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Misfiring?


flyshigh007
01-19-2008, 10:47 AM
I know this subject has been discussed before but I am having some issues with my 2000 Jaguar S-Type 3.0. Lately there has been some misfiring issues with the car. It hesitates when I press the gas and when I am idled at a stop, it dies out. I have taken it to a mechanic and they told me it was 3 injectors was the problem. Had them changed and still have the same problem going on but every so often now. Should I take it to the Jag dealer or what could be wrong?

Please help! :confused:

danielsatur
03-05-2008, 07:33 AM
1) Check BOOT + BONNET FLOOD

http://www.automotiveforums.com/vbulletin/showthread.php?t=893556

2) Check spark plug seal

http://www.automotiveforums.com/vbulletin/showthread.php?t=893206

3) Check COP (coil) Test

http://www.automotiveforums.com/vbulletin/showthread.php?t=906504

4) Fuel Injector check

http://www.automotiveforums.com/vbulletin/showthread.php?t=906693




The oil seals for spark plug boss tubes will leak oil ,THE BONNET will leak water and cause a short, thus causing misfiring, or shorted coils.

The misfires on cylinder 3 of a V6, and cylinder 4 of a V8 (L-banks)is usually caused by water rolling into the spark plug boss of those cylinders, the water will roll along the ignition buss line and into the COP cover in the rear.

Headnsouth
03-05-2008, 07:36 AM
What kind of plugs are you running OEM's? Have you checked for vacuum leaks?

ndcowboy
06-02-2008, 10:32 AM
How does jaguar number there cylinders? I have a #4 misfire code. Is it like GM with odds on the drivers side and evens in the passenger? Thinking about replacing all the plugs and coils and keeping the old coils for spares. Also what is the recomended plug gap?

Thanks in advance.

danielsatur
06-02-2008, 01:18 PM
1) Is MIL/CHK engine light on?
2) How many miles are on your car?
3) If Chk Eng light On,check DTC codes at AutoZone or Pepboys.
4) If NO,we are going to look at the throttle body for Cleaning + maint.

Lost HP with no codes is a symptom of a dirty throttle body,IACT & MAF sensor, it also can
cause random misfires on random cylinders while trying todo a WOT condition.

Spark plug Gap = .035-.039 NGK iridium

Physical cylinder, not firing order.

V6
TRAN
3 6
2 5
1 4
FAN

V8
TRAN
4 8
3 7
2 6
1 5
FAN

A Throttle plate will get stickey + Not get the response,the PCM needs a good signal.
You need alot of Air to produce 400HP.

Also clean PCV vacuum port on Left frnt side valve cover going to the throttle body.
This port provides breather Air when throttle plate is closed.

ndcowboy
06-02-2008, 04:56 PM
I will give you some more background and maybe it will help. The car is an 02 s-type with the 4.0 and belongs to my brother who lives 100 miles from me. It had around 45000 miles.

He complained it was idling rough and would stumble when accellerating. I plugged in my odbII scanner and no codes were present. Pulled off the coil covers and inspected the area around the coils and it was clean and dry. Pulled the front three plugs on the pass side and they had a white ash on them which I would say is normal. They were NGK plugs gapped at .035". Reassembled everything and replaced air filter which was dirty and the fuel filter. I then drove the car 2 days 15 miles to work on the interstate and back home and it run good. He picked up the car and drove home and said it ran fine. The next day it would stumble at idle in park and on accelleration, and the check engine light was on. He had OReileys read the codes and they told him it was a cyl #4 misfire.

I see coils on ebay #370045219684. Will the DG515 fit the 02. They are around $60 a piece locally with lifetime warranty. Is it ok to replace one coil or should all be replaced. I also assume if a new coil is installed all the plugs should be replaced. What is the correct gap? Should antisieze be used? I assume the heads are aluminum.

Hope this helps, and thanks in advance. The closest jag dealership is 6 hours away and we would like to fix this on our own.

danielsatur
06-02-2008, 06:59 PM
I would only replace bad coils as needed in your case,because of the miles.

* I checked with Alldata.com and the Spark plug AJ8 4575 .035-.039
There's also a S303-S193 ECM Reflash on some models!


When removing Coils + Spark plugs label them,so you know what cylinder they came out of
during visual Inspect:
Is there a Rust residue on rubber spark plug boot?
How about any Oil residue on the rubber spark plug boot?
Any evidence of either can short a COP, and cause a misfire.

* 45k miles on a 2002 S TYPE,I would put my money on a good Throttle
body cleaning.

When you put the pedal to the metal (WOT), how does the car react?

Does the computer have to think about it?

Does the engine choke,cough,or hesitate?

Did you lose some Horse Power?

Try running a 1/4 mile with your fingers up your nose + see what you would do!

The Throttle body has a speed sensor,Air bypass valve,and a Throttle body
control module.

There's a Heat Soak time,were unburned fuel builds up gunk,carbon,or varnish on the
air intake of body.The throttle plate is a electro magnetic switch ,that doesn't
react very good when sticky!

Caution - See Troubleshoot Jag P1589 http://www.automotiveforums.com/vbulletin/showthread.php?t=968873

** I used WD40 + Oil fog Spray,micro cloth, and exercise throttle plate by putting the ignition key to the on position and pump the electronic accelator pedal.

Also use CRC MAF sensor cleaner for MAF & IAT sensors.

Note: Don't take throttle body off,just take off all the air duck work off for cleaning.

Keep in mind -''Garbage in = Garbage out''

Ambient Air-> MAF sensor -> IAT sensor -> Data->PCM
Accelerator pedal sensor-> TPS sensor -> Throttle body control ->Data->PCM

The wrong Data to PCM will cause a misfire.

I actually designed the ACME AUTO EMISSION FILTER (AAEF), to protect my MAF, H02 sensors, IACT, Injectors, Throttle body, and Catalytic converters from
being contaminated with Emission gunk, thus giving the wrong data to the ECU.
See http://www.ideabuyer.com/ipavail/acme-auto-emissions-filter

ndcowboy
06-03-2008, 07:43 AM
When I step on the go pedal the car responds quickly however it does stumble like there is a miss. If the MAF sensor is dirty that should throw a code, correct?

please explain what you mean by:
LS gremlin
MIL
Heat soak

MAF is the mass air flow sensor near the air box (air filter)?

danielsatur
06-03-2008, 09:26 AM
The Air Inake is metered and the MAF needs to respond or react fast.
If one is a hard fault it will generate a code,but a slow one will not.

LS Germlin = Lincoln service Germlin (Germlin movie)

The Lincoln LS,T-BIRD,and S TYPE have the same DNA!

MIL - Maintenance indicator lamp,or Chk Eng Light

HEAT SOAK - Is the period when you drive your car to normal operating
Temp + Park, The temp of your engine will rampup, befor cool down.

AMBIENT - Out side air

PCM - Power Train Control module (Controls Air,fuel,and Timing) for Electronic Engine control.

MAF - Massive Air Flow sensor , the air is heated in the closed throttle plate condition.

IAT - Incoming Air Temp sensor will sense the HEATED/COOLED Air + send data to PCM for control.
It's near the MAF, or on some newer models built onto MAF sensor.

ndcowboy
06-05-2008, 08:00 AM
Thanks for all the info.

Last night replaced all the plugs and the #4 coil, did compression test which ranged from 120 to 150 psi. Cleaned the throttle plate. Started the car and in ran a little rough. Disconnected battery cable for 10 minutes. Restarted car and it runs smooth. Drove about 25 miles shutting down are restarting about five times. It accellerates smooth under hard and moderate accelleration and idles smooth. Seems to run great. The only problem now is the CATS fault is displayed. We disconnect the wire while working on the drivers side, which apparently throws a fault code that can only be cleared with a Jag code tool. I guess we wait and see if the car continues to run good.

Thats again.:smile:

danielsatur
06-05-2008, 03:40 PM
Thanks for the feed back.

Whats a ndcowboy brother doing with a JAG anyway ?

He wouldn't be having this problem,if he was driving an American Truck.

ndcowboy
06-09-2008, 10:47 AM
To answer your question, my brother graduated from med school this spring and has been driving a worn out 86 bonneville for the past 15 years and is moving 600 miles from home for 5 yrs of residency and wanted something better. He bought the Jag from a distant relative. 02 45,000 miles, new rubber and the car looks mint, for $7000. Thought the deal was too good to pass up. Seems to be running great now.

As far as the towncar, any experience I have had with antifreeze in the crankcase is bad news. Had a 78 350 chevy drove I figure less than 20 miles with a blown head gasket and an 89 cutlass with 3.1 drove that 60 miles discovering I had antifreeze in the oil. Both engines had completely worn out bearings down to the babbit (copper/brass core) when disassemble, rods mains and cam. The cranks in both engines were fine however there was no engine knock. When I was finished fixing the engines, they were basicly new short blocks. New rings, bearings, cams, lifters, and oil pumps. No head work, and both engines are still on the road. One has 65k and the other around 80k. Bottom line is antifreeze is extremely hard on the bearings and oil pumps.

danielsatur
06-09-2008, 12:12 PM
It sounds like a Real good deal + do it yourself repairs.
2000-2002 S TYPE

CAUTION - If water gets on electrical buss lines on motor + fuse box in Trunk this
will cause eletrical problems when it rains, or at the local car wash.

Don't forget to fix the water holes in this boat.

jagboy96
05-25-2013, 01:47 PM
I would only replace bad coils as needed in your case,because of the miles.

* I checked with Alldata.com and the Spark plug AJ8 4575 .035-.039
There's also a S303-S193 ECM Reflash on some models!


When removing Coils + Spark plugs label them,so you know what cylinder they came out of
during visual Inspect:
Is there a Rust residue on rubber spark plug boot?
How about any Oil residue on the rubber spark plug boot?
Any evidence of either can short a COP, and cause a misfire.

* 45k miles on a 2002 S TYPE,I would put my money on a good Throttle
body cleaning.

When you put the pedal to the metal (WOT), how does the car react?

Does the computer have to think about it?

Does the engine choke,cough,or hesitate?

Did you lose some Horse Power?

Try running a 1/4 mile with your fingers up your nose + see what you would do!

The Throttle body has a speed sensor,Air bypass valve,and a Throttle body
control module.

There's a Heat Soak time,were unburned fuel builds up gunk,carbon,or varnish on the
air intake of body.The throttle plate is a electro magnetic switch ,that doesn't
react very good when sticky!

Caution - See Troubleshoot Jag P1589 http://www.automotiveforums.com/vbulletin/showthread.php?t=968873

** I used WD40 + Oil fog Spray,micro cloth, and exercise throttle plate by putting the ignition key to the on position and pump the electronic accelator pedal.

Also use CRC MAF sensor cleaner for MAF & IAT sensors.

Note: Don't take throttle body off,just take off all the air duck work off for cleaning.

Keep in mind -''Garbage in = Garbage out''

Ambient Air-> MAF sensor -> IAT sensor -> Data->PCM
Accelerator pedal sensor-> TPS sensor -> Throttle body control ->Data->PCM

The wrong Data to PCM will cause a misfire.

I actually designed the ACME AUTO EMISSION FILTER (AAEF), to protect my MAF, H02 sensors, IACT, Injectors, Throttle body, and Catalytic converters from
being contaminated with Emission gunk, thus giving the wrong data to the ECU.
See http://www.ideabuyer.com/ipavail/acme-auto-emissions-filter

I just have 1 question as i am having a misfire in cly 4 how do i test the PCM data to see if its the right data

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