https://youtu.be/IyRaz1q9HEM?si=ikZwuoHyqUeTPKNx

The 3.0 version of e53 should run the fuel pump for about 6 seconds at key on. Note that the pressure does not drop before I crank the engine.

The comfort start models act differently and maybe your 3.0 has the more advanced start. (you can tell because the car will keep cranking when you release the key from crank position).

In any event the video above is after replacing the FPR. The bad FPR had the shaky needle at idle. Had handfuls of odd random misfire and occasional long cranks before the replacement.

After replacing the FPR the needle was rock steady at idle. At the autopsy was when I discovered the o-ring was toast and almost certainly the only problem. I could have just replaced 30¢ o-ring vs. $75 fuel filter plus FPR.

I didn't mind though the fuel filter was getting pretty full. Cut that in half to check and yeah it did it's job charcoal colored fuel on the dirty side it was very dirty. I think the odometer was about 160-170,000

If you haven't realized already, andrewwynn's vibrating needle, FPR o-ring theory is a load of crap.

Except it's exactly what happened. Those are the before and after videos from FPR swap and the only defect found post mortem was a horribly defective o-ring.

I am in fact correct far more often than I'm wrong. Prove me wrong. Fluid only flows from high to low pressure very simple laws of physics. FPR works by having excess pressure that is held back to release a regulated pressure. This means there is higher pressure coming from the pump than is coming out of the FPR. If there's a leak in the feedback it's not going to function as designed that's exactly what I measured.

If you have a better explanation for the measured results that came along with a fixed car then share them and be less of a ass while doing so.

The air intake runners show no sign of oil. Right where the runners connect to the side is where the seam can leak.
The inside looks normal for a high milage intake. I was surprised how clean mine was except for the DISA area.

Locally, a shop charges $125 for a smoke test.

My money is on an undetected vacuum leak…

you can get a decent unit for $100+, but you'll need peripheral equipment
 

from another thread, just now I agree with Effduration, it would be better to have a professional shop do your smoke testing, rather than piece together a homemade tester (in my case, a sauerkraut jar + soldering iron + $7-10 manual siphon pump), or make one that you have to blow thru a hose to furnish the air. I wasted money making my failed tester (twice), time doing that, and more time ordering and sending back two Chinesium cheapo testers; finally, I bought a decent one on Amazon (third time's is a charm), in November, but only got around to testing it today (preliminary to the actual smoke test, just to see if it works..it did).

I'll have to get a sealing bladder to keep the smoke in (unlike Lucas Electric equipment, famed for letting the smoke out, haha). That'll add another $25+ to the $101+ I bought the tester for (Black Friday deal, plus I got Amazon to throw in $25 credit, due to the fiasco caused by my previous two tester orders...it was a differnt brand). So, in all, I will have spent $101 for the good tester + $25 for the sealing bladder I'm ordering, minus the $25 I was credited...equalling $101 for the complete test outfit I'll use.

Of course, the same tester is up to $120 now, + $25 for the bladder ($145 total), but that doesn't include a compressor at home (which I would assume most of us DIY'ers have, mines a Husky 20-gallon), but I'm not adding that into the cost to test. If one doesn't have a compressor already, Autoline offers the same tester, but it has a small air supply attached, for another $10 @$130 (bringing the cost to test up to $155).

So, why didn't I get my BMW tested at a pro shop?

• 1) there are no BMW Indy shops within 40-50 miles (except for one that is a glorified tire shop/ricer shop),
• 2) the two local shops I went to last year (general mechanics) quoted me $150 and $160 for a smoke test, and
• 3) I have five old vehicles that need maintenance off & on, including emissions and engine bay smoke tests (I've had to redo several Evap systems at home, had to test & replace leaking gas caps, too, and now the intake smoke test on the X5); whereas I used to have a friend, back in the day, that had the gear at home, now I will, so I the gear I've bought should pay for itself several times over.

I could be wrong, and might never find any leaks, nor have to repair Evaps again, but at least I'll have the gear, which I can pass on, later, to friends or relatives.

Some less common air/vacuum leaks on the M54... one or sometimes two small vacuum caps on the rear of the intake manifold; they split and fall off. The tubing/vacuum valve that controls the secondary air pump is also back there. Dipstick o-ring where it enters the oil pan. The vacuum tube leading to the fuel filter/FPR splits; this leak will only be visible under the car. Any/all of the CCV hoses can crack.

I have a $50 smoke tester; the paint gun+regulator type and it works great to find leaks.

For sure! Mine had two with real back cracks. I'm surprised it didn't set any codes.

+1 for "paint gun+regulator type" smoke testers
 

Since I was unsuccessful at sealing-off the intake tube, I was unable to keep the smoke flowing further down the line in sufficient quantities to spot any leaks. I was stuck holding the vinyl/rubber glove in place (before the eventual leak), so I couldn't move to look at the rear of the engine, the SAP system above the exhaust manifold, nor underneath the truck at the fuel filter/FPR system.

I also couldn't see down to the dipstck O-ring connection, but I had a close look at the DISA, ICV, intake manifold (with the cover still on, unfortunately), and the flexible air intake tube, and saw zero leaks. I did say that I had 10+ minutes of smoke before the glove split, but that was probably closer to 3+ minutes, in actuality. Not enough time or smoke for a detailed exam.

I'm pleased with my Autoline $100 "paint gun+regulator type" smoke tester, used in conjunction with my 20-gallon air compressor, but the 4-mil Nitrile gloves just weren't working well enough in this application; a purpose-built "Universal Bladder Adapter" should solve the sealing problem. I will still have to remove the cowl cover. though, to be able to adequately view the rear of the engine, especially the two caps and the SAP vacuum control valve back there..

You can double/triple the glove


Sent from my iPhone using Tapatalk Pro