'64 Triumph TR4 Build

Made a few laps around the block last night. I'm having a fuel delivery issue that I hadn't experienced before. Runs fine for a minute or so under load, but then seems to starve out. Have to close the choke almost completely to keep it alive, at which point it perks back up for a little while. It didn't do this when I had it out a couple weeks ago; the only changes to the fuel system were the fuel cell (mounted lower, so not as much head pressure on the pump) and added a second in-line filter between the pump and the cell (would increase the pressure drop between the cell and the pump).

Long story short, I'm going to get a section of 5/16 fuel line and take the filter out of the equation and see if that works. If not, I may be SOL for this weekend...

Aside from that, I need to do a bit more brake bleeding, finetune the handbrake, and reinstall the DOT-approved lap belt for legality.

On that note, I'm going to have to be very careful with this car; it garners a LOT of attention. A LOT. Haven't attracted any LEO's yet, but I'm sure I will. So long as I've got my t's crossed and my i's dotted, and don't drive it like a hoon, I should be alright, but heaven forbid I step out of line.

In reply to JohnInKansas:

Is your fuel cell new? If not could it have some debris or gunk from old fuel in it? Try some cheap clear plastic fuel filters so you can see what's happening with the fuel flow. How about the fuel lines, did you put all new ones on? On more than one occasion I've found old fuel lines to be stopped up with debris at the lowest point. Dissconnect it F&R and blow through it with your mouth which is the best way to detect it being stopped up. Good luck, cool project!.

Another idea, are you using the mechanical pump or an electric? I built a 1275 Bugeye and put an electric pump on the fender well. The car ran but I had to choke it at high speed. I moved the pump to the rear of the car below the fuel tank and it ran fine, i.e. not enough inlet pressure.

Brand new cell.

Lines are all but new, put new line in less than 50 miles/3 months ago.

Using an electric pump with the mechanical removed and blocked off, but have the mechanical and a rebuild kit. That would be an option, now that you mention it. I'll rebuild it tonight, just in case.

Pump is currently mounted about 4 inches below the tank oultet, with no more than 12 inches of line between the two (well, 12 inches and a cheap metal fuel filter). Previous setup (original tank) had the pump about 10 inches below the outlet, and with no extra filter, just the one built into the pump.

I'm still having issues with stalling under load, though the idle is much better. Smoother, no stalling once its warm. Timing looks good, plugs are gapped correctly. I need to check for vacuum leaks this afternoon, and make doubly sure the tank outlet is clear and the tank is vented.

Drove a half-dozen two mile laps last night trying to dial in the fuel mixture. No joy, same symptoms (see "Sanity check me, por favor" thread). While I was out and about, I fried the generator, the fan relay, and the headlight switch. I'm picking up the stuff for an alternator conversion at lunch, should be able to track down a relay and a switch while I'm out.

What's different that it's idling better? Do you happen to know the flow of your fuel pump. Any chance it's getting too much or too much pressure? I was thinking the ZS carbs don't like more than 2-4 psi - jets clean - it's been sitting a a while right?

Idled better after I reset the mixture per the Haynes manual, but still crappy performance under load.

I was using a low-pressure (sub-5psi) electric pump with a pressure regulator, but cut that out of the equation by reverting to the mechanical pump. So it should be getting a suitable fuel pressure.

Carbs are clean. It sat for 4 years while I was in college, I started fooling with it a couple of months ago. It has run since then without issues.

The only other variable in the fuel system is the cell; same capacity, but the outlet is about 6" lower than the original tank, and the center of gravity of the fuel in the full cell is 12"+ lower than original. The original tank provided some static pressure to the pump inlet by the fact that the fuel c.o.g. was higher than the pump, but the new tank's c.o.g. is lower than the pump, so the pump has to draw fuel uphill from the tank.

Parallel fuel issue thread

If you've eliminated the vacuum leak theory my next step would be get a jug and run the pump for a minute..With jug at carb height. Maybe the change in cog does need more pump

Well, berkeley.

I've spent the last week trying to get to the bottom of this "idles okay, but won't drive worth E36M3" issue, with precisely no success. Still has exactly the same symptoms. Relocated the fuel cell 8" higher, removed the in-line filter, played with the mixture, played with the float height, nothin'. Just snapped off the oil pressure line when the wrench slipped off the fuel pump fitting, which resulted in oil every-berkeleying-where.

This car doesn't want to go racing tomorrow. I'm done. I've got all winter to berkeley with it, there's no point getting stressed out to no avail trying to get it done on a tight schedule.

Might you want a new induction system???

http://grassrootsmotorsports.com/forum/200x-classifieds/long-tube-tr4-manifold-and-su-hs8-carbs/60765/page1/