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TR6 74 TR6 headscratcher

Has anyone run an electric fuel pump (Facet) in conjunction with the original mechanical pump?
Thx
Will
You wont need the original pump. You can buy or make your own blanking plate to go on the engine block to blank off the hole where the old pump went. I have been driving with an electric pump for 20 years and never had an issue. Make sure you put a fuel filter between the gas tank and pump to keep miscellaneous crap out of the pump. my .02
 
All wiring checked. While checking, also metered the alternator (original) and it reads 12.7 (14 across the battery) with the engine running. Just did this and the car started up smoothly.
Where exactly are you measuring the 12.7 V, presumably with the engine running, and the battery at 14? You should not have that much voltage drop between the battery and elsewhere in the electrical system. That makes me think bad connection.

How exactly did you check the wiring?

Yes, your ignition switch may be new but new parts are not necessarily good and, in any case, the connectors are 50 years old.

I think you have a bad connection somewhere between the battery and the ignition coil. You can find it by attaching a voltmeter to the ignition coil's (+) connection, turning on the ignition, and pulling and jiggling all connections between the coil and the battery while looking for the voltage to drop out. Also wiggle the key in the ignition, in the on position. I think it's likely that you will find the intermittent connection.

Another possibility is the coil. There is no good way to test a coil, so, if the connection-jiggling doesn't work, it's worth the minor effort and cost to replace it.
 
You wont need the original pump. You can buy or make your own blanking plate to go on the engine block to blank off the hole where the old pump went. I have been driving with an electric pump for 20 years and never had an issue. Make sure you put a fuel filter between the gas tank and pump to keep miscellaneous crap out of the pump. my .02
Yes, I've often wondered about the possibility of using an electric pump back at the tank end of things, and retaining the original mechanical pump in the line but removing the two little one-way valves and the diaphragm actuating arm. This way, the original 'look' can be retained, and obviates the need to make up a blanking plate for the engine block.
 
I like the ignition switch theory. Sudden shut-offs are usually a loose wire or bad connection, like the contacts inside the switch. Even engine vibration can do it. Don't just ohm the wires, give 'em a wiggle and a tug. Also, use volt-drop check to find resistance. With the circuit live, check from the + battery post to the suspect point. Voltage not following its intended path will show up as volts on the meter. 0.1V is a problem. 0.2V is a big problem. This can also be done on the ground side of the circuit to the - battery post. Grounds give a lot more grief than they get credit for. This may point a finger at the atrocious industrial T-tap on the + battery cable that TR6 uses as a power source.
I had a blown fuse on one of my BSAs this summer. It would start-up and idle just fine, but died under any throttle application. The fuse element lay shut until engine vibration made it open.
 
It would start-up and idle just fine, but died under any throttle application

Reminds me of the prototype for the eventual DC-3 airplane. The plane sat on the ground with tail low and engines pointing upward. Started, reved, and idled fine. But with full throttle it started rolling down the runway, the wings gained lift, and the tail raised up. Engines would die every time.

Turned out that the carbs were adjusted as the plane was on the ground - with tail down and nose up. Gain speed, tail came up - fuel bowls emptied and weren't completely refilled.

Live and learn. (DC-3 and its sleeper version were one of the best commercial aircraft we ever built!)

Skysleeper-3.jpg


Tom M.
 
Yes, I've often wondered about the possibility of using an electric pump back at the tank end of things, and retaining the original mechanical pump in the line but removing the two little one-way valves and the diaphragm actuating arm. This way, the original 'look' can be retained, and obviates the need to make up a blanking plate for the engine block.
I located my fuel pump under the car near the middle of the frame rail but some locate it on the inner fender wall for easier filter access. According to the TR3 guru Bob Shaller in his book "More BS about Tr's" it's not a good idea to leave the old pump in. "Pumps running dry soon disintegrate and it will run dry and pump oil on the ground.You want to leave street oiling to the highway department." :smile:
 
Hd this happen on a mates car years ago, the coating that was painted on the inside of the tank had started to flake off.
when we removed the tank and emptied it out it was like a pile of wet leaves in there, they would slowlt=y get sucked towards the pick up pipe and block the filter,
after a little rest the vacuum would depllete and away she would go again,
Fit a three foot length of clear pipe between fuel pump and carbs, when she cuts out if the pipe is empty then its fuel related
 
Have:
* Checked wiring connection including ignition and all ok
* Drained fuel tank and checked with strobe. Clean
* Checked gas flow from existing OEM rebuilt pump - Ok
* Coil checks ok
* Installed new filter
* Car starts and runs ok. Will try another run but expecting same outcome.
So, back to the fuel pump. With the thought that the pump may be breaking down when run awhile, I thought that I would install a Facet electric pump to see if that corrects the problem.
My question: Before permanently installing the new pump and removing the original (and capping the hole), can you run the electric pump in line with the original? If OK, I wold simply install the new pump above the filter and run the line through the original pump. If the problem corrects itself, I would then proceed to a permanent install.Thx,
Will
 
Hi Will ... yes, I have run an electric pump in series with the mechanical one on my TR4. The engine seemed to run fine, although I wouldn't necessarily recommend it as a permanent mod. I made the suggestion back on Oct 15 (see above) that to run permanently I'd take out the two one-way valves and remove the diaphragm actuating arm (probably have to put back the pivot rod, to block the holes otherwise). This would effectively disable the mechanical pump without affecting gas flow from the electrical pump, yet still leave it in situ for original aesthetic appearance! (if that's important to you). Subsequently someone suggested that this may not work for long as the 'pump would be running dry' - presumably the thought was that the diaphragm material would eventually perish ... I don't necessarily agree as fuel would still be passing over the diaphragm on one side, and oil vapour from the engine on the other (just as before) so I don't see that as drying out the diaphragm.

Every best wish with your fault tracing ... I've had similar faults in the past. One was a faulty rotor arm, another was a cracked distributor cap - but you've checked all that. The third was a blocked fuel filter on an MGA (electric pump) but that was accompanied by spluttering, as is often the case with fuel delivery faults. Maybe a piece of clear fuel hose between mechanical pump to carburettors as suggested may well be worthwhile.

Do let us all know what you find. Gareth J
 
Sorry that I am late to the party...and I have not read everything, just your original post...AND, I am not at all versed in TR6's. That said...the initial description is common to a bad coil that goes open circuit when hot. I see you have a new coil, but unfortunately our modern repo parts leave a lot to be desired.
 
Thx CJD. The new coil is a Petronix, which was installed with the Petronix ignition. The old oil was still working. Will try switching them back out.
 
No difference. Back on the Petronix. Could not make the car have the problem again. Will try a longer run this week.
Thx.
 
There is no definitive test you can make to determine if a coil is bad. You have to replace it with a known good one.

Are you sure you have the right coil for your Pertronix ignition?

I would replace the Pertronix with points and a known-good 3-ohm coil. I like the NGK one, as it has the right characteristics, is a maker known for quality, and is made outside the normal parts-supply chain. I think it's safe to assume that a new one is good. See if it still misbehaves with that setup; if so, it's not the Pertronix unit. If it runs OK on points, it's possible that you had a loose connection that you inadvertently fixed. Reinstall the Pertronix and see if it misbehaves again. If it does, that's a pretty good indication that the Pertronix is the problem.

I think it's also likely that you have a loose connection that you just haven't found yet.
 
Bad earth strap caused me no end of grief.
Run a secondary earth. Don’t do anything at all to the existing strap or you will never know for sure if it was the issue.
This way you can revert back to the old strap to double check your cure (but once you know - you know).
I usually do my initial check with a jump lead.
On my VW Syncro16ā€, a friend pulled the engine to fix an oil leak and removed my secondary earth.
I got the van back and had no idea that it had not been put back. As a result I replaced a perfectly good starter (only one year old and could have been the same initial issue), removed a good emergency cut-off and associated wiring improvements to the leisure battery system and binned it and a myriad of other checks and, Finally while I was in the engine bay I noticed a very bright bolt hole and wondered what was missing. . . Hey-Presto
My mate still had the extra earth cable on his shelf!!
He too did a visual on the original strap and passed it as ā€˜Fit for service’ so removed my secondary.
Hope this might be of help, if not now. . .maybe in the future.
Regards Nick (Kent uk)
 
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