Randy Nielsen

iTrader: (4)

Have you tried regulating the fuel pressure down to about 36-38 psi?

Baja 272

Yes, adjusted pressure all around the scope and no changes. It's plumbed - tank to filter to pump to fuel rail to regulator and returning to tank. Using Aeromotive componants. The fuel rail still has the Merc pressure regulator at the front of it but I was told that should affect it. Does anyone know of a devise that can be installed in place of the regulator and still maintain a flow to the return line? If I knew how to post pics on here, I could show the plumbing.

Randy Nielsen

iTrader: (4)

After reading this thread again this morning I am wondering if you dont need to move your regulator to the inlet side instead of the return side. The reason I am thinking this is that aftermarket pumps can pump more fuel for high performance apps, the processor is programmed to cycle the injectors @ x number of miliseconds for a given rpm @ a given psi fuel pressure. If you have too much pressure at the injector it will flow too much fuel per duty cycle resulting in a rich condition. With no oxygen sensor in the system the processor cant see the rich condition to adjust the pulse width of the injector. If the processor is going into failsafe mode for any reason it can only back the timing down & or widen the pulse width (dump fuel) in an effort to save the motor which results in the motor falling on its face,limited rpm, & wet plugs. Just a thought I hope you are able to get it figured out. Randy

GPM

The regulator on the inlet side may limit pressure and volume to the injectors, might not be a good idea.

Baja 272

Engine serial# OF130452
ECM model# is 16159919

Any ideas what to try next? I'm still waiting on the contact info for the guy that did the tune on the ECM.

keith2500hd

what temp t-stat is in it and what is ecm looking for temp wise. if temp low, same as choke-on. does exhaust have black appearance. is engine rough at 4000rpm or just turns to that rpm and stop gaining.

Baja 272

Yes, rough (chocking) at 4000 (actually starts around 3200), black soot. 160 t-stat. I'm also chasing a temp gauge problem. Changed sending unit and gauge but no reading at gauge. Engine is not running hot though.

Mark Boos at Precision Marine did my tune. I believe he is on vacation this week so it will have to wait for next week. I'm going to try the only thing I have not tried yet and that is move the regulator to the inlet side of the fuel rail vs. the return side where I have it now. I am returning the fuel to the fuel tank into an unused port which I believe is an extra pick up tube. Does anyone see a problem doing this?

Raylar

My opinion is you most likely have an ECM reprogramming issue. I would recommend you contact Mark and Precision Marine in Kenner , LA. and talk to him about checking and reprogramming your MEFI ECM. There is a link here on OSO for his shop and number and email. He's the best at this in the country in my opinion and I think he will help find your issue.
Just as an addtional question, What is the LSA on your camshaft from Comp Cams?

Best Regards,
Ray @ Raylar

Baja 272

112.0 on the LSA. I'll try Mark on Monday, after that if not fixed, I'm going to pull the engine and send it to the Dyno. Tired and frustrated with EFI.

Martin718

Hey check your coil and make sure it has clean contact on mounting and ground wire. That's what mine was