65 L78 TI or Carb Issues
[FONT='Calibri','sans-serif']Been having issues with carb (or so I thought) (because the car would just die and this issue had been intermittent) and on good recommendation from our tech board, sent the 3124 off for professional rebuild. The carb was returned in short order and looks like new. Installed it yesterday and once gas filled all the chambers, the car ran great in the garage. Let the car come up to about 160 or more and shut it down. Let it heat soak for about 35-40 minutes. Restart was problematic and it settled in just a couple minutes later. With wife as co-pilot, off we went for the test drive. Car ran pretty well, but it seemed not to have all the power it should. Come to a stop and the engine wanted to die. Continued the test run for about 20 minutes at speeds of up to 50-60 and engine temp of 180. At our last stop on the way home, again the engine nearly died and with throttle, it came back to life. Shifting through the gears, and downhill to our home, the car dies and will not restart and as luck would have it, coasted into the driveway and to my shop. Let the car sit for a couple of hours and it fired off on a couple of cylinders and would not restart. Was not flooded, and there was gas squirting into primaries. This morning, engine started reluctantly and it was hell to keep it going. 1.5K was the base line to keep it going very roughly and at 2K it sounded wonderful, but, take off the gas and it dies until temperature was coming up, but again, idle was horrific. Adjusted the idle setting on the carb and achieved a little better idle. Shut off the engine and let it heat soak for 10 minutes and on restart had really crappy idle and very poor response to more fuel and at one point the engine back-fired. Checked ohms resistance of pick-up coil and read to be about 900K (at about 170+ degrees) and from our tech board discussions, the reading should be 300-600. Jiggled the pig tail and no difference appeared. TI harness is original to the car, the distributor is original to the car (that is to say I have no record of distributor rebuild) and I have replaced the amplifier about 5 years ago from Dave Fiedler as well as the 210 coil with a repop unit. There are about 30K original miles on the car. Replace all of the TI components? Call the fellow that rebuilt the carb? Your advice is always appreciated and thanks for reading this.[/FONT]
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Re: 65 L78 TI or Carb Issues
Daniel,
Almost sounds like a blown power valve in the carburetor. I agree with Clem, spark plugs are the best starting point..
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Re: 65 L78 TI or Carb Issues
Check the float(s) level, if too high they will flood the engine at idle, especially when hot.
This happened to our L-78 when I changed the wheels/tires. I installed 215-70's on the rear and 205-60's on the front, the resultant 'rake job' (high in the rear) caused the float level to be off enough to flood it out especially when coming to a stop going downhill. I lowered the front float level and the problem went away. Sounds crazy, but true.Comment
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Re: 65 L78 TI or Carb Issues
Daniel-
The reading on the TI coil P/U per GM is a range of 550-650 ohms. However, I do not use them if below 580 or higher than 630-found performance was less than normal. Not sure why you are reading in the 900 ohms range, unless it is truly degraded. A coil bobbin out of range or a weak magnet could cause the problems you describe.
Checking the plugs is a good start, but if you are experiencing ignition problems-the fuel may not be igniting properly anyway, so could lead you down the wrong path. Hate to see you tear into that newly restored carb and trash any warranty you may have, without fully knowing it is your problem. Might be worth sending back to the rebuilder to have him run on a test mule and confirm correct operation.
The aftermarket TI modules available 5+ years ago were all pretty much M&H, which do not have the best durability and/or performance history. I would suggest using OEM modules restored and converted with silicon transistors (check E-Bay) or the new module by K&B Special Products-see E-Bay for dealers offering the module or entire amp, coil P/U, bobbin, coil, etc. TI is highly susceptible to ground wire problems-a good ground is a must for the TI system to operate properly. So, clean all ground potential connectors with a wire brush or similar to insure good contact. I have seen cars that sit for a long time, create surface rust and tarnish on electrical connectors during hibernation, causing problem when re-activated.
Don't know the carb rebuilder you used, but I would assume they are experienced and should have solved any potential carb issues. One last thought on the fuel system-did you change the fuel after hibernation? If not, or did not use a fuel stabilizer: contaminated fuel could be your problem.
Mike Zamora
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Re: 65 L78 TI or Carb Issues
You stated that the TI Harness is original - even if it is not the problem I would replace it for sure if you intend to drive it much
Check your connections at the firewall below the master cylinder - you may have some corrosion issues there.
As stated above on old TI units check all the grounds and the magnets in the distributor. Sounds more electric than fuel. IMO
Good Luck !Comment
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Re: 65 L78 TI or Carb Issues
Guys,
Thanks again for your help.
Dan K.Comment
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