have just fitted the Max Milage Module to my truck, but since fitting it, the fuel pressure guage is all over the place, don't know if this is just a coincidence or the module is affecting to fuel pressure.
Before i fitted the Mod the fuel pressure was always between 13-15 psi, even when i floored it, now it fluctuates between 6-15 psi. it goes from one extreme to the other, there is no logic to it, and you get multible readings within seconds, even at the same speed and revs.
I replaced the LP about 6k ago, perhaps it needs replacing again. would like some of your views on the subject please, before i do some damage to the fuel system, the truck does not seem to lack any power, and drives like it always done.

 

I don't know anything about the Milage Module, but with the gauge acting up I would check/change the fuel filter first. Take care!

 

We need some details about the fuel pressure guage? Electric/mechanical? How is it installed?

Sounds just about normal to me since I dont see a lift pump upgrade in your signature. I assume this box is supposed to increase power. Could be a grounding issue if your fp guage is electric.

 

Thanks guys, it's a mechanical guage (Autometer) and been in about 2 1/2 years and hooked up on the fuel filter housing,then to an isolater, and been fine till now. Perhaps its the gauge thats faulty. don't think it's the filter, as i changed it about 6k ago about the same time i did the LP, perhaps the LP has an earthing fault, or other conection fault, i will have a look tomorrow in the daylight.
The MMM made by Quadzilla is a designed to enhance the engine management system, nothing else, no power gain etc, hopefully it will make the truck more fuel efficient being diesel is just over $8 per gallon, it just seems strange that this fault should show up exactly the same time i fitted the MMM. i might remove the module and set it up as stock and see if it returns to normal pressure. Think i will also email Quadzilla and ask them.

 

By all means, try it without the box.

You could also get a different pressure guage and temporarily bypass the isolator (isolators tend to cause problems like this).

Good luck.

BTW, $8 a GALLON ???

 

Is that the Queen's gallon, I assume (1.36 of our gallons IIRC), still, OUCH!!

 

Check the suction side of the fuel lines. Mine would "float" around because it was sucking some air. Fault was where they changed the line from steel to rubber to the lift pump. Was only a slip on fitting. Two hose clamps fixed the problem
Bob H

 

Thanks again guys. the fuel pressure seems to have settled down a bit now, can't explain it tho. Will have to keep my eye on it.

Thanks....Ade..