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Old 03-07-2012, 01:04 PM
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miss when taking off from a stop

So I have decided to leave the 307 in my camaro alone for the time being and concentrate on building up the 400 if and when gas comes down to a reasonable price again. In the mean time it has developed a slight issue. I took it out for a drive after it has sat for the last 3 mo or so and it has developed a miss or bog when taking off from a stop. If you push the gas down hard it pops out the carb and takes a while to get going. If you push the throttle down a couple times it goes fine. Is this a carb issue or a timing issue?

If you are already rolling and press the gas down it takes off and goes fine so that leads me to believe the carb and fuel system is fine. The distributor is a stock hei unit and the timing is set at 8deg.

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Old 03-07-2012, 05:43 PM
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Quote:
Originally Posted by camaro71633
So I have decided to leave the 307 in my camaro alone for the time being and concentrate on building up the 400 if and when gas comes down to a reasonable price again. In the mean time it has developed a slight issue. I took it out for a drive after it has sat for the last 3 mo or so and it has developed a miss or bog when taking off from a stop. If you push the gas down hard it pops out the carb and takes a while to get going. If you push the throttle down a couple times it goes fine. Is this a carb issue or a timing issue?

If you are already rolling and press the gas down it takes off and goes fine so that leads me to believe the carb and fuel system is fine. The distributor is a stock hei unit and the timing is set at 8deg.
Sounds like it could be both timing /carb. JMO What carb is on it ?
Is it doing this with a cold engine or after warm up ?


Cole
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Old 03-07-2012, 06:08 PM
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It does it hot for sure I dont know about cold I always let the car warm up before driving it. The carb is a small base rochester 2g
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Old 03-17-2012, 05:26 PM
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Well I got this thing figured out. It turns out there is something wrong with the distributor i was using. I put a msd 6al and billet dizzy on it and it runs fine now. I will have to get a different dizzy though as the one I have is a marine unit and it has no vac advance on it.
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Old 06-13-2012, 01:45 AM
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I have been driving the camaro almost every weekend and it still does not run right if you do not feather the throttle when taking off from a stop. While I was messing with it the other day checking to see if my timing moved or something I noticed something interesting while playing with the throttle leaver. If I hold forward on it against the stop the car idles down, if I push or pull on it sideways the idle changes as well. Could a vacuum leak at the throttle shaft cause it to go lean enough to cause a bog under heavy throttle?
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Old 06-13-2012, 01:59 AM
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Quote:
Originally Posted by camaro71633
I have been driving the camaro almost every weekend and it still does not run right if you do not feather the throttle when taking off from a stop. While I was messing with it the other day checking to see if my timing moved or something I noticed something interesting while playing with the throttle leaver. If I hold forward on it against the stop the car idles down, if I push or pull on it sideways the idle changes as well. Could a vacuum leak at the throttle shaft cause it to go lean enough to cause a bog under heavy throttle?
To check for leakage around the shaft, start the motor and spray either wd40 or carb cleaner around any suspecting areas (carb shaft, vacuum hoses, etc.). If the engine revs up, there is a vacuum leak at that point.
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Old 06-13-2012, 08:23 AM
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Is the accelerator pump functioning properly?
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Old 06-13-2012, 09:12 AM
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if it sat for a few months are the carb gaskets still good? could be sucking air at a gasket crack. i'd be looking around the carb if the car ran fine before it was parked. have you pulled your plugs to see what they can tell you? if you added an msd box did you open up your plug gaps? are you having a hot start issue? i had a 460 that sat for a while that had similar problems when i started running it last year. i found most of the issues were in the carb.
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Old 06-13-2012, 12:25 PM
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@S10 Racer, I checked for leaks with carb cleaner and it is indeed leaking around the throttle leaver

@bigblockragtop The acc pump seems to work fine, I get a nice strong stream when working the throttle

@robhardy the car the motor came from sat since 93' so I am going to assume the carb gasket have dried out and are now leaking. The car does have a hot start issue but it is a starter heatsoak issue and not a carb one.

I have a performer intake and 1405 carb on the shelf I will throw on when I get a chance I bet that will clear it right up. I have a 350 for the car I am going to freshen up as money allows but I will stick with the 307 for the rest of the summer and put the 350 in next spring.
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Old 08-06-2012, 08:52 PM
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Just though I would post an update on this issue.

With the death of my daily driver (honda) due to uni-body rust the camaro has been pressed into daily driver duty. Being currently un-employed means it only sees ~20mi a week running errands and doing odd jobs but it is driven almost daily none the less. Anyhow the off idle bog kept getting worse to the point the car was almost un-drive-able so I yanked the intake and 2g carb off and stuck on an old style eddy torker and 1405 carb that I had sitting in the garage. Now granted the torker isn't the best choice for this app but I already had it, the carb and even a set of gaskets sitting around and I figured it cant work any worse then the ailing 2g does.

When I first popped the intake off I was surprised to see that someone has been into the motor before judging by the rubber end seals and gobs of silicone sealant (I dont think they had that in 1970) It also appears someone had the heads off and had some work done to them. The ports look to have been hand ported and gasket matched. The head gaskets are also the steel shim type. I had a suspicion from the get go that this motor had a cam swap of some type in it and all the gasket sealant around the intake and timing cover seems to verify this. No idea why someone would go through all that trouble and then stick the tiny 2bbl back on though.

Anyhow long story short the car seems to run excellent now. Well as good as a 307 with a hodgepodge of miss matched parts can run anyhow. I still plan on building a decent 350 or 400 for it but in the mean time the little 307 will get me by fine.

car now consists of:

89 camaro rs (og v6 car)
th350 trans
"020" 307 block
possibly ported 70 307 heads
eddy original torker intake
unknown cam likely of the "rv" variety
eddy 1405 carb
msd pro billet "marine" dizzy (need to change this, no vac advance)
6al box
msd 8mm wires
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Old 08-07-2012, 01:25 PM
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Very cool. I hope your Camaro is not under collectors car insurance. If it is, it will not be covered if used as a daily driver.
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