Hello All!!

I have a new issue with my 1983 XJ-6 U.S. spec with 43,000 miles from new, and would appreciate any ideas you may have. When I start it cold, sometimes it fires right up. Sometimes I have to crank and crank. Recently, upon start up, it spews carbony water out the tail pipe for a minute or two. No black smoke. After I let it warm up a bit, when I put it into gear, the engine acts like it is going to die; RPMs go way low. On the highway, she purrs right along. The idle is also a bit lumpy. It feels to me as if it is running rich. When idling I smell a bizarre smell. It is not rotten eggs smell, but something a little different. What I have done so far: All vacuum hoses have been replaced and routed according to the diagrams. All fuel injectors are brand new (not remanned). The cold start injector is brand new. All sensors on the upper part of intake are all brand new. The fuel pressure regulator - you guessed it! - brand new! All fuel hoses are new. I installed a 123 ignition using their recommended HT leads and one of their coils. The wiring harness for the fuel injectors is brand new. I just installed a new crankcase breather cap. Fuel pump is new. Both fuel filters (the one in the trunk and the inline next to the intake manifold are brand new. I installed a new O2 sensor, and even added the extra ground strap modification. I have sealed up every vacuum leak I could find. It had a couple of small ones BEFORE it started acting this way. I bought another AFM and installed it (no change). I have set the timing at 14 BTDC. I have experimented with changing it to 16 BTDC as Doug had mentioned in another thread. I have the butterfly set at .002 and cleaned the bejesus out of it. When I cleaned it, I did note sludge inside the manifold. I cleaned it out, but I have noted fluid (oily looking) inside the intake since. I checked all of the spark plugs (which were new a few months ago). All look normal. I am out of ideas. If any of you have any ideas I would be very appreciative!!

 

Consider the capacitor mod. Your symptoms don't match exactly but, still, it would be worth a try

https://www.jag-lovers.org/xjlovers/xjfaq/efiover.htm

Cheers
DD

 

Quote:

Originally Posted by Childeric12

Hello All!!
I have a new issue with my 1983 XJ-6 U.S. spec with 43,000 miles from new ....... I installed a 123 ignition using their recommended HT leads and one of their coils.....
I am out of ideas. If any of you have any ideas I would be very appreciative!!

A few questions: Which 123 system did you install? pre-programed curves or the one you have to program the curves from OEM data?
if pre-programed, which curve did you select? 123 Tech data indicates that 10* is the initial advance setting with vacuum removed and capped? See attached.

Have you tried placing transmission in drive and turning the ignition switch to start, to prime the fuel rail for 3-5 seconds? Better start, or no difference?
Any difference between hot restart and cold start? length of time cranking?

Do you have smog check stations in your state? They can put their equipment in test mode and check tail pipe CO level .. The idle fuel ratio is set with tail pipe monitor and the screw on top of AFM. If CO is less than 1.0 it is Lean, if CO is more than 3.0 it is Rich.
If you do not have shop with tail pipe CO test capability in your area, you can try this: Since you feel its running rich, turn adjustment screw on top of AFM 1 full turn CCW Try cold start next morning. Better, Worse or no change. If not better, return screw to original setting. Try 1 full turn from original position CW. next morning, Better, Worse or no change? If no change or worse, return screw to original position.
Rgds
David

 

Thanks Doug! I will give this a try. I got the capacitor ordered from Amazon and should be able to get it in today! Fingers crossed!

 

I installed the newest 123 ignition with Bluetooth where you program the curve yourself.. I think there are preset curves to it as well. I programmed it myself. If I am not mistaken, the file you sent was for a non-US spec XK engine.

I am attaching pictures of my curves settings. We don't have smog check or emissions stations in my state. I might be able to go to an autoparts store and see if they have a sniffer for the exhaust. Thanks for the suggestions!!!

 

In this picture, you can see the carbony, sooty water residue from start up/warm up on the garage floor. This picture looks worse than it really is as it is from several days worth of start ups and I haven't cleaned the driveway, but you get the general idea for what I am seeing.

 

Well, some amount of that soot is to be expected. But maybe that's a bit much. When was the last time the car was out for a good long run? Or last time you really gave her the boot?

The cap mod might take care of this, as it was designed to address overfueling when cold

Cheers
DD

 

I was somewhat familiar with the 123 early distributors with selection of pre-programed curves... Looking at programable centrifugal plot description, says "0* static" not sure what this means; my plots show max advance including the static timing number. On vacuum advance, I use the recommended 4-8-8 unit; again not sure how this fits with your curve plot ( not familiar with the no vacuum advance below 1500 RPM).
After all my research ( XKE> Pertronix , 3.8S >Mallory unilite) I stayed with OEM distributor for XJ6 S3 with upgraded Pertronix 4 pin module D72000 in the Ign. AMP, allowing a 0.6 ohm coil. Instant starts when cold, usual 3 tries when warm.. my fuel system will not hold pressure in rail, so prime every start with transmission in D for 3 seconds. Have a new one way check valve for fuel line in trunk, but slow getting to it.

One more hack for over night T/S-ing: remove electrical connector from cold start injector over night and see if cold start in morning is Better, Worse or the same.
With these cars there is always one thing we have overlooked...
Rgds
David

 

Good idea on the Cold Start Injector. When triggered it dumps quite a bit of fuel into the manifold.

The common failure mode is the CSI to be inoperative.... but there's no reason to think it can't just as easily be "overly operative" and swamping the engine.

Cheers
DD

 

I spent a good cup of coffee this morning going over all data points for hard start and lumpy idle.
Thoughts: Hard (long cranking period) start. Ignition timing not at optimum advance point, hence long cranking period with cold start injector flooding manifold; result carbon suit out tail pipe on to driveway. (when Engine warm thermo-time switch keeps CSI from spraying fuel)

How to get optimum ignition advance for start: See attached sheet for theory. (notice how peaky the curves are, must be right on)

Quality of spark if advance is correct: Base line; XJ6 S3 OEM conditions, max timing verses RPM and as good, or better ignition coil output. I was trying to get data from 123 web-site, a few things jumped out at me: From 123 web-site 123\TUNE+ Bluetooth programmable ignition distributor Product no.: 10097
approved for Jaguar XJ6 2.8 3.4 4.2 S1 S2 ______? S3 missing.

123 ignition systems: Ignition Coils
3.0 Ohms for 4-cylinders up to 6,000 rpm
1.5 Ohms for 4-cylinders > 6,000 rpm and all 6-cylinders
1.5 Ohms for 8-cylinders up to 5,000 rpm

You should call tach. services for their comments: HOTLINE:+49(0)2452/9574661 WE SPEAK GERMAN, ENGLISH AND FRENCH

Moss Motors web-site
Jaguar XJ6 S3 ignition coil DLB198: APPLICATION E-Type V-12, XJ12 Ser. I-II & Early III, XJ6 Ser. II-III, XJS to (e) 8S.16399, TR8 Carbureted

Powerspark web-site
Genuine Lucas Sport Ignition Coil DLB198
This is a genuine Lucas Sports Ignition Coil, Lucas part number DLB198
0.8 Ohm resistance for High Energy Electronic Ignition
Delivers a high performance, faster spark, producing up to 40,000 volts with 0.8 Ohms primary resistance.

The only thing that is key and not OEM is distributor timing and coil. You have replaced all the other suspect parts with new OEM units.
Rgds
David

 

Guys, thanks for all the suggestions!! I am still working on it. Doug, you gave me an idea, and I put some BG 44K in the tank and went for a little drive on the highway where I could get it up to 75-80. David, I also saved a new map curve based on your suggestion. So far, I have had mixed results. I will keep working on it and let you know in a day or two how things work out. Thanks again for the suggestions, everyone on this forum is always so helpful and it really has helped me out significantly!!

 

Thanks a lot for this!! I will look it over and make some adjustments. I did confirm with 123 that the distributor and coil were correct for a series 3.

 

Still working on this but, I think I may have found a culprit, if not THE culprit. I was looking at wires at the coil just to make sure none were loose or arching onto something, etc. I found that the wire from the battery to the positive side of the coil (a solid white wire) was a "crispy critter". It had also been repaired. Below the repair I saw a part that the shielding was partially gone and another where the wire was almost snapped in two. I repaired that wire and tested it. Seems to be running better. If it was indeed shorting, that would make sense why sometimes the car was running fine and others it was not.

 

Low voltage at coil, during cranking has been a reported problem...some have added a relay at coil to get direct Battery Voltage when cranking.
Finding a real fault, when dealing with intermittent problem is a good day in Jag land.
Additional note: when researching the Jaguar adaptation of the GM 4 pin module to the XJ6 S3, I found in most cases, Jaguar used one gauge smaller wiring for each of the segments in the circuit.


Rgds
David

 

Not sure what you mean by 4-8-8 and I haven't been able to find that anywhere. Can you clarify? Maybe my map curve is wrong. So far, I have found the 123 Tune+ very frustrating to find the information for the curves.

 

(4"- 8") advance begins at 4" of vacuum (inches of mercury) and is fully advanced by 8" of vacuum. Maximum advance is 8* at distributor and 16* at the crank.
Now this is where 123 lost me.. "Absolute Pressure in Metric terms" I found one explanation several years ago, but it seemed to be in Dutch??? I was never confident that I got it right.
I tried to get the software to play with when the programable distributor was released, but it only came with the purchasing of a distributor; I finally gave up and drilled down on Pertronix ignition products, a California company with all information in same format as Jaguar/Lucas data.
We all look forward to you sorting this out!!!
Rgds
David

 

Thanks for that, it was helpful!! I have updated the curves to what you see in the pictures. I disconnected the CSI and didn't notice any difference on cold start up. I did add 2 cans of BG 44K to the tanks and took the car on a good long 50 mile drive at 75-80 mph. The sooty stuff on start up is gone, too. I am going to try to give it a little drive with this new map curve and see if it is any better.

 

I thinking you are getting close: on the note "ignore MAP below 500 RPM" I think this is correct... Cranking at 200 RPM no Vacuum Advance; then idle at 800 RPM where you need the vacuum advance. I would add another data point (2) and then flatten the curve after it is at maximum(3)
(found conversion for kPa. to "Hg. online)

1....... 0 ........0....................(WOT)
2 .....13.5..... 0 ..........4" Hg
3 .....27.1 ....16 .........8" Hg
4 ................16
5 ................16
6 .....60.1 ....16 ........18" Hg (Closed throttle idle)
7 .....200......16

Be sure to charge Battery overnight to give it it's best Coil voltage at cold start.
Rgds
David

 

I might give this a shot. I am just a little concerned that the total advance is going to be 50*+ BTDC. I had read that for the XK engine you want between 38*-44*. I also read that you should not operate the XK engine with over 44* total advance or it could harm the engine. That being said, I have read in other posts where the Series 3 XJ-6 has over 50* total advance. I just don't want to damage the engine. Also, I have -7 inches of mercury at idle (according to the app for the distributor. Is it possible that I still have a vacuum leak somewhere? If so, I don't know where it could possibly be. Also, I am not using the ignition module. I hooked up the distributor exactly as Adam at LWAC did for his. He said in his video that the engine in his XJ-6 is from a series 3. I also ordered another coil with lower resistance. The one I have is 1.5 ohms. I ordered one with .7 ohms resistance. Going to give it a try when I receive it later today.

 

The 50*+ advance only occurs at high RPM and closed throttle, once the RPM comes down and you added back a little throttle, the vacuum advance cuts out, and you are back to Max of 17* + 20* = 37* . No harm at +50* with closed throttle as there is very little fuel getting to cylinders and no power being produced. Additionally these are the OEM parameters, confirmed on dyno testing.

Be sure to confirm with 123 Tech department, that the distributor electronics will withstand the higher current from the lower resistance coil. This why they always say "matching coil". The hottest spark is obtained, with the highest current flow thru the coil (lowest ohm primary coil), that will not cause the points to burn, or the electronics to fail. Points distributors were limited to 3.0 ohm coils, Early GM 4 pin ignition modules were limited to 1.5 ohms.. (when the GM main diode got upgraded a ~1.0 ohm coil became useable). With a 0.9 ohm or lower coil, you can open up spark plug gap .005th inch over OEM book ( XJ6 S3 .035 > .040th). The larger gap, improves the ignition/ combustion process. With a 0.6 ohm, or lower coil, you should consider upgrade the ignition wires from 7mm to 8mm for long term reliability.

17 -18" of vacuum at idle is considered normal for a tight engine. If you removed the Ignition AMP from front of the intake manifold, did you put in 3/4" length replacement bolts in the mount holes to seal the intake manifold? https://www.freeasestudyguides.com/e...cuum-test.html
Rgds
David