I've got an '87 300D with a Greasecar kit, and I'd like to get a fuel pressure guage to monitor the clogging of my WVO filter. I've been surfing the web, and not really found what I think I should be looking for. As far as I know, my fuel pressure before the lift pump is fairly low, correct? Like 5-10 psi or something like that? The few guages I've seen were 0-60 psi, which is too big a range for my application. The guages I found that were 0-15 range were designed to be mounted outside the car. I need to see my fuel pressure while driving, so I can monitor what's happening. Anyone know where I can get a guage for this purpose. Also, are there fuel pressure guages that have electrical senders, so all I have to route to my car's cabin is an electicwire coming from a sender unit that would be mounted in the fuel line? I'd rather not have to run any tubing into the cabin.

Thanks, as always - this forum ROCKS!

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine

if you want a pressure gauge, it should be electric to prevent leaking hot oil in the cabin. i use a vac gauge between switching valve and the pump input. this gives readings on both filters.

try egauges.com

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

I'm bumping this thread up... I'm getting ready to do some work on the fuel system, so this will be a good time to install the fuel pressure guage. Does anyone know where to get one that has a low pressure range?

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine

A guy I know in Iowa has done a couple conversions on old benz's. Here is a schematic of a car he helped to convert, nor he or I made the schematic, I was sent a link to the pictures.

The fuel pressure gauge used is a Sunpro boost vacuum gauge from JC Whitney.

Attached Thumbnails

 

why not just use a gauge from a gasser?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

I think you want the pressure gauge before the filter rather than after if your lift pump is before the filters. The pressure after the filter is mostly controlled by the IP pressure relief on the IP.

If your lift pump pulls from the filters, then you need a vacuum gauge between the filter and the lift pump rather than a pressure gauge.

VDO makes mechanical pressure gauges at 15psi and 30 psi. Unfortunatly, electrical fuel pressure gauges cost about $200 to $300 more than mechanical gauges.

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Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY

the gassers economy gauge is 0-15 and is stock in the instrument panel....

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

If you want a mechanical fuel pressure gauge inside the cabin, a safe way to do it is to use an Auto Meter isolator, which runs about $100 for 300psi capacity...



...or a Mallory isolator, which runs about $65 for 80psi capacity...



BTW, "gauge" is spelled just that way -- with the "a" before the "u."

I have an auxillary electric fuel pump that pulls from the WVO tank and pushes it through the WVO filter. The stock lift pump then pulls the WVO from the filter and pushes it to the IP.

My goal is to be able to determine when my WVO filter is clogging. Taking all this into consideration, where do you recommend putting the gauge, and would it be pressure or vacuum?

Thanks!

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine

in that case, a vac gauge would be before any pump, and the pressure gauge would be best after all filters- that would indicate a clogging filter by decreased pressure.

have you looked at oil pressure gauges? cheaper. I'd still go with electrical, so no lines in the car.

I took a page out of the big trucks book, and installed a vac gauge after my switching valve. it gauges resistance on both filters.
this is on my cummins-
tank(s) to valve, vac gauge, filters, Lift pump, IP.

I dont see a need for a boost pump, especially if you have a heated tank, lines. those LP's pull alot of pressure.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

I found an electric pressure gauge for about $80. Here it is:

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_745259_-1_10677

It matches my greasecar fuel level gauge pretty closely, so it will look good on the dash as well.

BTW - Anyone know where I can get a new in-line sender for my WVO temp gauge? I screwed up my original sender.

Thanks!

Attached Thumbnails

 

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine

That looks alot like the one I designed.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine