Won't start, boot relay going like the clappers.

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Lastmin
Posts:79
Joined:Thu Mar 25, 2021 1:30 pm
Won't start, boot relay going like the clappers.

Postby Lastmin » Thu Dec 23, 2021 10:15 am

Morning,

My fault really life got in the way and not used the Jag for a few weeks.

The Jag has always started first time every time, yesterday when i reconnected the battery one of the boot mounted relays (the one closer to me) clicks and car wont start.

Anyone know what the two relays , specifically the one closer to me do?

Cheers
john

ptjs1

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Posts:3520
Joined:Thu Apr 27, 2006 7:14 pm
Location:Kent

Re: Won't start, boot relay going like the clappers.

Postby ptjs1 » Thu Dec 23, 2021 1:58 pm

John,

A number of questions:

- What model XJS and what year is your car?
- There are a number of relays in the boot. Whereabouts is the relay and what colour is it?
- Does it start clicking when you unlock the car, or when ignition goes to Pos I or to Pos Ii?
- Does the car turn over but not start, or doe the car not turn over?
- What is the voltage of the battery (before you turn on the ignition)?

Cheers

Paul
1995 XJS 4.0 Convertible
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)

Lastmin
Posts:79
Joined:Thu Mar 25, 2021 1:30 pm

Re: Won't start, boot relay going like the clappers.

Postby Lastmin » Fri Dec 24, 2021 12:55 pm

Hi,

Thanks for the reply, 5.3 v12, 1985/86 coupe.
When I connect battery just above the battery mounted on right hand side behind carpet trim are two relays, the closest one which is silver/metal grey coloured starts clicking constantly at speed.
When I put the keys in the ignition and turn to ignition 1 the clicking stops.
When I go to start the car it just turns all power off for a few seconds them seems to come back on.
I'll get the battery on charge over Christmas and see what's next. Picked up a relay and stopped it out but same result.

poprivet

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Location:Hampshire
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Re: Won't start, boot relay going like the clappers.

Postby poprivet » Fri Dec 24, 2021 2:34 pm

Dead battery?

ptjs1

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Posts:3520
Joined:Thu Apr 27, 2006 7:14 pm
Location:Kent

Re: Won't start, boot relay going like the clappers.

Postby ptjs1 » Fri Dec 24, 2021 4:47 pm

John,

What is the battery voltage with ignition off, and what foes it drop to when you try and turn starter?

Paul
1995 XJS 4.0 Convertible
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)

Lastmin
Posts:79
Joined:Thu Mar 25, 2021 1:30 pm

Re: Won't start, boot relay going like the clappers.

Postby Lastmin » Sun Dec 26, 2021 11:43 am

Hi thanks for the reply,

Re the battery it is new(ish) and had been disconnected for last few weeks my Ctek battery trickle charger shows its at 80% but knowing batteries and how fickle they can be its on charge.

I have a bigger battery i bought for my 911 which turns out didn't need i always felt the battery in my XJS seemed small for a lump this big.

Paul - i don't have a multimeter (i know, i know how can i own an old Lucas electrical British car without one) its on my Januaray sales list to buy.

Am also going to remove the quick battery disconnect as to help further reduce a possible issue.

Lastmin
Posts:79
Joined:Thu Mar 25, 2021 1:30 pm

Re: Won't start, boot relay going like the clappers.

Postby Lastmin » Wed Dec 29, 2021 10:27 pm

Little update, charged battery full reconnected and it starts. That relay though when battery is connected before you put keys in ignition clicks like crazy. Think fuel pump relay ?

When keys in the ignition it seems to cut whatever feed is making it click, same while running its quite. So basically this relay clicks while battery connected and stops when ignition is on. Kept battery charger on and pulled the relay for now. Maybe linked to a small red led light on the trans tunnel now on which I think linked to the old alarm. Maybe linked who knows. Thanks for help and any ideas welcome.


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