Hi folks;

Please bare with me as this is my first post for guidance. I recently purchased a 2000 Jaguar S Type 3.0 (v6) and have enjoyed the ride to date. I have put about 800 miles on it and initially experienced that the car bucks when climbing hills. It appears to move into a lower gear and then begins to buck as if too much gas. But idled fine. Well I had it detailed (everything including engine department) and now I have a rough idle with a check engine light on! Also now running at half power!

I'm in Massachusetts and there is not much for Jaguar dealers without waiting 3 weeks. A little poor too on catering to immediate needs....

I've checked the board and see a lot of V8 with coils being replaced but really would like more isolation based on the symptoms. I did check the gas cap and for a minute thought that was it but after re-seating and driving I still experience half power. I can't see anything dis-connected. Seems to occur when warmed up a bit. Not sure if washing the engine compartment was a coincident?

My questions
(1) Where is the ODB port? I see a connector under the drivers side towards the right side (acceleration leg in knee area)? I've seen videos and picture but none really are very good or accurate but play nice music...:-)

(2) I have a Actron ODB II Scanner but looks like the connector is different IF I'm see the correct ODB port on the car?

(3) Based on my symptoms, what are your areas of possibilities?

Thank you for your support! Hopefully my signature is added..

 

Sounds like misfires. They could be caused by coil(s), and your description makes that fairly likely, or an air leak - but the latter often causes a fast or rough idle.

The early 3.0 engine you have does suffer from a hose that perishes - Search on
hose elbow

so if you go in to check/replace coil(s) also do the hose that's deep under the manifold etc.

All S-Types use a standard (mandated by law) OBD II connector (aka DLC) so you're maybe looking at the wrong item. It'll be nearish your shin/ankle I think.

 

Thank you!

I will triple check in the morning for the OBD port. I've elected to take it to my standard mechanic as I'm anxious to completely fix the original issue. I will ask them to check the hose underneath and coils. If I do find the ODB port I'll see if I can get a reading and let you know.

Thank you again JagV8!

 

Well this morning I found the OBD port and that was the case. It has a cover. Thanks again for that information. As I mentioned yesterday I re-seated the gas cap which it did feel loose and not securely engaged. This morning after starting the car the "Check Engine" light was not on. So I assume it will go off over time IF it was part of the problem?

I also was capable of reading with my OBD a code of P0305 cylinder 5 misfire. Is this a coil issue? Could this cause sluggishness when heading up hills and transitioning into gears 2 or 3 around 40 - 50 MPH?

 

On these cars likely a coil. Don't leave it as it's causing fuel to burn in the cat and that'll damage it fast.

 

To late...I'm now getting a code regarding the catalyst!!

How much should I spend on the part and labor? I see I have two. Any chance that only one is failing? Any issues driving it ?

 

Do not operate the vehicle if the MIL is flashing as the catalytic converter(s) is being damaged.

There are many threads on this subject, so use the search function to learn about the possible causes.

If the vehicle has oil fouling of the coil units on Bank1, the inlet manifold must be removed. Since the DTC is for cylinder 5 (Bank2), when the engine is cold you can easily remove the plastic trim and coil unit to see if there is oil in the spark plug well.

 

Let me clarify. The check engine light has come on and the code from what I recall was associated to catalyst failure. It is out of measurement. I will read it again. I cleared the code. The oriiginal problem was resolved. Three coils were replaced as they were the reason for sluggish rough idle and loss of power. The result of the engine cleaned. Car drives very nice but now I have the check engine light.

I'll research the code on the board after reading it again.

 

If the MIL is on, and the the codes stored are P0420 (Bank1) or P0430 (Bank2), the catalyst associated with that cylinder bank is likely damaged and must be replaced.

 

I believe it was P0430. It makes sense! The check engine light (MIL?) is on again after driving it 30 - 40 miles so I'll read it one more time to confirm but it all makes sense.

If I replace with OEM part, what are we looking at for costs, roughly? I'm seeing a major difference from OEM to third party. I would like to keep the car all OEM but $975 for just the part seems way to high?

 

Don't just read the code. Erase all codes and see what comes back. You need to start with a blank slate and let the current conditions tell you if there are any problems.

After a repair it's very common to have a few codes as things get back to normal.

Let us know if it comes back.
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The Malfunction Indicator Light, often referred to as the 'check-engine-light' or 'cel' will be on if the problem persists or reoccurs after several starts. The system must return to the 'ready' mode for it to pass any emissions testing, which can take at least 50 miles.

Prior to making any repairs or replacing parts, clear the codes as tbird6 recommends and see if they return. If the codes P0420 or P0430 return, you most likely need to replace the catalyst for that cylinder bank.

Depending on the local jurisdiction where the vehicle is operated, it may be permissible to replace the catalytic converter with an approved aftermarket unit. Keeping the original equipment is a good idea if it makes economic sense, but in my experience, the aftermarket converters are quite acceptable if they are approved for use in your area. I have seen the CARB-approved S-Type converters sell for as little as 230$US installed.

 

My last XJR used to throw p0420 and p0430 codes every now and again, it had a free flow exhaust on it, which I attributed the problem to. It could go thousands of miles without doing it, so I don't think it is always 100% that the cats need replacing. As others have said, clear it and see if it comes back.

 

Sounds like you had changed the back pressure, which has the potential to cause such problems. Here, the OP seems to have the standard exhaust.

 

Thanks to all of you who contributed. Spot on! I've cleared the code now several times it it comes back "P0430, Catalyst efficiency below threshold (Bank 2)" .

I will replace the catalyst over the next few weeks If there is any one manufacturer better than another please let me know. I see CARB was mentioned by NBCat...any others?

 

In some jurisdictions, certification of an aftermarket catalytic converter is required for repair shops to legally install the part on OBD2 vehicles. In the US, as many as sixteen states have adopted the California Air Resources Board (CARB) rules, including those regarding replacement catalytic converters.

Be certain the one you choose meets the requirements for your local area so the car can pass any emissions tests that include inspection of the converters.

 

It's up to you but the cats are pretty expensive and the O2 sensors pretty easy to get at.

I would swap the O2 sensors BEHIND the cats to see if the code stays the same or jumps to the other side.

You could have an O2 sensor telling you the cat is bad when the O2 sensor is the problem.

Your call and this is extra work.
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In my experience, P0420 and P0430 have never been corrected by moving/replacing the oxygen sensors. It has always required replacing the catalytic converter for the cylinder bank indicated by the DTC.

 

Final follow-up on this issue

I replaced the catalytic converter with authentic Jag parts (ouch!) and everything is normal! $2200 later. This all stemmed from having the engine cleaned, getting misfire codes ultimately damaging the catalytic converter. Replaced 3 coils and 1 cat.....Expensive lesson!