S4 Starting problems

[ericbushby]

Hi 2 cams 70,
I agree with your principle of using a relay for the starter solenoid, but may I point out that you already had one in the form of the starter solenoid before you removed it.
No components or wiring would have been needed, and the old solenoid contacts would have had an easier life due to the reduced current required by a modern starter motor.
On mine the cable to the old starter fit perfectly on the new one, so no electrical work was required at all.
A possible side benefit is that you would not have a live cable under the car.
Eric in Burnley
1967 S3SE DHC

[2cams70]

Your LiPo battery's output voltage will not be the same as a lead acid battery hence the fact it starts with a LiPo does not mean the starting system is OK for a lead acid application.

It is usual for the ignition switch "start" contacts to fail intermittently first before the condition becomes permanent.

Did you make any modifications to the charging circuit when you fitted a LiPo battery? LiPo's and lead acid batteries have different charge characteristics. If the alternator regulator set voltage is not correctly matched to the battery type the battery will be under or overcharged - it's a sensitive adjustment (accuracy down to 0.1V). Personally I'd be pretty reluctant to substitute a LiPo directly in place of a Lead Acid battery. LiPo's are pretty dangerous if not charged correctly (eg. Samsung mobiles, etc).

[2cams70]

I would not recommend using the original inertia starter solenoid as a starter relay for the pre-engaged starter motor. The inertia starter solenoid is designed to switch the full starter current (maybe 100A+). When used as a relay for a pre-engaged starter motor it only has to switch maybe 10A or even less for the solenoid only.

All relays have what is called a "wetting current" (or minimum recommended current) design specification. Operate below this and there's not sufficient current for "self cleaning" of the relay contacts. The contact resistance of the relay will become high over time.

I'd suggest replacing the inertia starter solenoid with a standard 30A automotive type relay. Preferably one with built in diode protection

[ericbushby]

2cams70
But the solenoid switches 6 amps ( in my case) to operate the built in solenoid in the starter motor and then carries the 160 amps (again in my case) drawn by the motor itself. It then has to break the full current. Will this not maintain the contact condition that you are concerned about.
I fitted the Powerlite starter nearly 4 years ago and have had no trouble since.
Eric

[ericbushby]

Dan,
I have read all this through again and we all appear to be struggling.
Can you please confirm that the starter ring teeth are chamfered on the front edge, where the starter engages.
You may be able to see this by removing the tin can Bendix gear cover, and using a dentists mirror and light, or even reach in to feel it.
I thought that all starter rings were chamfered on both sides, but just maybe !!!
This may not explain why it has worked without trouble before.
Eric in Burnley
S3SE DHC

[2cams70]

2cams70
But the solenoid switches 6 amps ( in my case) to operate the built in solenoid in the starter motor and then carries the 160 amps (again in my case) drawn by the motor itself. It then has to break the full current. Will this not maintain the contact condition that you are concerned about.
I fitted the Powerlite starter nearly 4 years ago and have had no trouble since.
Eric

That's interesting. I'm not sure how you've wired it so that it breaks the full starter current. Could you do a wiring circuit sketch?

Will regards to the car with issues I'd still recommend the jump wire test as it eliminates quite a few possibilities. You could easily rig up a proper jump wire - alligator (or crocodile clip if you are from Australia !) at each end with a suitably rated momentary contact switch in the middle.

[collins_dan]

Let me go back to the beginning. I bought the car 13 years ago with a newly installed pre-engaged starter and no solenoid. For 13 years, I had not issues with it starting, so the installation without a solenoid or relay is fine. Over this past winter, when the car wasn't getting much use, I would occasionally turn the key and only get a click. I would try again and it would start fine. In the spring, as the car was getting more use, this happened with more frequency and then would not start. I was talking to Ken Gray at Dave Bean about something else and he said that it was not uncommon for the pre-engaged starters to build up corrosion inside, so the pinion won't fully engage. I decided to buy a new starter and planned to clean up the old and keep as a back-up. After removing the old and installing the new, I checked the old and it was fine and the new was given me the same issue. Cleaned the earth in the trunk/boot, it was better, but still occasionally a problem. I checked the voltage to the starter and found that it was only about 11.3, I used the engine earth as the ground to test this. If the battery was fully charged, I had no issue, but this was a challenge as the battery was old, so I got a new one. Problem basically went away, unless I was starting and stopping the car a number of times. I checked the ignition switch voltage using the ground under the dash to test voltage coming in, 12.5, and going out, 11.3. I replaced the ignition switch, but problem continues. Here's my struggle. The design is fine as it worked flawlessly for 13 years. Something has deteriorated over time, I will pull the starter and look to see if anything is blocking full engagement, but i think it is unlikely as the pinion on the old starter was perfect. I will check the engine earth. I think the jump wire test will reveal that if 12.5 volts goes to the starter it will work, as when the battery is fully charged, it works. The thing I continue to not understand is why the voltage drop through the ignition switch. I am going to do more testing of this. Try starting it without the key, using a screwdriver to see if for some reason it is not rotating enough to make good contact. I am going to try disconnecting other connections to see if something is causing a drain. Any suggestions on how to more fully test the ignition switch functionality would be appreciated. Thanks, Dan

[ericbushby]

Dan,
I think there are a lot of us out here reading and learning. Keep going and remember they are all easy afterwards.
I think 11 volts on the starter when it is cranking should be plenty. They used to say that the voltage dropped to 9 volts, which is why they used to fit a ballasted coil to give a full spark when starting. I have not measured that.

2cams 70.
I did nothing, just removed the Lucas starter and fitted the Powerlite. Two screws to fit it and one nut for the cable.
My point is that when the old solenoid is de-energised it is already moving before it disconnects the starter and it`s internal solenoid together, so is carrying the full current when it opens. The Powerlite solenoid is connected to the single power stud on the starter as supplied, and recommended by the makers.
Eric

[collins_dan]

I will carry on. Thanks for the all the ideas. Here's a question. What would happen, if sometime when it doesn't start, I disconnect the power line (brown/blue?) and the starter line (white/red) and touched them together? Essentially eliminating the ignition switch, just to see if the voltage drop is the problem. Thanks, Dan

[2cams70]

Dan,
I think there are a lot of us out here reading and learning. Keep going and remember they are all easy afterwards.
I think 11 volts on the starter when it is cranking should be plenty. They used to say that the voltage dropped to 9 volts, which is why they used to fit a ballasted coil to give a full spark when starting. I have not measured that.

2cams 70.
I did nothing, just removed the Lucas starter and fitted the Powerlite. Two screws to fit it and one nut for the cable.
My point is that when the old <a class="vglnk" href="http://www.autopartswarehouse.com/search/?Ntt=solenoid" target="_blank" rel="nofollow"><span>solenoid</span></a> is de-energised it is already moving before it disconnects the starter and it`s internal <a class="vglnk" href="http://www.autopartswarehouse.com/search/?Ntt=solenoid" target="_blank" rel="nofollow"><span>solenoid</span></a> together, so is carrying the full current when it opens. The Powerlite solenoid is connected to the single power stud on the starter as supplied, and recommended by the makers.
Eric

I've had a look at the powerlite fitting instructions on the web. Although they say you can leave the original inertia solenoid in place the recommendation is that if you experience starting difficulties to have it removed. If it was me I'd follow this recommendation regardless!!

Looking at the wiring diagram they have shown with the inertia solenoid still in place I'd say it's very dodgy. If wired this way start up of the motor and engagement of the pinion will both occur simultaneously - in which case you may as well still have an inertia starter, all the benefits of having a pre engaged starter are effectively negated. Link to Powerlite instructions below:

http://media.powerlite-units.com/upload ... 9.13_8.pdf

On the Lotus, apart from the 2 heavy duty battery feeds how many other terminals are used on the original inertia starter solenoid? 1 or 2? If 1 installation of a separate starter relay is very simple, if 2 then we need to add provision for the starter relay to also switch the ballast feed for the ignition coil.

[2cams70]

I will carry on. Thanks for the all the ideas. Here's a question. What would happen, if sometime when it doesn't start, I disconnect the power line (brown/blue?) and the starter line (white/red) and touched them together? Essentially eliminating the ignition switch, just to see if the voltage drop is the problem. Thanks, Dan

Hi Dan,
It still comes back to the fact that the starting system was never designed for the loads imposed by a pre-engaged starter solenoid. You may be able to get it running temporarily for a while by polishing all the terminals in the circuit with emery, gently squeezing any spade terminals to restore tension but it will fail again. It may take 13 years of Sunday drives but it will fail. Back in the 80's when this kind of failure was very common on Australian locally manufactured cars the OEM recommended service fix was to fit a separate starter relay. Once the relay is fitted the system is highly tolerant of terminal oxidation, etc. and the problem goes away. permanently. You will find that most if not all all new cars will have a starter relay fitted. The jump start test described will eliminate not only the ignition switch but all the wiring to and from also.

[nmauduit]

Looking at the wiring diagram they have shown with the inertia solenoid still in place I'd say it's very dodgy. If wired this way start up of the motor and engagement of the pinion will both occur simultaneously - in which case you may as well still have an inertia starter, all the benefits of having a pre engaged starter are effectively negated.

not quite, the main advantage of pre engaged modern starter is the torque.

Understood, a minimal voltage drop is lost with 2 solenoids in series in my setup, but I like the idea of retaining a stock harness and not having a hot wire hooked up underneath in the warmth and oil of the engine (though I have also added a safety circuit switch on the trunk wall in case of an engine fire - so that is 3 contacts in series actually, belt and suspenders...).

I was initially a bit concerned with charging a LiFePo battery with a Lucas ACR alternator, even if endowed with a new regulator unit set around 14V (dynamo modification I had done before changing the battery) but it has been fine for a couple years now (I had the experience of having done that swap on my motorcycle, a BMW r90s, on which I had installed an uprated regulator a 14.2V and was fine).

Quoting from Dan's last post elements that raised my attention :

Cleaned the earth in the trunk/boot, it was better, but still occasionally a problem.

That usually points to a wiring issue, probably oxidation at the chassis but I would check all wires and connections (I add contact grease when I do that) - which does not mean it is the only issue

this was a challenge as the battery was old, so I got a new one. Problem basically went away, unless I was starting and stopping the car a number of times.

That was typical of a lead battery going weak, less current output capability and eventually voltage drop. That would add to a wiring issue, but is cleared now.

I checked the ignition switch voltage using the ground under the dash to test voltage coming in, 12.5, and going out, 11.3. I replaced the ignition switch, but problem continues. Here's my struggle. The design is fine as it worked flawlessly for 13 years. Something has deteriorated over time, I will pull the starter and look to see if anything is blocking full engagement, but i think it is unlikely as the pinion on the old starter was perfect. I will check the engine earth. I think the jump wire test will reveal that if 12.5 volts goes to the starter it will work, as when the battery is fully charged, it works.

Before pulling the starter apart I would complete all electrical tests, esp. if indeed all works when the power is brought directly to the starter (jumper wire on the engine and solenoid output) then this would identify an electrical issue to be solved (poor contacts would be first on my list, but wire internal resistance can also give that kind of behavior, when copper is sufficiently oxidized inside the wire to let a small current go but not enough, thus exhibiting a non linear impedance).

The thing I continue to not understand is why the voltage drop through the ignition switch.

Just to be sure of what is what, maybe you can post a photo of the switch explaining what/where are the wires you referred to previously (brown/blue, sizes etc) e.g. when you mention white/red wire coming from the ignition, I understand it is from the dashboard (it could be that the corresponding switch is internally oxidized also, or if helped by a relay that this relay has developed some carbon deposit over time, then the resulting current to the power switch would be too weak which in turn not let enough strength at the solenoid to get to cranking position). One test you can do is to bring a strong, solid hot wire to the output of that dashboard switch to see if you can manually operate the end of the circuit, in other words test each element individually (wiring included).

[ericbushby]

2cams70
I think you must have missed something here. When the Powerlite solenoid is energised, it moves the pinion into engagement and then closes an internal contact to start the motor.
The motor can not start before the pinion is engaged.
This applies to all pre-engaged starters as far as I know, which is why they have that name.
I hope this makes sense and I can see no problem with it.
Eric

[2cams70]

Eric, nmauduit

Did either of you refer to the link I posted earlier from the Powerlite website showing how to wire up the Powerlite starter whilst still retaining the original inertia starter solenoid?

What they are saying is bollocks. Do it this way with one main lead only going to the starter and then a jump lead going from the main lead terminal to the trigger terminal on the starter mounted solenoid and you have effectively disabled the "pre-engaged" function of a pre-engaged type starter motor. With this set up torque will be applied to the pinion whilst it is being engaged with the ring gear. With a pre-engaged starter torque should only be applied after the pinion and ring gear are fully meshed. It certainly won't do anything for ring gear and pinion life doing it that way. What is supposed to happen is for the starter mounted solenoid trigger terminal to be activated first, the solenoid then engages the pinion and then finally it closes the main battery feed terminal contacts to power up the starter. Are your cars wired up the same way shown in the Powerlite fitting instructions for replacing an inertia type starter?

Appreciate if you could please review again and explain where my reasoning is incorrect.

[collins_dan]

2cams70, I hear your point. While I am trying to avoid modifications where I can, choosing to install a pre-engaged starter seems to have demanded another mod. How would I wire in the relay? I installed one for my foglights and horns via the fusebox, but I am not sure how to do it in this situation. Thanks, Dan