Hello everyone,

I have an '83 that when i start it in the morning idles fine, but if you slightly give it some gas it'll backfire on me. When it's warm it goes away and runs fine, but occationally comes back when I'm driving it a little harder than usual. I've changed the plugs, wires, cap, rotor, fuel filter, and adjusted the timing. The plug wires look to be in good shape. I have used set with nothing wrong with them that I may swap with the currently installed ones, but those wires do look good. Anyways I do hear a clicking sound coming from the pressure regulator...but I also feel that clicking on the fuel line by feeling the rubber fuel line before and after the fuel filter...which leads me to think... fuel pump... I don't think that clicking feel or sound at the fuel pressure regulator are normal.

Any educated guesses or opinions?

 

This might not answer any questions but I want to get this out of the way so we can try to help solve your problem. This clicking noise, is it fast pace? What I'm thinking you're feeling and hearing is the injector pulses and clicking. You can hear it and feel it. The pressure regulator is right by the injectors, so it might be hard to pinpoint the sound coming from there. That's my opinion.

 

Yeah... it's fast.

 

Does it change speeds when you rev it up?

 

That sound is most likely the injectors. If it were ticking valves you probably wouldn't be feeling it in the fuel lines. The clicking is normal, as long as it is the injectors. Try unplugging one of the injectors with the car running, if the clicking changes at all, then it's just your injectors. If you think it's your pressure regulator(not likely) then try disconnecting the Vacuum connection. If the clicking is related to the diaphram in the PR, then removing vaccum would stop it.

 

The clicking speeds up when you rev the motor. I'm more conserned with the backfire that happens when its cold and then goes away once the car is warm. Then the slight hesitation. I adjusted the timing because it was slightly off...retarded...But the car (tac) tends to surge when you are accelerating quickly. I need to drive it on the freeway to see if it still hesitates slightly... and I have to let it cool down to see if it still backfires when cold. So is the clicking supposed to be that loud... and a posibility it that I have a bad injector causing the backfire.

 

If it's only doing it while the car is cold I would point the blame somewhere in the area of your air regulator or cold start system. I'm leaning toward air regulator though. I had a bad air regulator and I don't know about the backfiring(my car backfires all the time anyways ) but the hesitation is definitely a problem I had when the car was cold. Once I found out the regulator was bunk I replaced it and my car idled better when cold and the hesitation was completely gone. The injectors get louder with age as they wear internally, but yeah the clicking is alright. Take a flathead screwdriver and place it to each injector as the car is running, if you put your ear to the end of the screwdriver you should be able to hear the injector clicking away. If it's weak or you don't hear it at all the injector could be bad, but more likely it's the wiring. If the wiring is corroded or loose, this may cause your surging as the wire breaks and regains contact causing the injector to misfire and then resume. If your losing an injector while driving from bad wiring it would definitely cause a hesitation while accelerating too because your car is only firing off of 5 cyl. I had this problem too. I didn't get around to fixing it until I lost my second injector, then it's really bad.

 

I think your right about the air regulator...the factory service manual says, "the air regulator by-passes the throttle valve to control the quantity of air for increasing the engine idling spreed at bimetal temp of below 176 degree F. A bimetal and a heater are built into the air regulator. When the ignition switch is turned to the "START" position or the engine electical current flows through the heater and bimetal, as it heated by the heater, it begins to move and closes the air passage in a few minutes. The air passage remains closed until the engine is stopped and the bimetal tem drops below 176 dregrees F." If the air regulator is not working properly it would effect the air/fuel mix causing the backfire. I think changing the air filter might help too. By the way I'm enjoying my Factory Service Manual.