TR6 PI runs rich and bad/no idle

[Peter Cobbold]

+1

But cure the switching-off fault first.

[Blue cedar]

+2.

 

Morton, I always feel my car likes to start with the minimum amount of choke that I can get it to fire up on and then push in it as soon as I can. I don't think these cars like being fired up, stopped and/ or. left idling when cold.

[DaveN]

Needs an Italian tune up!

[JohnTB]

Hello Morten,

 

If you haven't, it's also well worth cleaning the idle air circuit. Take a look at the TR Register Technicalities CD - Page L19 starting at "Inlet Manifolding" this continues onto Page L20, which describes how to do this. Tick over and low speed running should be much improved. If you haven't got the CD, give the TR Register Office a call.

 

Good luck

[MortenHoyseth]

Thank you for all suggestions. Highly appreciated.

1. The car starts easily now. That part seems to be fixed. It idles nicely.
2. The car will not stop after switching off the ignition, nor when cutting battery supply entirely. And it runs and runs and runs…

I’ve removed dash etc. to get good (well..”good”) access to wiring. Starting with the brown wiring from alternator/battery, switches, fusebox and ignition. Seems to be in good shape. I’m looking for something that feeds enough energy back to the relay operating the coil/fuel-pump. The energy must be produced by the alternator. Gone through the “white” wires from ignition switch to misc. places. Note that the alternator is uprated (18ACR/45A http://www.moss-europe.co.uk/alternator-18acr-45amp-geu2206.html?assoc=125732), the car is originally a ’73 US car with a 2.5PI ’71 engine fitted three decades back.

Questions – with reference to the attached wiring for a US TR6 ’73 (borrowed from www.advancedautowire.com):

1. Ignition switch – from my terminal 6, the Brown-Red goes from switch to…front of the car, right hand side, connected to nothing. There is also a white-purple wire going from the oil pressure switch (not connected), taped to the Brown-Red wire, going all the way to the front of the car. They are both terminated separately at that point, not connected to anything. According to the wire diagram, there should be an anti run-on valve there. Does that ONLY apply to US carb. Cars, or also PI cars? Seems like terminal 6 is not used on my car anyway.
   
2. The oil pressure switch is a TT2998 20psi bought from Moss. It has two terminals. I have connected a White-Brown wire from the low oil lamp, and the other one to ground.
   Is that correct? I cannot see any P, S, I letters on the switch for reference.
   
3. I’m using a relay controlled by terminal 3 on the ignition switch to give 12v to both coil and fuel pump. It could be to sensitive; I’m not sure what the trigger effect needs to be. Also, I’m using some LED lamps. The low energy using them could have an impact on energy available to operate the relay.

Edited May 15, 2017 by MortenHoyseth

[Steves_TR6]

Hi Morten

 

There is no anti run on fitted to pi cars.

 

You might try testing the relay coil positive feed with the ignition off, it should of course be 0 volts but it may not be.

 

Try with the engine not running and with it 'turned off and still running'

 

I suspect a back emf is holding the relay engaged?

This has been seen with electric fans but other electrical items could also cause it.

 

I think i would disconnect all non essential items and see if the fault goes away, then reconnect 1 at a time to isolate the culprit.

 

Good lucK

 

Steve

[barkerwilliams]

Morten,

running on

I would suspect that you problem is the Alternator Warning lamp circuit. When you turn the ignition on the white wires on the ignition switch are fed with 12 volts via the switch and the coil & pump relays operate. The 12 volts also feeds the alternator warning bulb which is earthed through the alternator coils and the lamp lights.

Once the engine is running and the alternator is charging the earth within the alternator coils begins to show a voltage and the lamp begins to dim as the voltage equalises on both sides of the lamp. Eventually the voltage on both sides of the lamp is equal and the warning lamp goes out.

When you turn the ignition key off the alternator is still producing a voltage (it is still spinning) which flows back through the lamp into the white wires on the ignition key.

Under “normal” operations the current passing back through the lamp is insufficient to power the coil and fuel pump and they cease to work and the engine dies.

However you have fitted relays and removed the load from the white wires and I suspect that the current flowing back through the lamp is sufficient to hold the relay coils energised and keep the coil and pump operating.

To test.

Also connected to the white wires on the ignition circuit are the windscreen wipers. Could I suggest that you turn on the wipers with the engine running and ignition off and see if the engine dies?

The wipers should attempt to draw too much current through the alternator warning lamp and the voltage in that circuit should fall and the relays de-energise.

Alan

Edited May 16, 2017 by barkerwilliams

[DaveN]

Relay on the ignition? Why? You've not popped a latching relay in there by mistake have you. Or a type B in place of a type A (or vice versa)?

[oldtuckunder]

Hi Morton

 

Ignoring the not stopping problem, which is a minor inconvenience compared to not running

 

Just so someone following this thread with a similar problem may find it useful can you confirm what the problem was or rather what solved it

 

We appear to go from not really starting at all with just about every piece of PI equipment being suspect!

 

to at post # 43 "I got the car running! I does not run very nice, but it runs."

to post # 55 "The car starts easily now. That part seems to be fixed. It idles nicely"

 

From the posts am I correct that the solution was

 

1) Remove Pertronix Ignitor and replace with points and condenser

2) Replace Flame thrower coil with known good standard one

3) New Plugs correctly gapped

4) Set the ignition timing somewhere about right

5) Drive it a bit!

 

Alan

[MortenHoyseth]

Thanks for your ideas and suggestions.

Alan - YES! I did as you suggested regarding switching on the wipers on when the car kept running after I switched it off. It stopped promptly. So it seems you are spot on. The Alternator feeds enough power back trough the ingition bulb/light to keep the relay closed.
I decided to open up the dash entirly prior to this, as there are some "legacy" wiring from previous owners that I now have cleaned away. Not connected to anything.

Q1:
As switching on the wipers to stop is not a long term solution, I'm thinking a diode on the white wire going to the ignition bulb might work, or even a switch to cut the connection. However should it be necessary? (well, obviously right now)...

Q2:
The oil pressure switch (TT2998 20psi bought from Moss). It has two terminals. I have connected a White-Brown wire from the low oil lamp, and the other one to ground.
Is that correct? I cannot see any P, S, I letters on the switch for reference.

A1:
DaveN - well, the relays I put in ages ago. I'm using a couple - for fuel pump/coil and headlamps. I'm feeding 12v from battery, and using the white wire from ignition switch to trigger the 12v supply to the mentioned. Right now - reading this post - it might not sound like a brilliant idea, but the coil is sensitive to 12v and relays have little loss. Same with headlights - in that case the relays came with "upgrade" kit.

[MortenHoyseth]

Alan (oldtuckunder) - right you are
Now the car runs and the issue left is minor (as far as I know) - looking positive for summer drive. Sorry that I'm so slow with feedback, I gets late in the evening before I can (..are alowed to) go out in the garage.

So - I haven't been driving it yet. Except from that the steps are spot on. I'll elaborate more one I've taken it for a drive and can verify that it actually runs.

Cheers,

Morten

[barkerwilliams]

Morten,

 

Q1:
As switching on the wipers to stop is not a long term solution, I'm thinking a diode on the white wire going to the ignition bulb might work, or even a switch to cut the connection. However should it be necessary? (well, obviously right now)..

 

 

Phew, I'm pleased about that.

 

I am thinking, probably wrongly, that a diode could be fitted at the alternator end, not buried behind the dash.

 

If you fit a female spade connector to one end of a diode, and a male spade connector to the other.

disconnect the small brown-yellow(?) wire from the alternator and plug the diode between the alternator and wire and insulate as appropriate.

 

The diode is then easily removable by hand if there are unforeseen problems and no need to cut any wires. After all you also have a backup wiper switch!!!

 

 

Alan

[DaveN]

Ignoring the headlight relays ...they are a sensible move! We come back to the engine not stopping. Sticking a switch in or indeed a diode is masking the problem. I'd be intrigued to know where it's getting the 12v from.

Have you tried a new relay? Make sure you get the right type!