98 gsx temp guage jumping around, going through thermostats quick

[gsxjohnny5]

When I first bought my car about a month later I needed a new thermostat. It was jumping around. It lasted about three months.

Someone then ran over my car and I got a new radiator , hood etc
The body shop never filled up my radiator with fluid and I made it half way home.

A few weeks later I needed a new thermostat and this one lasted a few weeks.

-I ran the car for 30min with cap off to let bubble out.
-Fan is working
-mixture is correct and I flushed to make sure and put new fluid in.
-No leaks

The part I bought was a failsafe thermostat
also the fuel gauge is not accurate, and I researched and found both guages on older cars for sure use a voltage limiter for both yet it was only mentioning if they were both not working and resolved by replacing fuses.

Also I feel this may be a rare case so I posted a new thermostat thread. Plus I only found arguing on the other forums.

I do have mods

16g turbo
dejon intercooler
maf translator
hks ssqv bov
a/c delete
aem eugo
550cc injectors
aem fuel rail
walbro 255
ngk spark plugs
rebuilt motor maybe 15k
aftermarket bottom end(not quite sure was done before I bought it)
timing belt , water pump
new radiator
powersteering pump
-sorry tried to name everything not sure may be more
( running 9psi and have been since stuff has been acting up and still went through one, also retuned to not be super lean nor rich incase that was increasing heat since its jumping and I tune with apexi safc and avcr and those are rpm related)
dejon intercooler

oh also lately its been on and off, gauge shows temp is half way then after a while will jump while moving generally or stay three quarters sometimes. It really depends each ride it has a mind of its own on what it wants to do. Also one thermostat ran a little too cold before jumping, and the next ran too hot before going crazy. But both were fine for a while.

 

[troppo loungo]

Could be a bad temperture sensor or loose wire or wire clip into the sensor. The gauge could also be faulty. It should not jump around if it was a bad thermostat it would not heat up if stuck open or it would overheat if stuck closed.

 

[shorty10011010]

I had the same problem as you are describing, a couple of things you can try are unplug the single wire for your temp gauge and ground it. There are two sensors there one for the ECU and one for the gauge cluster. Have you tried a radiator flush? My problem turned out to be the headgasket I bought was for a 4g63 n/t so the water jacket ports didn't match and I installed it like a noob. spun a rod bearing because of that. Another thing you can do is get a scanner and see what kinda temps the ecu sees instead of what the temp gauge sees.

 

[Talon IV]

I am gonna agree with shorty and troppo here. this sounds a bit more like an electrical issue with the sensor or gauge. I would grab the scan tool get the car to full operating temp and check what the ECU sees as the temp compared to what the gauge is reading. You can also get a multimeter and check the sensor. As nost temp sensors are negative thermistors, as the water temp rises the voltage signal should say drop from 5V down to >1V at full operating temp.

 

[dsmike1]

it does sound like something electrical, but why do you think its the thermostat. does anything change when you put a new thermostat in?

 

[Geier]

You need a logger to verify that the ECU is seeing the same erratic coolant temp behavior.

If it is seeing the same behavior, I would start testing/changing coolant items. If the ECU returns normal coolant temp operation, I would suspect the dash or sensor specific to the gauge.

 

[gsxjohnny5]

It actually ended up being the little plastic clip above the thermostat. When I did put a new one in it was better for a while. It was actually a bad connection. The very last time I tried the sensor wouldn't show any heat. After inspecting I noticed I must of knocked it off. I connected it and sure enough perfect temperature. I had a second pair of hands slightly wiggle it and sure enough it was an exact simulation to when I started accelerating or hitting high speeds. This would explain why at a stand still or certain gears it was perfect and others jumping around. Since this was a case that couldn't be solved with a zip tie I cut an end of a fuse and tightened up the connection and pasted it with electric grease just to be sure.

Thank you very much guys. You definitely lead by example on here. I have some questions on my 03 lancer if any of you can help. I really need to get my gsx in storage while its rust free. Also I could use advice on deleting vac lines and adding a catch can. Find me on face book John Kuson you will be saving a gsx from the rust monster of ohio

The 03 lancer , ha ha.
I pulled in my drive one day and it wouldnt shut off.
So i parked it for a couple weeks and eventually replaced the ignition switch. Bingo problem fixed.
Next the battery was completely bad and the altinator tested good.
So I replaced the battery.
Now after I shut off the car I hear a weird noice around the throttle body. Almost a humming that comes and goes. Also the door ding will go off even with sensors unplugged from inside the door.

Any Ideas? where do I start, I am in a race for snow