Running hot....?

[Loki]

Well I got my supposed JDM motor for my car last week. The motor was an earlier motor, so I swapped some things out and changed things around to make it drop in. Got the motor all dropped in and connected up, car fired right up but as soon as the temp gauge starts to move as it heats up it just keeps going and pegs the temp gauge.

I tried burping the cooling system, I tried flushing the cooling system out. I swapped thermostats, everything worked fine that I put in from the old motor, I tried all the things I could think of too fix it and nothing worked.

When the temp gauge is pegged the car will sit there and idle and run for the most part fine. Well it's running with the temp gauge pegged I can lay my hand on the valve covers and it's not that hot. I don't think that it's running as hot as the gauge is showing but I don't want to take any chances. If anyone has any ideas of what it could be, any help would be greatly appreciated.

I was getting code 51 which is the Switch Signal. I'm not sure what that means but hopefully one of you knows what could be causing that code.

It sucks though cause I wanted to get the car running before I moved but with the problem I'm having I can't drive it, so as of right now I'm about 1000km away from the car so I can't rush out and try things on it, but I'm going back to get it running in the next few weeks.

 

[koulee]

Fried coolant temp sensor?

 

[shaeff]

either a fried sensor, or the wire is grounding out somewhere. check that stuff.

most commonly, code 51 means your TPS is out of adjustment.

-shaeff

 

[miggles]

The wires are on the correct plug? (if you have the plugs on the end then disregard that)

Swap the coolant senser with your old one u know works.

 

[Loki]

As far as I know the coolant temp sensor works. I had to swap it over off my old motor to the new one because the plugs were different. I'm pretty sure the wires are on the correct plugs, one of the ends ripped off but I changed how they were attached and then the temp gauge wouldn't move at all even after having the car running for 15 minutes or so.

I wish I had the car here with me so I could check this stuff right away I have a spare coolant temp sensor off my old '89 so I can swap it out and check that. I will try adusting the TPS a bit too maybe that'll help it run better.

Thanks for the replies and I'll probably be updating this thread once I'm with the car and trying to fix it.

 

[Joel W.]

Pop off the thermostat housing and manually open the thermostat a few times with your thumbs... I'd bet it's stuck shut...

 

[Shawndude]

Does the temperature come up slowly, or just spike up? You sure you have the sensors connected properly (lots of junk in the area). If all else fails, time to pull out the sensor and test per TSRM.

 

[Loki]

Does the temperature come up slowly, or just spike up? You sure you have the sensors connected properly (lots of junk in the area). If all else fails, time to pull out the sensor and test per TSRM.

It'll sit down at the bottom and then as the car starts to heat up it starts to rise up. Instead of stoping half way up like it usually does it just keeps going and goes all the way to the top, past the H. The guage moves like normal it just keeps going :icon_conf

I'm pretty sure I have all the wires in there hooked up correctly, but I'm not sure because the gauge sensor and the a/c one are the same kind of plugs and I'm not sure which one goes to which but I tired it on both and when i swapped them around the temp guage didn't move at all so I'm pretty sure I had them right the first time.

Where in the TSRM does it have how to check it?

 

[Joel W.]

Did you check your thermostat yet Loki? You can toss it in a pan of water and place it on the stove, see what temp it opens at or if it opens? Or just replace it with a quality one....

The only other things i can think of would be a free spinning thermo clutch fan or the water pump impeller is fubar or the water pump belt is loose...

Also check the radiator and upper hose by hand or with temp gun and see if they are actually too hot? Cold spots in the radiator can mean its plugged up...

 

[GrimJack]

I'm still betting on an incompatible sensor from the JDM engine... plug the sensors from your old engine in, I bet this goes away.

 

[nicksupra1990]

if none of that works then open the rad cap an make sure that you got good flow . i just got used motor an everything waas diffent to but my last motor was always runnin hot an i thought it was the sensor too but on my new one i just made sure an got new radator an water pump. i think it was my radator it looked good but it was clouged at bottom i flushed it like 2or3 times if you did not get new radator and nothing else works change it

 

[johnathan1]

if none of that works then open the rad cap an make sure that you got good flow . i just got used motor an everything waas diffent to but my last motor was always runnin hot an i thought it was the sensor too but on my new one i just made sure an got new radator an water pump. i think it was my radator it looked good but it was clouged at bottom i flushed it like 2or3 times if you did not get new radator and nothing else works change it

Try your seperating sentences next time, it makes it much easier to read... :icon_wink

 

[Loki]

I'm still betting on an incompatible sensor from the JDM engine... plug the sensors from your old engine in, I bet this goes away.

I swapped the sensors over from my old motor to the new one, because the wiring harness wouldn't plug into the ones on the motor. My car is a '89 and the wiring harness that came with the motor had the yellow ECU connectors on it. If my harness wouldn't plug into the sensor or whatever it was I swapped it from the old motor.

Joel, I haven't checked the t-stat yet. The car isn't here with me, so I can't check the things out right now but I will check it out when I go back down to get the car running.

I'm still not completly convinced that my motor is a JDM, because I always read that the JDM ones don't have EGR but my motor that I got did :icon_conf

I tried flushing the system out, and even after that it still was saying it was running hot. I may try picking up an aftermarket temp guage and sticking it in and seeing how hot the engine is actually running at.

 

[supra90turbo]

JDM's don't have EGR's, so... you been lied to, son...

 

[GrimJack]

JDM's don't have EGR's, so... you been lied to, son...

Agreed.

 

[gixxer750]

I think you put the thermostat in backwards.... that or it is stuck...

 

[Loki]

I think you put the thermostat in backwards.... that or it is stuck...

I know it's not in backwards, so maybe I'll pick up a new one and slap that in and see how that goes.

Kind of sucks to know it's not a JDM but oh well. I don't think it's really important to be a JDM, it's just most JDM motors are supposed to be low mileage. So who knows how much is on this motor :icon_conf

 

[supra90turbo]

HAHA!!! You're not JDM tyte!!!

 

[tubbie]

bhg...........:nono:
My na supra that had a bhg did exactly what your describing.

 

[gixxer750]

JDM tyte is out..... Keeping your original block is in....lol