Starter issue.....

[britlude]

Got an unusual starter issue that has reared its head a couple of times now...
Try to start with the key, everything lights up as it should, but starter wont turn, jump pack, still the same issue...

Remove the small start wire from the starter motor, connect that terminal to the battery jump post in the engine compartment fuse box, it turns over instantly.... Ok, its something on the ignition switch side, BUT.....

Turn the key again and it starts up with no issue....

When it was in its 'fault state i tried a different main relay, that made no difference, cycled the auto selector, no difference, the only thing that did it was spinning the starter motor by hotwiring it, and all was well...

Most odd

I shall probably order up a starter relay (the one hidden with the computers above the sub) just for peace of mind... Even thoni checked that during first lockdown!

[goldnsx]

Ignition switch ever changed?
I've had the same when mine went fishy.

[britlude]

Yup, and got a spare.. Starter motor contacts renewed, starter cut relay (after i found it with help from Kaz) cleaned.....

But odd, as after hotwired to spin the motor it is fine with the ignition switch...

Just need to get a clearer diagram for the starter cut relay part number (awkward on my phone!) got this one, but not convinced its the right one.... 39797-se3-003.. Everything else in that circuut has been renewed...

[goldnsx]

Dumb question but do the lights dim down when you try to act the starter?

[britlude]

Yup they did, and the voltage dropped on gauge, so i suspected flat battery, tho didnt have the characteristic starter motor clicks normally associated... BUT... I if i then hotwire the motor, isolating any starter circuit, it spins fine.... It then starts up fine on the key straight after, no jump pack, no charger....

So must be a resistance in the starter circuit.... But again odd that its fine after the bypass test

[goldnsx]

Next question: how low does the voltage drop?
Did you clean the negative terminal behind the battery?
Does the car stay outside?

[britlude]

Cant remember how much it drops, but battery is nearly new... Batt neg not an issue as it spins fine when hotwired and after hotwiring...

It lives outdoors, yes!

Now suspicions are pointing to the low tension connector on the loom, as its ok after being disturbed...

[Kaz-kzukNA1]

Because the issue is intermittent and once the starter was hotwired, no more issues until next time, the cause could be within the starter, the external circuit or at both area.

Next time when you can repeatedly re-create the same issue, please measure the voltage at that single spade 250 terminal at the starter while asking someone to hold the IGSW in P3 START position.

This should tell something before hot wiring the solenoid.

Kaz

[britlude]

Yup, thats the annoying thing about intermittent faults, especially at 7am!!!

[goldnsx]

The ignition switch also starts to act intermittent. :) But as you already changed it I guess other Gremlins are at work outnight. Maybe install a webcam around the car to check if they're coming from Venus or from Mars. :D

[ozon02]

... or maybe it's a neighbor who wanted to buy a car for half price

[britlude]

So it did it again today.... Click from starter but not turning....

Monitored the voltage going to the unplugged starter low current connection, 3.5v when not trying to start, 11v when key turned to start position

Hmmm, odd, guessing the 3.5v is from the nsx start authorisation controllers, or maybe from the aftermarket immobiliser, but that is voltage free contacts...

Next time, i shall have to probe the starter circuit with it still connected to the starter.

Again, a quick 12v to the starter had the engine spinning, reconnect the original wire and its starts on the key as normal....

I shall have to wait again

[goldnsx]

There must be a big resistance from the battery to the starter. It must get hot, whatever it is.

How do the ground cables look like? They're not expensive to change.

[britlude]

i don't touch the main battery cables. only disturb the light solenoid wire in the key start circuit... so the main starter/battery wire is fine, the earths are fine, the issue is with the solenoid wire, BUT unplug it, give the solenoid a hotwire to spins the motor then reconnect the original NSX wire and it'll start no problem.....

quite confusing... i shall piggy back another wire to it tomorrow, so i can take voltages without disturbing anything when it does it again...

and i've got a starter cut relay on order, just for completeness

[Kaz-kzukNA1]

I never tried measuring the voltage at solenoid 250 spade terminal (S terminal) while keeping it disconnected from the starter but interesting that it can drop to 11V while in IGSW P3 START.
Don't know whether the drop is normal or not. I may try it to learn something new.

On the other hand, it's a solenoid pulling the starter plunger so don't know the minimum requirement but even with much lower power, should be able to push the drive gear towards the flywheel.
At least, it showed that the components (IGSW, AT Inhibit sw, starter relay, etc) involved on the solenoid side were operating.

When it failed to crank, please try listening to the single click of plunger movement when you turn the IGSW into P3.
Or, please read the voltage on the dash when in P2 and while trying to crank in P3.

Kaz

[Heineken]

Could it be a mechanical on top of an electrical issue? It somehow reminds me of an old motorbike that needed a blow with a hammer to engage the starter. Afterwards it would start fine.
Maybe hot wiring gives it just enough power to overcome the mechanical issue but the regular circuit is too weak?

PS: Maybe I'm totally wrong, just an idea that came to my mind.

[goldnsx]

Not sure but I think you've already revised your starter with a new internals. They are pretty cheap in the UK.

[britlude]

Not sure but I think you've already revised your starter with a new internals. They are pretty cheap in the UK.

Yup, twice now...

[lotusolly]

I wanted thinking the same as Heineken
As the lights are dimming and pulling down the voltage, could it be something mechanical catching and preventing the starter from spinning?
Olly

[britlude]

just to round up this thread (hopefully)

replaced the starter inhibitor relay...

https://live.staticflickr.com/65535/51180388716_6652bcff2d_c.jpg (https://flic.kr/p/2kYCSt7)IMG_20210508_154543 (https://flic.kr/p/2kYCSt7) by NSX Jon (https://www.flickr.com/photos/152809076@N06/), on Flickr

and so far, all seems well

[Old guy]

If the replacement starter cut relay fixes the problem, that would be perfect. If it doesn't, I suggest having a close look at the spade connector (S terminal) on the starter motor. Given the location, I recognize that 'close look' is going t be a problem. The fact that the starter circuit restores itself each time you disturb this connection suggests that it might be suspect. It is possible that the wire strands in the crimp on the female terminal have fractured or that the raised section on the female terminal that retains the female terminal on the male terminal has deformed resulting in a poor connection. It is also possible that there is an intermittent electrical connection between the exposed portion of the male terminal and the actual solenoid winding. Applying some electrically conducting grease to the spade terminal may help with the problem if the problem is at the spade terminal proper. Penetrox A and Ox-Gard are two conducting greases. Do not use dielectric grease because it is an insulator.

With luck its the starter cut relay and the problem will never re emerge.

[britlude]

Well, i was having an issue that prompted the relay swap, where i used the temp hardwired starter wire to spin the engine over , but touched nothing else, including the terminal.... And since the relay swap, no issues, touch wood, cross fingers, chuck salt over my shoulder, etc!!!

[britlude]

Starter issues seem to be flavour of the week!!!


The car has been standing a week and this morning it didn't want to turn over... OK, low battery is to be expected but I'd hope for a starter solenoid click or something.... As it was repeatably not turning over I had a chance to get the multimeter out....


Measuring the engine bay battery jump terminal to ground I had 11.7 volts, OK its down, not unexpected


Turning the key to the start position the dash lights dimmed a little and gauge values dropped, and I measured 11v at the jump terminal.... OK, but not disastrous


Now, I still have a lead from the starter motor low tension terminal so I can jump start it direct, but it also means I can read the voltage seen by that terminal when I go to start it....


5.8V..... Hmmmmm not very good at all. There must be a high resistance connection somewhere in the starter motor circuit...


Ignition on, I touched my remote start lead to the battery jump terminal and the starter span , and fired up straight away.... More investigation required...


On an aside, when we were driving around I did notice the dash volt meter drop from 13v to 12.5 v for a couple of seconds, repeating but not sure how regular, so i put the voltmeter on the cigarette lighter and that showed a healthy 14v, so guess the gauge feed is tired (replaced the caps during first lockdown!)

[Old guy]

The starter circuit is exceedingly simple.

14468

If you have good voltage at your jump start terminal that means the battery connections are good.

Fuse 29 is the IGN1 circuit which also powers up the dash cluster (voltmeter). However, if you were having problems with the IGN1 circuit you would likely have other significant problems (the ignition coils are supplied off of that circuit); but, it is easy to check the voltage at the fuse when attempting a start to confirm whether the problem is there or elsewhere.

That leaves the ignition switch and the starter interlock relay. I would check the ignition switch first just because it is easy to get to (relative to the interlock relay). On North American cars the interlock relay is well buried under the right dash area of the car adjacent to the stack of control modules.

[britlude]

today i had a quick delve... I disconnected the main power feed to the starter, so i could turn the key and monitor what was going on without the car actually starting...

whilst chasing the issue last year, after changing everything else, i have already replaced the interlock relay, after a detective session trying to find it!!! so i know where it is, and that it should be good (i also slotted the mounting bracket so it's a whole lot easier to remove!!!!

and after digging it out, probed it and had approx 7v at the contacts when it's trying to start....

checked the main feed fuse just in case too! full battery voltage coming out of that... Next I went to the ignition switch, that seems to have battery voltage leaving it when I want to start the car.... So somewhere between the switch and the relay seems to be losing the voltage.....

yup, It's not the most complicated of circuits.... Main fuse, ignition switch, inhibitor relay, loom link via the interior fusebox, starter solenoid... 12v should land at the starter solenoid, not around 6v!!! I shall have to check continuities to find the resistance next... or feel for a warm joint.... maybe an excuse for a cheap thermal imaging camera :)

[Old guy]

This is the diagram from the 1992 ETS manual.

14469

Its a direct connection from the plug at the ignition switch C466 to the plug at the starter cut relay C455. If you have good voltage at the back terminals on the ignition switch and bad voltage at the relay plug, you likely have a bad connection in C466 or C455. Or, you have the unthinkable - a wire sever somewhere in the wiring loom. I would not wish that on anybody.

[britlude]

right.... i have a new widget!!!
https://live.staticflickr.com/65535/51850496120_b8b0945b44_c.jpg (https://flic.kr/p/2mZRm43)2022-01-29_03-29-15 (https://flic.kr/p/2mZRm43) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

240x192 pixel resolution thermal imaging camera.... ok, lowish resolution, but didn't break the bank! i did see some at 32x24 resolution, but you might as well look at lego!

it works!
https://live.staticflickr.com/65535/51849907413_e805ee6301_c.jpg (https://flic.kr/p/2mZNk3V)IMG_20220121_134614 (https://flic.kr/p/2mZNk3V) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

so... disconnected the starter motor main feed, to stop the engine spinning and starting and set to....

i measured the voltage at the ignition switch, with it in the 'start' position, and measured the voltage at the starter solenoid terminal and was getting a consistent 3v drop somewhere between the 2... as we can see from the circuits above, it's not complicated and only has 1 relay and one junction box in the loop..

and 3v at solenoid currents must be having some reaction to the resistance in the circuit, current+resistance=heat.....hence the thermal imaging camera... (and i've always wanted one!)

the ignition switch connector
https://live.staticflickr.com/65535/51849907273_1c6edb808a_c.jpg (https://flic.kr/p/2mZNk1v)IMG_20220129_152523 (https://flic.kr/p/2mZNk1v) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

(excuse the quality, Flickr made me take pics of the pics as it didn't recognise them as pics! probably too small!)

and in thermo mode....
https://live.staticflickr.com/65535/51849907278_b1a3a00442_c.jpg (https://flic.kr/p/2mZNk1A)IMG_20220129_152624 (https://flic.kr/p/2mZNk1A) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

the camera software (on this setting) graduates the colour with reference to the hi and low temps it senses, so although the temps are not that different, it gets suitably highlighted!

in this pic, the main battery feed connection to the switch in on the right. bottom left is the wire going off to the starter relay...


the wires are getting hot, and the connector a bit hotter (presumably as it's inside a plastic case)... so I gave the terminals a bit of a clean, as much as i could considering it's position, added a bit of switch lube to the terminals too

the starter inhibitor relay (hanging in front of the sub speaker in this pic) didn't have any untoward heat
https://live.staticflickr.com/65535/51849841151_f7d1bf37cd_c.jpg (https://flic.kr/p/2mZMZmt)IMG_20220129_152607 (https://flic.kr/p/2mZMZmt) by jon sutherland (https://www.flickr.com/photos/152809076@N06/), on Flickr

so, current status... it's all back together, seems ok at the ignition switch and the relay, and starts fine, the voltage is better but still lower than i would expect.... next time i will have the glovebox out, and check the terminals on the back of the interior fuse box....

all else fails, it'll just put a slave relay in the engine bay!

[Old guy]

What did you use for switch lube on the terminals? Silicone dielectric greases are good at lubricating and preventing surface oxidation. If you have good mechanical contact they are very effective at preventing degradation of that connection. But, they do nothing to enhance electrical conductivity. Gardner Bender makes a product called Ox-Gard

Gardner Bender OX-100B Ox-Gard Anti-Oxidant Compound : Amazon.ca: Automotive (https://www.amazon.ca/Gardner-Bender-OX-100B-Anti-Oxidant-Compound/dp/B000BODU66?th=1)

Its a grease with a zinc suspension in it. When squeezed between two metal surfaces the zinc suspension improves the electrical connection. Power utilities use a similar product on high current / high voltage electrical connections. There is also a product called Caig De-Oxit. I used to think De-Oxit was snake oil; but, I have recently had excellent results with their F100-L product which is meant for use on composite non linear potentiometers. Their D100-L is meant for metal contacts. De-Oxit is a light viscosity liquid which means that it is easy to get into tight things. However, being a liquid, I don't know about its long term durability in rough service applications.

De-Oxit is on the expensive side and not so commonly available. Ox-Gard is inexpensive and in North America just about every 'big-box' home building supplier sells it. If you did not use a conductivity enhancing switch lube on the connector I would be inclined to replace it with Ox-Gard. Whenever I disturb electrical connections on an older car I apply Ox-Gard or De-Oxit to help prevent future problems (De-Oxit for low current stuff like terminations on control units).