Emissions Problem(Colorado)

Trying to get this to pass. I’ve gone thru twice. After the last time I had a emissions tech look at the car. Running rough(misfiring). New plugs, oxygen sensor, all is good. Tech said its probably the timing(dampner). To rusty to see the marks.
What is involved with repairing this? Any direction would be helpful and thank you in advance.

What is the year, model, and engine type in your Jaguar?

Paul

1987 XJ6. I guess that WOULD
be helpful. :smiley:

Scott Demaree :sunglasses:

I have a 1987 XJ6, & had to have it tested just two months ago. It did pass. The first thing you need to do is check the test report to see what items failed. Was it HC, NOX, or CO? This will give you a better idea what problems to look for. As for the timing marks, if you have your mechanic slowly turn the pulley, he will see where the timing mark is, even if it’s dirty and/or rusty. Once he finds it, have him mark it with white out or white nail polish or paint. Then with a timing light he can check what your timing is set to. Two years ago, my mechanic did that for my car. It was too advanced. He backed it up to 17 degrees BTDC as it is supposed to be, and it passed.

I really appreciate your info. Thanks.

In a message dated 11/16/2017 11:08:24 AM Mountain Standard Time, noreply@jag-lovers.com writes:

MRCHBMRCHB@aol.com
November 16I have a 1987 XJ6, & had to have it tested just two months ago. It did pass. The first thing you need to do is check the test report to see what items failed. Was it HC, NOX, or CO? This will give you a better idea what problems to look for. As for the timing marks, if you have your mechanic slowly turn the pulley, he will see where the timing mark is, even if it’s dirty and/or rusty. Once he finds it, have him mark it with white out or white nail polish or paint. Then with a timing light he can check what your timing is set to. Two years ago, my mechanic did that for my car. It was too advanced. He backed it up to 17 degrees BTDC as it is supposed to be, and it passed.
Visit Topic or reply to this email to respond.
In Reply ToDWMcGee
November 161987 XJ6. I guess that WOULD be helpful. :smiley: Scott Demaree :sunglasses:
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Misery loves company. My Lump passes as to #'s but yet flunked, it smokes. Black denoting rich… Work to find and fix post poned. Weather and a personal reason.

On DW’s. yep, engine timing is critical. Scott’s point are on the point. Apologies. I could not resist.
I might add that the outer part of the dampener can slip and thusly be out of phase with the true TDC mark and the others.

So, if it responds weirdly, verify TDC. Not hard on the DOHC. Remark, and time to that mark. But, plan for a pulley swap. it will get worse…

Carl

I need to get a new Harmonic Balancer. To rusty.

Scott Demaree :sunglasses:

**

Honestly, Scott; the ‘only’ reason for changing the harmonic balancer is that it’s rubbers are shot…:slight_smile:

As MRCHR remarks implies; the timing marks are stamped into the damper metal - and, even if access is a bit awkward, some work with emery paper should reveal the marks. It’s worth while if the damper is otherwise OK…

A complication is the pointer/marking should be calibrated; with #1 or #6 at TDC, the pointer should point to ‘0’ - sometimes the pointer gets bent, and can be adjusted. And if the damper has failed pointer will not be at ‘0’ either - turning the engine back and forth around TDC may reveal damper ‘slack’.

idling rough may indeed be caused by a defective damper, but there are heaps of reasons for the uneven idle beyond what you have checked. Like plug leads, distributor rotor and lid, wobbly dist axle or some injector faults…

But apart from working on the ign timing as described; you should emphatically run a compression test. It will reveal if engine itself is healthy - or is the cause of the unevenness and failed emission testing…

Frank
xj6 85 Sov Europe (UK/NZ)
**

Always appreciate feedback from “Brothers of the Jaguar”!!
Changed the plugs and new rotor. Fuel injectors are good. Had another mechanic look at it. Both could not see the marks on the dampner to check the timing. Rusted over pretty good…not dirty. Both agreed its a ignition timing issue. One of the mechanics has said the Harmonic Balancers go out a lot in these cars. The rubber deteriorates.
I like your idea of a compression check. Thanks again for the feedback.

In a message dated 11/17/2017 2:10:00 AM Mountain Standard Time, noreply@jag-lovers.com writes:

Frank_Andersen
November 17 DWMcGee:
I need to get a new Harmonic Balancer. To rusty**
Honestly, Scott; the ‘only’ reason for changing the harmonic balancer is that it’s rubbers are shot…:slight_smile:
As MRCHR remarks implies; the timing marks are stamped into the damper metal - and, even if access is a bit awkward, some work with emery paper should reveal the marks. It’s worth while if the damper is otherwise OK…
A complication is the pointer/marking should be calibrated; with #1 or #6 at TDC, the pointer should point to ‘0’ - sometimes the pointer gets bent, and can be adjusted. And if the damper has failed pointer will not be at ‘0’ either - turning the engine back and forth around TDC may reveal damper ‘slack’.
idling rough may indeed be caused by a defective damper, but there are heaps of reasons for the uneven idle beyond what you have checked. Like plug leads, distributor rotor and lid, wobbly dist axle or some injector faults…
But apart from working on the ign timing as described; you should emphatically run a compression test. It will reveal if engine itself is healthy - or is the cause of the unevenness and failed emission testing…
Frank
xj6 85 Sov Europe (UK/NZ)

Just sand off the rust, and use some phosphoric acid, then put white paint or similar, and you will be able to read the timing marks.

I use protractors to mark out the damper in 8* increments up to ~40*BTDC in different colored nail polish

be surprised if your damper rubber was deteriorated at that age…inspect it

DWMcGee,

I have been on the XJ Jag-Lovers list since 2000 and I don’t ever recall anyone ever having a problem with a harmonic balancer in the 4.2L XK engine. Are you sure that your shop understands and has worked on Jaguar XJ6s before? I had a problem with one in one of my 5.3L V12 Jaguars and I removed and replaced the harmonic balancer to fix it, but I have never had a harmonic balancer problem in any of my I6 XK engine cars. I suppose someone might have had a problem with one on the XJ list before, but I certainly don’t recall that being an issue, ever. There are lots of things that can cause a problem with emissions and there must be hundreds of posts in the archives on this. Seems to me the common problems are due to failing catalytic converters, misadjusted Air Flow Meters, bad Oxygen Sensors, or bad piston ring or valves.

Regards,

Paul M. Novak

1990 Series III V12 Vanden Plas

1990 XJ-S Classic Collection convertible

1987 XJ6 Vanden Plas

1984 XJ6 Vanden Plas

1969 E-Type FHC

1957 MK VIII Saloon

Ramona, CA USA

side question…the pointer has a somewhat blunted end, about 2 degrees wide

whilst working recently with another experienced Jag owner, we differed in that I use the mid-point of the timer, but he used the leading edge to set the timimg?

opinions?

You guys are kidding yourselves as unless you you’ve checked to see where TDC actually is, the pointer is only an approximate at best and it’s highly unlikely that you could tell the difference anyway.
Bob
889076
Plymouth, Mi

**
It’s possible for the balancer rubbers to deteriorate, Scot - it’s not common, or go undetected…:slight_smile:

Anyway; it is worth while to try using emery- or sandpaper, or whatever, to possibly make the timing markings visible. It’s absolutely essential to observe the timing marks for correct ign timing adjustments, of course - but changing the harmonic balancer for that purpose only seems a bit excessive…

Frank
xj6 85 Sov Europe (UK/NZ)
**

right on all 3 points :grinning: