are fuel pumos very specific?

[Monkey Wrench]

I was about to replace the Bosche fuel pump in my early 85 Porsche non turbo 2.5

and realized that I had a bosche pump for my 88 ford van already onhand. It's a 300 CI 6 cyl. It should have adequate flow but would it have the right pressure?

I saw reference to a fuel pressure regulator, i think it's near the pump right? i haven't yet removed it.

does anyone know what the fuel pressure should be after the regulator and does the regulator reduce the pressure to a certain pressure?

some cars have a return fuel line, but I'm not sure if my porsche does. my line from the tank went rotten but its just basically a hose, i believe there is no pressure other than gravity before the filter so I think that just needs to be fuel rated line. It's got a bend , maybe that's important. or maybe just normal fuel line is ok for that?

can I plumb in a gauge like I'd use for water pressure or oil pressure to measure fuel pressure. I assume it's around 60 or 70 PSI or near that,right? i know Il need to find some fittings to fit the line and the rail to plumb it in between there.

some parts seem pretty pricey like the fuel pressure regulator , the one that uses manifold vacuum to control fuel pressure.. the one located on the fuel rail.

If I can connect a gauge maybe I can check if it works right rather than replacing it on the presumption that it may fail to work properly.

the pressure gauges usually used for things like air pressure have a Bourdon tube made of brass inside so I doubt the gauge really cares what fluid is in it or even if it's air or water or some other fluid.

do others install a fuel pressure gauge if they want to keep an eye on it? I might consider connecting it temporarily. I dont really want another gauge in the car. If it's not dangerous it could be plumbed to a tap with Tee fitting along the fuel rail and live under the hood, so it could be turned on to read it. other times it might be shut off in case it ever leaked.

I assume the gauge might be similar to an oil pressure gauge, or an air gauge often goes up to 100 or 200 PSI or so,, does a gauge to measure fuel pressure really need to be some fancy specific tool?

Thanks for your insight !

[djnolan]

Check Clarkes for the fuel system configuration. If I am not mistaken all of the 944's have an fuel pressure regulator on the return line and a fuel pressure damper on the feed line. The standard 944 run 30 psi and the 16 valve cars run 45 psi.

Fuel Pressure Specifications
All 8V 944s and 944 Turbos
Engine Stopped - Relay Jumpered 2.5 bar +/- 0.2 bar (36 psig +/- 3 psig)
Engine Running at Idle 2 bar +/- 0.2 bar (29 psig +/- 3 psig)
20 Minute Leakdown Pressure 1 bar (14.5 psig)
All 16V 944s
Engine Stopped - Relay Jumpered 3.8 bar +/- 0.2 bar (55 psig +/- 3 psig)
Engine Running at Idle 3.3 bar +/- 0.2 bar (48 psig +/- 3 psig)
20 Minute Leakdown Pressure 2 bar (29 psig)

http://www.clarks-garage.com/graphics/na-fuel-vacuum-line-1.jpg

http://www.clarks-garage.com/graphics/na-fuel-vacuum-line-1.jpg

[Monkey Wrench]

Thanks for that info. I found the fuel pressure leakdown test and some notes on creating an adapter by searching the Clarks page. there seems to be a directory but It doesn't seem to have links into the pages. searches come up with lots though.
Maybe I'm just not viewing it right or something. I know there is more in there than I get from the link bar at the left.

maybe I can get flow and pressure rates of the actual pump from bosche part numbers. There might be Bosche spec sheets for the pumps.

failing that I'll just remove it and check the pump, I could compare flow rates with water if I flush it with fuel after or just use it like a fuel transfer pump from one jerry can to another. if it appears much different in flow or fittings, I'll just order the right pump. it won't make sense unless it just so happens to be very similar.

The pump probably didn't die yet but likely was never changed and I'm guessing it's due. It's never much fun when they fail.


I might find the lines the same as Volvo used if so I should have fittings that I can salvage to make an adapter up so it can Tee off to a 1/4 NPT fitting. That might be helpful for my 80's volvo's too, so I can do their leakdown tests. I've been meaning to make up the adapter anyway, for that. I'll compare to see if they used the same lines, like the Porsche they will be metric fittings.

mines an 85 , non turbo 8 valve , series 1

[Monkey Wrench]

I'm unsure if I can order through Pelican Parts, I don't think they will actually ship to Canada. I can get a PO box in the US but then I need to go get passport to go across the line. I'm only 20 mins from the US border.

here it is on Pelicanparts
Porsche Fuel Pump - 94460810204 - Bosch 69467

https://www.pelicanparts.com/More_Info/94460810204.htm?pn=944-608-102-04-M14

the one for my ford van is also very similar, the inlet side is set up for a smaller hose diameter and the threaded fittings on the output side could be different. I think Ill just try to obtain the correct part. Interesting to make a comparison though.



here is one from bosche but it is a bit different. I included it for reference, because it actually lists the pump specs for flow and pressure. (I put remove in the URL)

"The FP 165 is an inline roller cell pump for the installation outside the fuel tank.

It is capable of providing 165 l/h at 5 bar. Bio-fuel can be delivered up to E85 (shortens lifetime!).

The FP 165 is a production type fuel pump, combining good quality at a low price.

Mechanical connector intake side
M14x1.5

Mechanical connector pressure side
M12x1.5"

https://www.(remove)bosch-motorsport.com/content/downloads/Raceparts/en-GB/49658123113048459.html#/Tabs=49669771/

The pump itself doesn't develop pressure it needs a restriction to build pressure so I think most would function but one too large in flow wouldn't be helpful.

[djnolan]

Look at the renbay fuel line kit.

There is a directory on the home page: Clark's Garage Home Page

[Monkey Wrench]

Originally Posted by djnolan

Look at the renbay fuel line kit.

There is a directory on the home page: Clark's Garage Home Page

Yes that $100.00 Renbay kit would work , ill do that if my spare old Volvo fuel lines do not fit. I'm a millwright or Industrial Mechanic not an auto Mechanic, I can cobble together the adapter, I just need the correct fittings.

I found The Clark's Garage "shop manual" page has all the links. For some reason from my home computer it would not open any links from that page, but today I see it works from a different computer so maybe it was an " operator issue " ;-)

Thanks !

[djnolan]

The renbay kit uses a compression coupling and triple barb adapter instead of the original single barb and compression collar. You could just use fuel line and clamps with the old single barb fittings and hardline but it would not be as safe.

[Monkey Wrench]

right. I think I have a volvo fuel rail that might have the right fitting and the hose to the pump is about maybe 5 feet long and couples to the pump.

the rail shouldn't be hard to braise to but splicing the plastic line could be harder part. I guess I could perhaps just leave the fuel pump connector on the other end and use that threaded fitting and connect that to the TEE , i can cut an inch off the old rail and probably do a double flare like brake line or just braise it into a junction block.

It might look a bit awkward but I won't use it very often. someone that uses it often. like a real car Mechanic would want something more professional looking for sure.

If I dont cut the fuel line then I do ahave a fitting on the pump end of the fuel supply hose that I can use, and in that way , maybe avoid barbed fittings.

I know that for the first time, undoing these fittings can sometimes be a challenge. maybe the factory used red locktite or similar, but you can't heat a fuel line to break the loctite.

a ferrule fitting might work to seal that plastic line, then I could shorten it up, but the plastic line will be metric so then I'd be looking for a metric ferrule fitting.

[djnolan]

Everything you would ever want to know about 944 fuel lines here: https://secure242.inmotionhosting.com/~arnnwo5/catalog/index.php?main_page=page&id=17&chapter=1

[Monkey Wrench]

Thank you for that link, that helps !

Possibly there are other vehicles that use similar metric lines that have better representation from aftermarket suppliers.

[djnolan]

If you are doing the lines in the engine compartment the renbay kit is superior. I did an older car with aeroquip line and hose clamps and couldn't sleep at night. The renbay moves the junction outside of the engine compartment into the wheel well. So in case there is a leak it won't get ignited by the exhaust manifold. Also the fuel line is superior high temp material and since it is triple barb it doesn't need clamps that could break or loosen. For $100 you can't beat it.

[Monkey Wrench]

I think you are right, mucking around with that will cost as much anyway, no point reinventing

We have a highway here I’ll use, it has a really steep crazy long hill and almost every time I go there is someone there watching their car burn up..
happened to a friend he and girlfriend got to watch it burn, kid too, while they stood with their bags ., they don’t put them out.. the gas tank goes and tires pop and in the end very little left of these new limited lifespan cheap plastic cars especially

[walfreyydo]

Another fantastic resource (for a turbo but should be almost identical to any early 944):
https://www.deancent.com/porsche-944-fuel-line-build-and-install/

[Monkey Wrench]

Thank you so much for this !
that page also linked to a lot of other valuable info. I learned about some parts that I have on hand which fit the Porsche, That's great info for troubleshooting..

i've been fighting an issue with my volvo 240 where it idles very erratically when warm and sometimes gets very weak and almost stalls while driving. Its driving me a bit nuts.. i think its runnig way too lean at times. I learned the idle air valve is at least somewhat compatible with my 944 and i have used ones on hand. I've yet to find the cause but I shouldn't post about Volvo issues here. I'll keep swapping used parts in hopes of nailing the cause that issue, hopefully without too many "tow home" experiences ;-)

Thanks again , that link helped me a great deal.

[BoxsterGT]

I have been making replacement Fuel Lines and Hoses for most older Porsche models and all are E-85 Rated Crimped Metric fitment.

I also have an extensive inventory of Metric Fuel Fittings and am able to make up custom fittings and Hoses on request.

All are considered "Factory Level" or higher by those who know my products.











For information, please email me: len.cummings @ Verizon.net

[Monkey Wrench]

those look great Len. i like how they look original rather than the anodized fittings, not that mine is detailed or even clean yet.

[BoxsterGT]

I posted the above as this Bosch "Flow-Through" design Fuel Pump is now used worldwide by most auto manufacturers.

It has become almost "universal" in vehicle fuel systems, and so many are made today the cost has dropped dramatically.

Different pumps will vary in their fuel volume / delivery, but within that range of values, it's the Fuel Pressure of the system that determines the vehicles performance.

That is controlled by the individual motor.

I believe a Fuel Pump of this design can be used in many applications given the correct fittings and hose.

Just my two cents here. I can help with fittings and hose if needed.

Len

[Monkey Wrench]

I think the way Len is making up the lines is very professional, It would be very hard for most of us to replicate something so close to original.