Well I just purchased this 95 Valden Plas XJ6, the car was sitting up for roughly 6months give or take, it has 240kmiles on it!!! Dunno if that's bad or not I don't know anything about these cars lol, I couldn't pass the deal!! But anyways not the problem I'm having with this damn thing is that I'll try to crank it and I get nothing? My dash lights etc... Are working but it won't crank over when I try everything goes dead then once released lights come back on? I've installed an aftermarket radio without the correct harness, I've done ungodly amount of research and it just doesn't make sense !! Any help will be wonderful

 

Hello Cory,

With a little more background info I'm sure we can assist you. I bet by now you have already learned a lot about these cars compared to knowing nothing!

Was the car running at all in the last 6 months? If not the battery is probably dead. Even if the lights still work, the starter takes a ton more energy to crank the engine.

If unsure about it, the auto parts store can test and diagnose it for you. New ones aren't cheap, but it is the cornerstone (almost literally!) for everything. Make sure those clamps are clean and snug, and the ground cable is properly attached to the body near the battery.

These AJ16 engines are very durable, and can last a long, long time. But there are other parts that won't. There are lots of ways in which the car won't crank, but only one where the car WILL crank... with a good battery.

 

OK, I always head for basics.

You are in the USA I guess??

Ign ON, LOOK at the "P" on the gear selct panel next to the gearlever. It MUST be lit up RED. NO Red,. NO Crank, simple.
If you hace Red, move on.

The fact the system goes "dead" when Start is tried, is scary.

Aftermarket stuff is 85% the issue eventually, mainly Imobilisers etc, rarely radios, but who knows.

Did it Crank/Start prior to radio work??

My X300 had that moment ONCE, and I simply "locked and unlocked" the car, never happened again, Female 100%.

Next would be the battery connections, AT the battery, they can be fickle sometimes.
The battery EARTH lead, in the boot, where it attaches to the body, maybe cruddy, and needs a good clean, COMMON.

Once all that is ticked off properly, more can be suggested, but that is all I have ever had hissy with both X300 cars I have owned.

 

As Grant and SleekJag said....also, think maybe in the stickies, there is a thread I started "Gentlemen (no) Start your engines" that has links to a bunch of no-start threads and even a few solutions. I attempted to sort them between "Cranks won't start" and "won't even crank."
I had the exact thing you describe happen last weekend, for the first time EVER, across 4 X300's! I had just installed a fully-charged battery into the ol' SpruceBruce which had been sitting outside for the past 8-12 mo, and rarely fired up and only driven in and out of the shop and around the driveway for 2 yrs prior to that. (It's a long-term project) Got in, lights and dash brightly lit, turned key to Start position and, just like a US Navy ship doing BECCE's and BDECE's, HOT. DARK. SILENT! I proceeded aft to the cargo hold and measured 13.8VDC between battery posts, but only 2.36VDC between battery terminals! I then checked pos battery post to neg terminal and got 13.8, but only 2.3 between neg post and pos terminal. All posts and terminals were clean enough to eat from. I employed a digital computer trick: Pulled the positive terminal off and re-seated it and tightened it again. Next attempt:VROOM!!!
A possible difference with your failure is once I attempted to crank, that was it...no more lighty, no more buzzy, NOTHING. You haven't said, specifically, but a casual reading leaves one with the impression lights and all return after crank attempts?

Oh, typing this reminds me - back to Grant's red P....the TOPAZ car frequently, well as often as not, will not crank, but a quick jiggle of the gear change lever sets it right. I've noticed a spitball or some sort of paperwork down in there but haven't extracted it for fear that it will cancel the positive effect of the jiggle. Until I have more time to futz with it, just a lot easier to jangle the gear change lever and go, vs. disassemble, clean and set the switch. TBH, I don't recall what the lights and IP do during the no-crank attempts, nor whether or not the red P is glowing.

Also check the Earth connection between engine block and chassis. Or, diagnostically, if you have a long enough jumper, connect one end to a solid chunk of grounded engine block or attached bracket, and the opposite end to the neg batt post and attempt a crank.

Keep us posted

 

Agree with the above suggestions, but would add checking the inertia switch. It produces a lights on no crank outcome. Well documented elsewhere on here.

 

You may also want to check the megafuse nuts in the back and all battery connections.

 

This is a very common problem area. Also the bulkhead stud under the bonnet/hood at the top left of the firewall is notorious for corroding inside the rubber boot that covers the cable connection.