WTF happened to my thread? OK, I will try this again- Damn it!

OK, I have a fairly radical? daily driver that I have been tuning and tweeking on and my biggest driveability issue is this.

If I try to start my car after it has been sitting a while and fuel system pressure has bled off I have to either-

Flick the key to "on" position to pressurize the fuel system in the Haltech's "priming" cycle, then turn key to "off" position and back to "start" so that the BAC valve does its "priming" cycle opening as I crank. Doing this the car fires up with 1 second or less cranking on the starter.

If I just turn the key to "start" when the fuel system has no pressure it takes 2-3 seconds of cranking to fire up w/ a slight stumble (as it pressurizes the fuel system).

When I turn the key to "on" and let the fuel system pressurize before going on to "start" it takes 1.5-2 seconds of cranking to fire up as the BAC valve does not seem to be cycling as vigorously as it does in the "priming" cycle.

Any time the fuel system has pressure I can go straight to "start" and it fires up in 1 second or less.

But my fuel system seems to lose pressure quickly (an hour or three? to 0 psi), but I do not smell fuel.

I am running an Aeromotive dual port RFPR and a Walbro 250 LPH fuel pump.

Does the Walbro lack a checkvalve? Can I add one to the system to keep pressure longer?

Or can I tweak the Haltech some more? I already have optomized (pretty far off base map on some) priming inj. MS, coolant fuel %, air temp fuel %, BAC "openings" and MS, etc as best as I can.

I am including my Sig incase theat helps anyone- sorry for its length...Ian

 

I think most of them do have a checkvalve. I'm sure the gss341 I just put in does. Maybe yours has it disabled? It's the only thing I can think of that would drain all your fuel pressure if it's not going out the injectors (and it isn't since it's not flooding).

BTW, I really dig your IC setup. Can you tell if it's functioning at the level you expected?

 

This may sound odd but I figured I would post my experience. When I first setup my fuel system I was using an SX regulator and ran my fuel lines in series through the rails, so one of the inlet ports on the regulator had a boss plug in it. Well I had the same problem you speak of, trouble holding pressure. I went back in and remade the fuel lines, I now have a t-fitting after my fuel filter to run the fuel rails with thier own fuel line each (parallel). Ever since I changed my setup the pressure holds for a long time after shutdown, much longer than before. Maybe I did something wrong that was unrelated to the fuel line change, and ended up fixing it without realizing.. HTH.

Matt
93 SSM

 

Thanks for the replies!

Heffboost- I didn't check the inj. as they were new. But as you said there is no sign of flooding. It is nice to be rid of so many of the stock 2nd gen driveabiliy issues...

mjw- I am running parallel as well. I haven't really checked out the components/lines as I did not notice any gas leak smells. Perhaps I will dig a little deeper.

Ian