Minimum electrical needed to get car running

[Mike+2]

I'm stumped, beyond stumped. Would love some insight to this Lotus Electrical challenge.

History: (I've only owned the car three months) It's a 1969 Plus 2 Federal with Strombergs
1. drove the car from storage to my garage, 1/2 mile.
2. did fiberglass repair to rehang exhaust brackets properly
3. decided that I'd try to eliminate the electrical nightmare I inherited. Practically nothing electrical worked when purchased. Only a couple of gauges worked.. Headlights came on, but the pods don't lift. the Headlight switch was replaced and rewired with lamp cord and speaker wire. No brake lights, tail lights, indicators, you get the idea. Time to try to sort out a bit at a time.

My TR4a wire diagram is just so simple, and an accurate match to my car. I've done electrical before.

The Plus 2 wire diagram, if you can find one that matches even slightly close to what's on the car, it a nightmare. I'm using the one commonly referred to as March '68 to March '69. My car 50/1974 was an October of 69 build I believe

The main ground point, button, behind the lower dash had NOTHING attached.

The PO must have decided it was better to run a heavy gauge wire from the neg battery post up along the floor and up into the dash behind the glovebox (LHD car) and there were spliced in wires all along its path to serve as his ground. And when I talk about spliced in wires, I'm talking about black/red thin gauge speaker combined wire. It's everywhere. Sometimes each half is working a different circuit and another example, following the black half of the wire, it turned into (spliced) the red half of another speaker wire. Behind the dash is nothing but black/red wires everywhere, and several newer relays. Tracing each wire is almost impossible.

No more examples, but I wanted to make it known what I'm dealing with.

I discovered that the entire line of grounds wasn't even connected to the battery.. I had no continuity from the dash portion of that wire back to the battery connection when I took the wire off at the battery. So all of this mess was just inactive.

I began to start eliminating excess or disconnected wires. I guess I went one wire too far, as now the ignition will not turn over the starter. so.......

Starting at the starter, I found a gear reduction starter, wired with the solenoid on the starter active, but the firewall solenoid was by-passed as only one post on the firewall starter contained the positive IN from the battery and was connected to the positive OUT to the starter.

I installed a new firewall solenoid with a push button momentary switch, wired it properly, then at the starter I added the jump wire that by-passed the starter solenoid. Push the button on the solenoid, stater whirls like it should.

Prior to this, the White/Red wire from the loom was connected directly to the starter solenoid. I rerouted that wire to the trigger post on the new firewall solenoid. turn the ignition key, nothing. After probing several wires fault finding, I discovered the Brown/Blue wire to the ignition switch had no power. A test probe at the 2 fuse box terminal showed power coming in and going out of the fuse circuit. So somewhere in all my wire elimination process, I took away the power to the ignition switch. I wired a new power source to the ignition switch and again, the ignition switch won't trigger the starter.

I have to get this car started and running so I can get it out of the garage and back to my storage where I hope to just forget about it for a long time.

My last attempt was a '4 wire' bypass of the loom to get it started, running, and drivable for the short trip to my storage. I've attached a link to an article Hagerty put out on this process.

I've also attached the 'Lucas Coil' diagram that I drew out illustrating what I did.

My problem to be solved now, (and after all the verbiage above, which I needed to include to document my original starting point and where I am now.) The problem is I now have no current at the last wire, #4 in the diagram, from neg side of coil to distributor. I'm measuring with a test lamp at the neg side, hoping to see the lamp flash as I turn over the car using the momentary button on the solenoid.

Per the attached PDF.. I have a successful lamp test for 12v at the firewall solenoid. I have a successful lamp at the inline on/off switch at the input side. The output side with the switch off will not light up, but when I turn the switch on, then I get a lamp at both in and out.. the switch is working and in the proper direction. I then get a positive 12v lamp at the coil pos terminal. the neg shows no lamp, but that needs to be tested with the engine spinning on the starter to get the points to open/close and should cause the lamp to blink if I understand this properly. I replaced the coil with a new coil, same results.

So now that I'm a novelist and have over written what my issue is.. what is causing no output voltage at the negative side of the coil and why can't the car get spark to run?

If you hung in there with me, with this LONG post, your input would be greatly appreciated.

Mike

Lucas Coil.pdf

4 wires to get the car started

(280.8 KiB) Downloaded 184 times

https://www.hagerty.com/media/maintenance-and-tech/start-vintage-car-using-only-4-wires/

[Billmack]

Why don't you use the diagram for the production date of the car?

[Billmack]

To get a light on points side of coil the points need to be open. If no light with points open either the points are wired wrong(common problem) or the wire is shorted to ground. Its pretty simple. As to the points wiring...the loops for condenser and coil wires need to be touching the spring and insulated from the little stud I.e.. Under the plastic insulator.

[Craven]

Remove wire 4 from the negative terminal of coil, check with test lamp, negative coil connection to ground. If yes then the distributor is permanently connecting the coil negative to ground, check internal wiring of points, a common mistake is the wire is fitted the wrong side of the plastic insulator.

[Mike+2]

Remove wire 4 from the negative terminal of coil, check with test lamp, negative coil connection to ground. If yes then the distributor is permanently connecting the coil negative to ground, check internal wiring of points, a common mistake is the wire is fitted the wrong side of the plastic insulator.

Craven.. thanks for that suggestion.. I disconnected the wire from the distributor and now I have a test probe lighting up at the distributor end of that wire. So now, I'll need to look inside the distributor for the fault. Hard to believe anything changed since the distributor was working fine a week ago prior to all my monkeying around. But, that's were the fault finding leads me..

Again, thanks to you and Billmack for the kind response.

Mike+2

[paddy]

Is there a chance that the points are in fact an electronic points replacement (Lumenition or the like), and therefore there's a requirement for an additional positive supply to that module?

Paddy

[Mike+2]

Bringing this post back to the front. My Plus 2 has been in my garage for four weeks now in a non-start mode. I will have a flatbed move my Lotus from my garage to my storage units where I will lock the door and not return for a long time as I am in final stages of my TR4a restoration.

Just a quick review of what I've tried in the event it is obvious to anyone here.

My wire loom was a huge nest of speaker wire and lamp cord. Dangerous for sure. I have ordered a new loom from Autosparks back in early February, which I'm still waiting for.

Consequently, I wanted to bypass the entire loom to just get the car from garage to storage one mile away. This car hasn't been fully operational for nearly 20 years based on paperwork in the boot and a work invoice dated many years ago, with an odometer reading only a few miles from its current reading. I don't trust underrated thin speaker wire carrying all electrical currents.

I'm using a four wire basic setup as I described on the opening post.

NOTE, I'm not counting the heavy wire on the starter side of solenoid to starter.

In the boot, a brand new battery. 12.4 v using meter on battery posts. When moving the meter's neg probe down to the ground bolt, I did not have 12 volts. The neg cable from battery to ground bolt is brand new. Continuity proved the cable good. A good scrubbing under the car, a new bolt, washer and nut setup put the meter measure back to proper, meaning with the neg probe on bolt rather than the neg battery terminal, I was not getting 12 v. One issue solved.

Wire 1: Battery is now connected and properly grounded. Moving along the pos wire (wire 1) up to solenoid. 12.4 v measured at solenoid. Solenoid bracket is grounded if that matters as some diagrams show it both ways, grounded or not grounded.

Wire 2 and 3: Wire 2 runs through a switch and is on the input side. Wire 3 is the output wire from switch to pos on coil. With switch off, I can measure 12 v on the input side (wire 2), 0 volts on output (wire 3). Turn switch on, now I can measure 12 V on both sides of the switch, wire 2 and 3, where wire 3 runs down to positive on coil, where I measure 12 v with switch turned on.

Wire 4 is wire from neg side of coil to distributor.

@BillMack and @Craven both said to check the plastic insulator and to make sure I have the condenser wire and the LT wire from the plastic piece on outside of distributor both isolated from the post it mounts on, but in contact with the points spring. Check, and thanks again for the tip.

So now with everything assumed to be wired properly, lets test start it using the button on the solenoid. Engine turns over. But somewhere in the distributor, something is wrong.

- Yes, I put the rotor on.
- I have no light on the test lamp when turning the engine with power on. test lap grounded and connected to neg coil post.
- to confirm above, inline spark plug test probe has no blinking light either
- NEW: solenoid, coil, distributor cap, wires, rotor arm, and points.
- I've tried again with alternate coil, same.
- I've tried so many combinations of tests and changes, I'm so frustrated I can't recall them all now.

I'm planning on a flatbed next Wednesday, June 2, unless someone can spot any errors I've made or assumed to be correct.

Thanks again all.. for your time and considerations.

Mike+2

[HCA]

I have only sped read through your posts. My question is, you wired the car up per hagerty and drove the car to your garage without any issue, yes? In which case it should start up again UNLESS you removed/altered anything from your last known position - ie parking up in the garage.

I have sort of follwed your train, I might sketch it out better later, but my first thought is that there has been no mention of the condenser. I assume you have it connected and grounded?

As for your earthing issues, the PO in fact has done right in having a dedicated wire for all earths - it might just be that his/her execution of it went awry! OK, you have a new loom on the way that should sort things out. Would have been better to start from scratch and make a loom, but yes, to some this might be daunting!

Check out your condenser.

[Mike+2]

I have only sped read through your posts. My question is, you wired the car up per hagerty and drove the car to your garage without any issue, yes? In which case it should start up again UNLESS you removed/altered anything from your last known position - ie parking up in the garage.


Check out your condenser.

Hello HCA... I drove the car from storage to garage yes, on the old loom. Then I started tracing all the speaker wires to find source and destination and eliminated several that were just 'dead' meaning either a source or destination was not active. OR.. wires that start red, turn black, then connect to green. Those I did not eliminate as they were an active circuit, but ill installed connectors, thin wires, etc. I decided to just eliminate it all with the four wire setup so I could move it the one mile back and forth. Good reasoning, poor execution I'm afraid..

Condenser.. it's an orange wire condenser which I'm told is not as good as one with Black or Blue wires. None the less, using a multimeter, one probe on body, one at wire end, meter set to volts It would charge up to a number one on the meter. Switch the meter to ohms, and it would discharge back to zero so I assumed it was good. and when installed, the base is solid on the plate with screw tightened, and the wire is under the plastic isolator on post. I hope that is a good testing proceedure.

[HCA]

Not sure what a Number 1 on a meter is, but if you are satisfied it is working then good.

It is difficult diagnosing from an armchair - the list of possibilities goes on eg, carbon centre, cracked dist cap etc. I suggest - if you are sure the components are good - to do an independant wire as per Hagerty and what you did before. It is obvious your base loom is pretty shot.

[collins_dan]

Seems like your switch needs to both switch power to the coil AND power to the starter. Why not just use the ignition switch and have both connected to that? Dan

[Mike+2]

Seems like your switch needs to both switch power to the coil AND power to the starter. Why not just use the ignition switch and have both connected to that? Dan

Hi Collins_Dan.. assume Dan?

The ign switch wasn't wired properly, ex: should have White/Red triggering the solenoid, No White/Red at ign, and by the solenoid, there was a White/Red, but it exited the loom and just was there, laying there, not connected. So that was the first wire I was trying to sort out as there was the black portion of a speaker wire on the ign #3 terminal, and I was able to follow that out a hole in the firewall and onto the Solenoid. I pulled the black speaker wire connections off ign and solenoid, hooked the White/Red back on the solenoid, and after a neck ache, and some slight dizziness, was able to locate the White/Red tucked up under the dash above the steering. Cleaned the terminal, connected it to #3 terminal on Ign Switch, reconnect battery, turn the key, slight smell of wire burning and no starter turning. THAT'S when I had to go to the full four wire setup and dropped the loom completely.

As a side note.. this car was advertised by a 'car collector' and the advertisement pics looked good, and there was a YouTube vid of the car driving down the road. Lesson Learned: I did not do due diligence on this purchase.. I know, I know better now.. the seller answered my question of does it start, drive, stop? He replied Yes to all.. after purchase, when arranging shipping of the car, I was given a salvage yard address. You can see I was doomed badly with the car, even before it arrived in my garage.

[mbell]

So the issue is no spark. First thing is too find out if it low or high voltage side.

I'd put you test lamp between constant 12v and the coil negative connection (from dizzy) and see if it flashes when the engine turns over. If points condenser working I'd expect the lamp to flash on and off.

No flashing would mean you have points/condensor/disti/engine ground issue.

Flashing would suggest fault on high voltage side. Next I'd see if any of the plugs spark work. If no plugs spark then fault is likely in something common to them all, so coil power, coil, coil to cap HT lead, cap, rotor arm, engine ground.

[collins_dan]

From your hagerty article,

The positive connection is a thick, red wire that runs from the positive battery terminal to the big threaded post on the solenoid. There is no corresponding wire for the starter’s negative connection because the starter is grounded to the engine block, which in turn is connected to the negative battery terminal via a thick, black cable.

But there is a third connection—a thin wire connected to a small terminal on the solenoid via either a spade or a ring connector. When this terminal is fed 12 volts—as it should when you twist the ignition key to the “start” position—it engages the solenoid, which completes the positive connection to the starter and causes it to spin while also thrusting the pinion gear forward.

My point is you need the third connection from ignition switch to solenoid. My suggestion is to strip everything from ignition switch except white and white red wire. If you are concerned about white red wire, run a new one from ignition switch to solenoid.

I think you are getting not joy with your current configuration because you are not powering the pinion to deploy and turn the engine over.

Dan

[Mike+2]

Dan.. I have the solenoid with the momentary push button built in. When I push it, the starter turns the engine.. gear reduction starter, no pinion.

I believe pushing the button should connect both sides of the solenoid, which is why is sends 12 v to the starter while depressed, and additionally, eliminates the need for the White/Red wire from the IGN switch to the solenoid that energize that connection. Or so I believe.

Mike+2