Xjs won't start. No spark
 

Hey guys,

Went to crank her up and it turns over fuel pump is running but no spark. I pulled bank a and b coil and grounded to fuel rail with no spark.

Any advice is much appreciated!!!

Please spend 20 dollars on a multimeter, it will improve diagnostic abilities tenfold and prevent you from attempting to create a spark on a fuel rail...

Is there proper voltage TO the coil?

I have a multimeter. I admit spark testing on the fuel rail wasn't wise.

I just replaced all spark plugs, did silicone on marelli rotor, and replaced all fuel hoses. So I have a pretty understanding of what's under the hood. I just have NO idea what the pinouts are or where to check for voltage on the coil.

Should I be getting 12v on the connector while the ignition is on or only while starting?

On my 87 and 85 it was the ignition amp.

And I drove the car earlier in the week. So it's ran beautifully since doing the work mentioned.

It has bee slow to start for a bit - by that i mean the engine will instantly turn but it has to turn for about 2 or 3 seconds before it actually cranks.

Now that I think about it. The fuel rail was a terrible choice for a test, not only because of explosion possibility but it's suspended by fuel hose and doesn't make ground contact anywhere.

Not sure it would have sparked even it coils were getting spark.

lolol. It could be further back, I am just recommending you work your way back until you find the problem.

there should be 12v feeding into the coil

Make sure the front crank sensor is plugged in. Also, you might have tripped the inertia switch in the drivers side door jam.

When the battery is weak it is taken all the energy by the starter and can't afford to supply enough energy to the coils. You could check the battery too.

Where is the crank position sensor located?

Also, the tachometer has been down for a while. Stuck on 2000rpm, but it's been starting and running fine until a couple days ago. It's been slow to start for some time.

its gonna be right around the dampener up front somewhere. Since it is checking the crank position it has to be right on the crank. I don't personally know if its further to the left, right, up, or if its near something that makes it easier to find. It is hard to get a look down there, but there shouldn't be many other wires leading into that area.

The crank sensor is right under the crank pulley. You will have to see it from underneath the car.

The photo attached shows the sensor location, the blue arrows are the securing bolts (note the pulley is taken off)

http://jaglover.web.fc2.com/XJSmaint...s/p1090085.jpg

Doesn't the tachometer run off the rear speed sensor, which isn't involved in ignition timing?

At least the 26CU Marelli ignition cars take the taco signal from the ignition coil, so I think 16CU cars are the same.
To ignite, I think both sensors are needed.