Engine wont start - no fuel pressure

mick

Try anything
Aug 15, 2006
482
0
0
Forestdale. Brisbane.Australia
I just removed the new 10 Hole MDE Injectors and put the stock ones back in as there was one dud one and another half dud one that have been giving nothing but trouble since day one with this new motor, at the same time I took off the upper Valve Covers and replaced them with ones off my old engine as the builder didnt put the baffles in under the breather outlets and it was pumping oil out of the breathers. I had to remove and put back a bit of the wiring etc. I thought it might have been the Camshaft Sensor wiring that we modified when we first had problems starting the new engine. The codes kept coming up with cam Sensor. It was only after we mutilated the wiring to the sensor that we found out the builder left the Reluctor Plate off the end of the Camshaft. I pulled the front cover off and used the Reluctor Plate off my old engine. It has been running since then but he injectors have been crap.

Now the engine cranks but will not start. I put efi on and watch the screen as Im logging it and cranking it over and see the commanded fuel pressure is 5000 something while the actual is around 190-230. There is fuel at he cp3 and I can hear it humming with the key on. There is no air at the fuel filter at all. Anybody have any ideas?
 

RENODMAX

Dead Wrong
Mar 4, 2008
3,602
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0
Get a new harness to make everything less complicated. Check ficm and injector wiring. Double check cp3 too
 
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McRat

Diesel Hotrodder
Aug 2, 2006
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Norco CA
www.mcratracing.com
If you get the cam sensor and crank sensor wires swapped, it will not start. Try swapping and try again.

But, yeah, those pressure readings sound wrong, but I don't remember what is normal reading when cranking. Thought it was 4,000psi, but not sure.
 

mick

Try anything
Aug 15, 2006
482
0
0
Forestdale. Brisbane.Australia
If you get the cam sensor and crank sensor wires swapped, it will not start. Try swapping and try again.

But, yeah, those pressure readings sound wrong, but I don't remember what is normal reading when cranking. Thought it was 4,000psi, but not sure.

Thanks for the reply Pat

Cam Sensor plug hasnt been off since it ran last time.

Mike hooked up his efi and watched the screen as he cranked his and it hit 4000 - 4500 actual before it fired
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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64
Norco CA
www.mcratracing.com
Oh, and of course, make sure the lift pump is running if so equipped, and obviously there must be fuel in the tank. I know, dumb, but it happens to all of us now and then.
 

Mike

hmmm....
Feb 17, 2007
2,184
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36
San Angelo, TX
He said only a dribble came out of the return line. He has tons of volume and pressure to the cp3's from the tank but only a slight amount of return. Just maybe it's the fprv's stuck closed with trash????

Anyway, thanks for the help.
 

Mike

hmmm....
Feb 17, 2007
2,184
0
36
San Angelo, TX
If say he has pressure but the rail pressure sensor is not picking up pressure will the truck start? I mean say the pressure sensor was disconnected will the truck start?
 

mick

Try anything
Aug 15, 2006
482
0
0
Forestdale. Brisbane.Australia
I take pressure sensor out of rail and crank it over a a small stream of fuel comes out. As mike says - If engine cranked over without the pressure sensor plugged into rail should it still start or does it need that sensor to register enough pressure before it can start?
 
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Mike

hmmm....
Feb 17, 2007
2,184
0
36
San Angelo, TX
I tried this with my lb7. disconnected the truck started but ran bad then died. I tried starting afterwords and it would not start. After reconnecting it started right up?

Is the lly the same?
 

Mike

hmmm....
Feb 17, 2007
2,184
0
36
San Angelo, TX
In response to pats question about disconnected cp3.

By the way it does the same with both cp3's

just turns over the same. Now, my trickle could be less than his trickle. You know how his small chargers are???/

:D
 
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