Don't worry about using a known-good injector. That's just something that's nice to do when possible. The odds are pretty slim that a new one is bad right out of the box.

How about connecting a noid light to the #4 injector wire harness? This is a special little thingy that lights up to show the injector is getting the command to fire.

 

Have not used a noid light on it yet, I need to buy some of them. What I have done is leave the #4 coil in the motor, unplug it and plug the connector into another coil (known good) out of the car with a spark plug attached to it. It has consistent and strong spark. I did the same thing with the #1 cylinder and the spark patterns seem to be the same.

When the car is running, it obviously misfires but you can smell raw fuel at the tail pipe. Maybe a leaking intake manifold causing too much air and fuel to enter cylinder?? Going to take a break from it for a few days and just think before I start guessing and throwing parts at it.

 

Make sure all the injector connectors are firmly connected to the injectors at each cylinder.

Check all 8!

As you already know many of the injectors are kind of hidden under the manifold and almost impossible to see if a injector connector is firmly seated into the injector or loose.

Often when changing coils you can knock the injector connectors loose causing the condition your experiencing.

Check cyl #4 & 3 first, then the rest. Often the plastic locking tab breaks.

You have to push the harness down into the injector with a flat blade screwdriver..

 

Hello all. New to the Jag scene but have been an admirer for a while now. I have a 2001 S-Type. I'm getting misfire codes on different cylinders. Clear code and a different misfire code. My neighbour said he had the same problem with his GM truck and it was an O2 sensor. Is it possible that this could be my problem

 

Oxygen sensor does not cause random misfires.

Is the MIL on, if so, what codes are stored in the system?

 

NBCat. The O2 sensor idea seemed odd to me, my neighbour is quite knowledgeable about cars. The MIL was on with code P0301 and P0302 pending, I believe. Cleared the codes, another quick drive and MIL on with P0306 and P0303 pending. Uncertain about exact combinations. Could it be a fuel problem ?

 

Is it a 3.0 or 4.0?

It "could be" any of many things (even blocked cats) so look at OBD live data for clues. Fuel trims of course.

Stop clearing the codes and do not disconnect the battery. Then the values should have a chance to settle and be worth looking at.

If you don't have O2 codes then it's possible but unlikely they're the cause but live data can let you see.

Have you load tested the battery? It's a known cause of odd codes.

 

2001 s-type 3L. a bit difficult to start yesterday, turned over slow but started to crank and started.
Battery? Today I get codes p0302 and p0306. Pending codes reads p1586

 

If the battery has less than 12.2 volts when the ignition is in the off position, the battery must be replaced.

The file attached below shows the cylinder numbering scheme for the AJ-V6 engine. Check for oil fouling of the numbers two and six cylinders. If oil fouling is present, replace the cam cover gaskets and spark plug boss seals as well as the IMT o-rings. The spark plugs and coil units may also need to be replaced due to the age of the vehicle.

If you must replace the cam cover gaskets, spark plug boss seals and coil units, use OEM parts as they are less prone to failure. I personally have not had success with aftermarket seals and gaskets.

 

Thanks NBCat. I'll try to check things out on the weekend

 

Just to update everyone even though the original thread has gone in another direction.....
Finally got back to messing with my 01 S type, 4.0 with a cylinder 4 misfire. Had a new coil (3 actually), new injector, new plug, swapped coils, swapped injectors, compression test (140psi) etc....and still had a cylinder 4 misfire.

Pulled the intake and the valve cover off the car hoping for a cracked intake that was leaking vacuum. Engine was golden and clean inside the valve cover but it appears that the cam lobes on cylinder 4 intake cam have worn prematurely causing the intake valves not to open on time or long enough to inject enough fuel. Not sure how this happened since the rest of the motor was spotless, and the oil appears to have been changed and the rest of the lobes were noticeable larger. Compression still read good though because the valves are opening and closing, just not properly.

So, all in all, the car is going to need extensive work and is more cost effective just to replace the motor. I am not sure what I am going to do with it yet, but that was the finding on my car. Hopefully, this doesnt happen to anyone else.

 

Sorry to hear that - but interesting and puzzling, too.

 

Could you not just replace that camshaft?

I'm surprised that there was not a noticeable clatter from the engine given the excessive cam/valve clearance.

 

+1 replace the camshaft. Were the tensioners/chains previously replaced? Are they orange or white, the tensioners?

 

What condition are the inlet camshaft tappets and shims in for that cylinder?

Unless you can find a used 4.0 litre unit in good condition, it may be best to replace the inlet camshaft, timing chains, guides and tensioners. That is assuming the rest of the engine is in good shape.