4.6 fuel pressure...is 27 lbs enough?
02-21-2009, 12:06 PM
#1
4.6 fuel pressure...is 27 lbs enough?
I have a 1998 F150 with a 4.6. It won't start but tries firing on a couple of cylinders.
A fuel pressure check shows that at key-on, it goes to 27-30 lbs.
I also ran the codes and got P0174, P0305, P0308, and P0401. There was a code of B1302 and B1398 in the GEM.
My truck is a plain-jane truck without power windows or locks.
I got the codes deciphered but am leaning toward a bad fuel pump. Any suggestions?
A fuel pressure check shows that at key-on, it goes to 27-30 lbs.
I also ran the codes and got P0174, P0305, P0308, and P0401. There was a code of B1302 and B1398 in the GEM.
My truck is a plain-jane truck without power windows or locks.
I got the codes deciphered but am leaning toward a bad fuel pump. Any suggestions?
02-22-2009, 03:44 PM
#4
According to my Haynes book, the pressure should be 30-45 at idle with "vacuum hose attached" and 40-50 with "vacuum hose detached"...
So which vacuum hose?
Also it lists 65 psi as a max pressure.
My problem is that I can't get the truck to start and idle is not an option. While cranking, it sounds as if it wants to start and hits on a few cylinders but just is still short of hitting all of the way around.
I got a new fuel filter but haven't gotten it on yet.
Is the fuel pressure regulator something that I should be looking at? Also, if the EGR code is correct, if it sticks open/closed would it have caused it gradually drop rpm's and then not want to start again?
My '86 with a 6.9 is an easy diagnosis for me. After 454k miles and having owned it since it had just 4 on the odometer, it is old hat. These injected gassers are still a mystery to me.
I was raised with 350 and 454 Chevys.
So which vacuum hose?
Also it lists 65 psi as a max pressure.
My problem is that I can't get the truck to start and idle is not an option. While cranking, it sounds as if it wants to start and hits on a few cylinders but just is still short of hitting all of the way around.
I got a new fuel filter but haven't gotten it on yet.
Is the fuel pressure regulator something that I should be looking at? Also, if the EGR code is correct, if it sticks open/closed would it have caused it gradually drop rpm's and then not want to start again?
My '86 with a 6.9 is an easy diagnosis for me. After 454k miles and having owned it since it had just 4 on the odometer, it is old hat. These injected gassers are still a mystery to me.
I was raised with 350 and 454 Chevys.
02-24-2009, 10:06 AM
#6
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What Hose; How much Pressure:
[quote=Paints-n-cows;147375]According to my Haynes book, the pressure should be 30-45 at idle with "vacuum hose attached" and 40-50 with "vacuum hose detached"...
###Monitor fuel pressure at the Schrader valve on the fuel rail. The engine need not be running to check fuel pressure.
So which vacuum hose?
###The hose attached to the pressure regulator on the fuel rail.
Also it lists 65 psi as a max pressure.
FYI:
Code P0174, system too lean, bank 2. (P0171, system too lean, bank 1, should have been thrown as well.) These codes could be related to low system fuel pressure.
P0301-308 are all cylinder misfire codes possibly related to a faulty camshaft position sensor.
P0401 is low EGR flow....clogged EGR passages (unlikely) or a bad DP sensor.
The two B1---- codes are related to the body....no idea what they might be.
###The maximum pressure is present when the fuel pump is running, the fuel filter is clean and the vacuum hose is removed from the regulator.
My problem is that I can't get the truck to start and idle is not an option. While cranking, it sounds as if it wants to start and hits on a few cylinders but just is still short of hitting all of the way around.
### A major vacuum leak somewhere in the system below the throttle plate will cause a lean condition. Check all the vacuum lines, particularly the line to the evaporative emission connection at the rear of the intake gooseneck. An IAC (Idle Air Controller)stuck open can cause a lean condition as well.
I got a new fuel filter but haven't gotten it on yet.
Is the fuel pressure regulator something that I should be looking at? Also, if the EGR code is correct, if it sticks open/closed would it have caused it gradually drop rpm's and then not want to start again?
###If the EGR valve is stuck open the engine will likely not start due to an excessively lean condition, but the EGR valve would have nothing to do with system fuel pressure.
###Monitor fuel pressure at the Schrader valve on the fuel rail. The engine need not be running to check fuel pressure.
So which vacuum hose?
###The hose attached to the pressure regulator on the fuel rail.
Also it lists 65 psi as a max pressure.
FYI:
Code P0174, system too lean, bank 2. (P0171, system too lean, bank 1, should have been thrown as well.) These codes could be related to low system fuel pressure.
P0301-308 are all cylinder misfire codes possibly related to a faulty camshaft position sensor.
P0401 is low EGR flow....clogged EGR passages (unlikely) or a bad DP sensor.
The two B1---- codes are related to the body....no idea what they might be.
###The maximum pressure is present when the fuel pump is running, the fuel filter is clean and the vacuum hose is removed from the regulator.
My problem is that I can't get the truck to start and idle is not an option. While cranking, it sounds as if it wants to start and hits on a few cylinders but just is still short of hitting all of the way around.
### A major vacuum leak somewhere in the system below the throttle plate will cause a lean condition. Check all the vacuum lines, particularly the line to the evaporative emission connection at the rear of the intake gooseneck. An IAC (Idle Air Controller)stuck open can cause a lean condition as well.
I got a new fuel filter but haven't gotten it on yet.
Is the fuel pressure regulator something that I should be looking at? Also, if the EGR code is correct, if it sticks open/closed would it have caused it gradually drop rpm's and then not want to start again?
###If the EGR valve is stuck open the engine will likely not start due to an excessively lean condition, but the EGR valve would have nothing to do with system fuel pressure.
Last edited by Kattumaram; 02-24-2009 at 05:27 PM. Reason: Additional Info:
02-25-2009, 06:11 AM
#7
It did not thrown the "lean on bank 1 code"...just the indication of that on bank 2 and the two cylinders on opposite ends of the heads on that bank. While cranking over the engine, the oil pressure does come to life and there is nothing else obvious about a component failure within the engine.
I checked for vacuum leaks but without it running, a cursory check found nothing obvious.
I did pull the vacuum line off of the fuel regulator but there still no difference in the fuel pressure.
The fuel pump should be here today or tomorrow and I am still betting that is what it is.
I checked for vacuum leaks but without it running, a cursory check found nothing obvious.
I did pull the vacuum line off of the fuel regulator but there still no difference in the fuel pressure.
The fuel pump should be here today or tomorrow and I am still betting that is what it is.