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Help sc400 overheating with a/c ON

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Old 07-12-14, 11:44 PM   #1
Jdmsc5spd
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Default Help sc400 overheating with a/c ON

I am stumped I supercharged my sc400 and it only overheats when the a/c is on I can drive 20-30 minutes it is fine any longer it gets hot and will throw a code 55...I replaced the radiator with a koyo 3 row 160 t stat 2 shrouded zirgo fans and water wetter still nothing.... Checked a/c pressures low 35psi / 250psi it does not idle up when the a/c is engaged...any help is appreciated pulling out my hair there is no white smoke or oil in the coolant vice verse only other thing I can think of is a dragging a/c compressor it was making lots of vibration months ago then all the sudden stopped a/c works still or a weak water pump
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Old 07-13-14, 12:09 AM   #2
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What makes you think it's overheating? Code 55 is knock sensor #2.

I had a lot of knock sensor problems a few months back, but they've subsided of late. It happened more frequently when the A/C was on, especially accelerating onto freeway on-ramps. I finally tested it out on the highway with A/C this week and had no issues, "knock" on wood...

The things I did that seemed to have the most impact on cutting back the knock sensor trips were replacing all the dry old vacuum hoses, and getting the bad gas (*$%#@! dealer) out of the system and using several bouts of fuel system cleaners.
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Old 07-13-14, 12:23 AM   #3
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I think it's overheating cause the needle will go past 3/4 and turn the a/c off will come back down....I'll take a look at the vac lines
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Old 07-13-14, 12:38 AM   #4
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Okay, that's sound reasoning.

One of the common causes of knock sensor codes, supposedly, is degradation of the sub-harness because of its location and getting cooked over the years. If your car is indeed overheating, maybe some worn wiring is sensitive enough to trip it?
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Old 07-13-14, 02:09 AM   #5
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Yeah I just replaced a knock sensor plug trying to fix this issue found it cracked and broken on the passenger side of the engine idk if this number 2 or not...still no dice I'm more worried about the over temping
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Old 07-13-14, 04:04 AM   #6
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maybe bad water temp sensor :/
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Old 07-13-14, 10:02 AM   #7
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It's been replaced before but I haven't done the sender
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Old 07-13-14, 02:01 PM   #8
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How is your fan clutch?
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Old 07-13-14, 05:42 PM   #9
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No fan clutch removed hyd fan and installed e fans on a relay if that's what you mean
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Old 07-14-14, 12:31 PM   #10
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Any ideas?
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Old 07-14-14, 06:23 PM   #11
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Quote:
Originally Posted by Jdmsc5spd View Post
No fan clutch removed hyd fan and installed e fans on a relay if that's what you mean
Missed that. Sorry.
Are those fans moving a lot of hot air when they're running?
Does a water spray on the radiator fins help any? Common t-shooting step.
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Old 07-15-14, 12:24 AM   #12
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Yeah they seem to be moving a fair amount of air they are rated at 2700cfm each, yeah when I spray water through the condenser to the radiator it seems to help cool it down I'm going to be adding a extra 8in condensor fan see if that helps it
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Last edited by Jdmsc5spd; 07-15-14 at 12:49 AM..
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Old 07-15-14, 12:24 AM
 
 
 
 
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