Lotus Elan and Lotus Elan Plus 2 Forums

I'm on Bill's team. It was he who pointed out the very easy method of converting to a pre-engaged starter. It works a charm.

Guys, I can see how it works but somehow I don't think Colin would approve - more complex than necessary to achieve a desired outcome! Crank handle anyone?

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

Try eliminating the glove box kill switch in the circuit. It's a tiny, cheap slider switch that fails regularly.

It failed on me about 5 years ago and I replaced it with new, but I'll try that. Thanks, Dan

gjz30075 wrote:Try eliminating the glove box kill switch in the circuit. It's a tiny, cheap slider switch that fails regularly.

Greg, that kills the feed to the ignition circuit, not the starter motor.

Hmm, you're right about that. I jumped to a conclusion.

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

What you have described is completely normal for the voltage drop when the coil ballast resistor is bypassed by 12v being fed directly to a low impedance coil from the white starting feed.

12.5 is still a very healthy voltage for a starter motor be it pre-engaged or inertia.

From what you have described either your starter pinion is not pre-engaging so the solenoid contacts are not made or they are burnt/oxidised, assuming all other connections have been checked.

Retaining the existing solenoid will add unnecessary resistance to the starting circuit and the contacts may oxidise through too low a current passing.

Yes. Agree!

2cams70 wrote:Guys, I can see how it works but somehow I don't think Colin would approve - more complex than necessary to achieve a desired outcome! Crank handle anyone?

No you need a hefty rugby player to give you a push start. Oh hang on that weighs even more than a crank handle in the boot.

Chancer wrote:

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

What you have described is completely normal for the voltage drop when the coil ballast resistor is bypassed by 12v being fed directly to a low impedance coil from the white starting feed.

12.5 is still a very healthy voltage for a starter motor be it pre-engaged or inertia.

From what you have described either your starter pinion is not pre-engaging so the solenoid contacts are not made or they are burnt/oxidised, assuming all other connections have been checked.

Retaining the existing solenoid will add unnecessary resistance to the starting circuit and the contacts may oxidise through too low a current passing.

See my comments above, if you have a ballasted ignition coil you are going to need to faff around to provide a relay to feed the boost voltage direct to the coil bypassing the ballast resistor. It is MUCH simpler to retain the original starter solenoid. Starter Solenoids for ballast coils have 4 connectors plus the case needs earthing.

Retaining the existing solenoid will add unnecessary resistance to the starting circuit and the contacts may oxidise through too low a current passing.

Wrong: in the suggested circuits the original solenoid is carrying the full starter current.

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

If your coil resistance is just 1.5 ohms and your electronic ignition is of the type that has a long dwell time, that is holds the coil ? terminal low for a long time then the current flowing in that circuit will be some 8 amps which could well pull the voltage on the + terminal down.
It is possible that on the occasion when the car starts the electronic ignition is not drawing any current so the voltage will be high.
Check the voltage when pushed in second gear.

Dan,
I have been hoping that some one who knows more than I do would come on to help.
The workshop manual electrical equipment section M page 114 and 115 shows the connections to the solenoid with and without coil ballast resistor.
That will give you a start but next you need to know if your coil works with a ballast. The diagram shows the resistor as a physical component but sometimes it is a resistive wire in the loom.
As you have no solenoid now I suspect you have a 12 volt coil just working direct on the supply from the tacho. using a white wire. In which case this does not concern us.
The cable from the battery goes to one of the large studs and then a similar cable from the other large stud goes down to the starter motor. That may be too obvious so excuse me.
If the one you have looked at has only one small post, then that is the solenoid coil connection which may take a red/white wire from the ignition switch and the return is through the solenoid frame which needs a black earth wire. That type is not suitable to use with a ballast resistor.
I have no diagrams for the series 4 and most of this is from what I have gathered from reading posts on here.
At least you may be able to get started with this.
I think someone with more detail will come on to help.
Eric in Burnley
1967 S3SE DHC

Thanks, Eric.