i have a 67 vip 383. i put a edelbrock dp4b and a edelbrock 750 on it a couple months ago and it backfires thru the carb everyonce in a while when starting or first taking of (if i floor it too much) when its cold. Would a vacuum leak cause this? i think my booster is starting to leak but i'm not sure yet. any opinions on where to look would be great.
Could be Vacuum leak, timing, or the carb is running too lean. There's more, but thise are the most common.
If you have a vacuum gauge read what it says. Shoule be around 17 inches of vacuum. Pull all the plugs. Look at the arm and see if there are heavy white deposits on them. If there are, not the cylinders and check for leaks on the intake. If they are all whaite, then you may have a vacuum leak on a hose, maybe a bad brake booster, or the carb is too lean.
Joined: Fri Oct 07 2005, 12:03PM
Location: Central Ky.
Posts: 1575
If it's doing it JUST when cold & not after I'd also be looking at the choke setting. Too lean on the choke during warm-up will cause the "spits" as I call it.
Check everything else mentioned also just for piece of mind.
Joined: Wed Oct 12 2005, 12:21PM
Location: Jersey, the only state that doesn't need the New...
Posts: 676
Sorry for jumping on to your post but I'm having this exact same problem... What else is new...
First the choke wouldnt open at all... Mech says he adjusted it for the winter. yeah, and now she starts (hard) and dies (stalls) till i floor the bloody heck out of it for a minete or so... then even after shes warmed up everytime im off the throttle and go partialy back in... car bogs and then BOOM backfires... and so on...
Timing was adjusted and these are new plugs... Vac advance on or off no dif.
How do you adjust an automatic choke? I Scored both the 72 shop manuals (body and chasis) for ten bucks... Either does my big 66-73 Chilton book... but it doesnt really get into how to adjust em.