733i throttle response

[smitherz]

So I recently had replaced a fuel filter in this "new" car and discovered the tank was a mess of rust from obvious sitting too much. I pulled the tank and did a Evapo-rust/POR15 tank treatment to it. Tank came out beautiful. Instead of putting back the original in-tank pump and external one I did this mod/upgrade from here: http://www.mye28.com/viewtopic.php?f...c56cc8025488d6

Once I got the thing re-primed and started it seems to run really well. Well, almost... if I just nurse the acceleration it operates just fine. If I try to accelerate anything moderately hard it will barely hold its own like lack of fuel-vs-air. It seems to be fine sitting still in park and reving the engine up just not under any sort of load. I did remove the "damping unit" also which is item #13 here: http://www.realoem.com/bmw/enUS/show...diagId=16_0144

The pump I used was the TRE-340 as described in the mod thread so fuel pressure shouldn't be an issue.
Thoughts?

[smitherz]

So I thought I would follow up on my own post. Got a chance to dig into this issue today. I found there was not any power reaching the fuel pump. Did some troubleshooting by following the schematic in my electrical troubleshooting guide and I seem to be missing the +12 coming from the ECU to enable the combination relay and hence providing power to the pump. I did a quick and dirty jumper wire to get power to the pump and got it to run for nearly 15 minutes and restarted it a couple times. Sadly, when I backed it out of the garage to do a test drive I made it just far enough out before it stalled that I can't push it back in by hand. I am hoping it will start tomorrow once it cools off. I have a used ECM coming this week so hopefully it will resolve the issue.

[smitherz]

More follow up. After way more poking around that anyone should have to with a "simple" engine I got the car running. The electrical gremlin that I thought I had based on the electrical troubleshooting guide was not electrical at all. Apparently the tank shifted just enough to pinch off 80% of the pump output supply line to the filter. The issue I thought I had was that the line to the "86b" pin on the combo-relay that triggers the pump relay was not live when the key was in the "Run" position. The ECU showed that pin as a "Run" pin. Turns out that it goes live during "Start" and stays live in "Run" only after it starts....go figure. I now have several spare parts I would up buying trying to fix the issue including an ECU.

[TowJamma]

Wow, good find on the pinched hose. That's some trouble shooting skills.