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TR4/4A Fuel delivery problems in my '64 TR-4

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tr4boy

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Folks,
Not really sure what's going on with the car. I have developed a hot start problem that I can't seem to figure out. Car starts fine when cold but after warming up is hard to start. Changed out fuel lines and filter just as a precaution but no change. Checked to see if the fuel vent was clogged but since this is a later car (CT 38104L) it apparently doesn't have a vent line. Does anyone know if the cap is vented? I did notice that the clear fuel filter I use (FRAM G2) appears to be empty when the car is hot. Over about 30 minutes it will fill up again. Also, when empty, I can see the fuel pulses in the filter. They don't look uniform meaning that they are mostly random. Could my pump be going bad? Any thoughts on what I should check?

thanks,
Greg
 
I believe the tank vents through the cap on your car. You can test for vacuum in the tank with an ear to the cap when you pop it, you will hear an audible suction sound. If your no hot start is related to lack of vent, it should start right up with the cap open.
I doubt that's you issue though. Although it sounds a lot like vapor lock I would first rule out a bad ignition coil.
Tom
 
Last edited:
Hi Greg,

It could be the pump, but it might be a partially blocked fuel line. I've had 2 TR6s that had a crud/sediment build up where the line makes the vertical to horizontal bend coming from the tank. Both cars had sat for several years before I got them. You could 'rod out' the line with a copper wire, but I ended up cutting that part out and replacing with a longer rubber line to the tank outlet pipe.

Jeff
 
IMO you're chasing the wrong thing. The float bowls should still be full, meaning the engine would start even if the fuel pump was removed. You should first establish that you actually have a fuel problem (not ignition as Tom suggested, bad capacitors also sometimes fail only when hot), and then look at why the bowls are empty.

If the filter was full when you stopped and then empty after sitting a few minutes, you've also got an air leak in the fuel system. To be "empty", the filter has to actually fill with air and there shouldn't be any air there for it to fill with.
 
Well, for what it's worth I had exactly the same symptoms many years ago. Killed a battery and nearly killed a starter cranking a hot no-start condition.

Ultimately turned out that when I had asked an inept mechanic to adjust my carbs, he dialed them in sooo rich it was like having the choke on full time. Started great when cold but, would not start hot. I'm not saying that is your problem but, it may give you ideas of what to look for.

As a result, I now do two things
1. I perform nearly all my own work since I had similar bad experience with 3 different "British" car mechanics who didn't have a clue
2. I track my fuel mileage (MPG) now as it can be an early indicator of fuel or ignition issues. If I see a big unexplained variation in MPG I want to know why

Bob
 
I have seen engines that have such bad compression that when they get hot the compression is worse-no start. I would also look at the coil. Drive around get the motor hot then have a coil all set up at home with some small jumper cables. Unhook the old one and Wrap the different coil in a towel or something and just set it somewhere hook it up and see if it starts better. If no change try some starter fluid and see if that makes some difference for a fuel problem.
 
Do you have a stock distributor? When I switched to the pertronix, I had the same problem. Turned out to be the coil.
 
Thanks, folks,

I have the upgraded lucas coil and I'll test it this weekend. Compression test, too!

Greg
 
Don't know about a TR4 fuel pump, but my TR3 has priming lever. You can disconnect the fuel line before the filter and pump the priming lever to see if the pump is working properly. Then reconnect and disconnect at the carb. Pump again and see if the filter or line is causing a restriction.

If all is well, check the floats and the angle of the tab which allows the needle valve to open. Could be one or both needles aren't opening enough to fill the bowls or one of the floats is sunk. These checks will take all of about 5 minutes.
 
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