Hello once again....I have a 79 Tbird with a 2V302 V8...Starts and runs good but when you go into gear it detonates for about a seciond and quits all together....Replaced chain earlier, and timing is as it should be...Someone please offer ideas to help me allieviate this situation... She says,"It's either the car goes, or she goes", She had better get packing!!!!
Two things,, take the engine to top dead center and be sure of timing. Secondly, I suspect a vacuum leak. Follow thru on both and you will find your problem. Keep us posted. Dan
Timing reads on damper at TDC on compression stroke and rotor button dead at no.1 post on cap......Where are the most common vacuum leaks located.....Carb is old may need rebuilding....Hard Job? when you rev it up it studders its way thru the RPM's Also should the vacuum advance on the distributor be hooked up or does it matter? She says, "It's either the car goes, or she goes", She had better get packing!!!!
Yeah, Gene has good advice also.. wires, cap and rotor are crucial... but now I suspect your carb. Yeah vacuum advance should be hooked up when testing. Really suggest going thru the carb,, if you have not done before., take it to someone qualified. Dan
Thinking of an OEM rebuilt carbureator from AutoZone, $118,00 would be well worth the headaches of trying to do it myself or keeping on trying with a bad carb all together...Dan, I'd say your suspicions were right cause i was definately more on the lines of a defective carbureator, cause its timed dead on, new plugs wires dist cap and button dohickey....would someone have a vacuum diagram i could have, or some info on the changing onto the new unit...Much appreciation Guys....You ALL have been a tremendous help with the forgoing of my project, and may God bless you ALL!!!! She says "It's either the car goes,or she goes", She had better get packing!!!!
Way cheaper to rebuild. I have gotten many carbs that were bad or defective right out of the box also. Now as a rule I don't let go of my carb untill I get what I'm looking for.(or any other trade in parts for that matter)
I had a '79 LTD 302 with the Variable Venturi Carburetor. The "venturies" swelled and would not function properly. At the time, there was no 'cheap' replacement for it so I had to buy a rebuild - about $300. If you can get rid of that stock carb and replace it at a reasonable price, I'd go for it. IMO, those carbs were junkers (other's may differ on opinoin). Even if that's not the problem, you won't regret getting a good replacement for it. Good luck.
Do tell me this...Just a question What is the function of a power valve in a carb?????I have been told that when an engine backfires out the carb, it can cause this so called power valve to go bad? What are the usual symptoms of a bad power valve????
Another good question Some sources say that 10*ATDC with the rotor pointing at the #1 cap post will put me in the ball park.....some also told me as much as 14.....Mine is set dead on TC, New timing chain installed anddone with measuring it with straight edge 3 times to ensure the dots were lined correctly......Someone Please Help ME!!!!!Car still has no power and has pre ignition under a load such as in drive at idle
should be at or before TDC, unless your running some strange cam? try starting at around 10 btc and bring it towards around 5 and see if the power increases any.
If you have it set at "TC", as you say, then you have zero timing advance. You need to set it somewhere between 10 & 14 degrees before "TC" (which is Top Dead Center). With that year model I'd suggest 12 degrees. If it's stumbling all the way up then you have an ignition problem also. Check wires, plugs, cap, rotor. Replace as necessary. The power valve in the carb opens to allow additional fuel when the vacuum level drops below the power valve's setting. It's for partial-throttle fuel enrichment. If you've backfired the carb then chances are you've blown the power valve. Sounds to me like you need the timing set, get a new carb, check your ignition components. Also, set the timing with the vacuum advance line disconnected.
