STD Tuning Engine Fuel Pressure Gauge

Fuel Pressure Gauge

Fuel Pressure Gauge

 
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OneEyedWilly
Naturally-aspirated

13
10-04-2013, 02:00 AM #1
I have a 84 300D, in the process of tuning it up, doing maintenance and up keep. I have been thinking about different gauges I could put in there and one was a fuel pressure gauge, though when i thought about it I came to the conclusion that it would be hard to do, the line going to the IP is a vacuum, is it not? the IP draws fuel from the tank. so how would it pressurize a line behind the pump? and its all steel line after the pump.

Any help or ideas are greatly appreciated.
OneEyedWilly
10-04-2013, 02:00 AM #1

I have a 84 300D, in the process of tuning it up, doing maintenance and up keep. I have been thinking about different gauges I could put in there and one was a fuel pressure gauge, though when i thought about it I came to the conclusion that it would be hard to do, the line going to the IP is a vacuum, is it not? the IP draws fuel from the tank. so how would it pressurize a line behind the pump? and its all steel line after the pump.

Any help or ideas are greatly appreciated.

Simpler=Better
PORTED HEAD

2,127
10-04-2013, 07:50 AM #2
It goes tank->clear prefilter->lift pump->main filter->injection pump->overflow return line to tank.

I *think* you should plumb your gauge in on the line supplying the IP near the fuel pressure regulator

Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
10-04-2013, 07:50 AM #2

It goes tank->clear prefilter->lift pump->main filter->injection pump->overflow return line to tank.

I *think* you should plumb your gauge in on the line supplying the IP near the fuel pressure regulator


Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?

bricktron
'77 240D

174
10-04-2013, 11:10 AM #3
i assume there is a kind of pressure converter diaphragm which lets the fuel pressure push on some air that goes into the cabin, so the gauge side is far away from any substances, like a boost gauge. what is the name of this part, if i'm correct that it exists?


english red rat rod 1977 240D, OM617.952 burning B99.9, iron 4-speed & 2.88 diff, 195/60/R14 on alloys, 5mph bumpers, battery in the trunk, 25mm swaybar, 4x ECE H4 lamps, double brake lamps, deleted sunroof, export zoll & california blue plates




bricktron
10-04-2013, 11:10 AM #3

i assume there is a kind of pressure converter diaphragm which lets the fuel pressure push on some air that goes into the cabin, so the gauge side is far away from any substances, like a boost gauge. what is the name of this part, if i'm correct that it exists?



english red rat rod 1977 240D, OM617.952 burning B99.9, iron 4-speed & 2.88 diff, 195/60/R14 on alloys, 5mph bumpers, battery in the trunk, 25mm swaybar, 4x ECE H4 lamps, double brake lamps, deleted sunroof, export zoll & california blue plates




Tito
Holset

354
10-04-2013, 11:55 AM #4
Well, my exhaust boost gauge just pushes exhaust gas to the dash, and the original oil pressure sensor from my w123 flows oil to the dash. As long as it's not leaking, I see no problem. Even the brittle old plastic plumbing stayed intact after removing my dash.
Tito
10-04-2013, 11:55 AM #4

Well, my exhaust boost gauge just pushes exhaust gas to the dash, and the original oil pressure sensor from my w123 flows oil to the dash. As long as it's not leaking, I see no problem. Even the brittle old plastic plumbing stayed intact after removing my dash.

Simpler=Better
PORTED HEAD

2,127
10-04-2013, 12:27 PM #5
You can also get electric sender gauges. I know the old (70s/80s) Ford trucks had electric gauges, and the 300SD models use electric oil pressure gauges.

Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
10-04-2013, 12:27 PM #5

You can also get electric sender gauges. I know the old (70s/80s) Ford trucks had electric gauges, and the 300SD models use electric oil pressure gauges.


Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?

MFSuper90
Budget Builder

1,533
10-04-2013, 12:47 PM #6
9 out of 10 mechanical gauges just push straight fuel to the gauge via copper or plastic tubing

'82 300D -3" straight pipe, ALDA deleted, 3in1 glowshift gauge, HX30, egr-less manifold, A/W intercooler Big Grin
'14 Ram 6.7l cummins -G56 handshaker, wishing it was deleted         
MFSuper90
10-04-2013, 12:47 PM #6

9 out of 10 mechanical gauges just push straight fuel to the gauge via copper or plastic tubing


'82 300D -3" straight pipe, ALDA deleted, 3in1 glowshift gauge, HX30, egr-less manifold, A/W intercooler Big Grin
'14 Ram 6.7l cummins -G56 handshaker, wishing it was deleted         

Simpler=Better
PORTED HEAD

2,127
10-04-2013, 12:56 PM #7
If you're worried about diesel in the cabin (I'm not) you can always stick the gauges through the hood or under the wipers Smile

Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
10-04-2013, 12:56 PM #7

If you're worried about diesel in the cabin (I'm not) you can always stick the gauges through the hood or under the wipers Smile


Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?

OneEyedWilly
Naturally-aspirated

13
10-04-2013, 11:04 PM #8
Well I know they have Isolators that have a diaphragm that, on the cab side, use a mixture of anti-freeze and water to transfer pressure.

but what i am saying is that the fuel coming from the tank is basically a vacuum. Because the IP draws it from the fuel tank. SO, my issue is how will a suction push fuel up a line that breaks off from main line?

I know the return line is pressurized but the fact that its after the pump means I really wont be getting the info that I am looking for.
OneEyedWilly
10-04-2013, 11:04 PM #8

Well I know they have Isolators that have a diaphragm that, on the cab side, use a mixture of anti-freeze and water to transfer pressure.

but what i am saying is that the fuel coming from the tank is basically a vacuum. Because the IP draws it from the fuel tank. SO, my issue is how will a suction push fuel up a line that breaks off from main line?

I know the return line is pressurized but the fact that its after the pump means I really wont be getting the info that I am looking for.

Volker407
naturally aspirated

157
10-05-2013, 02:48 AM #9
Do you want to measure the vacuum or pressure side?

The fuel changes from vacuum to pressure state in the presupply pump.

Gruß
Volker
Volker407
10-05-2013, 02:48 AM #9

Do you want to measure the vacuum or pressure side?

The fuel changes from vacuum to pressure state in the presupply pump.

Gruß
Volker

OneEyedWilly
Naturally-aspirated

13
10-06-2013, 04:41 PM #10
I didnt know there was a presupply pump? if there was it would have to be inside the tank. is there one up in there?
OneEyedWilly
10-06-2013, 04:41 PM #10

I didnt know there was a presupply pump? if there was it would have to be inside the tank. is there one up in there?

Simpler=Better
PORTED HEAD

2,127
10-06-2013, 08:05 PM #11
The lift pump is mounted to the side of the injection pump, it sucks from the tank.

Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
10-06-2013, 08:05 PM #11

The lift pump is mounted to the side of the injection pump, it sucks from the tank.


Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?

OneEyedWilly
Naturally-aspirated

13
10-06-2013, 11:11 PM #12
I know, But, if the IP is "drawing" fuel from the tank, how will it "push" fuel up a line to a gauge?

I know it would work if there was a pump at the tank. because it would supply pressure up to the engine and to the gauge.

its a difference of push, and pull.
OneEyedWilly
10-06-2013, 11:11 PM #12

I know, But, if the IP is "drawing" fuel from the tank, how will it "push" fuel up a line to a gauge?

I know it would work if there was a pump at the tank. because it would supply pressure up to the engine and to the gauge.

its a difference of push, and pull.

Simpler=Better
PORTED HEAD

2,127
10-07-2013, 08:01 AM #13
Take a picture of your injection pump from the top and from an angle. I'll label where you probably want your gauge.

I don't think you're understanding what we have said so I'll try again:

The lift pump sucks fuel from the tank. The lift pump is the little guy on the side of the injection pump. The discharge side of the lift pump goes to the external spin-on filter. from the spin-on filter the fuel is then fed to the injection pump on the side that faces the engine. That's the line you probably want to tee into (it's pressurized). The fuel then goes into the pump, does it's thing, and excess fuel drains back to the tank.

The lines from the tank to the lift pump aren't pressurized.

The line from the lift pump to filter to injection pump are pressurized. I would suggest adding the gauge after the filter and before the pump, this way you can monitor fuel pressure. a clogged filter, worn fuel regulator spring, or tired lift pump will show low pressure.
This post was last modified: 10-07-2013, 08:04 AM by Simpler=Better.

Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
10-07-2013, 08:01 AM #13

Take a picture of your injection pump from the top and from an angle. I'll label where you probably want your gauge.

I don't think you're understanding what we have said so I'll try again:

The lift pump sucks fuel from the tank. The lift pump is the little guy on the side of the injection pump. The discharge side of the lift pump goes to the external spin-on filter. from the spin-on filter the fuel is then fed to the injection pump on the side that faces the engine. That's the line you probably want to tee into (it's pressurized). The fuel then goes into the pump, does it's thing, and excess fuel drains back to the tank.

The lines from the tank to the lift pump aren't pressurized.

The line from the lift pump to filter to injection pump are pressurized. I would suggest adding the gauge after the filter and before the pump, this way you can monitor fuel pressure. a clogged filter, worn fuel regulator spring, or tired lift pump will show low pressure.


Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?

OneEyedWilly
Naturally-aspirated

13
10-07-2013, 01:42 PM #14
Thank you, I dont know why I didnt understand before, but I got it now.

Thank you, Gents.
OneEyedWilly
10-07-2013, 01:42 PM #14

Thank you, I dont know why I didnt understand before, but I got it now.

Thank you, Gents.

Simpler=Better
PORTED HEAD

2,127
10-07-2013, 01:54 PM #15
(10-07-2013, 01:42 PM)OneEyedWilly Thank you, I dont know why I didnt understand before, but I got it now.

Thank you, Gents.

Anytime. We will beat it into your head :p

Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
10-07-2013, 01:54 PM #15

(10-07-2013, 01:42 PM)OneEyedWilly Thank you, I dont know why I didnt understand before, but I got it now.

Thank you, Gents.

Anytime. We will beat it into your head :p


Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?

 
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