jd483

Last year my stock 79 SC developed a miss or misfire. At the same time a strange sound began to eminate from what I thought was the dashboard. I recently traced the sound to the smugglers well. Thinking it was a relay or some such in the AC blower. I disconnected all of the components and the sound remained. This sound, like a geiger counter or agitated liquid, is coming from the fuel tank or pump. I replaced the pump about six months or so ago due to its random failures while on rides. I no longer have the breakdowns but the strange sound remains and the miss does too. I get a puh...pa puh from the tailpipe and congested traffic driving is treacherous due to the jerkness at lower driving rpms.

I have also replaced the fuel accumulator which was going bad too as well as the plugs, four not so bad injectors, wires (Beru), cap and rotor.

Any ideas or similar experiences? Looking forward to enjoying my car again.

Justin

jd483

Was that too weird? I know that the plastic material on the original filler cap was deteriorating so I replaced it. Is it possible that gasket material that may've fallen in is hung up on a screen in the tank? Longshot? I dunno.

Ed Hughes

That is a somewhat tough description to interpret. "like a geiger counter or agitated liquid" sound like to distincly different sounds to me.

Did the miss and the sound start at exactly the same time? Is it only at no load or low RPM's? What happens when you get on it-does it pull strong and rev to redline?

Hester

Hey Ed, I dig that Avatar. Fernando's co-pilot had the same problem trying to get pictures of Hester when we were on that road. I guess I tend to treat that road as a challenge more than a route.

Ed Hughes

It's hard to drive at speed with one hand on the camera and one eye (or more) on the viewfinder. I tried it again yesterday am, same results.

jd483

I know, it's a strange noise. A random rhythm of a gurgling clicking sound only when the car is running. Doesn't do it with the ignition on only. Still pulls strong on up to the redline but lower end driveability is compromised by the miss or misfire. Could be two distinct problems but they both occurred at or about the same time.

jd483

Okay, pulled the fuel level float out. Tank looks fairly clean considering its age. I kinda poked around at the screen inside the bagel looking thing. Could've possibly poked a hole in the screen but made no change to the condition. I'm pointing my finger at the fuel pump check valve at this point. It was a coin toss as to replace it or not when I replaced the fuel pump, and I skipped it.

jd483

Crap, I need more sleep. Looks like my '79 doesn't have a check valve according to Pelicans listings. Maybe that's why I didn't change it. However, I'm gonna change the screen on the pickup and see what happens. I always wondered about that big hex head.

TroyN

Does it stumble just under load or when stationary too? My shop was able to diagnose a problem by hooking up a CO meter to see whether my running issue was due to running rich or lean, and found that it was due to lean running, and that my air meter plate was out of adjustment. Another thing to try is hooking up a timing light to see if there is a miss that is due to ignition vs. fuel. I also had a CD box go bad recently, might try that, with a known good box.

Amber Gramps

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Steve Weiner-Rennsport Systems

IMHO, thats a VERY good idea.

You didn't say how many miles are on your car so I have no idea how old your fuel pump is, but those don't last forever.

I think this is the moment to mention that these pumps are cooled by the fuel that runs through them and so if these cars ever get VERY low on gas or run out, the fuel pumps are usually damaged enough to shorten their lifespan.

jd483

It's got 161K + miles, the odometer broke some time ago. However, I very recently replaced the fuel pump with a Bosch item. I tend to keep the fuel level above half so I should be good there. Just waiting on the part now, I'll let you all know if it solves the problem. Man, I hope it does!

jd483

Oh hell, I have just replaced the pick up screen and the percolating sound persists. It had a small amount of fuzzy, cruddy stuff but just in one small area. Ugh, I dunno what to do now!

Peter Zimmermann

Silly question, does the noise only occur when the car is at full operating temp?

jd483

It makes the noise at all times running. I'm wondering now if it could be a kinked or otherwise damaged fuel line in close proximity to the pump.