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TR6 Question for TR6 triple carb owners

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Do you run ok with a mechanical pump, or did you have to fit a low-psi electric?

Went to get the car back today. Runs great under 55mph. Tons of power - 3k-5.5k especially is super strong. It runs like a dog above 60. I got 7 miles down I-95 before it died on me (so if you were around exit 27 at noon and saw a red TR6 at the side of the road, that was me).

I'm still having the (original) fuel starvation symptoms. I got the mechanic to drive it on I-95 at speed and he now sees what I mean, so at least he doesn't think I'm insane...

I have a new TRF mechanical pump on the engine, but it looks like it might not be flowing enough. I'm looking at adding a 2.5 psi electric in series to see if that helps. I can't use the aeromotive in the trunk - it puts out way too much psi and there is no regulator on the market to take it from 45psi to 2.5...

What would make me feel better is hearing that I'm not alone here and someone else has had to do the same. Otherwise I'm a bit stumped as to why me, unless the stuff in the trunk is making a bottleneck.

I want a season driving on the carbs before I do anything else. I figure I'm owed at least that much...
 
Alan,

Its a shame to hear that you're still having problems with it. I can't remember your setup, but I assume you have the triple webbers? From the little bit of reading I've done, you'll need a fuel pressure up around 4 psi, not 2.5:

"The standard Triumph fuel pump is totally inadequate. Webers need lots of fuel flow but can't stand pressures over about 5psi (3-4psi is a good number). The shiny-toy pressure regulators sold in discount stores cannot flow enough fuel to keep three big float bowls full at high engine speed, unless you use one per carb. An unregulated stock fuel pump will put out up to 8psi at hi-rpm which will sink the floats, causing other problems." From https://www.hottr6.com/triumph/tr6weber.html

An option might be the Carter rotary fuel pumps listed on https://www.racetep.com/webfuelspark.html as these have the 4 psi and do not require a regulator.

Cheers,
Mark
 
I have triple Z-S's and have not had a problem with the fuel pump. I did have a problem with the filter plugging which was traced to the gas tank - naturally. That got the POR-15 treatment. Then found that the rubber hoses were 1/4" ID instead of 5/16", so those got replaced. The right filter to use is a Purolator F20011 or equivalent. If you just grab one that looks right it could give you problems.
 
Alan,
I seem to remember about this. Here is something to try. Run a hose from your fuel pump back into the fuel tank filler and let it run. See if the flow slows or stops after about the same amount of time it has been stopping on you.
If nothing else you could then absolutely eliminate that part of the fuel system from the problem.
Also do a timed fill of a pint container and see if it has enough flow volume.

Almost forgot, check for air bubbles in the fuel flow also. (just hold the end under the fuel level in a clear container)
 
I have a triple ZS setup.

I have a brand new custom stainless tank, with twin -8AN pickups to the filter/fuel pump assembly in the trunk, then -6AN to the front of the car. Tank is baffled (as am I). I'm pretty sure it isn't an air in the fuel problem, and there are no contaminants in the fuel or the lines - all are new, and the filters are clean.

There is splitter at the front firewall with a takeoff to the stock system (the other outlet is plugged for now). Stock pump, stock inline filter, stock fuel distribution setup from the firewall to the carbs.

Since the car is slightly warmed over it likely uses a bit more fuel than stock, so it appears either the (unpowered) fi pump in the trunk is restricting the flow, which seems odd, or the thing wants more fuel than the stock pump can give.

Anyway, the next step is to try a low pressure electric pump inline. We'll see if it helps when it comes...

I'd still dearly love to hear if anyone else has had to do this. Misery loves company.
/ubbthreads/images/graemlins/frown.gif
 
[ QUOTE ]
...

Since the car is slightly warmed over it likely uses a bit more fuel than stock, so it appears either the (unpowered) fi pump in the trunk is restricting the flow, ...
/ubbthreads/images/graemlins/frown.gif

[/ QUOTE ]

So, What I gather out of this, is that you have a high pressure fuel injection pump sitting in the tank anticipating your changeover to electronic fuel injection. However, since getting at it at a later date is a big hassle, you ran your fuel pick-up THROUGH the pump.

You mentioned you had this problem earlier...before the triple set-up. Did you have the FI pump in there then??? If you did, I'd bet that this is where the problem is.

I'd also guess that you have the fuel lines coming out of the top of the tank also. Since the original setup gravity fed the mechanical pump, now your asking it to suck it UP out of the tank THROUGH the high pressure pump and then up to the carbs. That's a lot of work for that little fuel pump.

If any or all of what I'm saying is correct, then your only option just might be an additional inline, low pressure pump.
 
I run an original AC pump--it is more than adequate for my Webers and I am running a Holley pressure regulator at 3psi. The after-market pumps maybe a little weak, find a rebuilt AC pump or rebuild one yourself you wont go wrong with it.
 
[ QUOTE ]

So, What I gather out of this, is that you have a high pressure fuel injection pump sitting in the tank anticipating your changeover to electronic fuel injection. However, since getting at it at a later date is a big hassle, you ran your fuel pick-up THROUGH the pump.
I'd also guess that you have the fuel lines coming out of the top of the tank also. Since the original setup gravity fed the mechanical pump, now your asking it to suck it UP out of the tank THROUGH the high pressure pump and then up to the carbs. That's a lot of work for that little fuel pump.

[/ QUOTE ]

Not quite. The tank is gravity fed. There are twin takeoffs at the bottom rear running to an external fi pump filter setup in the spare tire footwell. This is then fed through the floor to a hardline running along the chassis to a fitting at the drivers side firewall that then tees into the stock fuel setup from there forward.

[ QUOTE ]
You mentioned you had this problem earlier...before the triple set-up. Did you have the FI pump in there then??? If you did, I'd bet that this is where the problem is.

[/ QUOTE ]

Again, not quite. The car has been back at the shop since I flatbedded it back in mid-September. It has never run on anything but triples - I put them on as a temporary measure so I could get some running out of the car this year - ha ha. Since it went back, it has a had different dizzy from the rebuilt recurved one, another set of new carbs and has been retuned, as well as fixing a short that meant it wouldnt turn over and the cable release for the hood that went out on the day it went back - which is why its been there so long.

It runs fine up to about 60 mph, above that it doesn't... I originally thought it was down to fuel before it went back, I just thought it was vapor locking. Now two distributors and six carbs later, I'm convinced it is a flow problem.

I'm going to have him take the -8AN tee directly to the -6 main line, bypassing the fi pump/filters and add a low pressure electric pump inline at the front.

If that doesn't fix it I'll give up and go straight to fi...
 
Alan,
any way to mimic the stock system completely, that is, straight gravity feed from the bottom of the tank without this circuitous route throught the trunk? The mechanical fuel pump on the Triumph requires there to be a straight gravity feed with the only uphill portion being at and to the inlet of the fuel pump. Plumbing for electric pumps, as you obviously know, can go all over creation. Too, do you have all new gas lines, steel and rubber portions?


As you know, I have the trips and I can pull till I get scared. In fact, mine works best with load and at speed. That said, I have never ventured much past 5K rpm. Chicken.


Shouldn't be that big a project to replumb.


Bill
 
I have triple webers, with a carter fuel pump in the trunk with a filter before the pump. I also added a 5 psi pressure switch and T-ed it into the oil pressure switch on the block so the pump would not run unless there was oil pressure,ie engine running and I have not noticed any of the problems you mention but I mostly do in town driving and not 60 MPH continous on the interstate, that might change when I get my transmission rebuilt with the new OD installed. I am finally getting the webers jetted just right, no flat spot, a little rich but just ordered 170 air corrector jets to try for a while
 
Bill,

All it needs to take the stuff in the trunk out of play is a -8AN:-6AN male:male reducer. The lines in the trunk are braided steel and there is enough slack to get around all the hardware. It's all new btw - no way would I reuse stuff on something like this.

I'm going to have him bypass the pump and fit a low pressure electric one inline in the stock system at the front of the car. Probably on the drivers side wheelarch since it's only a temporary thing.

Between the two I hope that'll fix the problem and then I can get on with seeing how fast it'll go in fifth gear (on a private road of course) /ubbthreads/images/graemlins/grin.gif
 
Alan, First of all, glad to see you back here. It's been a while and I was wondering what was going on with you and your car.

Now to your question. It shouldn't be an issue with the stock pump as long as the flow is not restricted before it. You might be on to something with the inoperative FI restricting the flow though. When I set up my triple ZS's I asked Richard Good if he had seen any issues with the stock fuel pump while dyno testing and he had not. I am still using a stock style mechanical pump on my car and it still pulls hard past the ton. Hopefully the bypass will solve your problem.

I don't remember any issues while the engine was being broken in on the dyno and it seems the variable here is that the engine is now in the car and dependent upon the fuel system of the car vs the dyno room.
 
Shawn, I haven't been around here much because I was so PO'd with the car that I couldn't face talking about them.

I still am having a hard time seeing that the pump in the trunk is *that* restrictive. I always thought that they were pretty much open circuit unless operating.

Oh well you lives and learns. We'll see if the two changes help.

I have to say that it was a lot of fun driving it today. Even if it was briefer than I'd have wished...
 
let me get this straight, you are running through the bottom of the tank through a fuel injection filter to the mechanical fuel pump? if so thats your restriction right there, you cannot run fuel injection pieces with a carb set up because of the difference in operating pressures of the systems.
 
Alan, what brand pump from TRF?, If it is one of the after market brands I still think that could be problem.------How are your Ocla axles working, just got mine havent put them on yet.
 
[ QUOTE ]
let me get this straight, you are running through the bottom of the tank through a fuel injection filter to the mechanical fuel pump? if so thats your restriction right there, you cannot run fuel injection pieces with a carb set up because of the difference in operating pressures of the systems.

[/ QUOTE ]

I *know* that the pressure for an FI system is different to that of a carb system, by an order of magnitude. The FI pieces - two filters and the pump - aren't powered for that exact reason. They ought to not be restricting the flow, but it appears that that might not be the case, given that there are other triple ZS cars that are working fine with the stock pump.

[ QUOTE ]
Alan, what brand pump from TRF?, If it is one of the after market brands I still think that could be problem.------How are your Ocla axles working, just got mine havent put them on yet.

[/ QUOTE ]

ALLAN, I didn't put a lot of miles on the car, but the axles are working out really well so far. Coupled with the LSD and the rest of the suspension changes I made, they are a tremendous improvement over stock. I couldn't be happier so far, but ask me again in a thousand miles or so. The car is a screamer - now all I have to do is to get it to run on the freeway. Oh and the pump is the one TRF touts as "better" than the run of the mill aftermarket pumps...
 
I never heard the end of this story,How did it come out?
It reminded me of a horrible experience with a clear glass filter I had once long ago. It was very pretty and designed in heck!! It could stop the flow of fuel and NOT show the slightest sign of dirt. I spent an afternoon on I70 in western Ks heat(102) stopping every 10 miles or so as the carbs starved for fuel(tank full of gas). So if any of you has such a filter, please save yourself a lot of grief and SMASH it now!!
MD(mad dog)
 
MY tri-carb has been very trouble free with the stock pump, even though I used the stroms x 3 fuel economy is good(22or 23).
I assume for the sake of sanity that you have confirmed good fuel flow to the pump??(I once had a kid put a leaf into my tr3 gastank..I hope to find him some day and strangle his sorry butt).
MD(mad dog)
 
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