Odd HArd START??

[Trptguy]

So the saga continues.

I swapped in replacement M20 into my 325i.Since the swap the car has had issues starting up. Usually the first start of the day is ok (altho recently that has become rough too) subsequent starts though usually require the engine to crank at least 6-7 times before it catches. Once it does start it runs really rough until the engine is warmed up. Once the car is warmed up though it runs really quite good.

I am thinking it might be the FPR, or one of the fuel pumps (i have a 'vert). Not sure though how to test this out.

Any suggestions would be more than welcomed.

[jlevie]

The Bentley manual has a set of fuel system tests that will tell if you have a fuel delivery problem.

Based on the symptoms, I'd suspect intake leaks, or possibly a bad ECT sensor. A smoke test will reveal any and all intake leaks.

[Trptguy]

It has a brand new ECT sensor so I don;t think it is that.

I will check for intake leaks. Right now it has the BAv Auto intake on it which is something my mechanic hates....lol

[jlevie]

Run the fuel system tests and find a shop that can smoke test the intake.

[Trptguy]

yeah i will do the smoke test.

Anyone else ever had this issue?

[jlevie]

I've seen that set of symptoms a number of times.

[StereoInstaller1]

I've seen that set of symptoms a number of times.

Me too: my '87 325iS is terrible sometimes.

I always think it is a full drain of the fuel system or something, like a bad o ring on the FPR or something.

I just figure it is time for a swap into a motor I actually want.

[jlevie]

If the fuel pump(s) and FPR are operating correctly, normal rail pressure will be achieved within a couple of turn of the engine even if all pressure has been bled off the rail. If the check valve in the high pressure pump is worn or the FPR is failing, rail pressure will bleed off while the car is parked. If the problem is in the pump, the chances are that it is worn enough to be slow to pressurize the rail. Replacing the pump fixes both problems.

The test for a leaking FPR is to disconnect the return hose, point the return into a container and briefly jumper the fuel pump relay until normal rail pressure (as indicated by a gage) is achieved. Remove the jumper and see if flow from the outlet of the FPR ceases. If not, replace the FPR.

[StereoInstaller1]

Jim, you make that sound really easy...

[Trptguy]

he does make that sound easy...lol

Smoke test revealed no intake leaks. So next step FPR and fuel pumps.

[jlevie]

I'd recommend that you run the fuel system tests before you replace anything. Those tests will tell what needs to be replaced. And it is possible that there's nothing wrong with the fuel system.