Temperature matters
#1
03-15-2012, 08:10 PM
Temperature matters
Our 87 XJ6 has been in the family for years and I remember the dealership mechanic long ago telling me how important it was to get the engine temp in the green zone on the Series III. Failure to do so would cause the computer to rich up the mixture and lead to a rough running engine.
I recently replaced the the old stuck open thermostat with a new factory OE style (with jiggle pin). After that I found the temp needle would now reach the green but would still dart to the cold side from time to time during normal driving.
I then decide to try a SuperStant thermostat that claims to better meter the coolant through the engine to maintain temperature rather than cycling it through which tends to cause noticeable temp swings.
After installing, the temp needle would steadily ramp up to the green zone from a cold start and go a little hotter like 95 degrees and stay between the 90-98 range (always in the green) during my normal driving.
The engine now runs a little smoother than before and idle is little less lumpy because at least the computer is happy with the engine temp. I still have lots of other items to chase down in my pursuit of a smooth idle but at least I know that the computer isn't working against me anymore.
Just wanted to pass these observations along to anyone looking to improve their idle quality an engine temp stability.
I recently replaced the the old stuck open thermostat with a new factory OE style (with jiggle pin). After that I found the temp needle would now reach the green but would still dart to the cold side from time to time during normal driving.
I then decide to try a SuperStant thermostat that claims to better meter the coolant through the engine to maintain temperature rather than cycling it through which tends to cause noticeable temp swings.
After installing, the temp needle would steadily ramp up to the green zone from a cold start and go a little hotter like 95 degrees and stay between the 90-98 range (always in the green) during my normal driving.
The engine now runs a little smoother than before and idle is little less lumpy because at least the computer is happy with the engine temp. I still have lots of other items to chase down in my pursuit of a smooth idle but at least I know that the computer isn't working against me anymore.
Just wanted to pass these observations along to anyone looking to improve their idle quality an engine temp stability.
#2
03-15-2012, 09:14 PM
Veteran Member
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,743
Received 10,757 Likes
on
7,101 Posts
Yes, important to keep the engine well warmed up for the exact reason mentioned.
Actually, though, the cold enrichment is "done"...assuming a good coolant temp sensor....at about 80ēC and the green band starts at 90ēC.
It's interesting you have a smoother idle at higher temps. The old 4.2 usually is a bit smoother when slightly rich. Can't argue with sucess, though :-).
Straying a bit, unless you're having some unusually warm weather down there, the temp really should hover right around 88-90ēC in normal driving.
Cheers
DD
Actually, though, the cold enrichment is "done"...assuming a good coolant temp sensor....at about 80ēC and the green band starts at 90ēC.
It's interesting you have a smoother idle at higher temps. The old 4.2 usually is a bit smoother when slightly rich. Can't argue with sucess, though :-).
Straying a bit, unless you're having some unusually warm weather down there, the temp really should hover right around 88-90ēC in normal driving.
Cheers
DD
#3
03-15-2012, 09:54 PM
It could be the temp gauge in the dash is reading a little on the high side, not sure. Right now the only way I get the temp gauge to go below 90 once warm is the bank a hard right turn like a clover leaf on-ramp for instance -- I guess the water runs out of the water jacket while doing this. Other than that, 90 is lowest it goes.
Thread
Thread Starter
Forum
Replies
Last Post
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)