Question about 1991 Jaguar XJ6

1 Answer

1991 XJ6 cylinders 5/6 not firing

New plugs and wires. Fuel injectors appear fine (both electrical and fuel flow). No noticable problems. Running remarkably well on cylinders 1-4, but would rather have full use of all!

Posted by on

  • schuehle97 Oct 26, 2008

    Had tried th espark plug previously, successfully. Checked compression and have 30 PSI on 5 and 6 (1 - 4 are all 150 - 160 psi). Put some oil on top and they only came up to 40 psi. Suspecting head gasket between cylinders 5 and 6 ~ any other possibilities you can think of? As long as I've got to take th ehead off should I go ahead and do the rings anyway, or anything else?

    PS. 103,000 miles and gorgeous other than the cylinders (could be why it was only a couple of hundred dollars, but still reasonable to me!).

    Thanks very much for the advice.


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that gotĀ 5 achievements.


    An expert who has written 50 answers of more than 400 characters.


    An expert whose answer gotĀ voted for 20 times.

  • Expert
  • 104 Answers

Check for spark at the cylinders you mention. Unplug the wires from the spark plugs, put a spark plug in the end of the wires, and attach the body of the plugs to earth, or an exposed metal part of the engine. With the engine running, you should have spark at the plugs. If no spark, get the ignition system tested. If there is spark present, and you think the fuel is ok, then the compression must be at fault. The things that are required for combustion are: spark, fuel, and compression. Get a compression test done on the engine, but first check for any vacuum leaks in the inlet manifold around the cyl 5 and 6 area.

Posted on Oct 26, 2008

  • Mark Stuart
    Mark Stuart Oct 26, 2008

    I think your idea of it being the cylinder head gasket is the most likely, although if there is no obvious fault with it when you remove the head I would definitely get the head checked over, make sure the valves are in good condition and sealing properly. Good luck!


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Sons 91 olds cutlass wagon is not firing on all cylindrs, all fuel injectors and spark plugs and wires replaced

Fuel, spark, air, compression, timing. Essentials for an engine to run. You've addressed injectors (fuel) and spark (plugs and wires), and I assume it's getting air as it is running. The next thing I would do is a compression check. If you have low compression on a cylinder or cylinders, you may have mechanical problems with valves or rings.

Sep 14, 2016 | 1991 Oldsmobile Cutlass Cruiser

2 Answers

I have a 2000 gmc sierra. it has a number 7 cylinder missfire. iv changed the plugs,wires,and coil. i have good comprression and good fuel pressure. wut could b the problem

Check the fuel injector to that cylinder for power and ground, its best to use a noid light to check for proper firing. It would likely be plugged, no power or internally open electrically and not opening the injector to fire. See if you get it scanned at a parts retailer for better diagnosis. If its easy to access, remove it and swap with the fuel injector next to it. If the misfire changes to Cyl #5 then you know its no good.

Feb 24, 2011 | 2000 GMC New Sierra 1500

1 Answer

2000 S10 with 4.3 V6 has P0305 trouble code, replaced Cap, rotor, plugs, wires, still missing and running sluggish and hesitating. could Cat. Converter be bad? occassional rotten egg smell and lots of...

P0305 is the generic DTC (Data Trouble Code) for cylinder #5 mis-fire detected, and you have already eliminated the ignition tune-up parts as the problem, the next procedure should be a compression check, at least on the #5 cylinder to rule out the possibility of a mechanical mis-fire. If the compression is good then check the pick-up coil located inside of the distributor for any damage, and there is a possibility that a fuel injector is faulty or has a broken fuel line, and if the upper intake manifold is removed, and the large wire connector and fuel lines replaced back on the fuel injector assembly, then cycling the ignition key off and on several times will show if there is a fuel leak on any of the fuel injector lines, and removing the fuel injector nozzles from the lower intake manifold and then cranking the engine over (have the ignition coil connected but be certain to have the ignition coil high tension wire to the distributor cap grounded) will show if any fuel injectors are not firing or have a plugged up nozzle. The original fuel injector assembly in that vehicle has the actual fuel injector inside of the injector assembly block and the fuel travels through a small plastic tube out to a fuel nozzle attached out on the lower intake manifold for each cylinder, and a replacement fuel injection assembly is made a lot better and will have the fuel injector mounted out from the injector assembly block on the end of a larger heavier plastic tube with covered wires running back along the fuel tube to the injector block. Do you remember what the #5 spark plug looked like when you removed and replaced it and did any of the spark plugs have a black sooty carbon fouling? The #5 cylinder is located at the rear spark plug on the driver side and here is a firing order diagram to assist you. The catalytic converter would not be the suspect and moisture or clear liquid dripping from the tail-pipe is an indication that the catalytic converter is functioning properly, unless coolant or liquid is running out of the tail-pipe, then there might be a faulty intake manifold or cylinder head gasket, and a rotten egg smell is usually caused by poor fuel if the smell is coming from the exhaust, or an over-charging battery condition, (voltage at the battery should be between 14 an 16 volts when the engine is running) and let me know if you require the procedure to remove the upper intake plenum, or if you require any further assistance.



Oct 23, 2010 | 2000 Chevrolet S-10

1 Answer

The reason I'm checking the timing belt is that there is mis-fire in 1 & 2 cylinder. If the firing order is 1,2,3,4. I have continues fire out of 1 & 2, when plug wires are pulled out of head. 3...

unplug the fuel injectors, check the olhms on all. the readings should all be the same, around 11-11.5 olhms. Any readings that are higher is a sign of a bad injector which is what your problems sounds like., putting to much fuel to a cylinder causing different fuel amounts to each cylinder and causing it to backfire out of the throttle body , excess fuel . Also remove the throttle body and clean with cleaner and a toothbrush after replacing any injectors. Or there's a simpler answer and that the cambshaft is worn-out/round causing the lifters not to open enough to let in all the fuel. A worn belt would not cause misfires only on select cylinders but rather jump timing, slipping a notch on a gear and possibly bending a valve or valves and this cause a loud clacking or a really a sign to quit running the motor because it's broke! Good luck.

Oct 16, 2010 | 2004 Kia Rio

1 Answer

The engine on my sons 91 Mazda Miata is running ruff. Like on 3 cylinders. If I pull the spark plug wire on the #1 cylinder the engine runs the same. If I pull the spark plug wires on the #2,3, or 4...

You have done a great test but If I assk you to do a swap of the Ist cylinder plug and injector with one from the 3rd , we can come to a conclusion before we can change the full set of plugs and injectors for a good performance.( only if the mileage is time enough to do the change)
If you have confirmed with the spark and the fuel ( hope the fuel pressure is good and the pump calibrated , even though this is not relevant) please also check the wires to the first plug and the fuel line to the first injector.
I hope there is no issues in the pump finally for not releasing enough fuel to the first.( Check for presence of fuel pressure in this line)
I am sure you are confident enough to get to the fault .
Hope you credit me if this helps a bit. Good day

Aug 18, 2010 | 1991 Mazda MX-5

1 Answer

I have a 1991 Park Avenue. Only four cylinders fire.

Test the compression on the two cylinders that won't fire. Make sure their plug wiring is not crossed. Check those two spark plugs after running a short time--they should be wet with fuel if not firing. Any injector that won't stop leaking should be replaced. Fuses and relays should not be responsible for just two cylinders not running. The check engine light should be on--read the computer with a scanner. An engine with two cylinders inoperative SHOULD vibrate heavily. Good luck!

Feb 09, 2010 | 1991 Buick Park Avenue

2 Answers

Miss fire in cylinder 8 . already replaced plugs & wires

is there spark coming out of coil when running? ck compression? and then the fuel injector is next on the list. have a shop that has a tech2 scanner check it, or they they can do a "injector flow test" and see if its opening and flowing when commanded, could be plugged.

Oct 19, 2009 | 2002 GMC Yukon XL

2 Answers

95 Jimmy 4.3L

Try some injector cleaner in the fuel--might be a problem in # 3 injector. One cylinder misfiring should not cause the engine to stall. Replace the fuel filter, and check the air filter. Does this engine employ a distributor or a coil-pack?

Aug 08, 2009 | 1995 Chevrolet Blazer

1 Answer

Only firing on 5 pistons

try doing a cylinder balance test take one plug wire off the coil at a time while running the engine to locate the cylinder thats not firing . then check the plugwires with dmv meter should be 7000 ohms per foot also engine running u can disconnect one ijector at a time to see if it makes a difference too locate the problem the engine wont change if the injector is not flowing fuel if feel it pulsate its working electricly may be still plugged.

Jun 21, 2009 | 1991 Mitsubishi 3000GT

1 Answer

1991 chevy camaro 3.1

Mine had a similar problem, there is a wire that goes from the computer to the fuel rail and this wire sends info on how much fuel and when to inject the fuel... if that wire is grounding out then this will cause the lack of cylinders to fire and also explain the inconsistency. So i would start with the fuel rail..hope this is of some help

Oct 07, 2008 | 1991 Chevrolet Camaro

Not finding what you are looking for?
1991 Jaguar XJ6 Logo

Related Topics:

207 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jaguar Experts

Colin Stickland
Colin Stickland

Level 3 Expert

22059 Answers


Level 3 Expert

71162 Answers


Level 2 Expert

447 Answers

Are you a Jaguar Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides