So, I just put on my brand new Holley 600cfm carb. All new wires and plugs. New ballast and ECU. Battery fully charged. Fresh gas, new fuel filter. All this and she still gives me hell running. I'll pump the gas twice and she'll fire up immediately, then die right away. I'll go though the process of her starting/dying about 10X until I can get to the carb and finally coax her into staying running. Couple of backfires through the new carb and a few out the exhaust. After about 10 minutes of running she'll stay running but idle kind of fast. Even warm, I can't get her to kick down into a lower idle. Timing?
No more likely carb , if the choke is not fully engaging it may be difficult to keep running when cold , also the float level could be low
If it has high idle when warm it could be a vacuum leak at the base or one of the ports on the carb or there is a separate fast idle screw on the passenger side of the carb or again the choke could be sticking keeping the fast idle cam engaged .
It's a mechanical choke so I have her fully opened to start cold. Don't know why she starts immediately then dies right away. I checked for leaks and found none. Also, all vacuum lines are new.
What cam, compression and timing are you running? Fresh build?
Quote from: Cuda Cody on April 10, 2020, 11:29:22 PM
What cam, compression and timing are you running? Fresh build?
No idea on any of those. 1971 318 w/1991 swirl port heads. Got the car about 3 months ago and she was barely running. Heads look like they have been rebuilt, but not sure about the engine. Sounds strong when running, it just take a lot of work to get her to the point where she stays running.
Sounds simple but...do you have the spark plugs routed to the correct cylinders? Exhaust backfire tells me something is wrong with the ignition, valve timing/adjustment, or burnt valve maybe? Bad distributor cap? :notsure:
Quote from: Matt13 on April 10, 2020, 10:57:48 PM
It's a mechanical choke so I have her fully opened to start cold.
choke should be fully closed for cold start and opened gradually as engine warms
since you don't know anything about its past.
pull the cap. turn it over with a ratchet to your marks TDC.
were is the rotor pointing.
#1 hopefully.
check your wires again. ( firing order)
did you put a timing light on it.
it starts easily because you pump it , once running it immediately goes lean from lack of fuel with the choke off , the backfire is normal if it is lean .
If the idle is too high when warm there is a fast idle adjustment on the passenger side of the carb that may need adjustment .
I agree it may run better with more advance but that is not the cause of the stalling when cold
If it was me, I would start at the beginning. A basic compression check would be first on my list. Then I would set Top Dead Center and set the timing. Then work down the list to double check everything.
Agreed: You've proven it actually runs. Compression check, measure timing chain stretch, check TDC, check timing then tweak the carb.
Excellent. Thanks for all the advice guys. I've got some work to do!
Too bad I don't live near you. Sounds like fun. :cheers:
Quote from: headejm on April 11, 2020, 12:09:40 PM
Too bad I don't live near you. Sounds like fun. :cheers:
Actually from Illinois (Oak Lawn on the SW side)
If you grab both sides of the damper you can usually turn the damper side to side & fell when it picks up the extra load of the can etc to see if the timing chain is OK
Had a similar prob once, the intake was loose, sucking air.
First thing I do when I tune an engine is check intake & carb bolts
Carb bolts tightened when I changed to the new carb. Tightened in the proper criss-cross pattern as directed. As for the intake, I've checked the bolts and they all seem tight. Going to check for leaks there next.
Quote from: Matt13 on April 12, 2020, 12:42:15 PM
Carb bolts tightened when I changed to the new carb. Tightened in the proper criss-cross pattern as directed. As for the intake, I've checked the bolts and they all seem tight. Going to check for leaks there next.
I recall in previous posts that you were struggling with holding an idle at all. Now the ignition and carb have been changed out to no avail. It sounds to me like the timing was out of whack from the start. Charging a carb and swapping ignition parts really won't change any of that. I agree it's time to get to basics. Find TDC and if you have the ability set #1 up 10 degrees advanced. Then see if it will fire and warm up. After that get timing set then tune.
I'm in Libertyville area and am happy to help if this is not familiar for you. Timing has such a huge affect on these beasts!
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Quote from: 71383bee on April 12, 2020, 07:29:22 PM
Quote from: Matt13 on April 12, 2020, 12:42:15 PM
Carb bolts tightened when I changed to the new carb. Tightened in the proper criss-cross pattern as directed. As for the intake, I've checked the bolts and they all seem tight. Going to check for leaks there next.
I recall in previous posts that you were struggling with holding an idle at all. Now the ignition and carb have been changed out to no avail. It sounds to me like the timing was out of whack from the start. Charging a carb and swapping ignition parts really won't change any of that. I agree it's time to get to basics. Find TDC and if you have the ability set #1 up 10 degrees advanced. Then see if it will fire and warm up. After that get timing set then tune.
I'm in Libertyville area and am happy to help if this is not familiar for you. Timing has such a huge affect on these beasts!
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Thanks for the advice. I've done all the checks for vacuum leaks so timing is next. I'm glad I changed the carb because the old one was pretty worn out. A Holley tech told me the numbers on the date code show either 1981 or 1991. I'm guessing '81.
I used to be in Oak Lawn. We moved out here to CA. 6yrs ago. Hate the crowds here, don't miss the snow!
If it is a help I can call you for free anytime I walk through things with you :bigthumb:
Quote from: Matt13 on April 13, 2020, 01:50:07 AM
Quote from: 71383bee on April 12, 2020, 07:29:22 PM
Quote from: Matt13 on April 12, 2020, 12:42:15 PM
Carb bolts tightened when I changed to the new carb. Tightened in the proper criss-cross pattern as directed. As for the intake, I've checked the bolts and they all seem tight. Going to check for leaks there next.
I recall in previous posts that you were struggling with holding an idle at all. Now the ignition and carb have been changed out to no avail. It sounds to me like the timing was out of whack from the start. Charging a carb and swapping ignition parts really won't change any of that. I agree it's time to get to basics. Find TDC and if you have the ability set #1 up 10 degrees advanced. Then see if it will fire and warm up. After that get timing set then tune.
I'm in Libertyville area and am happy to help if this is not familiar for you. Timing has such a huge affect on these beasts!
Sent from my iPhone using Tapatalk
Thanks for the advice. I've done all the checks for vacuum leaks so timing is next. I'm glad I changed the carb because the old one was pretty worn out. A Holley tech told me the numbers on the date code show either 1981 or 1991. I'm guessing '81.
I used to be in Oak Lawn. We moved out here to CA. 6yrs ago. Hate the crowds here, don't miss the snow!
Ohh i see now. Your definitely not in IL anymore! Either way im happy to help.