fuel pump how hot is to hot 76-79 fuel injection

[Jetfxr69]

[Cap10323]

Have you tried a NEW, OEM Bosch fuel pump? You can get them on rockauto.

Why are you even bothering with these used pumps, for $100 you have a 'known good' you can test against, and determine restriction etc from there.

Until you have a verified good, OEM fuel pump, doing any sort of other testing is pointless IMO.

Once you replace the pump, then you can test flow, pressure etc.
_________________
-Ian

'77 Westfalia - 2.0 F.I

[vw76westy]

fuel pressure

was the first thing i tested

when i was still using 1st fuel pump


and retested with every fuel pump ive tried......



for the record
and for shit and giggles

i have drained gas tank
paying attention to the flow of gas
looking for hicups or anything inconsistent with flow

every drop of
7 gallons of gas poured out perfectly consistent

also inspected gas looking for any evidence of a dirty tank



not ruling out gas tank

but all the evidence keeps pointing to fuel pump and not dirty tank

this isnt a bus that was recently brought back to life
or a bus that sits for half the year



fact is a hot fuel pump is not good

fact is the fuel pump i had was bad

and before i assume anything about any other problems
i need to be 100% that the fuel pump is 100%
_________________
order your BAY WINDOW T-SHIRT here http://www.thesamba.com/vw/classifieds/detail.php?id=1526918

quote from bay window bus buyers guide........
The Type 4 engine is considered by many to be VW's finest air-cooled motor,

[vw76westy]

Cap10323

[60vwnewengland]

I bought a Bosch fuel pump from rockauto, no issues so far on a rebuilt motor with 150 or so miles. Haven’t done any long trips, but I assume I would had issues by now.
_________________
77 Westy - Cape Cod Sage
LLAP

[ImAddicted]

Just curious, what are you using for a filter?
I should have mentioned in my test that I did away with the Bosch pump and that tiny filer long ago after too many expensive and short live Bosch pumps so my results may not apply. The only time I’ve had a warm pump s from starvation, which doesn’t sound like your case unless that filter is restricted.
_________________
1979 Transporter (sold)
KC1MUR

[raygreenwood]

As I noted in my post......do not just check pressure.....check pump OUTPUT VOLUME. At idle....you can have great pressure even with a defective or restricted pump. You might notice a little more than standard oscillation to the gauge reading.

If the gauge needle takes a big dip for a split second when you rev it.....it can be indicating a volume problem. These pumps make pressure by supplying volume against a restriction.

You noted that you will be checking voltage soon. I would check voltage FIRST. All of these will run hot if voltage is low.

You noted ...please correct me if I got this wrong.....that you HAVE a new pump and it ran hot as well? What part number is it? If its something that is actually a good deal larger than the stock pump......it could be getting a restricted inlet from the stock filter.

Another easy check.....is to pull the return line off of the tank. Plug it at the tank and measure at idle....what is coming back through the return line...per minute. At idle you should not be using much.

Even at highway driving speed you are using only a few percent of the volume of fuel per second/minute/hour that is running through the loop.

Typically most decent pumps are putting out "about" 1 liter per minute.....at pressure.....and upwards to 1.5 liter/min unrestricted (meaning no regulator is connected). Looking at what is returned to the tank downstream of the regulator at idle can tell you if maybe the regulator itself is a restriction or there is something in line that is restricting you and loading up the pump.

Ray

[VDub Campers Ltd]

I’m struggling to fix this same issue on a customers bus. Fuel pump temp is 122F after idling for one hr. Previous original pump was the same so replaced pump. Same condition.
I’ve confirmed that the fuel pressure is correct until the symptom starts happening. Missfiring, stumbling, coincides with pressure drop on the gauge Engines then stalls Then won’t start. Leave for 3 minutes she’ll start. Run for another. 5-10 mins then same thing happens again.
Did you ever solve this?
_________________
Pics of current work at our google profile:
search VW Engineering Ltd on Google.

[VDub Campers Ltd]

I’m struggling to fix this same issue on a customers bus. Fuel pump temp is 122F after idling for one hr. Previous original pump was the same so replaced pump. Same condition.
I’ve confirmed that the fuel pressure is correct until the symptom starts happening. Missfiring, stumbling, and stalls soon after. Then won’t start. Leave for 3 minutes she’ll start. Run for another. 5-10 mins then same thing happens again.
Did you ever solve this?
_________________
Pics of current work at our google profile:
search VW Engineering Ltd on Google.

[Clatter]

Tram had the excellent suggestion for pumps.
Submerge it in a pail of clean diesel fuel and wire it backwards.
Some of them have an intake screen that’s tiny and can clog.

If it spews crud - there’s your answer.
_________________
Bus Motor Build

What’s That Noise?!?

[mikedjames]

The FI pump relies on that fuel returning freely via the pressure regulator to a large fuel tank in a cool space to cool down the motor in the pump,
Fuel flows through the motor including the commutator and the brushes on the way to the actual pump part.

Testing it into a can which is maybe 4 or 5 times smaller in volume than the fuel tank will result in it rising in temperature until the can is dissipating the heat from the pump.

Blocking off the flow means that maybe up to 100 watts of heat has to be dumped by the pump.

Some people buy 12 volt kettles and boil a cup of water using a similar amount of power.
_________________
Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[Wildthings]

[SGKent]