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Topic
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1996 BMW Z3 1.9 M44B19 Euro, Manual gearbox
Tried to install a DASC supercharger and something has messed up.
Engine turns over but doesn’t start.
Checked fuel hoses at the injector rail – they were empty.
Well, the problem is not the supercharger because I have reinstalled the standard intake manifold and it still doesn’t start.
If I remeber it correctly, one should hear fuel priming/fuel pump working (behind the passenger seat) for a few seconds after the ignition is ON. Well, now that fuel pump sound is definitely gone, no fuel going from the fuel tank to the injector rail.
Connected BMW INPA software to check for errors. There were no errors, except an older SRS airbag error. I am using a 20 pin adapter with some cheap 10$ K-DCAN cable (!)
Inside BMW INPA there is a test procedure for a fuel pump relay. And it worked! The fuel pump relay does click, the fuel pump turns on for ~20 seconds and fuel hoses get supplied with fuel (again I have disconnected fuel hoses at the rail to check). The fuel pressure regulator I have got with the DASC reads ~5 bar (!) while the fuel pump is on, then gradully drops down to 3 bar (in a minute), 2 bar (in 2 minutes), 0 bar (next morning). Adjusting the fuel pressure regulator doesn’t seem to affect the fuel pressure while the pump is on (always reads 5 bar), it only affects the speed of pressure dropping to 2 bar etc. I have removed the FPR from the fuel line a bit later and that didn’t solve anything. I wonder why the fuel pressure is not the standard ~3 BAR ??
I also have installed new crankshaft and camshaft sensors. These were reported to be a common cause for some people but that didn’t help.
So what I have know is a fuel pump that only activates via software, not with the ignition ON. Any thoughts?
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Replies
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I would start with check all fuses and any fuseable links.
Also inspect for any wiring that may have gotten damaged during the installation of the supercharger, and any miss wiring.All fuses and relays are ok, battery is fully charged, I also inspected wiring and sensor connectors. The supercharger is just a different intake manifold, pure mechanical, no electrical parts at all. The fuel pump seems to work but only when activated via BMW INPA (BMW diagnostics software), it not however activated when cranking or turning ignition on. I am thinking the DME is faulty.
You say, that you could usually hear the fuel pump when the ignition is turned on ? You are SURE of that ? Some cars don´t turn on the fuel pump until you crank the engine.
IF the pump should start when Ignition is turned on, I´ld check to verify that via a wiring diagram and try to find out, why it doesn´t turn on now. If the software can turn it on, but the car doesn´t, it does sound to me as if it only should switch on, when the car is cranked / running. Something is missing, if the ECU doesn´t tell the pump to switch on. Again, look at the wiring diagram and maýbe look at the crankshaft sensor. If the ECU is supposed to control the pump, it is probably missing some input from a sensor or something.
I had the car for 4 years, I know for sure it would prime fuel with the ignition on.
Crankshaft and camshaft sensors are already replaced with brand new ones.
I am getting a new plug and play DME from K-Data and see if it solves the problem.
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