So I just finally got my car running again. It's a S5 NA 13B with a medium street port and turbo 2 exhaust sleeves, emissions are blocked off. I just started the car yesterday and volts and the temperature aren't reading on my cluster. The sensor on top of the radiator looks like it is torn so I am not sure if that has anything to do with it. Also my idle is at 2k-2.3k. Does anyone know what the problems might be? Be advised I just installed a chassis harness before starting the motor (long story). Also, my brake lights are constantly on even when I don't have the lights on (rebuilt the booster, and brake master cylinder).


If anyone could give me advise on these problems I would greatly appreciate it. Trying to get my car on the road again

 

What did you find using your testlight,multimeter and a wiring diagram?

 

I don't have a multi-meter or the wiring diagram. Do you happen to know what part of the chassis harness gets the reading for the volts? or where it might be located?

 

anyone know how I could approach these problems? or what to look for?

 

voltage: check the connector at the back of the alternator for broken wires, this is very common.

temperature: there should be a clear bullett connector(usually yellowed by heat and grease) fit onto the temperature sender unit just below the oil filter and to the side of the gold bell shaped oil pressure sender unit.

2-2.2k idle: check for vacuum leaks with a can of carburetor cleaner spraying all around the intake tract to see if the idle drops or changes at all. any changes in RPM while spraying in a certain area indicates a vacuum leak. there is also a screw on top of the throttle body which is used to set the base idle, the old engine may have been in such poor shape that the idle was turned way up to compensate for lack of compression.

brake light: on the pedal inside the car there is a sensor which tells the brake lights to activate, it may need to be readjusted after all the work you did with the master cylinder and booster.

 

Karack I really appreciate all the information thank you so much. I'll get on it as soon as finish up with this week of school.

 

Okay, so I got the temp and volts working properly. The idle is still acting up at 2,000-2,300 rpm. Sometimes it drops to 1800-1900 rpm. I tried adjusting the throttle from the screw on top of the throttle body, but nothing happened, I turned it all the way down. I checked around for vacuum leaks and I didn't see any leaks.

 

So for the plug that goes connects into the temperature sending unit, the wire completely fell off the plug. what I had to do is find a random plug with wire and bridged them together. The temperature starting reading. It would hesitate at first but then pick up slowly. Until recently I would let the car idle for 15min and let it warm up. But today I did the same thing I usually did and the car started heating up. It got to the point where the coolant in the reservoir tank started boiling up. I let the car cool down and there was coolant missing in the reservoir completely empty and a tad missing in the radiator. Tried it once more and the same thing happened car started heating up. Be advised that the car has a fresh rebuild. Could it be that the car is heating up because I don't have a fan shroud on the Godspeed radiator? or could it be that the plug going to the sender unit is not working properly? Any information would be appreciated thanks

 

Fan shroud and under-belly pan is always a good friend.

 

+1

I added the fan shroud and the under tray (or pan) quite a while back and noticed way better temperatures.

 

My buddy asked me if I purged the coolant system correctly. He said i didn't do right because I never had the radiator cap open to let the air out of the system when the thermostat turned on. So could that be the problem? air in the system?

 

Not if you refill the rad and it keeps happening. Can you smell coolant around the engine bay? I've traced minor coolant leaks in my new rebuild for weeks, and even now I need to fill the reservoir every few months.

 

There are no leaks, I looked everywhere and I didn't find any trace of leaks around the engine bay or underneath the motor. This only happened once. I am going to try purging the system how my friend advised me to. Is there a thread or link to how to properly purge the coolant system for the rx7?

 

Assuming there are no leaks, nor problems with the rebuild, I'd say your friend is talking sense. Just fill it up on coolant, squeeze all coolant hoses a few times to "burp" the system. Drive it around a bit, and check when the engine has fully cooled.

 

So I made sure there was coolant all the way to the cap of the radiator. Turned on the heater then turned on the engine without the radiator cap. Bubbles started to come out once the car warmed up. The temperature was fine it stayed right where it had to be. While I was looking at the temperature inside of the car my brother was cleaning the excess coolant being shot out of the radiator. Once I ran it for roughly 8mins at the temperature did not fluctuate and stayed where it had to be I turned off the engine. Instantly coolant shot out of the radiator and made a mess. So i'm not sure if I was supposed to put the radiator cap on or turn off the heater before I turned off the engine. Regardless I made a mess. Idk if I should just take it to a shop and have them do it right while at the same time they fix my idle problem.

Also a curious question: I just have coolant in the system and no water. The Prestone bottle says do not add water. Does it mean "do not add water" to the gallon or do not add water to the system?

Regardless I am having it done professionally by the shop. Sometimes making repeated messes and same problem becomes a nuisance. But for reference I would like to know what I did wrong.

 

the system must be filled with the engine running.

 

Never had that happen. But it makes sense since there would be a pressure difference between a running and not running engine.

Coolant is a mixture of antifreeze and demineralized water. Usually in a 50/50 ratio. This may be adjusted for extreme climates. What you buy on a bottle can be either antifreeze or premixed coolant.

 

shot out of the radiator? so if you start the car cold, does coolant come out? or does it like jump out of the radiator? jumping is bad.

the do not add water might mean that the coolant is sold prediluted. usually an engine is supposed to get a 50/50 mix* of water and coolant, and in the past coolant was sold as coolant, and you added the water.

nowadays they are selling coolant prediluted with water, so you don't need to mix anything, just fill. the bottle should say something like premixed, or something like that. in this situation you can add water, but with the prediluted/premixed stuff you shouldn't have too.

the exact ratio isn't a big deal. mazda recommends 90% coolant for storage, and 30% coolant (or less) for racing. so if you're 51/49 its not important at all