Please help. 96 XJR 6cyl wont start with key but starts directly from the starter.
 

Please help I have a seriosu issue. My 96 xjr will not start from the key but a mechanic started it with some tool directly from the starter. My Engine Fans keep blowing fuses why?....... The main issue I need to address though is the stsrting problem please help me with this guys. The mechanic also played with the relays but it didnt fix the problem.

Thanks to anyone who helps. Vic

When it's in "no start" mode is the "P" on the gearshift indicator glowing red? It should be.

If not you probably need to adjust your "linear" switch which is mounted on the gear selector mechanism under the console woodgrain panel

Cheers
DD

The mechanic probably just 'shorted' the solenoid terminals to get the starter to operate. I f the engine started, then the fault is between the ignition key position & the solenoid itself. The solenoid may be faulty (it is essentially a very heavy duty relay to connect the battery directly to the starter motor) and if the contacts are not closing cleanly, the starter won't operate. It would seem that the BeCM (computer) is reading everything else when you turn the ignition key to the run position, or else it would probably not allow the engine to start.

The fan fuses blowing is probably a different problem, and you should get an Auto Electrician to look into that. Something is overloading the circuit to cause the fuses to blow, and that will be 'cooking' the wiring if it is allowed to continue. You definitely don't want the fans to fail when you are driving, since 'idiot lights' generally only come on when most or all of the damage is done. I cannot image that rebuilding a seized XJR engine would be cheap.

Cheers
Languid

The fuse for each fan is 30 amps. If the fans are worn and draw more than that, then the fuse blows. I have a stack of old fans that I hooked to a battery to measure current draw and some had a current draw in excess of 30 amps. I marked them all with the current draw and MOST were about 25 amps.

I suggest you measure the current draw before you 'chase-your-tail' with additional diagnostics.

bob gauff

Ok thank you guys I really appreciate the help.

I was just thinking about just replacing the fans because I dont think the lower one isnt working at all. I will be honest, I do not want to Pay the $768 I was quoted for a brand new fan so I was wondering if getting the fans rebuilt would be a good Idea?

Shoot, you can get used fans for $100 or less on Ebay all day long.

Cheers
DD

Yea thats very true so im going to look into it.

About the starting,issue, im not close to the car at the moment guys but I,will be,tomorrow. Ill be posting,updates through,out next week and hopefully we can get an archive made out of this thread. But please keep helping me bevause im new to the jags and this one I love and,really want,to keep and maintain.

Thanks

Well, the one blown fan is the answer to the blown fuses. The fans are designed to start in series, then switch to parallel, to reduce starting mechanical shock and current. So, A jammed fan will provide no "back emf" resulting in a full voltage start on the other fan.

As to the no crank, at least you DO NOT have the key transponder to worry about, so the diagnosis is somewhat simpler. Heed Doug's great advice and check the gearshift position.

Yup the "P" on the shifter is on... What next?

WoW you guys know your stuff. I love this forum. Ok well i was planning on having the electric motors in the fans rebuilt. Would you guys reccomend I do that? Or should I find some custom high performance fans?.. Replacement fans from Jag is not an option. Wayyyy too much money, $768

And yes the P on the shifter is lit red... So what,do,i do now?

Glowing white or glowing red?

Assuming it's glowing red there are a number of other possible faults. I'd begin by checking the starter relay. Do you have a test meter or 12v test light?

Cheers
DD

Yea its glowing red. And no I do not have a tedt light but I can purchase one today. Where is the starter relay located? And what exactly is it that I need to do?

The relay is behind the left headlight. It has green/orange, white, white/pink, and brown/white wires.

Brown/white should have 12v at all times. Check fuse #3 in the LH engine bay fuse box

White/pink should have 12v whenever the key is "on". Fuse #12, RH engine bay fuse box

White should have 12v with the key turned to "start". This is the wire that goes to the starter to energize the solenoid

Green/orange should be ground with the key turned to start.

Cheers
DD

Ok thank you doug I will be checking these wires later today. If this isnt the problem what else could it be,because the mechanic did also mess with the relays and it didnt fix anything for him. But I will be giving this a try.

What Doug described, of course, is a "logical troubleshooting sequence" around the relay circuit. You diod not mention if your mechanic tested theat circuit with a meter. If not, his "mess"ing was just that.

Ok I check it put and each fuse had power running to it. The only thing I have to do now is check the power in the relay.

I'm thinking about how these fans are wired, and how they operate. According to my bus partner, who is the mechanic of our operation, they start in series and switch over to parallel. That means that each fan starts with a voltage drop across itself of 6 volts. That also means that the current draw for each fan at 6volts has to be double that of its design current @ 12volts. I know I'm getting old, but something doesn't seem right about that. Murray tells me that the bottom fan always burns out first. It would seem to me that they should start & run in parallel to reduce the current darw through each. Otherwise the windings are going to have more current flow than they were designed to handle. (Watts = Volts x Amps, and since Watts are how they are each ultimately calculated, lower voltage across each means that each needs more current which equals extra heat through winding losses - EMF to overcome the load). Anyone out there with some thoughts?

Cheers,

Languid

Damn, another p.s. $330 for a full shroud with both fans + freight to wherever from a low kilometre 'wreck' (dismantled otherwise excellent vehicle chopped up to import it due to Australian Import Regs) - 60 to 80m thousand K's on clock for the most part.

Languid

Languid, thats for both fans? And thats for an xjr right? Because I plan on making this car alot quicker and meaner. But plase let me kno bcuz I need to fix the car asap. You have any prices on radiator hoses?

Ok guys I stil need help with my starting issue, the relay seems to have power running through it and it seems to be ok. What else could the problem be?

"Seems" ???



Cheers
DD