Hey guys, I am new to the third gen family so bear with me if these are easy ones. I have a 1984 Z28 5.0 H.O. I'm having a few problems that I was hoping to get insight on.

#1. After driving about 30 minutes, the car knocks, backfires and stalls. If you wait 5-10 minutes it starts back up and then 5 minutes later does it again. Granted the car sat for 6 years with a little gas in the tank...am I going to have to keep changing fuel filters till this clears out? I read this could be the ignition switch.

#2. When key is in acc, constant non stop clicking noise around the carb.

#3. When key is in acc, check engine light flashes code 12 constantly until I start it...but I don't have a clip in the ecm.

Thanks guys, all help is appreciated

 

1. Yes, sounds like plugged up fuel system: could be the fuel filter, could be the sock in the tank, could be the lines themselves (in the tank) are built up with the crusties. Wait until the car is almost out of gas; add a gallon of lacquer thinner to the tank; let it run for a few minutes; let it sit like that for a few days; drive it 15 - 20 miles; fill it full of clean gas; change the filter. If it still does it, drop the tank and rod the pickup line out with a coat hanger, and replace the sock. http://www.rockauto.com/en/moreinfo....035492&jsn=435 Pray you don't have the electric "helper" pump in the tank.

2. Normal for when the key is in On (NOT Acc). That's the carb mixture solenoid. Not normal in Acc.

3. Also, Abby someone.


#2 & #3 are related. Sounds to me like somebody has been hacking on your wiring somewhere: the ECM is getting power in Acc, which it should not. Can't tell you what's been done, you know how those POs are, some people should simply not be allowed to own dykes. You'll just have to track it down.

 

Thanks man, I was worried about the clicking never shutting off, but if it's normal then cool...I appreciate it!

 

Tell me , when you first start it , and untill the 30ish minute stall happens , how does it run ? Does it start up OK stone cold , and then run good till the backfiring & stalling happens ? Cause if so , that's the textbook description of a bad ICM and may be what got the car parked 6 years ago ?

I ask because a plugged up fuel system , gummed up with waxy old fuel , would make it run bad all the time , and not let it run good on startup , only to fail half an hour later . If it backfires and runs like crap from the cold start and then finally stalls sure , then yes it could be clogged up .

PS , Sofa is right , if your car is behaving as though the ALDL is always jumpered to access the codes with the key in the accessory position , then someone has been monkeying around with the wires . Hey , the good news is that code 12 is supposed to mean there are no major failures with the ECM's input and output devices .....

 

When I start it cold it starts up great and then runs great... I did replace the fuel filter and there was crap in it....ran it today and no problems yet, but one thing I noticed before it started backfiring yesterday, it started surging almost, barely, but noticible....after about 20 to 30 minutes of driving today noticed the surging but no backfiring yet

 

Update: replaced icm, fuel filter, dist cap and rotor, plugs and wires....problem still exists...so newbie question, could my carb be out of adjustment so that when it warms up fully it's just not getting enough gas?