7.4L Volvo No Power

[fishraiser]

Hi All,
I have a 2000 7.4L Volvo Gi gas engine that just had the heads redone, new fuel pump,lines everything up to the fuel rail.Ran off a seperate tk. had computer on it no codes @ idle or under load.Idles great,starts up every time, can go anywhere @ 1800 rpm's,when you go to give it to her she doesn't get over 2400 & sometimes backfires thru the flame arrestor.Please Help.
Thanks,
Joe
p.s.-engine serial=4012030380 (3869060)

 

[Don S]

Re: 7.4L Volvo No Power

Have you checked the engine fuel filter for water?
Have you checked both the low and high pressure fuel pump pressure?

 

[fishraiser]

Re: 7.4L Volvo No Power

yes the fuel filter is new along with the pump the LS press.=20# & the HS=50#

 

[Todd157k]

Re: 7.4L Volvo No Power

a "sometimes" backfire usually leads to ignition timing or crossed spark plug wires.

 

[Don S]

Re: 7.4L Volvo No Power

There is part of your problem right there. Very high fuel pump pressures.
The Low pressure pump should be 8 ? 4 psi, and the high pressure should only be 39 ? 3 psi.

Here is a link to the OEM manual, you may want to start doing so reading.
http://www.4shared.com/account/document/-5lOOm8i/7797354_EF_EFI_Diagnostic.html

 

[fishraiser]

Re: 7.4L Volvo No Power

thanks Don what would cause that on a brand new fuel cell?

 

[Don S]

Re: 7.4L Volvo No Power

I don't know, I would have to do some troubleshooting to find out.

You don't by any chance have another electric fuel pump hooked up before the fuel cell do you?

 

[fishraiser]

Re: 7.4L Volvo No Power

no right from the tk to the fuel cell

 

[fishraiser]

Re: 7.4L Volvo No Power

$476.00 for a Fuel pressure regulator thats no bigger than my thumb!!!

 

[alindquist]

Re: 7.4L Volvo No Power

I'm having a very similar problem (I have a 1999 7.4 Volvo GI) that I'm hoping to fix with a new high pressure fuel pump (it's old and has never been replaced)... Where is the fuel pressure regulator and how can you tell if it's bad? Are you sure that is what your problem is?

 

[fishraiser]

Re: 7.4L Volvo No Power

it is located under the upper intake manifold on the fuel rail from what I'm reading in the OEM.I've changed everything else & there is also a screen inside the regulator.When placed on the diagnostic computer no codes come up,brand new 786.00 fuel cell is putting out too high pressure,new fuel lines it has to be it

 

[Don S]

Re: 7.4L Volvo No Power

Might want to check your fuel pump pressure gauges and see if they could be off by 10 lbs.

 

[fishraiser]

Re: 7.4L Volvo No Power

Brand new guage but I will be re-checking thanks Don

 

[fishraiser]

Re: 7.4L Volvo No Power

when I put an external tk on with a primer bulb & pumped the bulb I can get enough fuel to it to get it up to 4000 rpm's thats as fast as I can pump