TR2 & TR3 Forum

1960 TR3A - The Problem: As succinct as I can make it:

- Car runs but starves for fuel - first symptom is rear carb float chamber runs dry, then the car stalls. It will starve for fuel at high idle in the garage, and stalls after less than a minute on the road. If I fill the carb fuel bowls, it cranks right up and I can limp home.

- When I first got the car running in October, it would drive for 30-45 minute trips, but at some point it started the stalling routine

What I have done….

- Put glass fuel filter prior to carbs, also shows dry when car stalls. I stress that engine runs pretty well when getting fuel.
- Rebuilt carbs, new seat/needle, float, fork, gaskets, etc. tuned carbs . I thought maybe fuel chamber float needle was not dropping…..still stalls.
- New fuel line from pump to carbs…..still stalls.
- Replaced mechanical pump with electric Faucet pump. Still stalls. Returned to mechanical pump. Fuel appears to be spurting appropriately with both…..still stalls.
- Replaced points, condenser and a frayed wire in the original distributor, reset timing. Still stalls.
- Replaced with Pertronix electronic ignition and reset timing…..still stalls.
- I am to the point that I think there is a clog in the fuel line from the fuel tank to the pump (there is a patch or two in the metal fuel line) causing intermittent or reduced fuel flow to the pump. That still doesn’t seem quite right to me, as the fuel bowl at the pump stays full….although I constantly find debris has settled in the glass bowl.
- I am at my wits end and am seeking advice. I have replaced or tuned everything I can think of but am no expert on these engines and solicit any advice from the experts out there.
- Does this ring a bell with anyone?

I would add that the fuel bowl on the pump will always look full because the fuel drops into the bowl and exits out the top.
Work on the fuel line behind the pump and the fuel tank.
Charley

There is a rubber tube just after the initial exit pipe from the tank which joins the pipe that does the long run up to the fuel pump.
It can clog up and if it is non ethanol resistant as per the original piece it turns to jelly and closes up.
If that is OK have a look at the membrane on the pump. Again if it is not ethanol resistant it will deteriorate.
Also blow through the copper pipes with some compressed air while you have things in bits.
Is the bottom of the fuel tank clear / clean?

james

James. You are of my way of thinking. I have checked the fuel pump membrane and it feels firm and “normal”. In looking down into the tank, some parts look brassy and other parts are brown. Can’t tell if the brown is sediment or discoloration. Plan to run tank dry and give it a better examination. Does anyone have suggestions on how to clean a fuel tank. Is it possible to clean it in place, or vacuum out any debris? I will drain the fuel line then as well and blow it out. I see the one rubber hose at the bend, James but there is another one several inches forward. Thanks for the suggestions.

I am struggling with understanding how the bowl can be full from the gravity feed from the tank but not be pumped steadily to the carbs. The fuel bowl is full, the pump seems to be pumping (but with the original mechanical pump, a new Moss mechanical pump and/or new Facet electric pump) but yet the glass fuel filter and float bowls run dry.

Thank you.

Is your vent plugged? Some caps are vented as well by PO

https://www.triumphexp.com/forum/tr2-and-tr3-forum.6/fuel-tank-vent.1355169/

My first thought was the float needles, as I had the ball style that would do the same as your symptoms. Then I reread your post a couple of times.

It almost sounds like one he rubber hose(s) is collapsing internally. Outside looks fine but the inside collapses when a "vacum" (your fuel pump sucking) the inside collapses. with no vacum the hose pressure equalizes and flows from the tank to the pump. I would just replace any rubber lines from the tank to the fuel pump. My bet is that you will find your tank fairly clean.

---

1958 TR3A TS26957L Mods for reliabilty: Electric fan, Electronic Distributor, Starter. Mods for fun: Oversize sleeves, Cam, Flywheel lightened, HS6 SU carbs TR4 4 speed trans

Check that the line connection to the pump inlet is tight. If air is getting tucked in it will affect the pumps suction.

But it sounds like you have a restriction in.the fuel line somewhere between tank and carb bowls.

The pump must be capable of delivering at least about a quart in 30 seconds.

It also needs to be capable of 4 psi (factory spec). The pressure is needed in order to generate the necessary flow rate.

If there is a restriction, you won't get adequate flow to keep the bowls refilled.

You said in one event, the rear bowl was dry. Was the front also low or dry? If only the rear, check that there is not a restriction in the line to the rear carb.

Also verify the carb bowl float needles are not stickung.

Quote

I am struggling with understanding how the bowl can be full from the gravity feed from the tank but not be pumped steadily to the carbs. The fuel bowl is full, the pump seems to be pumping (but with the original mechanical pump, a new Moss mechanical pump and/or new Facet electric pump) but yet the glass fuel filter and float bowls run dry.
[/quote]

What I was trying to relate to you about the full fuel bowl is that once the fuel bowl is full -- if the fuel coming into the bowl is stopped. The bowl will appear full but in reality the fuel level is below the top and is not passing fuel into the pump.
Charley

If you have not doe so, check that the screen filter is not blocked. Refer to the attached diagrams.

Also, if an air gap exists at top of the bowl, the pump suction will be lost or spotty.