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TR2/3/3A Mechanical fuel pump output

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deuce

deuce

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Hello all.. I am having a issue with my 1960 TR3 cutting out badly accelerating after driving for a while. I'm wondering if the fuel pump isn't keeping up with the engine..know what I mean.
So how would I test pump output. It does pump..it will start and run at idle. I have to start somewhere. Thanks
I did rebuild the pump with a kit from TRF
 
One of my mentors many years ago told me that most fuel related issues were electrical in nature. I'd check the ignition system, points, plugs, wiring, condenser, etc.
In my experience mechanical fuel pumps either they worked or they didn't. You could I suppose,check the flow rate but only at low rpm with the starter. I don't know of hand if there is any data on that either.
Tom
 
I couldn't find a specific value for the pump's flow rate. But you could disconnect the fuel line at the carbs and direct it into a jar. You should see a series of healthy squirts when you crank the engine. You can also test the output pressure. It should be around 2-3 PSI.

That said, sudden cutting out is usually not the fuel pump. It's usually something electrical. When the car cuts out because of fuel starvation, it's usually preceded by a lot of sputtering and missing.
 
Sarastro said:
I couldn't find a specific value for the pump's flow rate. But you could disconnect the fuel line at the carbs and direct it into a jar. You should see a series of healthy squirts when you crank the engine. You can also test the output pressure. It should be around 2-3 PSI.

That said, sudden cutting out is usually not the fuel pump. It's usually something electrical. When the car cuts out because of fuel starvation, it's usually preceded by a lot of sputtering and missing.
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Thanks for the reply. That is what it does. After driving for awhile at speed..50-60 it starts cutting out if I give it some gas. If I slow down..35-40 it runs ok. That's why I thought fuel, but I'm not a technician though I built my car from the ground up. So I'm open to suggestions
 
This one's obvious, but it's worth checking and cleaning or replacing ALL fuel filters in the system. Especially the little plastic of glass ones that were added to the car long after it was built. I had a glass-bodied filter in the fuel line to the carbs that gave me no end of trouble about a year ago, even to the eye it looked OK. As soon as it was gone, the problem was solved.
 
groupdeville said:
This one's obvious, but it's worth checking and cleaning or replacing ALL fuel filters in the system. Especially the little plastic of glass ones that were added to the car long after it was built. I had a glass-bodied filter in the fuel line to the carbs that gave me no end of trouble about a year ago, even to the eye it looked OK. As soon as it was gone, the problem was solved.
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And if you do not have a online fuel filter you should remove the glass bowl on the fuel pump and pull the fine screen located above where the glass bowl was. If that is clean then check your float bowls.
Charley
 
As noted by Charlie, check the float chambers. I had similar performance issue a number of years ago. The rear float chamber was dry which was caused by dirt holding the float chamber valve closed. Cleaned that and good as new.
 
Yet again ,there are AM fuel pumps that fail in just this way due to a TERRIBLE design change.
The best thing to do with these pumps is to cannibalise the parts to rebuild an original pump.
Mad dog
 
The failure mode for a mechanical pump is it starts spewing fuel out of the vent hole on the pump. Second most common is if one of the check valves sticks open...in which case it stops pumping at all.

Low fuel flow would likely be a clogged filter, not the pump.

Cutting out when hot would most likely be cause by either vapour lock or an ignition coil starting to go bad.
 
The other failure mode is filling the sump with gas.(VERY nasty).But again there are a lot of crappy AM
fuel pumps on the market. If you inspect the attachment of the pump arm , the fulcrum pin is set into a grove
and staked into place.This fails very quickly and the arm losses action as the pin works loose. The result is
less flow and then even less.
Any time a fuel pump is fitted LOOK at the way the fulcrum pin is fitted .The OE design was a roll pin was pressed through
the housing, not set in a groove.
Any one that sets a filter inline before the pump is begging for trouble!!
Mad dog
 
Hi everyone I bought a TR3 A a month ago , trying to get it running. The fuel pump won’t pump gas while I crank it over but will pump gas when I hand pump it with the lever on bottom of pump. I have taken the pump off a couple times & it has plenty of suction. Does the cam have to be in specific spot when I install the pump? Can I put my finger in the block & turn motor by hand to find the right spot? The tank was dipped with new fuel lines before I bought it. Flustered here in Oregon!🤗
 
Melton, that is the classic ,defining symptom of the made in India P.O.S. fuel pump. It is junk.
When you take it off you will see how the roll pin is come adrift.
Mad dog
 
I've had a new fuel pump on the shelf "just in case" for several years but have always rebuilt the old ones. I get excellent kits and parts as well as support from this vendor: > Contact Us | Then and Now Automotive < (I am not connected with them in any way)
 
Melton,
When you insert the fuel pump arm into the engine block. Make sure that you have the pump level or even better have the arm positioned slightly higher than the pump. It is possible if you insert the arm pointed slightly down to get it underneath the cam lobe. I did it once.
Charley
 
My experience has been if the fuel pump is not keeping up the engine just loses power from fuel starvation and calmly slows down. When you say cutting out badly, is the engine actually missing and popping? If you have back firer noises the spark is cutting out and coming back on and igniting the unburned fuel.

My first guess is the coil fading out. I would put a new coil on and see what happens. You can also turn the lights out in the garage and maybe see the coil or some other area sparking.

steve
 
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