I have been working on my recently purchased '79 RX-7 on the weekends. It didn't run when I bought it so I got a carb rebuild kit and rebuilt it. I used carb cleaner and cleaned out all of the jets very well.

After I got the carb put back together, the car ran. I fired it up several times that afternoon. That evening, I started it up and it ran for a few seconds, then just died. It hasn't run since.

The engine turns over but won't fire. The only way it will run is if I squirt gas into the carb. I replaced the fuel filter and the fuel pump is running. I disconnected the fuel lines from the carb and fuel is getting to the carb, but no fuel is getting through.

Does anyone have any insight into this problem?

If nothing else, I will tear the carb apart again this weekend and running flexible brushes through all of the areas fuel will be going through.

 

Damn I'm doing the same thing a yellow 1979 RX-7 10/79
Rebuilt the carb
cleaned the gas tank / new pump fitters etc...

half way thourgh the bring back to life project

Then I'm selling it for $500

hopefully someone knows I sure hope Mine runs!

 

Anyone have any ideas? I am heading home this afternoon to work on the car. Any help would be very welcome.

 

Could be stuck float needles valves. Try banging on the top of the carb with the handle of a large screwdriver or something similar. Sometimes that will get them freed up...

 

I will try that when I get home tonight, but I completely rebuilt the carb about 3 weeks ago and part of the kit was new float valves. Thanks for the tip though. Hopefully, it will free up whatever is jammed up in the carb.

One other thing that I thought of, are there any solenoids that allow fuel to go through that would be jammed up? My grandpa suggested that some valve might be stuck closed either by solenoid or vacuum line.

I wanna drive my car.

 

yea, that's what kentetsu is talkin about. the needle valve will get stuck in the seat not allowing fuel to fill the bowls. i just went thru this a couple days ago after tuning my rebuilt nikki. you gotta tap the banjo bolt with the handle of a screwdriver or something like that. it will free it up. this may happen a coule times, but don't worry about it. just drive it around a little so fuel is constantly flowing thru and it will help. mine doesnt do it anymore.

edit: i thought of something else as well that works. if you have an adjustable pressure regulator (which if it's all stock you dont) then turn the base pressure up and it will push threw real quick. hell i run 6.5psi as a base pressure anyways.

 

My car still isn't running. No fuel is getting through. Even when I press down on the gas pedal, the accelerator pump isn't squirting. The float bowls have fuel in them a little over halfway up the sight glass. Any other suggestions?

 

You said it starts if you squirt gas directly into the carb. Does it stay running if you start it that way? If so, then the problem may be in the accel pump circuit or accel pump adjustment.

 

It runs as long as I am squirting gas down the carb. As soon as I stop, the engine dies.

 

The float bowls are about 1/2 full, right? Next thing to check is what the idle mix screw is set at. It should be about 3 turns out from full stop. If you screwed it all the way in when you put the carb back together, you won't have any fuel flowing at idle.

The AP pulls fuel from the rear bowl only, and it pulls from a lilttle hole rather than through the main jet at the bottom of the bowl. So a blocked passage to the idle port - below the throttle plate - won't affect the AP. I think you have two different problems. One is the AP and why you don't see a shot from it. The other is lack of fuel when starting.

Do you have the carb choked when you're trying to start and keep it running? I don't know what the temp is Iowa today, but it's not quite warm enough in KC to keep a cold engine running without the choke and/or fast idle rod working.

Did you check the throttle plate opening when you rebuilt the carb? It has to be open slightly. There's a measurement in the manual.

 

I made sure to turn out the idle mix screw when I rebuilt it. When I go home this weekend, I will check the butterflies to make sure they are open a little bit and will look at the hole in the float bowl for the AP. Thanks for the suggestions.

 

Chances are you have a problem with the AP circuit itself.
A missing or stuck checkball is my guess. You'll know quickly enough if, while there is a level of fuel half way in the site glass in the rear bowl, as you trun the primary throttle shaft you view the two streams of fuel shooting into the primary venturis.

If one of your needles is sticking closed, then try dead-heading the return line. This will give the fuel pressure no escape route to bypass the needle valve. The return fuel system, I believe, the reason sticking needle valves are so common in freshly rebuilt Nikkis.

 

What do you mean by "dead-heading" the return line? Do you mean block it? If so, will the pressure make fuel squirt out so I know when it is clear and can turn the fuel pump off?

 

Yeah, he means blocking or plugging the return line. Have you tried doing a volume test on the pump? Maybe its not even pumping at all?

 

Yea, its pumping plenty of gas. I have pulled the fuel supply line off and turned on the car and a good amount of gas came out.

What is the actual purpose of blocking the return line? Will that blow fuel through all of the paths or just to make sure the carb is getting enough fuel? Could someone explain this to me. Thanks

 

It will increase the fuel pressure in the carb and may unstick the float needles if they are stuck in the closed position. If they are stuck closed, fuel cannot flow into the bowls.

 

But he's saying his fuel bowls are half full through the site glass so wouldn't a stuck float needle be before his problem of the carb not feeding the motor gas...????

just thinking outloud....

 

If the pump is supplying fuel to the carb, but the carb is not supplying the motor, then there must be an blockage inside of the carb. Right?

 

that's what I just said...

 

Thanks everyone for all of the help. This is the first carbed vehicle I have ever worked on, but am learning a lot. Hopefully, I will figure out why the carb hates me, try to talk nice to it and we can be friends. It is killing me not being able to drive my car...it is starting to keep me up at night trying to figure out what could be wrong. Yea, I know...I got it bad. Again, thanks everyone for the help in getting my car running.

 

Not trying to hi-jack this but I am having similar problems with an 82. After rebuilding the carb. It is not getting fuel to the engine. Fuel is flowing to the carb. the float bowls have correct amout of gas in them but it is not getting to the engine. Accel. pump works correctly and if I pump the accel. pedal it squirts gas into the intake. After reading some of the suggestions here I thought I may have some stuck float valves. I tried blocking off the fuel return hose. This puts fuel into the engine and I will start and run this way but will not Idle. I have to keep the rpms at about 3500 to 4000 to keep it running. When I reconnect the return line goes back to the same problem. No fuel getting to the engine. Motor starts for a second or two and then dies. I probably did something wrond during the rebuild but can't figure out what it was. This is my third carb. rebuild and the first two worked great.

?????????????????????

 

Helloooooo...... Anybody............