M70 still runs rough-DKs cleaned-stumped

[bshupe]

I find this most perplexing. I replaced the plugs, the wires, the O2s and now cleaned the DKs. One DK was obviously dirty with grease on the armature (so I found the problem - no!). Each one of these steps helped smooth out the engine under acceleration, but then the shakes would come back. After the O2 sensors it ran acceptably well for over 4 weeks (still had a slight shake on acceleration). After the Dk cleaning it had some EML issues. Disconected and charged the battery, cleared out the codes per shogun instruction. Next day ran seemingly very well - fixed - no. Now two days later it will barely get me home, EML comes on etc. I filled the tank thinging maybe the primer pump is getting weak - no change. I guess next step is to monitor fuel pressure. It is not blowing black smoke so I gather it is not runnign rich. Maybe a fuel regulator or pump.

Any ideas?

[Highline]

check fuel pressure and fuel pumps first, you have to eliminate possible causes step by step.
Did you also mesure the DK's? On on my website there are the resting data under rerefence data.
Do you get any fault codes?
Looks like when you clear all faults with disconnecting the battery for a while to make a reset, it works fine, but then the system 're-learns' the faults.
Also battery voltage is very important for all the electronic parts, the battery might still be strong enough to start the engine, but not enough to get the electronics running clean.
So also check the battery voltage and the cranking voltage and also at the battery plus pole under the hood. And at the DME relays. Just to make sure your fusable links do not have cracks.
Shogun E32 Tech Tips: http://twrite.org/shogunnew/topmenu.html

[bshupe]

Its weird, it seems to go back to its "old ways"
I'll go thru your check list - thanks.

The odometer capacitor has never worked since I owned the car, so I would not think this would be a problem but thought I would ask.

[Highline]

The M30 fuel pump is originally Bosch 0580464995
operating pressure is 3 bar
conveying capcity at 12 V 1.9 liter/minute
conveying capacity against counterpressure 875 ccm/30 seconds
Power consumption is 5A

The M70 has 2 pumps, so 1 for 6 cylinders, each:
Bosch part number is 0580112507 (according to an old repair book)
operating pressure is 3 bar
conveying capacity at 12 V 1.7 liter/minute = less than the M30 pump
capacity against counterpressure 875 cc/30 seconds
power consumption 5.5A

I have some original ones here, the BMW part number is 16141179710

http://bmwe32.masscom.net/sean750/fuel_pressure_regulators/FuelPressureRegulators.htm

http://bmwe32.masscom.net/sean750/fuelpump_replacement/Fuelpump.htmShogun E32 Tech Tips: http://twrite.org/shogunnew/topmenu.html

[whiteghost]

signed a sweet e30 327i & e32 735i + 750iL

[Highline]

than the 2 M70 pumps. As you know the M70 has 2 pumps but they have to fit thru that small hole into the tank. Therefore the M70 pumps are much more expensive than the M30 pumps. From viewpoint of capacity and pressure the M30 pumps will do. Have tested even a M70 with one pump only (used a y-piece to distribute the fuel from pump coming to both cylinder banks). Under normal conditions that is even enough, unless you might go full throttle. The E38 750 also has only one pump, simplified for cost savings for production.
You can go on the 750 for Tre-performance pumps, they are even smaller than the 750 original pumps and have a capacity of 255 l/h, at least that is what they claim. Installation instructions I have posted on BB. For the 750 the pump type TRE-342 for better fitting of the accessories, that is used for Honda, Toyota etc.
TRE-340 is the same pump but the accessory set is different.
h tt p://ww w.bim mer boa rd.com/for ums/po sts/710 531/Shogun E32 Tech Tips: http://twrite.org/shogunnew/topmenu.html