General Q&A

[captgrady]

Hey, just wonderin', the fuel level sender is 240-33 ohms, correct? Also, what is proper boost/vacuum gauge for 7.3L, 30HG/45PSI, or 30/20, or 30/30? (how hard to install?)
Thanks.
Oh yea, how is pressure built up, pump comes on and comes up to, what, 75 psi? so pressure sensor is inline after pump? or is this pressure between tank & pump? how would oil fuel lines come up to pressure w/o putting wvo into fuel rails? please humor my ignorance!

[Fordnut74]

Hey, just wonderin', the fuel level sender is 240-33 ohms, correct? Also, what is proper boost/vacuum gauge for 7.3L, 30HG/45PSI, or 30/20, or 30/30? (how hard to install?)
Thanks.
Oh yea, how is pressure built up, pump comes on and comes up to, what, 75 psi? so pressure sensor is inline after pump? or is this pressure between tank & pump? how would oil fuel lines come up to pressure w/o putting wvo into fuel rails? please humor my ignorance!

Capt- The fuel level sender is a 240 empty to 33 full ohm range. You only need a boost gage for the PSD, they NEVER operate under vacum like youwould see on a gasser. In stock or mildly modified trim a 0-35psi boost gage will be all you need. Only after some serious mdoficiatios will you ever see over 35. Word of cation though. From the facotry these trucks only make about 18psi of boost. But with the right defeats and programming the stock turbo "CAN" make over 30psi of boost. However running thm at anything over 25 regularly will grenade the turbo bushings in short order.

Also, the pressure switch is in the manifold after the pump and secondary filter (so it can detect the condition of the WVO filter) but prior to the check valve so that it is not seeing the diesel pressure. I will be posting a hydraulic schematic of the V3 in the near future as well so that people can understand just how it ticks. Then you will be able to know WHY it is better than anything else, and not just assume it is. Cheers!

[Elvia]

Great! I can't wait to see the schematic. Lots of time people ask how the system works, and all I can say is that it does.

[captgrady]

Thanks so much Jason.
I have a strange little thing going on. The V3 takes about 14 miles to come on, unless I put the A/C on max, then it comes on sooner. Also V3 sometimes turns off when in idle @ stop light, but only at first startup, (within 15 minutes,) then I switch the A/C to max or hit the throttle & it comes back on, then is good for the rest off the day. Do I need to tweak pressure sensor?
Jason, I really want to thank you again, I got this running in the nick of time, it's my work/daily driver vehicle & with work slow right now, it's one overhead I don't have to worry about! & is keepin' my head above water.

[Elvia]

I won't say for sure, but it sounds like a thermostat replacement is due. Maybe its getting stuck at first then pops open. The symptoms you have sound like a heat problem. I think that if it comes on and off only when you first start driving, maybe its switching over too soon.
Just a thought. I have the 203 degree thermostat and once I switch over )usually in 1.5 miles). it never turns back.

[Marv]

From the facotry these trucks only make about 18psi of boost. But with the right defeats and programming the stock turbo "CAN" make over 30psi of boost. However running thm at anything over 25 regularly will grenade the turbo bushings in short order.

So the stock turbos are physically limited to 18psi?

Reason I ask is there have been a few times in my truck when climbing hills that the trans will downshift and the boost gauge will go up to almost 25-27 psi - this is on the stock gauge by the way. Never has hit 30, but the gauge does get up there.

I've seen better than 20psi (22-23psi) quite often when downshifting to pass traffic.

Maybe my gauge is off?

Thanks!

[Jack_Toepfer]

Your turbo will make almost 30psi... from the factory, Ford won't let it go that high though. They limit it to about 18psi.

If you have a tuner, you could see pressure above 25psi no problem.

The turbos that come on these trucks lose efficiency after 20-24psi, so if you plan on boosting it more and not blowing anything up, get a bigger turbo.

[Fordnut74]

Marv- Your gage may be off, or it may not. Unless you have had the truck from new it is hard to tell whether or not the PCM has been reprogrammed with a performance tune. From the factory there are three safety's that prevent the truck from overboosting. One is the wastegate solenoid. That little bundle of vacum hoses on the front of the intake spider controls the wastegate actuator by allowing manifold boost pressure to actuate the wastegate bypassing exhaust around the turbine reducing boost. This action is controlled by the PCM based off readings from the MAP sensor. Overboost control #2 is the adjustment of the wastegate actuator rod. This adjustment puts preload on the wastegate and is often set to allow the wastegate to open by mechanical force by overriding the spring tension in the wastegate actuator, even if the PCM has not activated it(or say you unplugged that little red line going to it). The third control measure in place is that the PCM will defuel the truck if it sees boost over about 20psi for more than a few seconds, and cause a SES light. All of this can be somewhat easily defeated to allow the truck to make more than 18psi of boost, but bone stock truck simply will not go over 18 but for rare situations and briefly at that. SO long as you are not seeing sustained boost above 25psi I wouldn't worry about a thing.

[Clay]

So the stock turbos are physically limited to 18psi?

Reason I ask is there have been a few times in my truck when climbing hills that the trans will downshift and the boost gauge will go up to almost 25-27 psi - this is on the stock gauge by the way. Never has hit 30, but the gauge does get up there.

I've seen better than 20psi (22-23psi) quite often when downshifting to pass traffic.

Maybe my gauge is off?

Thanks!

Jason is talking about a 2000 7.3, they had a smaller turbo, quite a bit different from yours.

[Marv]

Your turbo will make almost 30psi... from the factory, Ford won't let it go that high though. They limit it to about 18psi.

If you have a tuner, you could see pressure above 25psi no problem.

The turbos that come on these trucks lose efficiency after 20-24psi, so if you plan on boosting it more and not blowing anything up, get a bigger turbo.

Ah, I got ya. Wastegate I take it?

[Clay]

Jason is talking about a 2000 7.3, they had a smaller turbo, quite a bit different from yours.

or maybe not...i'll shut up now.

I see 24-25 psi in stock mode pretty regularly.
29-30 with my tunner

[Marv]

Jason is talking about a 2000 7.3, they had a smaller turbo, quite a bit different from yours.

Oh okay...I got ya. I think I'm on the same page now.

Jason, thanks for the details by the way!

[Marv]

or maybe not...i'll shut up now.

I see 24-25 psi in stock mode pretty regularly.
29-30 with my tunner

Haha...man, don't worry about it. I'm a bit "turbo ignorant" really - first vehicle I've owned that's got one.

[Fordnut74]

Clay- Thank you for catching that. . Here I am stuck in my own little 7.3 world again....

[greasyX]

There is another world besides 7.3ville..........grease out