Car not reaching temperature or staying at temp!

[87AccordLXDude]

I recently rebuilt my carb'ed 87 accord lx engine and now after that my car takes much longer to reach operating temperature from a cold start while I'm driving, say to work. Before I did any work the vehical would reach temp maybe 5 minutes into my drive to work, now it takes like 20. If I sit at a light my temperature gauge will go up to normal temp and my fans will turn on if I'm sitting for a while.
Heres another thing, if my car is at temp and I start to drive on say the highway my temperature gauge will slowly fall untill its all the way to the cold side. Then if I stop for a few minutes my car's temp will rise to operating temperature. :wtf:
It has a new thermostat and although I did reuse the temperature sensor, it functioned fine before I did any work to the engine.

I don't know if this has anything to do with this problem but I junked the original engine and put in a rebuilt fuel injected block and head (A20A3) and just bolted my carb intake and exhaust to it. While I was looking around I noticed a collant line that is under my intake that bypasses the thermostat could that be causing the problem. See my picture.
Sorry for the long post just wanted to be very clear. Any help would be really appricated, thanks everyone.

[A20A1]

Do you have enough coolant in the system?
Did you bleed the system?
Is your water pump working?
a good way to check if your cooling system is woking is run the heater full blast, if it's cold something is wrong and the water pump could be to blame. My heater got real cold when when my pump died on the highway once.

[shepherd79]

sounds like you bypassed the coolant line for the carb. well, you have two choices:
1. put the line back and it will fix the problem, since the temp. gaugse sensor is on the back of the in take manifold. as i understand it is not getting any coolant. what you are seeing is temp of the intake manifold under driving conditions.
2. you can get thermostat housing. It will look almost the same, except the temp gauge sensor will be mounted on the side. if you do that, just extend the wire from he back of the intake manifold to the sensor.

[A20A1]

I don't see a picture but I thought he said he thinks that the hose that heats the carburetor is bypassing something?

Anyways coolant will still flow in the intake manifold there are two main hoses on either side of the manifold that flow coolant.

http://i23.photobucket.com/albums/b351/Wendy_girl/diagram_07.jpg

[88Accord-DX]

Sounds to me, if he aint loosing coolant from this "bypass" hose anywhere. I would think the thermostat isn't working right. (stuck open)


Edit- Did you face the spring on the thermostat towards the block? Make sure you bleed the coolant system of any air pockets. To see if the water pump is working, look down the radiator for coolant moving after your car reaches operating temp., also is a good indication if your thermostat is working properly.

[87AccordLXDude]

I have a new water pump, and thermostat - yes the spring is facing the engine block. I'll try bleeding the system again and see if the heater is producing hot air.
Shepherd79 could you elaborate more. Thanks all.

[chitown si]

I have a 1989 lx. I have the same issue. If I start the car and let it idle till its warm its okay. If I start and take off the temp guage stays at cold. When I do the warm up the engine is smooth when stopped at a light. (automatic carb). When I do the cold take off, the car idles rough at stop lights. It is like 18 degrees in the morning here and the car never gets to temp if I dont do the warm up drill.

[russiankid]

I have a 1989 lx. I have the same issue. If I start the car and let it idle till its warm its okay. If I start and take off the temp guage stays at cold. When I do the warm up the engine is smooth when stopped at a light. (automatic carb). When I do the cold take off, the car idles rough at stop lights. It is like 18 degrees in the morning here and the car never gets to temp if I dont do the warm up drill.Im thinking you both have air in the system. try bleeding it.