NexGenSPEED

Well my Dad and I did the dirty deed on my 94 RX-7 using the vacuum diagram supplied in this forum. Besides changing out all the vacuum hoses we replaced the pulley belts and the oxygen sensor, replaced spark plugs and wires, and replaced several radiator lines. We were very careful and methodical, even color coordinated everything just to make sure. Started the car up last night and may have a few "issues" that may be normal, but I wanted a second opinion.

To begin with, we have only run the car long enough to warm up the radiator fluid to normal operating temperature. With that in mind, here are some of the issues that have surfaced.

First, since we disconnected the battery and added a new O2 sensor, wouldn't it be normal for the idle to hunt around (its running high -- 1500 RPMs -- at the moment) for a while until the computer re-learns all the parameters again? If so, how long does it normally take before things settle down to normal again? If not, what could we have done to mess it up?

Second, even as the water came up to normal operating temperature the car's heater, which we turned on to check, was only blowing cold air. Could this be caused by an air bubble or block in the cooling system and, if so, how do you get rid of it? If not, what should we be looking for?

Third, and this is more of a curiosity issue, there is a hose that comes off the driver side of the air filter box that does not seem to have anyplace to go. When we started the project it was just sitting down near the front of the engine and wasn't attached to anything (we couldn't see anything for it to attach to either) other than the cold air box. As you look in the inside of the air box you see a separate closed box that has two hoses going into it. One goes to the a tube attached to the back of the engine or air intake manifold which comes out of the air box with the rest of the hoses and the other is the one in question which comes out the side of the box and appears to go nowhere. Any idea what this is and where it should go?

We want to take it out for a spin, but thought it would be best to sort these things out before romping around with it. Any help you can provide would be very helpful.

DamonB

Sounds like the idle was just high at warmup; that's normal. After warming up (about 5 minutes) it should settle to about 750 rpm with no lights or a/c on. If the idle isn't sputtering and hunting up and down you're probably alright. The ecu should have everything ironed out within 10 minutes.


[/QUOTE]Second, even as the water came up to normal operating temperature the car's heater, which we turned on to check, was only blowing cold air. Could this be caused by an air bubble or block in the cooling system and, if so, how do you get rid of it? If not, what should we be looking for?[/QUOTE]


Make sure your vent settings were set on either the floor only, defrost only, or floor/defrost. The third gen doesn't blow warm air out the passenger vents by design; only the floor and defroster. I don't know why Mazda did that either, but it's true.


[/QUOTE]Third, and this is more of a curiosity issue, there is a hose that comes off the driver side of the air filter box that does not seem to have anyplace to go. When we started the project it was just sitting down near the front of the engine and wasn't attached to anything (we couldn't see anything for it to attach to either) other than the cold air box. As you look in the inside of the air box you see a separate closed box that has two hoses going into it. One goes to the a tube attached to the back of the engine or air intake manifold which comes out of the air box with the rest of the hoses and the other is the one in question which comes out the side of the box and appears to go nowhere. Any idea what this is and where it should go?[/QUOTE]


You have found the famous mystery hose. It goes nowhere, just vents under the intake box.


[/QUOTE]We want to take it out for a spin, but thought it would be best to sort these things out before romping around with it. Any help you can provide would be very helpful.[/QUOTE]


You are safe to drive it once you have water in it. Search this site for coolant advice. The system is bad about air bubbles. Remove the coolant fill cap from the thermostat housing, the AST cap and the upper heater hose on the throttle body. Removing the hose lets the air vent out and makes filling much easier. You will hear a lot of gurgling from it as you fill. When you see water come out, put it all back to together and warm the motor again. Check your water level, you should only need another pint or so.

NexGenSPEED

Thanks, we seem to have ironed out everything now. The mystery hose...another GREAT idea from Mazda. Thanks again!