Carrier/facet pump observations

[IDIBRONCO]

You could also rev up the truck at a standstill and compare both gauges that way too.

 

[laserjock]

I think what that data is telling you is that the limitation is your plumbing not the pump. Which tank were you on? I can see a difference from front to rear tank. I suspect the difference is several more feet of line.

 

[tbrumm]

Well, I hooked up the mechanical gauge the results of that tell me the electric gauge has problems. The mechanical reads 10psi with engine off and 9psi at idle. Revving the truck up, there was nothing I could do to drop below 6psi, and the needle was rock steady. So the pump seems fine pressure-wise. I guess I will send the gauge into Autometer to have it looked at.

 

[Garbage_Mechan]

I have a long hose on my test gauge and I tie wrap it to the windshield wiper for on road testing. Remember the Facet pump is a piston pump which puts out pressure pulses. You may not see them on the mechanical gauge because of fluid dynamics but the electric sensor maybe effected. Try putting a needle valve or an orfice (gauge snubber) Also along these lines, a suction restriction may amplify this.
I would blow back through the lines to be sure they are clear, once had a piece of an old shower head (suction screen / bell) stuck in the inlet of the tank selector valve......starved out on the top end. Vacuum gage tee’d into the pump inlet will tell a lot too.

 

[subway]

. I suspect the difference is several more feet of line.

that and about 8 more bends in the line itself to the rear tank

 

[laserjock]

Well, I hooked up the mechanical gauge the results of that tell me the electric gauge has problems. The mechanical reads 10psi with engine off and 9psi at idle. Revving the truck up, there was nothing I could do to drop below 6psi, and the needle was rock steady. So the pump seems fine pressure-wise. I guess I will send the gauge into Autometer to have it looked at.

I have a hard time getting mine to drop. Just free reving it really doesn’t seem to do much. I want until she was loaded and working hard that it made a noticeable difference.

I’m still very curious to see how this shakes out.

 

[Garbage_Mechan]

So once a person is more familiar with the curve can anything be learned by measuring and plotting the advance curve beyond the “ run it at 2000 rpm and set it at 9 degrees. That’s it you are done”

The internal advance, which the hydraulic portion of the advance curve, keeps acting as long as engine rpms keep increasing. The mechanical advance done by the advance piston acted on by the light load advance arm works against the hydraulic advance by rotating the cam ring away from the rotation of the rotor. Ford set the 2000 rpm spec for timing just because its the middle of the rpm range, ultimately wide open throttle at hp peak is where timing is most critical for power, but with worn pumps and hard parts wearing differently, a pump that is set to 11* at 3000 rpms can make less timing down low than another rebuilt pump set at the same spec at 3000 rpms.

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[Thewespaul]

So once a person is more familiar with the curve can anything be learned by measuring and plotting the advance curve beyond the “ run it at 2000 rpm and set it at 9 degrees. That’s it you are done”

Absolutely, this topic could really use a thread in itself, it’s something I’ve wanted to know for a long time. I’m currently building a db4 for a customer and to get more data I’m machining some parts so we can actually watch transfer pressure in the cab with a regular gauge. Knowing transfer pressure we can calculate exactly how much timing we have, and with have a sensor output for transfer pressure I can use some electronics that will convert that number for us and show timing degree as a readout on another gauge.

Spending some time on the dyno, we can watch that timing/pressure curve and manipulate it to improve the torque curve significantly, where the 2000 rpm spec is more of a “close enough” from ford, I can produce some pretty exact numbers from idle to 4500 rpms and show what amount of timing makes the most power at specific rpm points. This will really help with running larger chargers because we can use timing instead of bulk fuel to make these bigger turbos spool quicker, and the nice thing about being able to use timing vs fuel is timing won’t smoke out a highway, or kill fuel mileage.

 

[tbrumm]

I wish I had some hard and fast pressure data for everybody. If I could rig up my mechanical pressure gauge so I could mount it outside on the cowl without having to drill a hole through the firewall and into the cowl areal I would do it, but there is not enough room between the cowl and the hood to accommodate the hose without pinching it off. I did have a stray thought about the sender though. The sender has three wires running into it, one of which I figured was a ground. The sender is remotely mounted in a rubber lined clamp and is connected to the filter head with a braided stainless hose. If the sender needs to ground through the sender body, and one of the three wires connecting to the sender is not a ground, that could be the reason for the erratic gauge readings. I will have to check the wiring diagram for the gauge when I get home tonight. If the sender body needs to be grounded through mounting, maybe it worked before because it was grounding through the SS hose and back to the filter head. Maybe I disturbed that replacing the pump and sender. In any event, the truck runs great and is not starving for fuel regardless of the apparently inaccurate gauge readings.

 

[IDIBRONCO]

or kill fuel mileage.

Or pistons?

 

[Thewespaul]

Or pistons?

That’s my best guess, don’t have the engine torn down so can’t say yet. Valvetrain all checked out

 

[IDIBRONCO]

That’s my best guess, don’t have the engine torn down so can’t say yet. Valvetrain all checked out

Oh well. You're not pushing the limits unless you break something once in a while.

 

[03wr250f]

@SPR1NK

 

[tbrumm]

I finally got around to contacting Autometer over the weekend, and received a reply today. The customer service rep. gave me a list of voltages that the sender should be putting out for each psi from 1 through 15. Back-probing the wire harness at the back of the gauge, I found that (at least sitting in the driveway) the sender is putting out the proper voltage for the psi reading on the gauge. So, it appears the gauge and sender are working correctly, at least while revving the engine while sitting in the driveway. This doesn't explain the erratic 2-3 psi swings of the needle at times just cruising - unless there is an intermittent short or loss of continuity in the gauge wire harness. I have a new wire harness for the gauge, but I wasn't going to fish that through under the dash and through the firewall until I eliminated the gauge and sender as being at fault. Since the sender and gauge appear to be okay, I guess the next thing I will do is install the new gauge harness and see what that does. If we ignore the occasional erratic gauge reading for the moment, the gauge reads about 10 psi when the pump is turned on and before the engine is started. Upon engine start and idle, the gauge reads about 7-8 psi. Generally cruising will see a fuel pressure of 5-6 psi. Pulling a grade (truck empty but accelerating to increase speed) the gauge will read 3-4 psi. Putting the skinny pedal to the floor suddenly while pulling the grade will see the needle dip to 1psi or slightly below, but almost immediately recover to 3psi. Again, the truck never feels like it is running out of fuel, but that quick pressure drop when punching it is disconcerting. This could be function of "lag" in the electric gauge, or it could just be a case of the pump not keeping up with the sudden high fuel demand. The mechanical fuel pressure gauge would probably tell the tale for certain, so I need to figure out a way to rig that up on the cowl.

 

[The_Josh_Bear]

I finally got around to contacting Autometer over the weekend, and received a reply today. The customer service rep. gave me a list of voltages that the sender should be putting out for each psi from 1 through 15. Back-probing the wire harness at the back of the gauge, I found that (at least sitting in the driveway) the sender is putting out the proper voltage for the psi reading on the gauge. So, it appears the gauge and sender are working correctly, at least while revving the engine while sitting in the driveway. This doesn't explain the erratic 2-3 psi swings of the needle at times just cruising - unless there is an intermittent short or loss of continuity in the gauge wire harness. I have a new wire harness for the gauge, but I wasn't going to fish that through under the dash and through the firewall until I eliminated the gauge and sender as being at fault. Since the sender and gauge appear to be okay, I guess the next thing I will do is install the new gauge harness and see what that does. If we ignore the occasional erratic gauge reading for the moment, the gauge reads about 10 psi when the pump is turned on and before the engine is started. Upon engine start and idle, the gauge reads about 7-8 psi. Generally cruising will see a fuel pressure of 5-6 psi. Pulling a grade (truck empty but accelerating to increase speed) the gauge will read 3-4 psi. Putting the skinny pedal to the floor suddenly while pulling the grade will see the needle dip to 1psi or slightly below, but almost immediately recover to 3psi. Again, the truck never feels like it is running out of fuel, but that quick pressure drop when punching it is disconcerting. This could be function of "lag" in the electric gauge, or it could just be a case of the pump not keeping up with the sudden high fuel demand. The mechanical fuel pressure gauge would probably tell the tale for certain, so I need to figure out a way to rig that up on the cowl.

That's about the same psi and general behavior I was seeing with a mechanical gauge, FYI. Pretty typical Facet behavior for those of us that have put a gauge on it.