84 gs (12a) 5 speed manual with inhibitor bypassed
engine dies at 50mph?
checked timming, fuel pump, vacuum leaks, car idles smooth.
HELP91111111111!!!!!!!!!!!!!

 

have you checked the converters?

 

Sorry, I'm running a rb header with pre- silencer

 

have you inspected the fuel filter? all it takes are small little things like that. also, check the plug wires for proper resistance. you may have a small break. are you sure compression is good?

 

if you are suspecting the carb, you can rig up the secondaries to be mechanical instead of vaccume operated. that would eliminate the solenoids on the carb. if you are looking for a great carb, check out sterling's carbs. do a search on "sterling carb" and you will have all the info you need at your fingertips.

 

I will replace the wires and cap,rotor, allthough I've tried the ones off my salvage RX

 

very interested in hooking up secondaries for mechanical operation, definately would show if thats the problem, although it sounds like its openning but not getting gas. I did replace the accelurator pump, and visually inspected the secondary bellows diaphragm.

 

I'm not an expert on this but I'm guessing if your secondaries are not opening the car would still 'run' at or above 50mph. The primaries would still be open and supplying fuel. You would have no 'oomphh', but she'd still run.

I wonder if a coil going bad would fault out at higher rpms??

 

i've had the same problem with my 83. On the highway she doesn't pass 60 mph. Everything was in working order but my carb was full of crap and im in the process of cleaning her up and im gonna see if this was my main problem. When i took off the top off the carb the float bowls where loaded with crap on the bottom of them and so was clogging some little holes at the bottom which i think haven't been supplying enough fuel to the secondaries.

 

if i were you i would replace the fuel filter before doing anything. out of all the information given you, this is the cheapest and very easy to do. always start with the cheapest parts, and work your way up. a fuel filter only costs a few bucks!

 

and a fuel filter is a good thing to change anyways. I usally change mine yearly.

 

When I rebuilt my carb on my '82 GSL, I put one of the gaskets on wrong. The vacuum signal could not get to the secondaries, so I ran on a glorified 2 barrel carb for about a week. Ran like a high performance Chevette (oxymoron). I could get to 55 MPH highway speed, just took longer. A long time ago I let my fuel filter get dirty. The engine would start sputtering if I was running 55 and tried to accelerate. Otherwise the engine ran smooth and idled fine. The filter really did not look dirty, but it fixed the problem. I agree with replacing the fuel filter. It can't hurt.

 

Guys, the fuel filter is new, I changed the fuel pump when the problem started just in case that was the cause, I think rneoaz82 my be right. Clogged main jets. We will see!

 

perhaps you should look into the sterling carb.

 

Is the new fuel pump aftermarket or a oem replacement? If it is aftermarket does it supply enough fuel? And make sure the fuel filter is in the right directetion. I acidentally put mine is backwards once and the car would not even stay running.

 

Stopped at the Mazda dealer yesterday and found in the microfish a cutaway of the gas tank, it seems to have a strainer inside the tank. This is not shown in the Mazada Factory Manual. Well now, I guess i'm going to have to drop the tank and rebuild the carb this weekend.

 

god luck. i havent heard of this alleged strainer though?. the only thing in there that i know of is the fuel level sender. hmmmm

 

Ok, I've rebuilt carb, replaced rotor, cap, wires. still had problem. car runs real well up to 50. I have now removed gas tank. Strainer is clean, but found a tablespoon of rust particles in tank. Could that small amount cause enough clogging?