Is the MAF related to fan operation?
Thread Starter
Registered User
Joined: Dec 2007
Posts: 16
Likes: 0
From: AZ
Is the MAF related to fan operation? My car recently started overheating. I put in a new thermostat, the coolant is clean, but continues to get hot. When I disconnect the MAF sensor, the fans automatically turn on and stay on and the temp drops, so I assume they are related and maybe a bad MAF sensor??
Thread Starter
Registered User
Joined: Dec 2007
Posts: 16
Likes: 0
From: AZ
Oh, that could be it. I didn't know that, but it would make sense. I appreciate it... so I guess a new waterpump or see if the radiator is clogged is the next step. The system gets way too much pressure build up and coolant boils like its not passing through the radiator.
Thread Starter
Registered User
Joined: Dec 2007
Posts: 16
Likes: 0
From: AZ
This car has many problems. It just started backfiring, so I will have to get a new cat also. I'm sure its probably the water pump, but is there any way to find out if it is the water pump for sure without making a huge mess?
TECH Fanatic
Joined: Jan 2005
Posts: 1,162
Likes: 0
From: St. Augustine, FL
okay, so, you said the fans come on with the maf unplugged. Does the temp stay normal like that? If it does stay normal then, your coolant system is doing its job just fine and there's a problem ONLY with the fans not turning on. The Temperature sensor would also probably affect how the motor runs to since fuel and timing are probably affected by the "potentially incorrect" temperature readings. There's two temperature sensors on the LT1. one in the head and one in the waterpump. The one in the waterpump is the one that the computer goes by and that may be messing up your fan turn on if its not sending the correct temp to the computer. Not sure how you check it without a scanner or an extra sensor laying around. I dont know if there's a fuse or relay that would be causing the fans to not turn on but, you DID SAY that they WILL turn on with the maf unplugged so, YOU KNOW they work at least. This probably isn't much help but, hopefully gives you something to start with if you haven't already fixed it.
LT1 coolant temp sensor- PCM (pump) (AC-D #213-310) (93-97) , GM part number: 15326386 (formerly - 12146312)
Also, you said you put in a new thermostat, is it stock or is it a lower temperature stat? You'll need to have your computer tuned to change the stock fan turn on temp or you wont get the full benifit of the new stat unless the car is moving. You could also hook up a manual fan switch instead.
LT1 coolant temp sensor- PCM (pump) (AC-D #213-310) (93-97) , GM part number: 15326386 (formerly - 12146312)
Also, you said you put in a new thermostat, is it stock or is it a lower temperature stat? You'll need to have your computer tuned to change the stock fan turn on temp or you wont get the full benifit of the new stat unless the car is moving. You could also hook up a manual fan switch instead.
Last edited by hyperzone; Mar 9, 2008 at 07:43 PM.
Trending Topics
On The Tree
Joined: Nov 2007
Posts: 130
Likes: 0
Turning on the AC should keep the fans running at low speed. Also, if you are familiar with electrical diagrams this one from shbox could help " http://shbox.com/1/fan_schematic_1995.jpg " . I was able to pull the fan relays in the relay box and attach a thin wire about 6 inches long to the turn on pins. Then replugged the relays and manually started the fan(s) by grounding the wire(s) with an alligator clip. As hyperzone said above if temp goes down its probably the sensor or circuit to the pcm. Are you sure you have an LT1 t-stat in there, not a regular GM 350 t-stat.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo Thread Starter
Registered User
Joined: Dec 2007
Posts: 16
Likes: 0
From: AZ
The car starts overheating after awhile, then I can unplug the MAF and the fans come on, stabilizing the temp to normal. The temperature gauge is right in the car, but does that only go off of the sensor in the block and not in the water pump? So if one of the sensors was bad, then the fans won't come on, but the temp gauge will still be right?
I used a stock thermostat, even though the one I pulled out seemed good. bobdec... I know the fans work, so the relays and operation of the fans are ok. So I guess the computer just isn't reading the temperature correctly, so this would be a bad sensor in the water pump or block??
I'm not doubting infinitebird, he seems right, but is it correct that the fans come on when I unplug the MAF only because the computer is programmed to turn them on when a certain code shows up?
I used a stock thermostat, even though the one I pulled out seemed good. bobdec... I know the fans work, so the relays and operation of the fans are ok. So I guess the computer just isn't reading the temperature correctly, so this would be a bad sensor in the water pump or block??
I'm not doubting infinitebird, he seems right, but is it correct that the fans come on when I unplug the MAF only because the computer is programmed to turn them on when a certain code shows up?
Thread Starter
Registered User
Joined: Dec 2007
Posts: 16
Likes: 0
From: AZ
And another thing... when the car starts overheating, I unpressurize the system at the radiator cap, and the coolant starts boiling and rising (eventually overflowing) out of the resevoir. There is A LOT of pressure in the radiator and takes awhile to stabilize. Seems like the water pump is goin bad or somethings clogged. Thought it was a sticking thermostat, but that wasn't it...
Yes that's correct. The sensor on the water pump is used by the computer. The one on the driver's side head is used for the dash display.
And another thing... when the car starts overheating, I unpressurize the system at the radiator cap, and the coolant starts boiling and rising (eventually overflowing) out of the resevoir. There is A LOT of pressure in the radiator and takes awhile to stabilize. Seems like the water pump is goin bad or somethings clogged. Thought it was a sticking thermostat, but that wasn't it...
Thread Starter
Registered User
Joined: Dec 2007
Posts: 16
Likes: 0
From: AZ
Yes, I have bled the air out. So I guess my next task is to replace the sensor in the water pump huh? This could explain the fans not coming on, but what about all the pressure build up? Cap, coolant, thermostat are good, and it only builds up and boils once in awhile. Even if the fans worked, it shouldn't get that hot at all. And throwing in a new $150 water pump would suck if it is something small and simple...
