Please help, Injector leak, or is it?

[nariusb]

WTF?
I'm tracking the residual pressure leak to solve long cranking. I changed FPR to new, changed rubber fuel lines, no gas smell below the car, replaced BMW check valve fix AGAIN. Replaced injectors to Five-O Denso ones.
Still loosing pressure.
So I took out the fuel rail and charged it with fuel relay activation trying to find injector leaking from the nozlle, found two. I found two from my original ones that were NOT leaking. Charged again and waited overnight.
Now, get this, NO leaking with fuel rail/injectors out of the manifold.
I put it back together and resid. pressure leaks out in 2/3 hours.
My question: is there some kind of electrical triger making injectors open up?
What else am I missing. There's nothing else left to change!

[nariusb]

I know that the inlet of the injector is exposed to fuel rail pressure and outlet of the injector is exposed to manifold vacuum, about 15 inches of Hg or -7.3 psi at idle.
Would this vaccum & pressure make injectors that don't leak out of the manifold leak in the manofold?


WTF?
I'm tracking the residual pressure leak to solve long cranking. I changed FPR to new, changed rubber fuel lines, no gas smell below the car, replaced BMW check valve fix AGAIN. Replaced injectors to Five-O Denso ones.
Still loosing pressure.
So I took out the fuel rail and charged it with fuel relay activation trying to find injector leaking from the nozlle, found two. I found two from my original ones that were NOT leaking. Charged again and waited overnight.
Now, get this, NO leaking with fuel rail/injectors out of the manifold.
I put it back together and resid. pressure leaks out in 2/3 hours.
My question: is there some kind of electrical triger making injectors open up?
What else am I missing. There's nothing else left to change!

[632 Regal]

not when the car is off, which as I read is your problem.


I know that the inlet of the injector is exposed to fuel rail pressure and outlet of the injector is exposed to manifold vacuum, about 15 inches of Hg or -7.3 psi at idle.
Would this vaccum & pressure make injectors that don't leak out of the manifold leak in the manofold?

[nariusb]

Thanks Regal for you reply, that's what I suspected all along. I have to assume that Five-O injectors, they are Denso, are driping at the nozzle. When I asked them about it and they replied that a little drip at the nozzle - doesn't mean there's something wrong with it. But it is! My residual pressure is gone, hense hard starting. They must have been reconditioned ones.


not when the car is off, which as I read is your problem.

[632 Regal]

ok, my car doesnt fire instantly either, I turn the key to the on position 3-4 seconds before turning it over and it makes a world of difference on mine.

Hope this helps.

[nariusb]

Your fuel pump, Regal, probably works when key is in ignition ON position. My fuel pump only works when cranking. I have 89 525i m20. So there's no difference for me with waiting. Just to mention, that the car will grab or start grabbing instantly and start occasionally. I can't see any pattern though.


ok, my car doesnt fire instantly either, I turn the key to the on position 3-4 seconds before turning it over and it makes a world of difference on mine.

Hope this helps.

[nariusb]

Lets' take a survey here. Who has an instant start and who has to crank from 2 seconds and longer, especially on m20 engine?

[DaveVoorhis]

I'd say mine averages less than a second of spinning 'til start. WuhWuhWuhWuhWuhVOOOM! Like that.

[Alexlind123]

My new injectors are in, and i had the long crank problem. I will tell you if they fix it.

[nariusb]

Please let me know. I'm getting some new 19lb ford injectors and 535i AFM mode done in the next week or so. I also hope to fix the problem.


My new injectors are in, and i had the long crank problem. I will tell you if they fix it.

[gt90]

My new injectors are in, and i had the long crank problem. I will tell you if they fix it.

my current and previous m30's both crank 4-5 times before starting, but on occasion start instantly.
Please let us know if the injectors help.

[nariusb]

Yes I will let you know. I'm waiting for 535i AFM to arrive. It should work well with 19lb injectors providing more air. I will also replace my wires. I'll do this in steps trying to find the cause.
So one thing is common on many 34 - the long cranking and it is intermittent, providing occasional relief.



my current and previous m30's both crank 4-5 times before starting, but on occasion start instantly.
Please let us know if the injectors help.

[Alexlind123]

Arent the OEM injectors 19lb?

[nariusb]

On mine, m20 engine, they are 14lb, but your m30 engine they are 18lb, I believe. This is a very controvertial tweek I'm doing but it's very popular with the e30 crowd. I'll just have to try it myself hoping to the very least I'll fix my leaking injectors/long crank.


Arent the OEM injectors 19lb?

[nariusb]

This is an update.
It's been a couple of weeks and I finally got the 19lb injectors and m30 AFM swap done. The Difference is Noticable!! The throttle really came allive and the acceleration is much better and I did have new 16lb injectors replaced before with Five-O Delco ones, so it's not just fresh injectors.
I had to cut the opening in the filter box a little to fit the larger m30 hole and boiling water helped to stretch the rubber boot on the other side. I swaped the circuit boards as suggested also.
The driveability is better but my residual pressure is still leaking, ARRRRRRR..
I made sure it's not via supply or return hoses by crimping both super well. So it can only leak through injectors/nozzles.
Can it be that I bought second supposedly new set of injectors and both sets are leaking. Are they that bad? It can't be. It surelly must be something else.
But what?

[Blitzkrieg Bob]

But it has new injectors, cap, rotor, plugs and a valve adjustemnt.

The injectors are 15#

[Alexlind123]

My injectors didnt fix the hard start either. Perhaps the FPR is the next thing to go after.

[nariusb]

My injectors didnt fix the hard start either. Perhaps the FPR is the next thing to go after.


I changed FPR ones with used and ones with brand new one - no change. I'd say that changing ignition wires to new did the difference for better start.

[nariusb]

Mine fires up in one crank two and I did all you did it just that the cranking is loneger than I would think it should be. Is is possible to have it start instantly or is this the way m20 are designed?
As far as my residual pressure I took out the pressure gauge and It looks like the pressure is holding better - the hose is stiffer, but I have no gauge to confirm it.
It did not do enything for instant start though. So the hunt continues.

[E34-520iSE]

When starting from cold my M20B20 goes 'wuhwuhwuhFIREwuhwuhwuhwuhwuhwuhFIREwuhwuhVROOM-WHOOSH!', sometimes you need to add a few wuh's in there.
When the engine is warm it fires up on one crank.

HTH,

Shaun