I have a couple of extra coils and I think the spark plug tip is removable along with the rubber boot

Main thing you want is a unburnt connection tip on the spark plug

Look for cracks along the side of the coil barrel and the made in Japan sticker as these are the preferred OEM

Inside the valve cover ignition coil wells look for arcing damage to the metal

The valve cover doesn't need to come off

 

Yes the rubber spark plugs is removible. I have tested the spark unplugging the coil connector and the car start to shake a lot (with all connectors).

I replace the o rings from valve cover because there were oil linkages.

 

So the IAC, is it correct? The screw rails are broken. I don't have to worry about that, right?

 

I have to say that all coils have one or two small crakes on their bodies... here the most biggest crakes:







Answering the question about unassembled rubber coil... yes it is removible...

There are two ways


Option 1

Option 2


I prefer option 1

 

So the IAC, is it correct? The screw rails are broken. I don't have to worry about that, right?

screw rails are ?

Thinking

Ignition coils :

Without electrical test proof the cracks are a sign of heat build up inside of the coil from the insulation between the coil wire windings breaking down or a high resistance from the conducting wire winding having a bad spot

This would degrade the quality of your spark

How this would effect your idle after it has reached close loop mode is the O2 sensors are only looking at unconsumed O2 and nothing else

The O2 was never going to be completely consumed by design as the fuel / air ratio leaves some O2 left over for the catalytic converter

But an excess amount of O2 is being sensed if you have a underperforming combustion so the ECU will give it more fuel to consume it

This in turn could increase your idle speed unless the CKPS puts a exact value on what that observed idle speed should be

But it appears that the CKPS has no bearing on the ECU commanded idle speed by adjusting the pulse width of your fuel injector pulse but the fact the TPS is on idle stop.....

I am assuming the IAC has scheduled and settled down to it's almost closed position and is steady

But then you have other factors effecting this like A / C on or the Transmission ECU by way of the transmission connector

Test the EVAP valve as it should be closed at idle ? can be tested with a 9 volt battery

Vacuum hose routing, correct ?

I had a hose missing at the EVAP from the previous owner

But now we are looking at the cost of replacing the coils after X number of miles

I agree with option 1

 

FWIW, and that may be nothing at all inasmuch as essentially different engine and gearbox: I attempted to crank my 97 4.0L NA XJ-6 one cold morning recently only to be confronted with a flat battery. Performed a jump-start with my diesel tractor as booster. Revs went to 1700 and gearbox fault illuminated. I let it run a few minutes whilst unhooking the jumpers and such. Shut down, performed an immediate restart. Revs zoomed to 2500 with gearbox fault still illuminated. I quick shut it down b/c there is a TSB out there somewhere saying revs above 2000 in Park can damage the (ZF 4HP24) gearbox. I do not recall if the warning is also applicable to neutral nor whether it also applies to the GM gearbox - non of those situations would ever apply to me so I haven't garbaged up my brain with those details.

Anyway, I swapped in a fully charged battery, and she lit off as normal, no untoward dashboard warnings, cautions or advisories, and idle was normal.

So....a lot of meticulous troubleshooting has gone before....but have you checked the battery?

 

I forgot to mention, Red "BATT" illuminated the entire time and ammeter pegged on minimum. Both indications corrected (no BATT light and ammeter registering 14V) after startup with fully charged battery.

 

As you could see on the #66 post the battery volts are correct. Also the volts meter on the dash shows the correct volts. What is the battery you have installed in your car?

 

I had received my "new" coils and I had installed on the car... the car sounds better (maybe) but it is still with its high revs. I will put a stronger spring on the throttle in order to improve the butterfly return. I also test the vacuum (disconnecting the brackets vacuum hose) in the revs goes down... so it subject me that there is no leaks...

 

after engine start period the key would be stable 13.5 to 14.5 volts with your data reader while quickly changing the engine PRMs

During the start period you would have recharging the depleted battery from the cranking , heater electric water pump draw as well as cabin blower fans , seat heating , window defog so you would have to keep these off to simulate a summer start period or total car electrical demand sequence over time

There was a case of a unstable voltage regulator ( SC engine ) seen on their device but not seen on the the instrument cluster that has a dampener in it

The damper keeps the needle from jumping around

It is this true stable voltage that is important

 

Alejandro,

Does the car stay at the same high rev when idling, or is the RPMs moving all the time? It sounds like you may simply need to have the TPS reset.

 

Its depends, for example the TPS readings is 11,3 what it is okay as far as I know, now with the new coils, the idle is about 1300 rpms at P/N but when I select R or D 1000rpms (more or less). About 300 rpm more than manual shop indications.


Thanks all for your comments

 

I also started the engine with other using starter clamps and it was high idle too.
The battery readings should be at 14,5 or 13,5 volts and it is what I see on the dash... I will check also with my tester directly on the battery.
thanks Parker

 

I want to order an IAC that is the following descriptions:

INTERMOTOR: 14815, ELTA AUTOMOTIVE:
FDB1558, JAGUAR: JLM12185, MOTAQUIP:
LVIS112, QUINTON HAZELL: XICV54,
SMPE: EIC048

Am I correct? is it the correct air control actuator?
The PN written on the conector side is not available. It semms to be an old reference.

thanks in advance for your answers

 

Item # 15

That's what I would have gone for even though you tested it

Genuine Throttle Body Assembly-4.0 Litre Supercharged (4.0 Litre Supercharged) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) Classic | Jaguar Land Rover Classic Parts

There is the possibility the ECU or TPS was changed and your 11.3 % is in good range but..........