Yep the more reading one does ... the more apparrent that is. Tis why Ive taken an interest in the variations in the types ... so as to understand why some posters persist in telling me things which are irrelevant info for my OBDII system.
Whilst I can only comment on my OBDII experiences .... there seems to be a majority forum mentality ... all forums that is ... That all XJs are the same in regard to closed loop / fuel use / emissions etc.
Personal experience shows most of the "beliefs" are a bit "misleading"
e.g.
MUST have a 195' thermostat:
Particularly a genuine OEM factory one ...
Yet chrysler lists a 180' as an option and an OBDII will go closed loop without a thermostat.
Interestingly ... the factory 195' thermostat isnt specced to be fully open untill nearly 220' ... compared to the aftermarket, 195' thermostat I'm currently using - Which is designed to be fully open at about 205' .....
I prefer the 15' headstart on better coolant flow ... Its a bit like having an over-ride switch for the e-fan ..... Saves you waiting for the computer to finally realise the engine is overheating
Increased emissions at lower temps:
Quite likely ... but what percentage increase ??? ... If the OBDII O2s are showing too low a variation in oxygen levels ... the system throws a code about poor emission levels .... so obviously there has to be some variable allowances in the system - to make up for aging vehicle components.
And Im guessing the earlier systems with little control methods would have had even larger variable allowances.
Increased fuel use at lower temps:
Guarranteed ... but what rate of use - per lower degree ???? .... Certainly wont be any cylinder wall washing happening at 190' ..... and if there was ... One might expect some flooding symptoms or fouled plugs or something to prove it.
Ive always got 330+ miles from a tank whether at 185 'or 190' or 200' .... yet so many at 210' temps only get 200 miles ... go figure ???
Bit of vehicle setup to take into consideration there of course.
BTW ... XJs didnt get different capacity tanks like the TJ did they ??? ... as TJ posts are always worth a chuckle when the "mines bigger than yours" distance achievements come up ... :laugh:
Too cold an engine:
Again theres an OBDII code for that ..... the temp preset condition is 20' along with some movement sensor requirements etc.
FSM stated "warmed up" temps of 160' .... Now even I am not happy with engine running temps less than 180'-185' .... but the persistence in maintaining a 210' temp when it causes so many overheating issues is beyond me ...
....... but then - I dont need to quickly warm my toes after shovelling snow off the driveway either ....
... Sludge buildups in engines ??? .... Been happening in vehicles running too cold - for a lot of years before the XJ design ever hit the road ...... hence my preference for a 190'-195 constant temp .... and a bit of regular maintenance / suitable oil type helps a bit there too.
Thanks ... would be appreciated.
Would be great if there was a tech reference supported, post somewhere that highlighted the actual operating variations between the three systems ... for easy reference.
Or have I missed an existing one ???
:cheers:
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