Losing Fuel Pressure after shut down.. FPR or Injectors?

[Madhatter]

If you ever suspected the injectors, just check your oil. You'll smell of fuel and the level will usually rise as the fuel contaminates the oil.

Mine used to go up about a litre of oil every couple of months before I swapped out for a new set of injectors.

[Alex Mc]

I just finished replacing the blue stock injectors with green M50 injectors. I also swapped in an ECT sensor despite it testing out previously.

Of note, I also swapped the stock eprom for my hot chip..

Anyway, car cranked perfectly and has run fine for 20 miles. Hot start tests out great with a short crank time. Let's hope she's fixed!

[Alex Mc]

After 3 days of driving I am an say that the starting/loss of fuel pressure issue was definitely a leaky injector. Engine runs great now.

[studawg]

Good thread, thanks for posting the results, I think I may have an injector issue....

[Quinthirty]

I actually experienced this drop in fuel pressure resulting to hard starts. I noticed that the line connected to the FPR needed some tightening. No more hard starts.

[digger]

i had a similar issue the engine would crank for a while on a hot start (ie when upto temp turn it off and try start again 5-10 min later crank, crank, crank....)

i had fuel pressure decaying to zero after considerable time 30min or so.

i checked ECU, FPR, pump and not until i replaced the injectors (borrowed a set for testing) and problem solved

during trouble shooting i sent the "faulty" ones to be cleaned and check and no problem were found.

the newer injectors that solved the start issue still behaved the same in that pressure decayed even though they weren't leaking.

not sure it matters about pressure falling since the pump is primed for a second or so when you put ignition on (IIRC)

there was something about the old injectors that didnt like a hot start but never found out what actually was going on just that newer injectors did the trick.

[Nutzy]

I have no check valve, pressure in the rail is like zero pretty much straight away. The motor starts instantly, even after a month of no use.

Good to see you found the culprit.

[TC Baur MD]

+1 for m20 ---> rebuilt M50 injectors. What a difference. Bought mine here

http://www.ebay.com/itm/BMW-E36-M3-325i-525i-323is-528E-Fuel-Injectors-M50-M52-Upgrade-for-M20-Engine-/201000247575?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ecc8c6117&vxp=mtr#ht_2336wt_921