Hey guys. I sold Bowstick my intake and carb (torker289 and edelbrock 600) and he has done the swap but says he gets a backfire when he starts it almost every time. Can we help him out? What, besides firing order (he has quadruple checked that) would cause a pop?
did he remove te distributor? coul be off when it went back in. or, and this happens a lot. he was 180 out when he thought he was at tdc.
He swears he did not take the dizzy out and that he has verified that the firing order is right and wires are right. I need to get him to join this thread and get this resolved. I gave him a money-back guarantee on that carb and don't want him to think it is the carb making the backfires. So, any help would be greatly appreciated.... Anything else anyone can think of that he may have done while doing a carb/intake swap that would cause a backfire? Same exact setup I had on mine except stock cam and exhaust manifolds.
i do hear a wierd drip after i turn the engine off....BUt if i dont start it for around 30 minutes...it wont backfire...it usually backfires when i start it ...turn it off...and then turn it back on quickly...and i didnt change ANYTHING on the dizzy... and scott...pretty much no matter what happens i will keep the carb because its running a lot better once it gets going.. just a gunshot when i start it sometimes thanks for making this thread. pat
check the float setting/if its good,check the enrichment needles,see if one is not seating in its jet causing fuel to leak into the manifold.Did you mess with the valve train when you took it apart?? if so you may have over adjusted a vlave and its hanging open(doubt it though)does the car run well???? when its running or is it not right.Shutting the car down and turning it back on while the engine is still turning will cause that pop out the tail pipe.(you shouldnt do that anyways)Seen a guy blow the muffler off his car that way.It was funny,told him it ws not good,he found out soon enough.Good luck hope this helps you.
If it backfires through the carb when starting but will run ok once it is started then the choke needs to be richer. A lean condition will cause a backfire through the carb. bad or sticking valves can also cause backfires. Exhaust valve will backfire through the exhaust and an intake will cause backfire through the carb. If it only backfires and won't run then it is probably a timing issue or vacuum leak.
Key banging, as mavmanerick said, is similar to what I described in your PM about driving and turning the engine off while still moving, then turning the key back on. That is what I describe that usually blows your muffler up. Gas continues to go through the system (or fresh gas is still in there from last run) and when you quickly turn the key back on, it all ignites immediately for some fun pyrotechnics, and a trip to the muffler shop. Just before I gave it to him, I put the stock metering rods and jets in it since mine ran great on the stock configuration with that carb before I started building the engine up. His is stock so I figured the stock Edelbrock config (out of the box) would work for him. So, if it is a drip from the metering rod, that would be easy to check. and since I never ran it after I converted it back, this could be a place to start, if it isn't more the "key banging" issue.
AND it still idles high(as in 1300 rpms) do yall think it still has to do with the A/F ratio or maybe a small vacuum leak
A/F should be fine. Is it idling that high with the throttle cable disconnected? If so, be sure the choke is completely disengaging. That is the sorta rounded brass thing behind the throttle linkage that has a serrated edge. If the choke is on at all, it will be stiff. If off completely, it will wiggle a little like it is just hanging there. You can roll that up until all the serrations are off the throttle link, and then your choke is completely off. Then set the idle, and adjust the choke back a bit.
Bowstick PMed me today and said he has it idling smoothly at 500 rpm, or wherever he wants it. No more backfiring,etc. I got on the phone with him last night and I had him disconnect the throttle cable completely, because it sounded to me like he was having to pull the carb linkage back in order to connect it, so it was not going all the way back to idle when he let off the gas. We also messed with the choke, and it apparently was engaging too high, keeping the idle up around 1500-1700. Once we got those two things squared away, he seems to be running much better, and will now have to fab up or find a new throttle cable bracket (T289 sits at an angle, and needs special bracket shape).
scott i got the stock throttle bracket to work with some persuasion....now it pushes the throttle linkage fowards and works great....also no more smoke(that i know of) but it still backfires but only if i start it ...turn it off....start it and turn it off THEN it will backfire....so things are going great but it kinda hesitates when i just stomp on it ....what do you think?
