Hi guys, For some time now I've been having the problem of: 1. The engine cranking for 5-10 seconds before firing (hot or cold). 2. Once it fires, half the time it's perfect, the other half it runs rough (but not like dropping a cylinder - it's not a coilpack). 3. If it's running a bit rough, it has a tendency to conk out completely if some revs are applied (in gear or not) and it's then allowed to go back to idle - only it goes too far and stalls. If I start driving with some speed and higher engine revs it tends to sort itself out quickly though. Me and my old man have been wondering what the issue has been for some time now, and he's put forward the idea that perhaps the fuel system isn't being properly pressurised between the fuel pump and injectors. So when I fire the starter, it takes 5-10 seconds for the system to pressurise enough for the engine to properly start. And then I suppose it may take some time to actually come to full operating pressure, hence the rough running occasionally, and the odd stall (until I put reasonably load on the engine). Does this sound feasible? Does anyone know how I'd be able to check the fuel system pressure between the fuel pump and injectors? Has anyone had this sort of problem before? Any information would be great. Thanks guys, Captain Mark
Sounds like your injector O-rings are leaking ...>> When you stop the engine the fuel system depressurises into the plenum and floods a cylinder or two. The depressurised fuel system makes it harder to start and the flooded cylinder(s) make it run roughly (over fuelled and fouled plug). That's my guess.
Bypass the FPCU and see if that fixs the problem when FPCU fail its normally terminal. the bypass should be in the tech section, if not its back on the static site. The other thing is PTU's can fail like this and give the same symptons. your best bet is too 1 ecu diag. 2 bypass the FPCU. 3 swap a PTU. 4 start checking injectors shadow
Is this still the same old problem, Mark? More in-depth analysis via ConZult/NDScan required & pressure test ... MikeZ has test gauge I think? See you at Dyno day?
Re: Is this still the same old problem, Mark? sounds similar to my problem (minus the hard to start) i'm weeding out all the electrical possibilities first.. because you cant really tell if its an injector.. and injectors are a PITA to change (plenum pull)
Thanks for the info guys. You've given me a bunch of stuff to go on now, so hopefully I can narrow down a few things and get this mongrel problem fixed once and for all. K-Zed, yep, same problem. Chances are I won't be able to make it to this tech-day unfortunately, what with time constraints and all. For now I'll have to be happy with tinkering on the car in the shed late at night, laptop on, trawling through tech articles. Cheers all.
Hey Mark. I have a fuel pressure gauge at home. If you're near my place over the weekend I'll be in my garage working on the Zed and we can check it over. I also have my special FPCU bypass tool (piece of wire with aligator clip on one end) and a spare FPCU.
Hey Mike Hi Mike, thanks for the offer! Much appreciated. As with the techday, it's going to be very hard for me to get away. I imagine I'll be down your way eventually though. When I am I'll drop you a line and perhaps we can have a tinker with things then. Cheers
