1996 1.8 T cranking time before start

[FrenchAudi]

As it takes so little time, and is so easy to do now I have the equipment, I randomly check the fuel pressure from time to time, after problems with a faulty fuel pressure regulator (FPR).

By separating the system on each side of the union where the feed hose joins the fuel rail during the test, by means of a couple of shutoff valves, I find that pressure on the rail, which includes the injectors and the FPR, is held indefinitely, and that there is a slow leakage back to the tank via the fuel pump and its check valve. I can live with the latter, as it does not affect the fuel pressure when the engine is running.

However, the engine has always taken longer to start when it has been standing for some time. I now know that this is because the fuel pump does not run until the starter motor begins to turn. In fact, the engine does not fire until the fuel pressure reaches about 3 bar.

My Alfa's fuel pump runs for about a second when the key is turned to the "Run" position. This is long enough to make sure the fuel pressure is at the set value before the starter motor begins to turn, and the engine starts immediately.

I thought about modifying the Audi's wiring so that the fuel pump runs as soon as the key is switched on, in order to get a quicker start.

However, I then thought that perhaps it is better for the engine to make a couple of turns before it fires, so that the oil pump has had a chance to prime, and start to feed at least some oil to the system, particularly to the crankshaft bearings, so decided to leave things as they are.

Any thoughts on that?

[robbobjm]

Ignition amplifier is on its way out

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[FrenchAudi]

Ignition amplifier is on its way out

Possibly, thank you.

However, testing and work on the FPR was last year, and no problem now. See this thread