Car running "cold"?

[al1dere]

Okay so I swapped my engine a while back, it has about 1,800 miles on it so far. I've noticed that no matter how long I drive my car or let it warm up, the temperature gauge barely moves. It's always running "cold". Here are the things I think it might be, but of course I'm posting because I'm not sure. I have a fail safe thermostat, could it be that it seized open and it's continuously cycling the water? Or could it be that I have my original ECU and the new engine has a side mount oil cooler that could be cause the ECU to not compensate for it?

Another problem I've been having is with my miles per gallon. I'm at about 15-16 miles per gallon. I thought maybe I wrote it down wrong or something, but after the third tank of gas I went through, I was right all along. There isn't a leak anywhere, or at least that I know of...now could it be because my car is running "cold" that the car is running through an open circuit, giving more gas?

Okie, thanks!

 

[andymoraitis]

I would start by replacing the thermostat since as you suspect, it may be stuck in the open position. Also, you may want to replace the coolant temp sensors if the thermostat doesn't cure the issue. Mileage will certainly suffer if the motor doesn't come up to operating temp as will performance since you'll never see full timing.

Hope that helps,

Andy

 

[blackGSX2g]

I agree. Your car dumps more fuel when the ECU thinks the motor is cold. If your car never warms up, its continuously trying to add fuel. Do the thermostat first and see if you can log your coolant temps afterwards. If you don't have a logger, watch to see if your gas mileage increases. The sensor is fairly cheap even if it does need to be replaced.

 

[44pirate]

So what temperature range is warmed up?

 

[blackGSX2g]

On my 2g, the stock guage says its fully warmed up around 185*. I consider it fully warmed up when my aftermarket gauge says 210*.

 

[Talesin]

Thermostat. I had the same problem.. it'd hover around the first (leftmost) line, no matter if I was stuck in traffic, idling for an hour, or doing a hill climb that ended with a turbo you could read by. New thermo, and now it's just about straight up no matter what, once it's warmed.

If not that, check your gauge cluster temp sender. Grab a test light, clip it to ground, and turn the car on. Have a buddy watching the gauge and tap the single-wire spade connector with the test light probe. The gauge should shoot to overheat. If not, check the wire to make sure the connection is good.

 

[Defiant]

I have a fail safe thermostat, could it be that it seized open and it's continuously cycling the water?

Yes. I'd not bother with another Fail-Safe, just Mits.

Or could it be that I have my original ECU and the new engine has a side mount oil cooler that could be cause the ECU to not compensate for it?

No. The cooler has its own thermostat. The oil doesn't do enough engine cooling to keep it from warming up.

Another problem I've been having is with my miles per gallon. I'm at about 15-16 miles per gallon.

I'd be suspect of the front O2 sensor.

 

[al1dere]

Well I did go out and buy a new thermostat last night, but won't get around to it until tomorrow. But I was thinking about the O2 sensor as well, as far as the gas mileage concern. So thanks guys...hopefully it all works out.