Have a 1995 4.0 XJS Convertible that had been sitting a while. Charged the battery and it fired right up. Took it out for quick drive and went to put it in the garage a few hours later and it won't turn over. It sounds like it almost turns over and then clicks a few times but then all the lights go off, the gauges drop, etc. A few second later they come back on, it's almost like some overcurrent device triggers and reset. Anyone have any similar experience or thoughts? I swapped in a new battery and switched the starter solenoid so far to no avail. Not sure what could be left other than the starter, but curious about the weird power out/back on, haven't seen that before on any vehicle.

Thanks,
Scott

 

I'm sorry as I am not so familiar with the newer 4.0s and 95s but I'll just offer some general advise. I think it might be time to get in there with some hi grit sand paper, some steel wool and the like and to start cleaning both ground and positive connections. Sounds like you have a bad connection somewhere. Maybe at the body ground (near and around the battery) itself. Cleaning all/many/most of the connection points minor and major takes a while but it really pays off.

 

Hi Tromper

100% with Jay on this, as it does sound like you do have a bad earth somewhere, or possibly even dirty battery Terminals

But when you say 'You swapped in a New Battery' did you mean a 'Brand New Battery' or just another Battery? (that may not hold its charge)

Could you also expand on what you meant by 'Switched the Starter Solenoid' not quite sure what you meant there

 

It's a brand new battery that was fully charged before I swapped it in, all of those connections were cleaned (there was no visible corrosion to start with, but I cleaned them anyway). There is a blue starter solenoid relay on the passenger side engine compartment, I switched in a different one just in case that was causing an issue. It isn't the isolated silver Lucas one like on earlier models, it's a Hella 4A relay that gets used in a few different places. I'll check the ground connections and see if there are any issues there. The symptoms are indeed very similar to a bad or corroded terminal connection (which I've had a few times on other vehicles), but if that's the issue, it is not at the battery, it's has to be further downstream. I'll check those and see if I can find anything. It's a really clean, low-mileage (50k), vehicle that has always been stored indoors, so there isn't much corrosion anywhere, but something could be loose and not making enough contact for the full starter amperage draw.

Thanks,
Scott

 

Scott,

Disconnect and clean the battery terminals on the bulkhead / firewall. There are terminals on both sides and there are both negative and positive terminals, so be careful. I would disconnect the terminals at the battery first. Also, once cleaned and reconnected, check your battery voltage via those terminals and see what you get.

Good luck

Paul

 

Hi Scott

It could well be that Relay Blades are not making very good contact in the socket, have you got another one that you could try or even one of a different make and see if that makes any difference, as some Relays are known to have thicker Blades than others and in fact I did have a similar problem myself

 

I did swap another relay (same type, different purpose) and no change. The blades and sockets all looked fine, however, no signs of any corrosion. I'll check the battery terminals on the bulkhead/firewall later today, this is my first vehicle with the battery in the trunk (or boot I should say) and 5 different fuse panels, so still getting adjusted to where things are at. Thanks for all of the assistance.

-S-

 

This could be the CPS. The crank sensors in these cars fail in strange ways.

 

Would the CPS prevent it from cranking? I can see it preventing it from actually firing/starting, but I am not even cranking and didn't think the CPS would be in play electrically to turn the starter.

-S-

 

That is correct...

 

HI Scott

If She isn't Cranking then as you say the CPS is unlikely to be the cause of the problem at this stage in the game but other thoughts to consider could be the immobilizer or even the ignition switch itself

Though what I would do to begin with is to check all the fuses as apart from anything else its also very handy to see what some of them do and I'll come back if I thing of anything else

 

I recall having a “crank no start” failure with the CPS, but maybe I am wrong

 

Hi Scott

It has been known that Changing the Battery can Trigger the Immobilizer

Though much more likely it could be a Faulty Neutral Safety Switch on the Shifter

Try Starting in 'Park' then Try Starting in 'Neutral' and in the event that doesn't work, run the Shifter up and down the Gate a few times and then try it again

If no success then you may have to get under the 'Ski Slope' to see if maybe you have a Broken Neutral Safely Switch

Or maybe the Self Starter has locked up and needs a bit of a little Tap with a hammer

Good Luck

Alex (OB)

 

Scott,

Lots of useful suggestions form the guys.

For me, your symptoms sound like a big current draw that is unable to crank the starter, rather than any other problem.

I would start by absolutely knowing that you have voltage and are pulling current at the starter when you turn the key. That's a little tricky to check unless you have a good multimeter that can measure volts and high amps and has long leads, so you can view it when operating the key.

Alternatively, connect to the bulkhead power terminals and measure there when operating the key.

I wouldn't bother checking or changing anything else until you know what is the situation on current to the starter motor.

Cheers

Paul

 

It's definitely a current issue to the starter. I checked both bulkhead connections and they were fine, full battery voltage, tight and no evidence of any corrosion. I then traced the supply cable from the bulkhead + terminal to the starter itself and did the same in the boot (traced the positive to where it exits the boot) and it then started right up. The heavy gauge supply from the battery to the firewall looks fine at both connections and it would be odd for such a thick, stranded cable to have an issue somewhere in the middle. Now that I know it's one of two possible things, I'll just isolate them one at a time if it happens again and replace the offender. Thanks to all for the suggestions.

-Scott-

 

Hey Scott. It's not as strange or as odd as it sounds (and I'm NOT saying that it is the problem). I'm not saying it IS the problem, I'm just laying out a scenario. Say the insulation on that heavy gauge wire got knicked a the factory when installing, or by a service guy, or or or... Water or moisture for years gets in and corrodes that little section, it turns a nice shade of greenish red, and BAM, there it is. Lots of resistance and heat... Anyways,,,

So, a few inches from the starter on most cars is a very heavy gauge earth cable (earth strap) that grounds the engine AND importantly creates a path for that huge amperage dump that runs the starter on key turn... It brings back a lot of current to the negative battery cable in the boot - a cable connected to the battery on one end and the chasie on the other. That ground point is often neglected and important... I think you need to have a look at all these points.

Also, many people have taught me to run a second/redundant and dedicated ground right from the alternator (the engine block) mount to the chasie somehow somewhere. Purchase a long negative battery cable from the parts store, find to points you can bolt two, one on the engine the other on the chasie and youre good.

Also, the bolt on connection point ON the starter itself UNDER the car.... It's exposed to the elements, underside of the car, and can get gunked up and rusty/corroded.

Youre in for a little bit of a chase but it's awesome because you'll end up exploring areas of the car that ya nevah saw BeFo...