Hi,

I need help with starting issues I am having with 2000 XJ8 VDP. We got the vehicle last October and it was driven through Winter and Spring without any issues. Until summer break started and we started having random start up issues. We had leaking coolant from a cracked plastic distribution tube and valve covers were leaking some oil and we were curious to see if anything was done to the chain tensioners. So we decided to get parts and fix all the issues while chasing the non-start problem.

We fixed everything, replaced spark plugs as well. The car continued to have random start up issues.

It will also give different codes for problems. First time it was coils plus limp mode message. After a while it was knock sensor plus limp mode message. When it started again and no codes present and no limp mode message.

I will list the things we did so far to diagnose the issue.

Battery: New battery, plus jump starting. Doesn’t help. We do hear starter plunger engaging. It clicks.

Starter relay: Bench tested, switched with other one. We do hear starter plunger engaging. I ruled this out because without it we don’t hear starter plunger engage.

Exciter ring. Ohm tested, plus unplugging it we do not hear the starter plunger engaging, it does when it is connected.

I am getting 12 volts through high power disconnects in the trunk, to connectors next to ECU housing, to the starter and to the alternator.

The grounding wire next to the starter works.

Alternator: Removed it and bench tested at Autozone. It passed.

Starter: Removed it and bench tested with battery, it worked. Opened it up and replaced copper connectors. The plunger with the rebuild kit was shorter so reused the old plunger. Checked brushes, they have a lot of life left. Bench tested after assembly and worked fine. Installed it back and just hear the plunger click.

All we hear is click from the starter; it does not attempt to spin. We have radio, lights and stc work.
Thanks

 

have you checked the main power cable that goes to a stud on the right hand side of the plastic firewall isn’t melted inside

 

All studs getting the voltage

 

rig up an h7 test light that meter is not going to cut it

 

Just to clarify. I need to get H7 bulb and use it as a test bulb connecting to hot and ground at the studs.

Thanks

 

yes

 

Remove the starter relay. Using a thick gauge wire, jump pin 30 and 87 right across from each other. If you still only hear a click, it’s possible the ground wire on the bottom of the engine has high resistance. I’d remove the bolt and check to make sure that there’s no corrosion on the threads.

 

I hope I did the light test right. It was the same brightness at all studs. Even the starter stud.

tried to start the car again and got restricted performance message. Pulled the codes. Will crankshaft sensor prevent car from starting

thanks

 

Is there voltage at the starter in the thick wire when it just cliks ? Another guy turns the key and keeps it in start position while you measure. Is ground still okay in the same situation? I mean measure the ground. Not just look.

 

If you are getting the crankshaft position sensor code even after resetting it, I'd check the connector. If it's clean and securely plugged in, change the sensor. Your car will not run right if this is faulty or intermittently working.

 

It certainly sounds like a ground problem to me.

 

Quick update. Had time today to go under the car and see where the crankshaft sensor is. It was easily accessible so unplugged the connector and plugged it back. The car started, cleared the codes and ran the car for 10-15 minutes. No other codes came up. Turned off the car and it restarted again. Left it alone for several hours and it restarted again. No problem codes or restricted mode appeared so far. Ordered new sensor just in case.

Will let you know if anything happens again.

 

Well sir, that is great news. All it takes is a little corrosion to affect conductivity.

 

something isn’t right

a p0335 during a no start can happen because the ecm expects the crank to turn. the starter should turn even with it unplugged

 

The p0335 code was present when I first pulled the codes when problems started. It was cleared but came back later. Will keep updated.

Here are some other codes which came and went. At the moment no codes present.

 

Crank sensor has nothing to do with the starter motor not spinning. Crank sensor fault will certainly pop up when ecm doesn't detect crank speed but do detect key in start position.

 

Some updates. The car ran for couple days beautifully. Yesterday restricted performance light came on.

Did not start today. Checked battery and it’s 11.5 volts.

That was the issue to start with and that’s why I pulled alternator and tested at auto zone. Brand new battery as well.

it seems all other issues are not related.

please let me know what you think. Only code p0335 showing again.

Ground cable. Seems good to me

 

Quick update. It’s a little embarrassing but I hope will help somebody in future.

the fact that brand new battery was under 12 volts and suggestions that ground might be at fault I started tracing all the main wires. Starting in the trunk and removing big fuses. They were fine.

Next I decided to completely disassemble the bulkhead stud connector.

I will let pictures tell the story. Visual inspection and voltmeter did not reveal things hiding behind the bolts. Car started and working at the moment. Battery is getting around 14.4 volts. Before I was getting anywhere between 12.2 to 13 volts.

Thanks for all the help

 

Poor ground can be hard to sort. My old Bimmer has a braided cable that somebody pulled part.
Took me a while to figure that out, as it was not entirely apparent.