Lotus Elan

S4 Starting problems

PostPost by: Chancer » Tue Sep 19, 2017 10:51 am

collins_dan wrote:Chancer, you've lost me. I only have 11.3 volts going to the starter or the coil when the white wire is connecting the ignition switch to the coil, which is insufficient to fully engage the pinion.


I dont believe that 11.3 volts (assuming your voltmeter is accurate) will prevent the pre-engage solenoid from operating (engaging the pinion) if all the contacts are good, its more likely to be a mechanical problem with the pinion/ring gear teeth or it is engaging but the starter contacts are oxidised, possibly the seperate solenoid.

All you need to do is disconnect the coil and turn the ignition key to the start position, the engine should whip over, try it repeatedly in case its an intermittent fault, if it is not 100% good then the problem is not a tiny volt drop.
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PostPost by: Orsom Weels » Tue Sep 19, 2017 3:23 pm

I have to agree with Chancer here. As I said in my earlier post, the voltages you are seeing should be ample to engage the solenoid & crank the engine, all be it possibly a bit slower than usual. You have more or less proved this by rocking the car in gear & then being able to start it. Rocking the car in gear will not add any charge to the battery & will have no effect on the ignition switch, you are simply moving the flywheel/ring gear in relation to the starter.
If the starter is not even trying to turn the engine, it implies the solenoid is not moving far enough to complete the connection of the internal contacts, or there is a problem with them, ie burnt or oxidised. As you have tried a new starter & it hasn't changed anything, it suggests to me that something is restricting the movement of the solenoids. Most likely candidate would be the starter pinion fouling on something, possibly the ring gear teeth. I would be investigating this & any other possible mechanical issues before spending time & money adding another solenoid.
Whilst the system will work perfectly well with an additional OE solenoid in the line, it isn't best practice to incorporate more high resistance connections than necessary, & is only really adding another weak link. The idea of leaving the OE solenoid when converting to a pre engaged starter is to simplify the job & remove the need for any wiring alterations, & powerlite do suggest that you remove it if you experience starting difficulties. As yours has already been removed, I can't see any advantage to re-fitting one, it could even make things worse.

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PostPost by: collins_dan » Tue Sep 19, 2017 9:11 pm

I feel a bit like a dog chasing his tail. I started with the assumption that the problem was mechanical, so replaced the starter. I found the old starter to be fine, and the problem continued despite the new starter. I will pull it out and check again. Very early in this post, it was noted that I should check voltage under load to the starter. When I stated that it was 11.3, I was told that was too low to fully engage the pinion of the pre-engaged starter. So opinions seem to diverge on that point. I have worked to improve the voltage to the starter by cleaning contacts, a new battery and a new ignition switch as the voltage going into the switch is fine, but it continues to be coming out too low unless the battery is fully charged. The problem is not random. It is directly related to the charge on the battery, so I truly believe it to be electrical and related to my coil. I will try the idea of disconnecting the coil at the ignition switch and seeing if the problem occurs. If it does not, then I know where to focus my energy. Thanks, Dan
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PostPost by: 2cams70 » Wed Sep 20, 2017 3:56 am

Dan,

I can see now the Lotus starting circuit from the image posted by pharriso. It's a very simple circuit that shouldn't be that hard to diagnose. If we first work on the assumption that you don't want to fit an extra start relay (even though i'd highly recommend it for the longer term) can you please clarify the following:
1. Is the original inertia starter solenoid still in circuit or not?
2. Does the car still have it's original generator and RB340 regulator in place or has it been converted to alternator?
This information will help diagnose further so I can point you in the direction of where to take a few more measurements
If the voltage at the coil (white wire) drops to 11.3 volt with the ignition key turned to the run (not start) position whilst the voltage at the battery terminals under these conditions still stays at 12.5V the circuit does have excessive resistance somewhere. From this circuit I can see there's no provision for a ballasted coil either - unless that was a later design change not covered by this particular circuit diagram.

As part of my everyday job I help diagnose problems caused when new truck wiring systems have been modified (butchered!) my 3rd party body equipment suppliers. These wiring systems are a bit more complex than the Elan's !
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PostPost by: Orsom Weels » Thu Sep 21, 2017 8:12 am

2cams70 wrote:Dan,
1. Is the original inertia starter solenoid still in circuit or not?


Dan has already confirmed that the OE solenoid was removed prior to his ownership

2cams70 wrote:If the voltage at the coil (white wire) drops to 11.3 volt with the ignition key turned to the run (not start) position whilst the voltage at the battery terminals under these conditions still stays at 12.5V the circuit does have excessive resistance somewhere. From this circuit I can see there's no provision for a ballasted coil either - unless that was a later design change not covered by this particular circuit diagram.


Reading back through earlier posts, it sounds like we have 12.8 volts going in to the ignition switch, & 11.7 coming out on the White/Red wire going to the solenoid, do I have that correct?

collins_dan wrote: I checked voltage at battery, then voltage at starter and it was the same. I checked voltage from ignition and it was much lower 11.7 vs 12.8. I replaced the white red wire coming out of the ignition and tested that and it was also 11.7. Checked the power coming into the switch via brown blue wire and it is 12.8.


But then later we are talking about the White wire to/from the tacho etc that is causing the voltage drop & seeing different voltages ?

collins_dan wrote:So I figured out that the white wire is causing the drain to the starter. If that is disconnected, voltage to the starter goes right up to 12.5. I realize the white wire goes to the tach, the glove box kill switch, then to the coil. Anything thoughts as to what could be causing it to drain away voltage? If I check voltage at the coil using the negative pole as the ground, it reads 11.3. It reads 11.9 if I use the engine strap as ground. Bad coil? Dan


Firstly, the negative pole of the coil goes to the points, or whatever 'modern' replacement you may have, it doesn't go directly to ground, so we won't get an accurate voltage measurement there, but we have 11.9 volts when going direct to the engine earth strap, so a similar voltage drop through the ignition switch on both the White/Red wire & the White wire. This is a bigger drop than I would expect, but not enough to stop the starter solenoid engaging. Does this voltage drop only show up when the White wire is still connected to the coil? If so, it sounds like the coil is simply pulling a healthy share of power, (see other comments in this thread) this is unimportant in relation to the more pressing problem.

The simplest way to eliminate any other components/wiring is to make sure we have a good sound battery lead from battery to the starter main battery connection terminal. Then a good earth lead connection from battery to chassis, make sure this is sound, as you tighten the nut in the boot, it can have the tendency to loosen the bolt in the chassis, causing a resistance. Then make sure the earth strap from engine to chassis is also good & clean. This will ensure we are getting as much battery power to the starter motor as possible. Next, disconnect the original White/Red wire from the solenoid & make up a temporary wire to replace it that will run all the way from the solenoid to the battery in the boot, it can just run along the outside of the car. Now, with ignition switched OFF, touch the temp wire to the positive terminal on the battery (assuming negative earth). There should be a bit of a spark as the wire makes contact with the terminal, but the starter should engage & crank the engine. if the starter still does not engage & crank, we have now ruled out any electrical problems as much as possible & can start looking at mechanical issues. If all works as it should, repeatedly, we now know the problem is electrical & lies between the battery & the starter motor.

Hope this helps a little,

Regards, Tim
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PostPost by: 2cams70 » Thu Sep 21, 2017 12:06 pm

The best method If you want to methodically isolate the source of high resistance is trace the ignition circuit with the help of the wiring diagram from the battery and take relative rather than absolute voltage measurements. Connect the positive lead of the test voltmeter direct to the battery positive terminal. Turn the ignition on to the "run" position and leave it there in order to apply an electrical load. Then with the negative lead of the test voltmeter touch it on either side of each terminal junction from the beginning to the end of the circuit. The connection/s with a high resistance will give a high voltage drop (>0.5V) when tested in this manner. You may have to make up an extension for your voltmeter test leads.

The reason why I ask whether the car still has it's original Generator and regulator is because the main feed for almost every circuit in the Elan is from a single spade terminal connected to the regulator! It's highly stressed and a prime candidate for developing high resistance. You can see it on the circuit diagram. It's the ignition switch main battery feed.
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PostPost by: billwill » Thu Sep 21, 2017 6:12 pm

collins_dan wrote:Chancer, you've lost me. I only have 11.3 volts going to the starter or the coil when the white wire is connecting the ignition switch to the coil, which is insufficient to fully engage the pinion. Are you saying I need a ballast resistor connected to the system? The starter has been wired this way and worked for 13 years. I have a low resistance pertronix flamethrower coil that goes with my electronic ignition. Are you saying that I have always lost voltage in this way for 13 years?

Also, if someone could please post how to wire up the solenoid, I would like to know what i need to do. Looking at the picture on Ray's site, there appears to be two large posts and one small post.

Thanks, Dan


No you don't need a ballast resistor; you have electronic ignition which would already provide an enhanced spark.

I would expect 11.3 volts to be more than enough to pull-in the starter gear.

On an Elan with a standard starter, the starter solenoid is bolted to the 'firewall' bulkhead near the rear carburettor. Its case is earthed with a black (?) wire going to chassis somewhere. This thin wire only ever carries the current to activate the starter solenoid and does not need to be thick.

You say yours has two thick connectors and one small one. {a solenoid for a ballasted coil would have 2 thick and two small ones} The wire to the small terminal comes from the start position of the ignition switch in the cabin and current flows from it to the earted case through the coil of the solenoid. The resulting magnetic field pulls the solenoid causing heavy duty contacts to connect the two large posts together.

A big fat wire from the battery runs across near the top of the bulkhead and is bolted on the fat post nearest the bulkhead i.e the rear one. This connector also has a biggish spade connector to which is connected a medium thick brown wire, which disappears into the bulkhead. This brown wire is the main electric feed from the battery to ALL the other circuits.

The other fat post only has any voltage on it when the solenoid is activated and is the feed to the starter motor using a fat wire. The fat wires and fat connectors and heavy duty contacts inside ensure that there is very little electric resistance.

On a standard Lucas starter, the power on that output terminal post starts the motor spinning and centrifugal force throws the Bendix gear to engage with the ring gear on the flywheel and start the engine turning.

With your pre-engaged starter, my recommended circuit is to use the fat wire from the original solenoid output terminal to the fat input terminal of your starter AND ALSO CONNECT ANY THIN CONNECTOR ON THE MOTOR TO ITS OWN FAT TERMINAL. that thin connector will be the activating terminal for the internal solenoid.

The way it works then is that your starter position on the ignition switch pulls in the original bulkhead solenoid putting battery voltage onto the fat wire going down to the starter. The thin connector on the pre-engage starter then pulls in its internal solenoid which engages the gear into the ring gear and in the engaged position also closes a second set of heavy duty contacts which allows high current to flow from the motor's fat terminal to ground through the motor windings. The motor turns and turns the engine.

When you release the start position of the ignition switch, the bulkhead solenoid disconnects its heavy contacts so the battery voltage down to the starter motor goes away. The motor stops pulling and its internal solenoid also withdraws by spring, pulling the motor gear out of the ring gear.

The original bulkhead starter solenoid is a reliable item and it is not worth worrying about a tiny reduction in overall reliability by having both solenoids in circuit.

~~~

If you are having problems it is almost certainly due to poor earthing, either of the starter motor to the engine or of the engine to the chassis or the point at which the other battery lead connects to the chassis in the boot. Connections need to be bare metal to metal. Use a wire brush to scrape off any paint or rust and add a smear of Vaseline to prevent future rusting.
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PostPost by: billwill » Thu Sep 21, 2017 6:33 pm

If you have already removed the original solenoid which it seems you have, you must have made some provision for handling the wires which were previously connected to the solenoid.

Show a photo of what you have done!

To do this properly, you would need a heavy duty single post terminal block onto which the two fat wires should be cleaned, wirebrushed and bolted together and including the big spade connector so that the thickish brown wire can be connected here to provide all the electricity to the car circuits. The white/red wire (which is the solenoid activation wire from the START position of the ignition switch) should NOT be connected to this terminal, instead it should be extended and go down (strapped to the fat wire? ) to the activation terminal of the pre-engaged starter motor.
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PostPost by: collins_dan » Tue Oct 03, 2017 2:52 pm

Still unpacking boxes after the move to the new house. I will pick this back up shortly, but to answer a couple of questions -

2cams, no solenoid and converted to alternator. Sounds like I need to thoroughly check for voltage loss along the white wire, starting at the back of the tach, then the kill switch, then the coil. I will also look at the wire bundle connected to the terminal block that I installed 5 years ago when swapping over to alternator.

Billwill, the wiring to the preengaged starter is very simple the heavy wire from the battery goes to the starter, main power line connected to the same terminal on the starter, the solenoid trigger wire connected to the solenoid connection on the starter. No ground wire, as grounding is via the engine block. Thanks for the suggestions for how to wire in a new solenoid.

All the best, Dan
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PostPost by: collins_dan » Mon Aug 27, 2018 9:19 pm

Well after a year of trying to track down where I am losing 1 volt from one side of the ignition switch to the other, I am resigning myself to installing a relay. Spent even more time this weekend and the white wire is the culprit. If I detach it, voltage goes back up to the starter. If I leave it attached by detach at the coil, I gain back 0.5 volts, which I think is to be expected. The other 0.5 volts, I have no idea. I am sure it is a ground somewhere, as it seems random when it happens. I replaced the fuse box because one of the fuses wouldn't stay in and the problem went away for a couple weeks, but its back now. I'll update if the relay does the job. Dan
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