Car won't start - occasionally

[Neil220]

My car is a 1996 1.6 K series.

Twice in the past few months it wouldn't start.

Turn key, ignition on, fuel pump primes.

Key to crank position-Nothing, no sound, no clicking of starter solenoid. 

First time I left the car for 20 minutes, it started fine when I came back.

2nd time, bump started it no problem.

Battery is less than a year old and fully charged. 

Any suggestions as to what to check very much appreciated. 

I plan to check the ignition switch terminals tomorrow 

[Jonathan Kay]

There's a lot of possible causes, and I recommend keeping an open mind for the time being.

1  As well as those switch connections check all of the relevant wires and connections: battery, starter, earths including engine earth. Inspect, wiggle, disconnect, clean, reconnect.

2 What's the battery voltage at rest, minimum during cranking, and at 3,000 rpm?

3 If it's a battery that can be topped up check the fluid levels.

Do you have a multimeter and would you like the appropriate wiring diagram?

Jonathan

[Neil220]

Many thanks,

I'll check all the connections you mention.

I have a multi meter and the wiring diagram thanks.

Problem is it only happens very occasionally so unless I see something obviously wrong I won't know if I've fixed it or not!

[Jonathan Kay]

Yes, it's much easier when it fails consistently!

But that starting (!) list will eliminate a lot of possibilities.

Jonathan

[Gridgway]

One of the normal things to blame is the mfru.

First thing I'd diagnose is whether you are getting 12v to the starter solenoid when it won't crank. That would eliminate the starter motor (or point to it as the culprit).  I might go as far as to wire in a fly lead from the 12v on the solenoid up to the battery area (taking care that nothing can short).  Then if it fails again it's easy to put a volt meter on.

[Neil220]

#5

Thanks

If it happens again I'll try hitting the mfru to see if that cures it.

I've got spare relays that I removed from a broken unit so can replace if it turns out to be that 

[Gridgway]

Excellent approach - hit it with a hammer! [Mr Gumby - for those who remember such things]

[Neil220]

#7

I was tending towards tapping rather than hitting on the assumption that it's so infrequent if it was the MFRB then the contacts of the relay would be "sticking" and if a tap/hit cured it then I'd know the root cause?

[Toby S]

#7 You mean a BL Longbridge screwdriver

[Toby S]

More seriously though, and I had a similar problem on my 1400 Supersport K series - given there is no click or anything, I would suggest you check the ignition key barrel connections and barrel itself - that was the problem on mine when I had a similar problem and in the end I ditched the barrel and went for a dash mounted rocker type ignition switch

[22daz]

Have you checked the wires from the battery to the starter? My old K started fine but on inspection (when I had the engine out for something else) they run nearby the hot manifold and were crispy. Literally baked hard and snapped easily. I wonder if yours is similarly affected. 
22daz

[SM25T]

The small trigger wire to the solenoid is the one that normally fatigued and fails inside the insulation. Easy to replace

[Neil220]

#10

#11

Thanks for your advice 

[SLR No.77]

Has the setup been modified with an extra relay (to solve the "K-click") or is it as standard?

[Neil220]

I have the relay to make the mod but haven't installed it yet.

Currently when the fault occurs there is no click, just deathly silence!

[Gridgway]

Perhaps pull the supply to the solenoid, activate the starter and see if you can hear a click work it's working as it were.  Then if you have clear evidence of a click normally and no click when it doesn't work it's more likely to be the relay in the mfru.

[SLR No.77]

You need to do the relay mod. It can be done either with the MFRU still in circuit or bypass it completely. If it's in circuit the MFRU relay activates with a small click, which in turn activates the new relay which then provides power directly from the battery.

If you currently have no click from the MFRU it would be better to bypass the MFRU relay completely.

There's absolutely no point in looking at alternative solutions until you've done the mod with an additional/new relay.

Stu.

[DanRo]

I've just done the mod, with some advice from a kind Paul Richards and his LF article.   

It has worked a treat. Symptoms started as occasional non-starts when cold or hot and a quiet click from behind the dash. They progressed to a slow turning starter and then a proper hot starting problem in France in June this year. 

Following the mod, I've had absolutely no starting issues, including at a track day this week. 

I've just done a track day this week and all starts were fine. 

[Neil220]

#16

What do you mean by "pull the supply to the solenoid, activate the starter"

By pull do you mean disconnect?

Then, how do I activate the starter motor?

Are you suggesting that I  listen for a click from the relay in the MFRU?

Appreciate your help, just don't quite follow!

[Neil220]

#17

Where can I find how to bypass the MFRU?

[Neil220]

#17

Where can I find how to bypass the MFRU?

[Neil220]

#18

Thanks, which issue of LF do I need to look for?

[DanRo]

Sorry Neil

Here is the Link

I needed a bit of extra info from Paul due to ineptitude. Message me if needed and I can give you more detail on what I did. 
 

Dan
 

 

 

[DanRo]

Sorry, that link seems to take you to the LF search. Try this one

[Neil220]

Many thanks 

I think I'll do the mod, waiting for info on how to bypass the MFRU.

Heat isn't a factor for my problem though