Luis Gonzalez

Hello, I am a 16 year old in high school who owns a 1983 Mazda RX-7 GSL.
I have recently encountered the problem that it seems to not want to idle on its own, and me loving and having a passion for this car (my first car), has dropped me into a small down slide toward depression road. If I cant fix this problem soon, i'm going to get rid of it, to make/try to get rid of the depression.

Anyways, sorry for the backstory.

The car when started w/ the choke, will stay on forever, but when the choke is removed, the car only stays alive for a matter of seconds, before the car dies out. Once the car is warm, it can stay alive for 20 seconds tops w/ out the choke. I have a Carb rebuild kit, (Walker Kit) but have not had the time/or energy to fix it. I ususally would be very enthusiastic about fixing it, but its gotten to the point where the car has sat for a month now, and it needs to be fixed. Any, really, ANY help will be appreciated. If someone could possibly link me to a Guide on how to remove the NIKKI CARB, and maybe some carb swaps ( or a possible Fourm to Swap in a 305 chevy, since my school shop has given me 3 at my disposal. )


Thank you so much, I haven't been here long, but I have read and seen many amazing things from this club, and as a major car enthusiast, I cant bare to see my car sitting.

KansasCityREPU

iTrader: (9)

DO NOT REMOVE THE CARB OR REBUILD TILL THE REAL ISSUE IS DIAGNOSED.

Before doing anything, lets walk through some common things that can cause a high idle. I don't think a carb rebuild will solve this problem.

The first thing to do is a compression test. You can use a regular compression tester with the valve pressed down. Label the two coil wires and then disconnect them. Front coil is leading and rear is training.

Auto parts store will loan a compression tester. Put the tester in the lower front spark plug hole. Crank and look for three even bounces. Do same for rear. Do not pump the gas or use the choke.

I'm sure there are better write ups on this forum on how to do a compression test.

This is a start. There are a lot of knowledgeable folks here on the forum that can help. They will take care of you.

Luis Gonzalez

Thank you very much my friend, this car is very dear to my heart, This community is amazing.

For the compression test, What is a Good test for a 12A?

t_g_farrell

iTrader: (1)

Your looking for even bounces more and consistent readings on those bounces more than a
specific pressure reading. Mazda makes a rotary compression tester that can get you those
numbers but for now you just need to make sure you have even compression on both rotors.

I doubt your issue is compression, sounds like a fuel delivery issue or a carb issue.

Many times idle issues like this are vacuum leaks. So check for any vacuum leaks.
Check all hoses, if it still has the stock rats nest then you probably have some cracked or
bad hoses causing vacuum leaks.

For the carb, remove the air cleaner and clean it real good outside and spray carb cleaner
while its running into the carb to see if some cleaning would help. Next take some seafoam
and dump it in the tank (make sure tank is at least 1/2 full with good gas, repeat good gas).
Run it with the seafoam for awhile and see if it helps. This may clean up the carb internals
enough to fix the issue at least temporarily.

For fuel deilvery make sure to check these things:

1. Fuel pressure should be 2.5 to 3.5 psi.
2. Fuel flow should be about 25 GPH, so in about 30 seconds it should pump 1/2 gallon or so.
3. Change the fuel filter. If its got a lot crud you may need to drop and clean the tank.
4. If the tank is dirty it may blog the pickup. No way to know this unless you drop the tank.

If you do the 1st 3 above and still have problems it may be the pickup in the tank getting
clogged or the pump isn't healthy.

If you get through all of this and still have issues, a carb rebuild might be in order.

Luis Gonzalez

can you tell me what things exactly i should look for in the rats nest? the car was rebuilt twice i think at rotorsports in santa clara california. (just more information about the car.)

TomSmy

iTrader: (11)

Lots of good information and things already suggested for you to check.

In addition; have you fiddled with the timing or the idle mixture?

(Note i am not suggesting you mess with them right now, i am just asking if, for any reason, you may have adjusted them to cause this situation?).

I had an issue where my car wouldn't idle without the choke and timing was the reason. No idea how it got out of line, but it had. It's a VERY easy check to see if your timing is good. Idle mixture take a little more effort.

Reason I am leaning towards the issue being timing or idle mixture is because you said that it will "run" with the choke on.

Tom

t_g_farrell

iTrader: (1)

Get the FSM here foxed.ca and then make sure all the vacuum lines are connected
and not leaking. There are various ways to test for leaks. The easiest is to listen
for the worse ones. Then try using wd40 or starter fluid to isolate the small ones.

Luis Gonzalez

Thank you very much for the info!

Luis Gonzalez

UPDATE: I did the compression tests and they go as follow

First Lower Front Plug: 70,70,70 PSI
Last Lower Front Plug: 65,65,65 PSI

EDIT: also found that one of my plugs was very loose, may be the culprate.