Honda Prelude Forum banner
1 - 10 of 10 Posts

·
Premium Member
Joined
·
114 Posts
Discussion Starter · #1 ·
Hey everyone... I finally got my 1991 Prelude 4WS, and this weekend, I got it smogged.

It required changing the 02 sensor, replacing the Check Engine light, replacing the ERG Valve and Solenoid...

Then, I did the Cap, rotor, Plugs, Wires, Timing Belt, Water Pump, Coolant Flush, Oil Change.

Anyways, to make a long story short, The first time I started my car, the temperature sensor went straight to HOT.

Even after almost thirty minutes of the engine OFF, when I switch the Key ON, with engine OFF, it jumps to HOT.

So... First I thought something may have happened when I replaced the check engine bulb, but everything looks OK.

I read the service manual and it asks you to check the sending unit.

I just bought a new sending unit, and replaced it, but the car still has the same problem.

Key on, it goes straight to HOT, but the engine does not really seem to be hot.

If anyone has any idea on this one, please help....

Thank you all!
 

·
Premium Member
Joined
·
4,294,967,295 Posts
did you bleed the water neck? also the sensor you replaced was it the small brass one with single wire? That is the one that controls gauge. Welcome to the site.
 

·
Premium Member
Joined
·
2,091 Posts
try again with the sensor unpluged if it still goes to hot (1 wire sensor) , grab the multimeter and measure the wire to ground is it's a direct short then the wire is pinched otherwise the temp gauge could be bad.
 

·
Premium Member
Joined
·
114 Posts
Discussion Starter · #4 ·
Thanks

Thank you guys for the help and the welcome...

What is "bleed the water neck"? I drained all of the fluid after I removed the water pump and blew air directly to the radiator until no more fluids remained, and it still had the problem after.

With the sensor unplugged, it does not rise.... Old sensor or new one plugged in it rises (yes the small brass one red wire sensor on the thermostat housing)

I went to my local salvage yard and they had another 91 SI Automatic cluster for $80.... do you know, can I use a NON 4ws cluster in a 4WS? It looks the same visually...
 

·
Premium Member
Joined
·
4,656 Posts
cluster will work fine. when he asked about bleeding the neck, there is a bleeder port similar to that on brake caliper. if you crack that open and let car warm up, air can escape from it as it is the highest point in the system. after coolant starts to come out you can re tighten and secure your rad cap. then check the needle. should take about 10-20 mins to do the job.
 

·
Registered
Joined
·
20 Posts
yes you can use the cluster it is only different between at and mt but thats only because of the gear indicators in the at cluster are not in the mt cluster
 

·
Premium Member
Joined
·
4,294,967,295 Posts
Yeah man sounds like you got the right sensor! As far as bleeding the water neck anytime you change the thermostat or waterpump etc you need to bleed the system as it sets a lot higher in our car then the radiator when comparing other cars. It looks like a big brake cylinder bleed screw and is right next to the sensor you replaced. This will also probably get rid of any idle fluctuations if you have any. As far as if the gauge is bad I know for a fact that ALL 90-91 water and gas dual gauge is the same with the same part number! It makes no difference if it is an SI, Or SI w/4ws, or 2.0SI with the b20a5 obd II or even the s model on the 90 ludes with a carberator. The difference lies within the redline on the tach and speedo. But yeah if you are taking apart the gauge cluster the gas / water temp gauge is the same on all 90-91 preludes.
 
1 - 10 of 10 Posts
Top