you may do well to replace the filter+FPR assembly it's very very rare for them to fail. Having read dozens literally of threads where somebody replaced the FPR/filter only in about 3/40 cases was it actually the filter or FPR being the root cause.

It will for example help a weak fuel pump when the filter is changed it can be masking the problem.

I myself would definitely check the fuel pressure before and after the FPR swap.

If for example there is no effective change , or if as I suspect the fuel pressure drops when sitting hot, it's more often the check valve in the pump than the FPR but the FPR does fail, I'll be very interested to see the 4th of 40 cases that it actually was the filter / fpr.


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[nextelbuddy]

Originally Posted by andrewwynn

As upallnight mentioned in that thread and I mentioned, its symptomatic of the check valve in the pump failing. Even though you may do well to replace the filter+FPR assembly it's very very rare for them to fail. Having read dozens literally of threads where somebody replaced the FPR/filter only in about 3/40 cases was it actually the filter or FPR being the root cause.

It will for example help a weak fuel pump when the filter is changed it can be masking the problem.

I myself would definitely check the fuel pressure before and after the FPR swap.

If for example there is no effective change , or if as I suspect the fuel pressure drops when sitting hot, it's more often the check valve in the pump than the FPR but the FPR does fail, I'll be very interested to see the 4th of 40 cases that it actually was the filter / fpr.


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I'm sorry I'm not really understanding where you're trying to go with this. it sounds like you're saying that there's a check valve in my fuel pump is failing meaning I need to replace the fuel pump??

But I've already changed the fuel pump twice once with a unit from the local pull a part salvage yard and then once with a brand new one from FCP Euro.

Is there something else I'm not replacing in regards to the fuel pump with this check valve or are you saying that I got a bad fuel pump from FCP Euro I need to get another one?

[andrewwynn]

I'm saying the odds are actually better yes, that the new pump is defective than the fuel filter is plugged or that the FPR is defective. My guess is 8:1 odds. That said 1:8 odds it is the FPR or filter so not ruled out.

You already have the FPR coming but take some readings before and after so you know that you found the problem.

Definitely measure your rail pressure after 30 and 60 minutes. I forget what it's supposed to be but not much loss from 50 while running.

[oldskewel]

Originally Posted by nextelbuddy

my new to me 4.8is had the fuel pump replaced 2 years ago for $650ish dollars...it died on me a few days after taking ownership. I removed it and found that they did not use an OEM fuel pump, it was a generic 3rd party pump that had no markings on the pump itself. literally a no name brand pump and sending unit for $600+ dollars what? lol
...

LOL yeah! Amazing, isn't it. I found similar stuff all through my 3.0i, where the PO got ripped off time and time again by dealers and indy's alike. Un-necessary work done. Work that should be done skipped. Lots of jobs billed and not done. For my car though, when they actually did stuff, they almost always did use genuine BMW parts.

My pump wore out at 174k miles about a year after I got the car. It is made by Pierburg, which was later bought out by TI Automotive. So my replacement pump said Pierburg on the box, sealed with a hologram sticker, and then TI Automotive (and no Pierburg) was stamped in the aluminum body of the pump.

I cut open the failed pump and confirmed it looked perfect except that one of the brushes had worn all the way down. So it simply wore out. Predictable. I also saved the old one, and pulled it out earlier to look for the check valve.

The valve is in the top plastic portion where the fuel exits. When I tried to blow back into that tube, it's absolutely blocked solid. Very simple, but I can imagine if you got a non-Pierburg pump it's the sort of simple easy thing that someone might try to save a few pennies using cheaper materials that maybe melt in the presence of ethanol? Kidding, but not completely.

I changed my filter when I put in the new pump. Maybe un-needed, but I did it anyway. Good chance for you to inspect the brake lines, etc. down there.

Good luck. No real advice from me here, just some info that might help.

[andrewwynn]

I would never veto a fuel filter swap over 150000 miles but caution any expectation of the filter or FPR being the root cause of a problem.

I have a problem now where my left sender unit reports more gas than actual.

I

That's 10L more than possible.

The only time I know how much fuel I have is when I have 29L. When more or less is just a guess.

There is a TIS about the issue and fix so I'm hoping I can fix and add to my siphon jet repair thread


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