Temp gauge causing issues
08-06-2012, 08:46 PM
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Temp gauge causing issues Hey guys,
New guy here, first of all i'm new to cars (always had a truck) and having fun with my 01 SS. The issue I was hoping to get some help with was that my temp gauge keeps dropping. It happens at random times, but it seems like it happens more frequently when I am cruising down the interstate. When this happens at a stop, the car will occasionally die. If its at 0 and I come to a stop, the car feels like its pushing through the breaks. When I am driving and the gauge goes to 0, it feels like I lose power and will even downshift on occasion. Since this started, I have changed all 4 02 sensors, new MAF, new temp sending unit, and got a new pcm with a tune from frost. Car also has new wires and spark plugs. I would really appreciate some help as this one is driving me crazy. Thanks
PS When cruising, a hard throttle will often fix it for a little while
New guy here, first of all i'm new to cars (always had a truck) and having fun with my 01 SS. The issue I was hoping to get some help with was that my temp gauge keeps dropping. It happens at random times, but it seems like it happens more frequently when I am cruising down the interstate. When this happens at a stop, the car will occasionally die. If its at 0 and I come to a stop, the car feels like its pushing through the breaks. When I am driving and the gauge goes to 0, it feels like I lose power and will even downshift on occasion. Since this started, I have changed all 4 02 sensors, new MAF, new temp sending unit, and got a new pcm with a tune from frost. Car also has new wires and spark plugs. I would really appreciate some help as this one is driving me crazy. Thanks
PS When cruising, a hard throttle will often fix it for a little while
Last edited by Camar01SS; 08-06-2012 at 09:06 PM.
08-06-2012, 09:36 PM
#4
This is a total guess, but bad temp reading is not gonna make you car die, I don't think. Could you have a bad ground on that leg of the harness? I believe there are three, they bolt to the back of the head, drivers in this case. 15mm bolts, a stubby gear wrench is your friend for these.
08-06-2012, 11:03 PM
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LSxGuy widda 9sec Mustang
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On 1999-2002 F-bodies, the coolant temp gauge is an output from the ECM. So if the temp gauge drops and the car runs like crap at the same time, I would have to think that the ECM is reading that the temperature has dropped too.
On the cars I've seen with that problem, the coolant temp sensor reading ends up being -40F due to a bad connection or bad coolant temp sensor. Since you changed that out already, I would look at the temp sensor pigtail and do a wiring and connection wiggle test, wiggle the coolant temp pigtail while having someone watch the gauge, or while watching the data stream with a scanner (such as HP Tuners or equivalent).
It could easily be a bad connection or a broken wire inside the wiring insulation. Normally these are found right near the end of the wiring itself, right at the connector. Also, the small wiring terminals inside the connector can over time become loose and not make good contact, I've had good luck in the past bending them back into position to make a good connection, but I would recommend replacing that pigtail with a new one from GM just to eliminate all issues with age/heat/etc. Wires don't last forever unfortunately, especially in that location.
As a previous member has posted, it is also not uncommon for grounds to be an issue. On F-bodies, there are the 3 ground points on the back of the drivers side cylinder head. These could cause issues. Even battery cable corrosion could cause weird issues with the way a car runs. The ground side is just as important as any other wire in the circuit. Without a complete loop, there is not a good circuit made. Just like turning off a light switch if a ground wire is missing or loose.
Anyway, look closely at that coolant temp sensor wiring. I'd think that there is a strong possibility it is just in that connection, or very close to it.
On the cars I've seen with that problem, the coolant temp sensor reading ends up being -40F due to a bad connection or bad coolant temp sensor. Since you changed that out already, I would look at the temp sensor pigtail and do a wiring and connection wiggle test, wiggle the coolant temp pigtail while having someone watch the gauge, or while watching the data stream with a scanner (such as HP Tuners or equivalent).
It could easily be a bad connection or a broken wire inside the wiring insulation. Normally these are found right near the end of the wiring itself, right at the connector. Also, the small wiring terminals inside the connector can over time become loose and not make good contact, I've had good luck in the past bending them back into position to make a good connection, but I would recommend replacing that pigtail with a new one from GM just to eliminate all issues with age/heat/etc. Wires don't last forever unfortunately, especially in that location.
As a previous member has posted, it is also not uncommon for grounds to be an issue. On F-bodies, there are the 3 ground points on the back of the drivers side cylinder head. These could cause issues. Even battery cable corrosion could cause weird issues with the way a car runs. The ground side is just as important as any other wire in the circuit. Without a complete loop, there is not a good circuit made. Just like turning off a light switch if a ground wire is missing or loose.
Anyway, look closely at that coolant temp sensor wiring. I'd think that there is a strong possibility it is just in that connection, or very close to it.
