As regards fuel economy, not much can be said for a variety of reasons:

1) there have only been a handful sold in this thread

2) the new owners have not had much time to run many tankfuls through

3) most of the owners drive enthusiastically and fuel economy is secondary

Having said that, conventional wisdom is that running just at the threshold of over advance yields the best fuel economy for a given engine.

 

well Ive had mine on for alittle over 2weeks, and not through a tank yet. my reset on the highway showed 24mpg, beforeI could barely squeek out 22. around town seems to be around .5mpg better. Noticible differance on throttle response. The biggest problem on why I cant give more feedback is because......I just put 4.56 gears in the back diff of my 05 Nissan Frontier thats heavily modded with supercharger, cams, pistons, rods, ported heads, full stainless exhaust etc... I went from 3.36 to 4.56 no change in mpg on that because Im alot heavier than stock and need alot more gear. But the differance in the truck is night and day. So it normally sits at home because its mpg is 10 and I daily drive the jag. But since I gear swapped Ive been REALLY enjoying the truck for now. But that will change and Ill start driving the jag again next week
the bracket is worth it from any aspect. I did have to use alittle sand paper to refit the crank sensor into it. because
1 its very dirty and
2 its aftermarkert and maybe slightly bigger,
But its was not much, all I can say is test fit before you bolt the bracket on. It didnt take 5 minutes to change from the top of the engine compartment including cleaning the sensor and sanding the bracket opening for the sensor

 

Andy shipped mine Monday....not here yet but if install is as simple as Brutal describes (But I'm not on Brutal's skill-level - remember that!) I should have some reasonable fuel figures within a couple of weeks of delivery. X300 is my daily driver and gets 100 mi/day, I fill up about every 4 days on average and track all my fill-ups...so I have a lot of sound baseline data. Mileage dropped-off by 1 mpg or so a few mo. ago...not sure whether to attribute it to "winter gas" or the const. on 820 in FTW?

 

I only ask because knowone seemed to want to say if in fact MPG would or has improve with this modificates. My XJR at 70 to 75 MPH does 25 to 27 all ready with my own upgades, Re:good plugs, air filter, ect. and puts me in my seat if I realt step on it.

As stated before the car has more that enough HP for me right now so not too worried about that.

Seems to me though unless you tweek the ECM as well your only doing half the job.. Has that part been done yet?

 

XJRengineer has another thread where the availability of a ECM remap is now available. The remap takes the place of the CPS bracket because it can all be manipulated within the remap.

As for calling the use of the bracket without a "tweek" of the ECM, well the bracket is in effect itself a "tweek" of the ECM in that it is lying to the ECM. That's all it does.

On pre-ecm cars, there is no ECM to "tweek", and advancing ignition timing was still a useful tuning technique.

If "good plugs, air filter, etc." is sufficient for you, then fine ... there is really no point in the bracket for you ... but others see the point and understand the benefits.

It so happens that the bracket is only possible because XJRengineer knows the exact baseline from which the bracket varies. Very few other people would be in that position.

 

Okay I get the point just wanted to get all the facts. Will have to buy one of these CPS and see for myself, I had read someplace that the increase was only giving some a 23 to 24 mpg on the motorways and all I was stating was that mine seems to do that already with plugs, air filter etc.

If I have Offended anyone it was not my goal to do so. I understand that forums like this one are for discusion and that's all that I was hoping to get, Lines like others see the point and understand the benefits are not realy needed, I understand that others may see the point but to blindly install something on an engine is not good in some cases so some of us just want more input on how it works so we ask question of those that do know. As a marine engineer early timing is a no no. So I was just trying to figure it out in my head what it would do to a car engine...And that's all..

Hope this makes sence to you Plums

 

Simprof, dont mistake my now 24mpg to what youll get. Its to say that my mpg went up 2 mpg. I used to get that when I had the factory 16" tires and wheels. When I swapped to 01 XKR 18's 275/40, and 255/40 I increase unsprung weight and rolling resistance loosing 2mpg at that time. So Im very happy with a $100 mod

 

You are failing to make the distinction between "early" ignition timing and "optimised" ignition timing.

In post #1, XJRengineer clearly states that:

1) the bracket makes up the difference between the deliberate "late" ignition timing implemented by Jaguar engineering policy and what he observed in real life tests as "optimised" timing; and

2) the "optimised" timing is based on short bursts at full load.

With respect to point number 2, marine engines operate under a completely different load profile in that they are at full or heavy load all of the time in a narrow RPM band.

For something as big as the 17,000 KW marine diesel you described, it is likely that it has already been fully optimised for its application. Any change will make it less efficient. Even so, a diesel engine has no spark advance to play with and is a totally different animal from a four stroke spark ignition engine.

It is statements like:

And subsequently introducing:

Is where "discussion" becomes "beating a dead horse".


++

 

I read XJR's first post but like I said if we don't ask questions and take everything as being TRUE then we learn NOTHING.. O and by the way you can advance or retard a marine diesel by ajusting one or more of the fuel pump cams.

But Your right we are both "beating a dead horse".

 

Hope to get 'round to fitting it this weekend:

 

Disconnect the wiring:


Remove the bolts from the old bracket:


Check-fit new bracket over the locating pins:


Transfer the crankshaft position sensor from old to new bracket:




Fit the new bracket and secure with bolts previously removed:


Reconnect and secure the wiring:

 

please send me info 1996 xj6 usa

aj16 or aj6 ??

thanks jim v jsv737@msn.com

 

thanks aholbro, veery simple a caveman can do it!

 

Most welcome, Vmax. Don't know what surprises the supercharged version may have waiting for you up front, but on the NA it's an easy change!
I broke the retention tang on the wiring connector getting it off (Stuck a screwdriver between connector and bracket and gave a li'l tweak and that was that) Never found any loose pieces so I don't really know what it's supposed to look like, but a zip-tie (ratchet strap?) secured it quite nicely.

Jim, help us help you? Not really sure what the question is?
Pretty sure the entire X300 series (95-97 in US) used the AJ16 - but if you want info on the crank sensor bracket, just drop XJREngineer a note.

 

Sorry that you broke your connector retaining latch while fitting my bracket.

I have a suggestion for anyone else undertaking this task. I think the front ABS wheel sensors use the same design of connector (2pin Sumitomo) as the crank position sensor. If someone is planning to remove the crank sensor connector from its mounting tang for any reason (not just fitting my bracket) they may find it helpful to have a close look at the ABS sensor connectors. These are mounted under the trim panels that run down both side of the engine bay. They are much more accessible than the crank sensor, so it is easier to see how the connector is mounted to the bracket. It should be possible to see how to operate the latch to release the connector from the bracket without the risk of breaking it off. It is probably more obvious to see what is going on if the harness end is unplug from the sensor, before trying to see how the sensor latch works

 

And you really do not need to undo the connector from the bracket. I did the whole thing leaning over the fender on the drivers side. I only unbolted the sensor from the bracket first then test fit right there in the bay. If yours is clean and slips right in the bracket, youde be hard pressed to spend more than a minute doing the swap
Oh and my mileage increase is still holding true. .5mpg city and 2mpg steady state highway worthit? you betcha baby

 

I was just happy I didn't bust one side or another of the connector body - retention tang was more or less an expectation. Just been through half a tank thus far....definitely a fuel economy increase, Brutal's numbers sound good based on preliminary computer numbers I'm seeing. I'll do a chart when I've put enough miles on it to get meaningful data.

I also had to sand the the sensor a bit, but I'm reasonably sure it was just dried grease/dirt that didn't come off with several hits of MAF cleaner and a rag.

 

Ok...Filled my tank for the 10th time today since fitting Andy's bracket:
3,501 miles and 168.422 gal for an average of 20.8 mpg

For the 10 fill-ups immediately preceding fitment of Andy's bracket:
3,373 miles and 169.575 gal for 19.9 mpg.

Overall, the car was averaging 20.3 long-term but as I mentioned earlier...something of a drop-off down into the 19's in the months prior to fitment.

My driving is slightly over 50% highway.
54% > 50 mph (mostly meaning 70-73 mph)
12% Idle
8% between 30 and 50 mph

 

I had a number of orders for my bracket following recent post so I quickly ran out of stock. I now have more brackets available if anyone wants one.

 

Dear All,
Demand for my revised crank sensor brackets seems to have dried up. After selling nearly 150 I guess that everyone who wants one has one now. I probably wont make another batch after my current stock is sold unless I get some confirmed orders first. So if anyone wants ones without having to wait for it to be made to order, then I suggest that you cantact me soon.