The definitive K-series click cure?

[Bricol]

What is it?

 

Mine, after 25,000 miles and 6 yrs has just started doing it when hot . . .

 

Bri

[Paul Richards]

Bricol

YHM

The problem lies with the relay in the Multi Function Unit. You can cure in 2 ways, either by replacing the relay or adding an additional relay. I have done the latter and it has worked faultlessly on my car for 6 years.

 

Paul Richards

Area Representative - L.A.D.S. (Lancashire and District Sevens)

www.lads7.co.uk

Growing old is compulsory - Growing up is optional

[Mick Day]

Bricol

 

What is it?

Basically we don't know but there are several theories, ranging from dry joints in the starter itself (caused by heat), to carbon dust falling into the solenoid from the motor brushes, to voltage drop in the long wiring from battery to the starter solenoid.

 

Try connecting a fly lead from the starter solenoid connection to the battery +ve. If this starts the car then there is a voltage drop in the OEM starter circuit.

 

Ensure your starter is in good condition.

 

So what can you do? Well do a search & see how some have solved (partially?) the problem. I have done the following:

 

1. Wrapped my Magneton starter to try & insulate it from the heat.

2. By-passed the starter relay in the MFU & shortened the wiring path. Incidentally the theory behind this is that the MFU starter relay gets carbon build up resulting in a voltage drop. This along with the long wiring exacerbates the problem, with the result that the solenoid cannot actuate the starter resulting in the click. The click is the solenoid travelling part way down its bore but not reaching the end. So now my starter button only initiates the new starter relay, which in turn switches 12v (from the battery) to the starter solenoid by the shortest path.

3. All starter & alternator wiring is enclosed in a heatproof sleeve & replaced every few years.

4. Starter relay is replaced every year.

 

Mick

 

[Beelzebub]

Not wishing to muddy the waters but I'm not convinced that wrapping the starter to resolve any percieved thermal issues is the way to go. Getting rid of heat conducted from the block to the starter is only going to be achieved by passing cool air over the starter which lagging effectively prevents. Preventing radiated heat from the primaries affecting the starter would be better addressed by lagging the primaries & making a reflective heat shield .

 

My own take on this is that wrapping the starter is only going to keep the heat in. Akin to your hot water cylinder.

 

D.

 

Just my tupenceworth

[Mick Day]

Dave

 

I think you're right on the wrapping issue. I did this 3 or 4 years ago & it's just kind of stayed that way, as with all my mods, I only get the occasional click. It's never failed to start on the 2nd go.............yet. Wrapping the headers IMHO only invokes other problems. Yes a dedicated radiant heatshield would be best & so would some dedicated airflow. Maybe loosely wrapping the starter protects it from radiant header heat when the car stops?

 

The "click" is probably caused by a myriad of factors all influencing each other.

 

Mick

 

Edited by - Mick Day on 24 Jun 2007 13:45:59

[Dartmoor7]

Definitive?

Fit the non-'race' 'inside-the-skin-manifold' exhaust.

Has anyone had the click with this fitted?

I've never had a sniff of it.

 

Mick, I doubt it's voltage drop, I've had a non-standard battery for a number of years which necessitated a new starter lead, the garage got a bit carried away and my lead is at least 30 inches long, as it works I've never bothered to shorten it.

 

MY BLAT-O-METER

2007: 38 (to 17th June)

2006: 89

2005: 91

2004: 64

2003: 66

2002: 66

2001: 79

2000: 32 (divorce!)

1999: NRA

[Mick Day]

Fit the non-'race' 'inside-the-skin-manifold' exhaust.

Has anyone had the click with this fitted?

---

Yes, now using a 4:2:1.

Mick, I doubt it's voltage drop

Try connecting a fly lead from the starter solenoid connection to the battery +ve. If this starts the car then there is a voltage drop in the OEM starter circuit. This is exactly where I started & many others have verified this.

necessitated a new starter lead, the garage got a bit carried away and my lead is at least 30 inches long

Your starter has 2 wires connected to it: a big fat red lead which supplies 12v+ve to the motor & a white/red thinner wire which goes to the solenoid. It's the white/red lead which suffers from the voltage drop preventing the solenoid from operating properly.

[jd2]

Fit the non-'race' 'inside-the-skin-manifold' exhaust.

Has anyone had the click with this fitted?

---

 

Yep me but only once... and the manifold is wrapped!

[Colin Mill]

I think the relay contacts in the MFU are a likely candidate as they are switching an inductive load (the solenoid) so they are likely to suffer some burn on releasing. I have been meaning to put a heavy diode across these contacts to divert the inductive kick away from the contacts. You need to fit the diode so that its reverse biased under normal conditions.

 

Colin

[Dartmoor7]

>>Your starter has 2 wires connected to it: a big fat red lead which supplies 12v+ve to >>the motor & a white/red thinner wire which goes to the solenoid. It's the white/red >>lead which suffers from the voltage drop preventing the solenoid from operating >>properly

 

Mick,

Not on my unmodified 1400SS.

There is the big red one, and two thinner (but still decent size) browns which go into the loom and reappear, these are both at least 30 inches long too.

Maybe this is why I've had no trouble.

 

[Mick Day]

There is the big red one, and two thinner (but still decent size) browns which go into the loom and reappear, these are both at least 30 inches long too.

My car too started out as a 1.4SS, 1994 vintage. Using 2 (brown?) wires in parallel is a good way of preventing voltage drop. However it's possible that you could be mistaking these wires (brown/Purple?) for the alternator to battery +ve connection, which on my car used to pass around the engine.

[Dartmoor7]

There are two wholely brown wires away from the battery +, one is slightly thicker than the other.

There are two wholely brown unequal size wires to the starter (+red), one goes to same terminal as big red wire, one attaches to the side.

Of course, I can't tell what happens where they are inside the loom wrap.

 

Edited by - Custer Cat on 24 Jun 2007 19:37:01

[k80rum]

Hi Bri, Sorry to hear you've got The Click ☹️

 

As Mick mentions, there seem to be a number of possible causes. People seem to cure it in different ways. I tried the relay mod with no success - my click appeared infrequently when hot. I had a wrapped 4-1 SLR manifold with the smaller geared starter (unwrapped)

 

There was a very interesting post quite recently supporting a theory of wearing of the solenoid. I only skim-read it but i do think it was the most likely cause of my problems, since the relay mod didn't help me - it may be what you have too. Sorry I can't be more specific, but an archive search goin back over the last 3 months should bring it up. It detailed an obvious failing in the starter in question and a method of addressing it.

 

Best of luck with getting it sorted.

 

Darren E

 

Website and Emerald maps library

 

Superlight R #54

 

 

[Peter Carmichael]

The following is correct for the EU2 spec loom and MFU (it won't be much different for later specs):

 

The two brown wires from the battery go to the fusebox (for a car with a master switch these end up relocated to the master switch. The Big Brown does everything in the car (lights, horn, wipers). The small brown just goes through the ECU fuse and emerges to connect back to the engine loom as the purple cable that attaches via a spade connector to the big brown. This is fed to two contacts on the MFU. The MFU then controls switching that power to the main relay, fuel pump relay and the oxygen sensor. The starter relay is activated by a feed through the grey multi-plug, with a return earth also going to the multi-plug. This earth is part of the vehicle loom and attaches via the earth point at the front brake pipe union. Typically, the other connections on the starter motor are... the big brown alternator output cable and a brown/red from the MFU activating the solenoid.

 

Therefore...

 

... poor electrics in the starter circuit could be caused by...

a) an old cable from starter to battery, degraded by heat and corrosion after many years

b) a dodgy master switch, if you have one

c) dodgy contacts in the fusebox on the ECU fuse (age)

d) dodgy spade connector!!! (this is usually in very poor repair)

e) grey multi-plug showing its age and too many unpluggings

f) dodgy chassis earth from battery

g) knackered starter motor/solenoid

 

So, in their wisdom Caterham have designed in about as many points of failure in the starter circuit as is imaginable. The best way to fix this is... to start again.

 

Here's a good one too. The ECU fuse (20A, but usually recommended to be upgraded to 30A) provides all current to the devices switched by the MFU, including the fuel pump. The fuel pump output then returns via the inertia switch through the grey multi-plug all the way back to the fusebox and goes through a 15A fuse before going down the tunnel and reaching the fuel pump. The earth for the fuel pump is then delivered down the wiring loom to the front brake union where it goes via the chassis to whatever chassis earth strap you have installed (usually chassis to engine and thereafter engine to battery).

 

You may gather from this in-depth review that I have just rewired my car. It is dead simple to do if you cut out the innumerable idiosyncracies of the original loom.

 

I now have...

 

... two inline fuses feeding power to the separate twin circuits of the MFU, direct from a remote master switch. This gives me two separate 15A fused circuits matched to the load of A) Main relay (coil, injectors, ECU, alternator regulator) and Fuel pump and B) starter circuit and oxygen sensor. The engine loom provides a feed to the ignition switch, which in turn activates the ignition, start and alternator light circuits (four low current connections via a new multi-plug)

... the fuel pump feed goes direct from the MFU to the new multi-plug and straight to the fuel pump, seeing as it already on a fused 15A supply it doesn't have to do anything more complicated. The inertia switch now operates on the relay low current circuit.

 

In fact the engine can operate without the benefit of the fusebox and the fusebox exists only to serve the vehicle loads.

 

All the earths have been brought to a common point using the rearmost mounting bolt of the engine bay diagonal (universal chassis).

 

For those that wanted a definitive solution to the k-series click, well done for reading this far. As long as you have a normally operative starter motor, the above recipe will solve all starter click issues. Before resorting to voodoo, I recommend checking your chassis earths and the brown to purple connection.

 

Edited by - Peter Carmichael on 24 Jun 2007 22:54:23

[SLR No.77]

Bri - go back to Paul's first response to your post. I've had 2 Caterhams both with the dreaded click. Both have been cured faultlessly by the simple addition of a second relay, and yes i tried many of the alternative fixes!

 

Stu.

 

www.superse7ens.co.uk..........the rebuild 😬

 

 

[Jason Plato]

try this .......

 

when the click occurs

 

get out of the car and try connecting a length of thickish wire between the battery +ve and the starter motor +ve .

 

if the engine turns over then this indictes its a feed issue rather than a mechanical one.

 

If it still doesnt start, get someone to hold the ignition on and then carefully (so that you dot electricute yourself) try gently wiggleing the spade terminal on the starter motor - you may have a cracked spade terminal inside the solenoid. < that was my reason for failier.

 

Wrapping the headers IMHO only invokes other problems

??? such as ???

I have run for 10 years with wrapped headers with no temperature or valve issues.

 

Peter - surprised you didnt do a proper job of the wiring loom and remove the MFU and install seperate quality relays inside the cockpit . I will be having a new loom this winter with these modifications

 

 

 

 

[Mike Oxbiggar]

Having tried all the fixes (including new wires, solenoid, battery etc...) my 7 has been cured by the second relay too... No more clicks (much to the relief of the Taffia who were push-starting me far too often).

 

See Myles' AR7E site for simple instructions...

 

K16OOC - Bailey's MANGO Handbag

 

Webshots here

[Tony Whitley]

then carefully (so that you dot electricute yourself) try gently wiggleing the spade terminal on the starter motor

It'd be quite an achievement to electrocute yourself with a car's 12V supply

[Colin Mill]

It'd be quite an achievement to electrocute yourself with a car's 12V supply

 

Well, the starter motor and its solenoid are nice big inductances so you can get a interesting jolt when disconnecting 😬 V=-L dI/dt and all that stuff.

[Jason Plato]

*wink*Give it a go Tony and report back

 

 

[Peter Carmichael]

Peter - surprised you didnt do a proper job of the wiring loom and remove the MFU and install seperate quality relays inside the cockpit . I will be having a new loom this winter with these modifications

 

Humph I'm pretty sure I've delivered the definition of a proper job in my wiring loom. No point in putting relays on the other side of a bulkhead and then sending high current loads across a connector. Better to have the relays one wire away from the load and one wire away from the power supply, with as few connections as possible. Never had a problem with an MFU that couldn't be traced back to rubbish connectors and rubbish earths.

 

If you read the list of happy non-clicky people on this thread, many have achieved success with the relay mod. Ask yourself how the power has been fed to the relay mod. Usually direct via an in-line fuse, with direct feed. The classic click problem is not on the switching side of the relay but on power delivery via a tortuous path of multiple (cr@p) connectors.

 

[Jason Plato]

Humph

 

😬

 

I'm pretty sure I've delivered the definition of a proper job in my wiring loom

 

its your modesty I admire 😬

 

The MFU was described by the sparky that does the British superbikes and Tourings cars as Mighty fecking Unreliable . The only reason for placing seperate relays inside the cockpit is that the relays are not IP rated.

 

I did the relay mod on my K series despite not having the dreaded click, and it certainly provided a more urgent action from the starter motor.

 

 

 

 

[anthonym]

My click of death story here the comments to which are aqlso very useful.

and then when I thought it was all over: more click of death here

 

Clearly the relay mod is very effective perhaps even in a majority of cases, but there are many causes and they all involve reduced power feed one way or another, from flat battery to broken braid inside the starter motor (see many pics of all these in the above links). Having suffered multiple causes all at once I am wary of any one soultion and would love to see a definitive list of all reasons experienced, who knows we might actually capture all of them.

 

A "broken starter" is a not exactly very specific.. you'll see in my pics various reasons why a starter motor's innards might have reduced current supply.

 

Anthony

anyone got a spare Raceco skin?

[irrotational]

My solenoid had a post sticking out that the small positive wire connects too - this was so loose it was almost falling out!

 

Re-attached/soldered it, and heat wrapped it and havent had a problem since (although i am surei will now i have written this!)

 

done a few thousand miles and a few trackdays - all good.

 

so check that before you faff with these fangly relay wotsits...

 

---

this is a local sig for local people!

[wag]

I had an embarrassing development of the click at LeMans. First the click, so no starter, as we were queuingfor the ferry. Then, at the campsite, the solenoid stuck in the 'engagd' position, so starter whirring. Managed to stop that, foolishly tried again, and had smoke from under bonnet. Some swift disconnecting and we had a working vehicle, but the lad is fed up with all the push starting.