I recently installed a fuel pressure gauge in my Suburban for many reasons but mostly to know when to change my WVO filter.

I found some interesting results that I am curious about and would like to improve.

On both the stock LP and the WVO lift pump I will get a 1-2 psi pressure drop at idle when I turn on the lights and activate the power windows. With the WVO lift pump you can hear a slight dip in the motor speed so I know there is a voltage drop of some kind but only when I run things like windows, rear blower, headlights, etc.

Automotive electricity is not my strong point so I am wondering if this is a bad ground somewhere or I need to re-think my add-ons.

Since I am towing and running WVO I have some additional electrical connections on the +side of the battery.

So far this is not affecting the drivability of the truck but I think my fuel pressure while towing is lower than it should be and I am concerned I may damage the IP at some point.

Thanks.

Alternator? may not be big enough to power all of those.

Is it standard 105A?

Do you have the same problem when turning AC?

At any rate, check all the ground and probably add more ground points.

At any rate, check all the ground and probably add more ground points.
Remove each ground wire, clean the connectors, clean the chassis or frame where contact is made, put a very light coat of some anticorrosion past on each connector and tighten every thing up real nice when your done. When you're all finished look around and you'll probably find more ;)
A dremel with a brush works great - Watch them fingers.

Grounds on these trucks are problematic and really need to be part of our basic PM. Just tighten them up when you change oil once they've been cleaned. Having your ground system solid will keep a bunch of gremlins away in the future :)

I might add that once you've done this twice it just takes a minute from then on.

[quote=HamOP;2890196]Remove each ground wire, clean the connectors, clean the chassis or frame where contact is made, put a very light coat of some anticorrosion past on each connector and tighten every thing up real nice when your done. When you're all finished look around and you'll probably find more ;)
quote]

bah!!! that was my idea, thieving little bugger are you!!! hahaha. yes HamOP makes a very good point. same with JMJnet.

What you want to do is pull up all the old grounds. wire brush them till they are nice and shiny, and a bit smoother than before(better connection with more surface area touching), put this stuff caled anti-ox(caled penetrox in the elctrical world) goes by other names too. you can find it at home depot or lowes in the elctrical isle, or an electrical supply house. its in a white elmers glue like bottle. Its a grey paste substance. first, you want to fill the thread hole with it where the grounding bolt goes. next, put a small ring on either side of the grounding piece. tighen it up nice and tight. that will halt any and all oxidation and make removing the lugs later on a snap.

Also, yes adding more ground points will help. I'll post pictures of my design tomorrow should you be curious.

An additional helpful hint. the small copper wire that connects your 2 batteries together? screw it. get a bigger wire. MUCH BIGGER i have 4/0 connecting mine. its some huge wire. that will reduce voltage drop between the batteries, and allow current to flow easier, with less resistance and will help with the reduction brought on by the high heat under the hood .(wires maximum ampacity will drop signifficantly under high heat.) add a heavy load and your in for quite a mess.

If you really want great ground connections.Go heavy gold or silver plate on all your connectors.Even the battery terminals can be plated.You can buy gold plated connectors and terminals now.A lot of the audio guys use them.3 years ago when i rewired the engine room on my yacht,i went with all gold connectors and battery terminals.It has been 3 years in a salt water environment and the gold is still holding up with no electrical problems.I even have my own gold plating machine.What i do is buy the gold connectors and terminals.Put them into my machine and add another heavy coat of gold on them.Also you can use silver plated ground straps.Find a military or old computer mainframe surplus store.The old IBM mainframes used a heavy duty silver on copper ground strap.Last resort,your local scrap yard.Prices on scrap are falling every week,nows the time to buy what you need for cheep!

You'll see a little drop off when high loads are added to the electrical system at Idle. You should see this on the volt meter as a slight drop in voltage. (like a 0.5 to 1 volt)
This is because the alternator can not make full load at idle.

You'll see an example of this dramatically at cold start up while the glow plugs are cycling. The volt meter drops to 10.5 to 11v when the glows cycle on and back to 14v when they cycle off. Idle up the truck during this and the voltage drop will go away.

IMHO, I call the pressure drop you see as normal from this slight voltage drop. You could do due diligence to verify your connections are clean and proper, but you should expect this drop off at idle.

As a point of reference, in my dual alternator setup, I no longer see the voltage drop below 12v from the glow plug cycling after startup. The voltage still does drop slightly during cycling.(like to 13v from 13.5~14volts)

Note: Running WVO increases the risk of IP wear and failure. Seperate water and filter, filter, filter to minimize the risk.