Hello-

Recently a friend and myself built a GSR motor. We replaced absolutely everything. We used oversized pistons with gsr rods, got ourselves some new valves and springs. Every o ring and gasket is new. We also replaced the water pump, timing belt, AC, PS, and alt belt.

Upon first startup, the motor would flucuate idle slightly, but when it warmed up the fluctuations stopped.

Today we were going to drive it around and while it sat we noticed it would overheat. The overheating would cause the coolant gauge to climb to 3/4 or so, then return to 1/2... and repeat. Some things we checked include the thermostat (opened around 180 - 190 F) and all the hoses. To bleed the system we filled with coolant, squeezed the hoses, and refilled. We ran the motor for ~30 mins keeping squeezing and refilling if need be.

The needle still fluctuates between 1/2 and 3/4. We have noticed the radiator fan come on, although we noticed it didnt come on until 3/4.

Could his uberdata'd ecu be causing this? On another unrelated and less important note... the motor idles so rough that we cant even drive the car although we blame this on the loose throttle cable.

Any suggestions?

Cliffs:
New motor - new valvetrain, new pistons, new water pump, new belts, new gaskets and o rings all around. Overheats and fluctuates in temp between 1/2 and 3/4, Fan comes on late.

 

have you checked for vac. leaks, coolant leaks, hook up a coolant pressure tester, put it up to 16psi and listen or look for leaks. You don't need to squeeze the hoses to bleed the system. Take the radiator cap off start the car up keep adding coolant so it's full at the cap and just let the air bubbles come out. I doubt it has anything to do with the computer. When I did my swap I just hooked the fan up to a switch inside the car. I have a fully built GSR in my sol. Check the engine coolant temp sensor. If you have a haynes manual it will tell you how to fun tests on it.

 

change to thermostat

 

When you flushed it did it come out with not problem. When rebuilding this beast did you perhaps by chance accidentally drop something in the coolant passages causing blockage. The cooling system has nothing to do with the ECU. The fact that you fan does come on is a good thing. Also that your thermostat opens at a given temperature. So either your heat gauge in your car is missreading or you have coolant flow problems. That's the way I see it. Try running yoru heat on full blast with the fan blowing like crazy and see if it makes a difference.

Cheers.

 

we pulled out the thermostat and tested it by putting it in a pot of boiling water and sure enough it opened up.

 

You may still have air left in the system, could be as simple as that.

 

id have to agree with him ^^^^ . Redo your coolant.

 

you might have put in the head gasket backwards...assuming you did everything right....LOL....and I ve seen that happen..if you used an oem head gasket...then look below the cam seal where the head gasket is at and see it you see a the silver part with some numbers on it...if yes then its on right..if not...take a picture and post it on...ill come back to it..

 

Okay Ima reply to everyone, dont take offense I just wanna get this thig working!!!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93c1sol &raquo;</TD></TR><TR><TD CLASS="quote">have you checked for vac. leaks, coolant leaks, hook up a coolant pressure tester, put it up to 16psi and listen or look for leaks. </TD></TR></TABLE>
Did a quick check for vac leaks and didnt find any. It was late at night we will check again today. We also checked for coolant leaks and found none.

We do not have a pressure tester for the coolant system, could we make one?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93c1sol &raquo;</TD></TR><TR><TD CLASS="quote">Check the engine coolant temp sensor. If you have a haynes manual it will tell you how to fun tests on it.</TD></TR></TABLE>

Okay, I assume the tests for the sensors are much like the tests for the thermostat. Heat in water, and watch the characteristics of the switch. We can do that today!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ekek888 &raquo;</TD></TR><TR><TD CLASS="quote">change to thermostat</TD></TR></TABLE>

checked it, and it opened at 190 F. Why should we replace it?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by old man neri &raquo;</TD></TR><TR><TD CLASS="quote">When you flushed it did it come out with not problem. </TD></TR></TABLE>

We didnt flush it. Good advice!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by old man neri &raquo;</TD></TR><TR><TD CLASS="quote"> The cooling system has nothing to do with the ECU. </TD></TR></TABLE>
are you sure? I know there are two fan switches on the side of the head, I was under the influence one of them went to the ecu?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by old man neri &raquo;</TD></TR><TR><TD CLASS="quote">Try running yoru heat on full blast with the fan blowing like crazy and see if it makes a difference.</TD></TR></TABLE>

we ran the heat on full blast for over an hour. No heat. The line leading from the head to the water valve was hot on the head side, and cold on the valev side. MAYBE there is somethin blockign it in there???

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by methanemotorworks &raquo;</TD></TR><TR><TD CLASS="quote">you might have put in the head gasket backwards...assuming you did everything right....LOL....and I ve seen that happen..if you used an oem head gasket...then look below the cam seal where the head gasket is at and see it you see a the silver part with some numbers on it...if yes then its on right..if not...take a picture and post it on...ill come back to it..</TD></TR></TABLE>

Lol yeh we also thought of this, its on correctly.

When can we do a compression test on a fresh motor? Would it affect the seating fo the rings to do a test too early?

THANKS !!!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18EG6 &raquo;</TD></TR><TR><TD CLASS="quote">
We didnt flush it. Good advice!
</TD></TR></TABLE>

Try it, you have nothign to lose other than a bit of coolant and some wet clothes in the the process.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">

are you sure? I know there are two fan switches on the side of the head, I was under the influence one of them went to the ecu?
</TD></TR></TABLE>

I was under the impression that they either ran just straigh to the fan or straight to the guage in the car. I don't see a need to run it to the ECU. I could be wrong however. eitherway, it should not over heat on the highway even if you had no ecu, the thermostat is purely thermo-mechanical and the pump is always on.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
we ran the heat on full blast for over an hour. No heat. The line leading from the head to the water valve was hot on the head side, and cold on the valev side. MAYBE there is somethin blockign it in there???
</TD></TR></TABLE>


if your car is over heating you should have heat, somethign is not right there. Maybe you have a bubble in there or some other blockage. Sometimes when doing a rebuild something falls in the coolant passages, like a nut, washer, rag....etc.

When you flush make sure you flush every part and water flows out easily.


Cheers and good luck.

 

The car is perfect now thanks!

 

post the findings and how you fixed it....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicFerioViRs &raquo;</TD></TR><TR><TD CLASS="quote">The car is perfect now thanks!</TD></TR></TABLE>

please enlighten us to the cause and subsequent solution.

 

i kid you not when i say this but i ran the car for a 15-30 minutes without turning on the heat. after doing that i turned on the heat and there was heat. as for the fluctuation, i the alt belt tension wasnt tight enough. I thought it was tight enough because there was no squeeling, Lastly the tps and the map sensor were reversed. Someone on H-T has misinformed us and told us that if the sensors were not in the right place the ecu would fry up. well turns out thats not true because i had them on backwards the whole enitre time