1984 GS
12A
Nikki Carb
Bone Stock

I'm going to get this out of the way now, I'm still learning cars.

I was driving home this morning, when my car suddenly just died. I immediately coasted into the nearest parking lot. Now the car starts fine, but it doesn't stay running. It wont idle, and even if I apply my foot to the gas it doesn't stay running. Just goes for about 15 seconds and quits. The battery and alternator are both good, and the carb was rebuilt exactly a year ago now.

From what I understand, the way the car is behaving means that it isn't getting enough fuel? So it would be best to start with changing the fuel filter, then I go to the fuel pump, or am I missing another thing to check first?

If it is the fuel pump, would a universal electric pump work?
I was looking at this one from Schuck's.

Thanks in advance for your help.

 

Check for leaks in the fuel lines. I had a leak in the hose that goes from the tank to the pump and the pump was pumping more air than fuel.... the mpg was good but the car didn´t go very far....

 

Check fuses just to make sure one didn't blow. Does the tach work when the car starts? The 84/85 cars do have a fuel pump relay that can go bad too. I ask about the tach because the ECU uses a signal from trailing ignition (same signal as the tach) to tell if the car is running. If it gets the signal, it turns the fuel pump on. So no trailing spark = no fuel.

You can also seach in the 1st gen archive. There is a thread in there about bypassing the fuel pump relay. I would try this. If you do, you should hear the fuel pump running when the key is 'ON'. If you bypass and still don't hear the pump, then the pump probably died. It would also be a good idea to remove the driver side storage bin as the wiring for the fuel pump runs under there. You can check to make sure if the pump is getting power (relay bypassed, key in 'ON' position). If no power, then it is a fuse/wiring issue. If there is power, but no pumping, then it is a pump problem.

 

I think the fuel filter is the winner.

Well if the fuel pump were actually completely dead, the car would not start at all. You could check the pump fuse first. Fuel filter is always a good idea. To check, you could always pull the rubber hose from the carburetor and put it in a small catch can and turn the key to on. If fuel drips out, it could be a clog in the filter or line, if it comes out with a bit of force, than the pump is fine. Poor man's fuel pressure gauge.

I had a weak fuel pump and it was the weenie wires that went to the pump. I ran a new wire and a relay to the pump and it was fine.

But I don't think that this would be the prob since it happened so suddenly. I think your best bet is the fuel filter.

 

The tach was working this morning. I was watching it praying that it would magically stay idle instead of of go back to 0 and die.

I will hunt down that thread, and try to do that test at some point later today (still trying to find a way to get my car home to work on it).

 

if it's still starting at all, i don't think it's the pump. i'd more suspect the filter.

 

I changed the fuel filter in a last ditched effort to get my car home tonight, and it didn't work (Yes, I checked the arrows on the new filter and made sure to install it the same way). It actually wouldn't start up at all after sitting all day. It now tries to start, but never quiet makes it.

 

Maybe pull the fuel line TO the carb from fuel pump off at the carb, stick it in a jar/container and turn on the ignition and see if pump is pumping?

Is the gas tank full or near empty? Some times the fuel TANK starts shedding gunk/rust into the fuel pick up and blocking the outlet. This tends to happen when the tank is below 1/3-1/4. Runs fine when full as the gunk is in suspension in the fuel. Only solution is to pull tank, clean and reseal. Been there.


Stu Aull
80GS
Alaska

 

Can you hear if the fuel pump is running? On an '84, it should only run when cranking.

One reason for the fuel pump not to run, is if the trailing ignitor is bad. The fuel pump will only run once it verifies that you have spark (as a safety measure). But since your tach is still working, that would indicate that the trailing ignitor is still good (unless someone played with the wiring, maybe switched the tach lead to the leading ignition instead of trailing). You might want to verify spark yourself, and you might as well check leading and trailing when you do it.

Another reason for the pump not to function would be a blown fuse. This would be the fuse labeled "meter", if I recall correctly.

If the fuse is good, but the pump still won't run, then we can move on to the relay. There is a thread in the archive on how to bypass the relay. Pretty simple job.

So, verify that you have spark. Then, move back to investigating the fuel pump. That's my advice anyway. Good luck!

 

I just wanted to confirm that changing the fuel pump did solve the problem. Not sure how long it will last though, I ended up with a cheap universal pump.