Balancer moving 4 degrees: when it idles up it is about 12 to 14, then when it starts its idle problem it drops to between 8 and 10rpms, back forth.backforth.backforth 8/10 to 12/14(watching the degrees the balancer is turning back and forth as it makes the messy idle sound).
Your talking about timing? If so this is your problem! The timing needs to be stable at idle. Get your RPM down, and watch the timing. If it doesn't stay put you need new, stronger timing springs.
FYI: I keep stating SMOG motor. It is stock, but none of the smog system exists (I am also running headers...3" to 2 1/2" to 2 1/2" Flow Masters then turned down). I am using a 79 Thunderbird 351W in place of my original 351W displacement 69 Mustang in my 69 Mustang Fastback. This is why I only use the Auto Tranny vacuum. I also tried hooking up a PCV, but that didn't make any changes. Normally I figure out problems pretty quick, but this one I don't know (6-8 months running). My #1 handicap is the carb operations, I can rebuild anything if I took it apart, and have done many carbs for friends (even tuned), but this issue I haven't seen before (idle up and down on idle but run like a mad man with a touch of gas). Sorry for the novels. Again, any advise provided, Thank you in advance!
sorry your reply wasn't there before I typed my last novel. Still trying to learn this sight. Springs sound like a good possibility, MSD may have changed my springs from what I had on the distributor (they replaced everything except the base cap and base cover shaft). It was running good until they rebuilt it, but of course they had too since the shaft was warped kept breaking bottom role pin (Dist. was from a different motor). I will look around for my other springs that were in my MSD kit.
yes I have a vacuum gauge. I can only hook it to the carb, the Edelbrock RPM intake manifold doesn't have a port (I could probably make something to fit in the runner port that I have blocked off to hook the gauge too). The vacuum gauge needle bounces/flutters about 1psi at the same time the harmonic balancer moves back and forth the 4 degrees and when the idle sounds erratic. All three are in conjuctions to one another on idle.
I would check the fuel pressure, the edlebrocks dont like any thing over 5.5 lbs. you can check this with a guage or a quick check is to pinch your fuel line a couple of quick revs and see if it idles better. If it does two poss. here float set a tad high or the fuel pressure is to high. That slight miss at idle coulde be a burnt valve. As your chokes on and its ritch you dont notice it, till it leans out. check with your vacume gauge hooked to the drivers side port. if it flutters about 2inchs of vac. could be worth checkin into. Hope this helps.
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Jason After No Fear.. Comes, Oh Sh......
FTE Ride of the week 4-6-09
I would check the fuel pressure, the edlebrocks dont like any thing over 5.5 lbs. you can check this with a guage or a quick check is to pinch your fuel line a couple of quick revs and see if it idles better. If it does two poss. here float set a tad high or the fuel pressure is to high. That slight miss at idle coulde be a burnt valve. As your chokes on and its ritch you dont notice it, till it leans out. check with your vacume gauge hooked to the drivers side port. if it flutters about 2inchs of vac. could be worth checkin into. Hope this helps.
Fuel pressure is not an issue here, to high a fuel pressure would cause the carb to runneth over and we already know that's not happening here.
I have the fuel set with a regulator and the gauge is reading between 4 1/2 to 5. I have tried all ranges between 4 and 5 1/2, doesn't make any difference. Do you think I could be vapor locking with the thin carb base gasket? I have had vehicles do it before, but they wouldn't just fire off with a touch of the key (had to use wd-40 to jump start). Don't know if would cause the timing to do this, because once they were running everything was fine. As for the position of the electric choke cap, it doesn't change anything. It happens as soon as the carb butterfly opens(car is only about 140 degrees at this time, still cold).
Well still at point A. MSD walked me through their tests, but all was good with the exception that one tech was curious about the distributor advance springs. One tech said it had nothing to do with the timing the other tech said the distributor did. I hate circles since they return you to point A.lol
!!!!!One thing I didn't do with the carb. When I put the electric choke system on the carburetor, the instructions said to block a vacuum port on the bottom of the carb with JB weld or suitable sub, I didn't do this since I never did with previous Edelbrocks (they were 750's not 600/may matter). I can't compare with my Holley since it had a crushable ball for that hole (sealed with choke bracket). I am thinking about sending the entire MSD system in for G wis checks. 6 months of this is getting old, plus weary on the wallet. thanks in advance for anymore help.
Changed the springs, it didn't help anything. I do have some rifles that need their scopes adjusted, the motor would be a great target. Going to try a different Carb, in a minute. The carb is too big for the basically stock motor, but at least I will be able to see if it is a mechanical/electrical problem if the timing still jumps around or carburetor problem, I don't care about having to change the plugs after I try. Whats 10 minutes added to this over 6 month trial and error crap. I wish the car was a hoopty so I would be willing to tub it and drop in my drag motor.
Yall are excellent and thanks for the advice. I found the problem, finally after over 6 months. For starters (the beginning of chasing) the intake manifold wouldn't seal, replaced that. Couldn't believe the issue you all were trying to help me with recently, my new edelbrock carb was no good. When I sprayed the ether last night next to the elec choke the motor rev'd up (don't want to type the words I said, lol). The main rod going through the bottom of the carb (primaries) was sucking a tremendous amount of vacuum. Gotta love new parts that suck (litteraly in this case,lol). I put my big Holley on and no issues, purred like a kitten at idle, no timing fluctuation. Don't know how long the plugs will last, but oh well 10 min max to change them here and there. Thanks again!
thanks! But, too bad deal my '69 Fastback may still sit a bit. Big Double Pumper Holley's tend not to like stock heads/cams. Amazingly though, when I originally had that carb on the leaky intake at 7 psi it made me smell like I took a bath in gas (in work shed). Left regulater set at 5 to 5 1/2 (never touched adjustments) it is barely ritch, now. I will drive the pretty/awesome car ritch, but couldn't see myself before bringing it out missing. With all the experiments, I can't afford another carb, but if you could recommend the slight solution to tame down the fuel a bit, I would be greatful. Not good at the double-pumper top screws (for floats) versus the needle screw adjustments. I always had someone else do the double-pumper(even tried what they showed me; I'm close to having the feel/sound). One thing about having these problems, I learn (at the cost of alot of money...S%it), but with us all talking and sharing, we all learn/come to a solution to fix a problem. Thanks again!
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After No Fear.. Comes, Oh Sh......
