Tuning Issue? Running Lean?
07-14-2008, 11:38 AM
#1
Tuning Issue? Running Lean? First time in here I'll try to be brief...
After Mods in sig car were done runs 225*-230* with air on. Temps are reading from a scan tool not guage. This is 90* outside temps in traffic with air on. I am now thinking the tune might be lean in the lower RPM's. 12.3 across the board WOT. Water never boils even at these temps and coolant overflow just gets warm
Car will cool back down to lower 200's* after running at speed with a 195* stat.
Knowns:
Radiator good
Themostat good
WP seems to circulate water fine
Fans work and come on high at 185*
No air in system
no water in oil or disappearing so no blown HG.
Could UD pulley and a tranny cooler do this?
No other H/C car of I know have this issue
I know these cars run hotter than the old Gen I stuff but this just seems a little hot to me. Am I overly concerned?
I don't know what to look at next
THANKS for any input
After Mods in sig car were done runs 225*-230* with air on. Temps are reading from a scan tool not guage. This is 90* outside temps in traffic with air on. I am now thinking the tune might be lean in the lower RPM's. 12.3 across the board WOT. Water never boils even at these temps and coolant overflow just gets warm
Car will cool back down to lower 200's* after running at speed with a 195* stat.
Knowns:
Radiator good
Themostat good
WP seems to circulate water fine
Fans work and come on high at 185*
No air in system
no water in oil or disappearing so no blown HG.
Could UD pulley and a tranny cooler do this?
No other H/C car of I know have this issue
I know these cars run hotter than the old Gen I stuff but this just seems a little hot to me. Am I overly concerned?
I don't know what to look at next
THANKS for any input
07-15-2008, 05:57 AM
#3
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That is a bit on the warm side. Sounds like you have covered all the bases though. You runnin a 50/50 mix of antifreeze and water? If it is a high mileage water pump, might wanna consider replacing it just to be sure.
The only other thing I would do is run another LS6 style coolant crossover on the back of the heads (in place of the block-offs) and run a rubber hose from it to join the front crossover tube - this prevents steam pockets that can form in the back of the heads. GM changed to the front only crossover when they went to the LS6 intake, but in my opinion, that was a mistake - and ported heads only make it worse by thinning out the water jackets...
The only other thing I would do is run another LS6 style coolant crossover on the back of the heads (in place of the block-offs) and run a rubber hose from it to join the front crossover tube - this prevents steam pockets that can form in the back of the heads. GM changed to the front only crossover when they went to the LS6 intake, but in my opinion, that was a mistake - and ported heads only make it worse by thinning out the water jackets...
07-15-2008, 06:52 AM
#4
That is a bit on the warm side. Sounds like you have covered all the bases though. You runnin a 50/50 mix of antifreeze and water? If it is a high mileage water pump, might wanna consider replacing it just to be sure.
The only other thing I would do is run another LS6 style coolant crossover on the back of the heads (in place of the block-offs) and run a rubber hose from it to join the front crossover tube - this prevents steam pockets that can form in the back of the heads. GM changed to the front only crossover when they went to the LS6 intake, but in my opinion, that was a mistake - and ported heads only make it worse by thinning out the water jackets...
The only other thing I would do is run another LS6 style coolant crossover on the back of the heads (in place of the block-offs) and run a rubber hose from it to join the front crossover tube - this prevents steam pockets that can form in the back of the heads. GM changed to the front only crossover when they went to the LS6 intake, but in my opinion, that was a mistake - and ported heads only make it worse by thinning out the water jackets...
Should I see about getting on a wideband and looking at the low rpm AFR? Thanks again for the input BLACK02WS6
07-15-2008, 08:08 AM
#5
Most of the time, when you have this exact problem its caused by a partial blockage in the radiator. It only takes a few tubes to be blocked up, and it reduces the efficiency enough that it runs hotter with the AC on.
Best way to check, is to remove your fans, run the car (keep an eye on the temp) and feel the radiator FROM TOP TO BOTTOM. You have to remove the fans to get access to the core. You most likely will find the lower portion of the radiator is going to be cool.
You can also do this with an infrared temp gun, but you still have to pull the fans out to get a shot at the core. Again, check the temp from top to bottom.
Best way to check, is to remove your fans, run the car (keep an eye on the temp) and feel the radiator FROM TOP TO BOTTOM. You have to remove the fans to get access to the core. You most likely will find the lower portion of the radiator is going to be cool.
You can also do this with an infrared temp gun, but you still have to pull the fans out to get a shot at the core. Again, check the temp from top to bottom.
07-15-2008, 08:10 AM
#6
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I had this happen once... Turned out to be a plastic bag that got sucked up and was covering 1/3 of the radiator. After I removed the bag I was back to the steady 190-192 reading.
