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Triumph TR6 - Here's one for you...

Just converted over to triple Strombergs on my '73. I'm still setting the mixtures and now have an annoying hesitation on acceleration out of a turn (happens 3-4 times for about 1/2 second at 2 second intervals - kinda like its related to a needle valve opening & closing) that I'm pretty sure to fix by float level adjustment.

The mystery, though, is that if the brakes are tapped while crusing the engine loses power for 1/3 to 1/2 second! WTF? My best guess is that the vacuum servo on the brakes is causing a lmomentary loss of vacuum when applied which is causing the carb air valves to drop. I've never heard of that happening, though. I'll put a restrictor in the vacuum line and see if that helps.

Brent B

Here's an update - pulled the carb with the rich plugs, checked the diaphragm (good), then pulled the Grose jet, blew it out with compressed air, reinstalled, set float "level" to 17mm. Hesitation problem solved. It was most likely caused by the Grose jet not seating off due to some crap in the new fuel manifold to the triple carbs. I say this because the "new" carb, which has a needle valve, failed about 1 minute after inital start-up - gas was pouring out of it. There was an extra needle valve in my parts supply, so just changed it out. Sure wish I'd thought to blow out the new manifold before installation!!!

The triple carbs are very nice! Idle is good, and acceleration is significantly better. Air flow is sync'd, but still fine tuning the mixtures.

In tracking down the power 'blip' when the brakes are applied, I isolated the brake servo from the manifold as a test. Started the car, touched the brakes, the 'blip' was still there. OK - it's NOT a vacuum problem. Hummm...

Oh yeah - my starter went out 2 weeks ago and I got a nice gear reduction model off e-bay rather than do a rebuild. The starter that came off had terminals for the power cable from the battery, a brown wire with a wide spade fitting on the solenoid, and a smaller white wire with a narrow spade fitting. also off the solenoid. The new starter had a power cable connection and a wide spade fitting for the solenoid.

The new started was installed only using the 1 solenoid connection. I left the white wire hanging. THAT is the source of the power blip when I tap the brakes. I don't know what to do about it, though.

I did some voltmeter checking and decided to tie it into the power cable connection. I did so, the car started fine, and the 'blip' was gone. Only problem I noticed was the ignition light was still on. Nuts - turned the key 'off' and the car kept on running. I got a good laugh out of that, pulled the white wire off, and she stopped.

By now I've also noticed the turn signals no longer work. Add that to the voltage "drain" to the ignition (which causes the 'blip') when the brake lights are supposed to go on and it's apparent I've got a wiring problem. Does anyone have any ideas about where that wire should be hooked up?

Brent B

The simple answer to your problem is you have a system shorting to could be the brake electrical system.
The big question...did everything work before the change of the starter motor??
It appears u have 2 problems
1: where does the white wire go to?
2: The momentary loss of power at brake application.
One at a time..
#1. The white wire (are u sure it is not white with red tracer?) should go to the solenoid. A starter motor needs 3 connections to it. Ground (BAT-),power (BAT+), and ignition. Ignition meaning power to the solenoid to energize the starter. The energizer bunnny comes from the ignition switch. This is your white (red) wire. Ground is accomplished via attachment to the engine and BAT+ is the large heavy black wire direct from the BAT (obviously:). I am not familiar with the gear reduction starter but is HAS to have a connection to it that is MOMENTARY from the ignition switch start position. You also have 2 brown wires from the solenoid that go back to 1: the ammeter, 2: the fuse block for constant voltage supply to assorted electrical systems. The white(red) will NOT be the same connection on the starter as the browns and the BAT black wires. So that should sort one problem out.

#2. ((I make the assumption you have not changed wiring to the fuse block (NES PAS?)). Lift ONLY the Green/purple wire from the brake you get the power blip? If yes post that message, if no then bad brake switch or ground fault after the switch. Reattach G/P wire, remove both R and L bulbs do you get blip? if yes then probably bad switch...if no replace L and R bulbs one at a time and which one gives you the blip ( + side of bulb grounding).
Hope this helps.
Rick C
Rick Crawford

Only 3 wires to the starter - the power cable from the battery, a 12 gauge or so brown wire to the solenoid, and the smaller white wire. No ammeter here - just a volt meter. The new starter works fine with just the power cable and single brown wire to solenoid. Ground, of course, is back through the engine.

I'm beginning to suspect the white wire was energized when the solenoid was engaged as the start-up by-pass around the coil ballast resistor. Something must be crossed up on the other end, though, because when I measure voltage to ground on the wire with the key "on" it's 12v. With the key 'off' it's 0v. But if it went through the ignition switch the engine would not have run on. It's a head scratcher!! More testing is in order. Maybe a few beers to help me think like a British engineer...
Brent B

Ok - fixed the electrical problem by "brute force" - jumpered the white wire end at the starter over to the fuse box and plugged it into the "keyed" circut. I hate having a(nother) 4' wire stretched behind the battery going from one side to the other, but what the hell. This one is weird - the other end of the white wire goes to the coil (+), but the turn signals & brake lights are affected... And it still doesn't answer how that terminal on the old solenoid functioned...
Brent B

Eletrical 101: Potential difference. If you have 12 volts you have a feed when that 12 volts goes away you have a potential ground.

With the key on the white wire has 12 volts constant which is killing your ground for other devices. White wire is mostly a ground. And should only have 12v in crank position.

Originally it only had 12v when solenoid engaged cranking for bypass feed to coil giving full voltage. When not cranking white wire is now a ground unless hanging?

Not sure on TR but on many the design was to take out any unneeded devices like turn signals and give full V/A to starter and coil. Same applies for many new vehicle running lights. Folks think they just go out because the starter is taking all the juice.

Sorry to butt in Rick.

Bill Brayford

This might be Electrical 201... I haven't tried going to ground with the white wire yet. I will, but it seems the car probably wouldn't start as the alternate feed to the coil would then be grounded.

I did find some GOOD wiring diagrams for our Triumphs here:

The PDF file is really worth it. Showed exactly what should be there with my '73.
Brent B

Sorry Brent

Not what I meant. The white? wire only has 12 volts on it when the original starting motor is engaged. The rest of the time it is at ground level or 0 volts neutral.

If you have a haynes the diagram is on page 170. Item 7 connector marked ign.. top left as to how the starter worked.

If the wire in your car is at 12 volts when the ignition is in the run position thats not good. The wire from the starter should be white with red tracer. And should have been connected to the IGN. large spade only.

By your post things and wires have changed. I can't see what is going on after that. But if you have made a change that leaves one wire in question thats where to look.

After the car starts ground that wire you should have your brake and turn although it may have popped the flasher unit and the car should not quit? I am assuming that by the small spade connector you meant there are 2 and the white wire was on the small 1. If it was on the small one it would by the diagram only have coil voltage to drive the solenoid at ignition. Notice that it also goes to ground when not charged.

Your blips turning and braking are caused by momentary losses of current flow. When you had the turn signals on cornering, power to the coil was being lost same as brake. Now with the 12 volts applied at all times there is no potential difference so the units don't work.

If that wire is grounded your car will not start though from what I have read without taking white to 12 volts.

I hope this is clearer?


Bill Brayford

This thread was discussed between 24/03/2003 and 29/03/2003

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