I have had a problem with WOT for a while, and thought it might be fuel delivery, timing, points, etc. But today, I did a little test... If I punch the pedal but stop about an inch off the floor, it will accelerate wonderfully, but if I hit the floor, it immediately does the SPit And Sputter (SPAS, from here forward). Did it again, but stopped the accelerator just above the floor and no problem, and quickly hit the floor, SPAS, let off just a bit, it stops sputtering but continues to accelerate, then hit floor again and SPAS. It feels more like an issue of the opening of the carb than it does timing or fuel delivery (by the way, the fuel pressure guage does not drop significantly when I do this). Can I possibly be opening the carb PAST WOT thereby losing flow. This is a definite point of loud popping SPAS, not a gradual loss of power and gain of noise. There is a precise point where I can accelerate and it immediately goes into SAS and loss of power. And the popping is not a backfire-gunshot type pop, but about half as loud, and it is not burning the air filter (not flaming back up through the carb). Up until about 30 minutes ago, I thought is was an advance issue, but I am thinking not now. I am still going to pull apart the distributor and check the points, dwell gap, timing, and advance "curve". Any other suggestions? I know I need a new electronic system, but cannot afford it right now. Soon though (added onto the ever-increasing Maverick Shopping List!!! Damn that list is getting long )
Just as an update...I checked the points, which are fairly new with the new distributor (stock replacement, maybe 1000 miles on them) and they look good. I went ahead and ran a chunk of fine sand paper between them to clean the contact points off, they are set at around .018-.019, took the sand paper to the edge of the rotor, just to make it shiny, and checked the timing, which was pretty close to where it needed to be (10 degrees at idle, much higher 40-ish at 2500-3000 rpms. Still think it is carb opening up too much. If I set the floored throttle to open the carb to as far as I can open it by hand, is that correct, or is there some place I should stop before the carb stops moving?
the throttle blade should be vertical at wide open throttle when you look down the carb throat. have someone step on the pedal all the way while you check to make sure the linkage is moving all the way.
Can you check the wide open position by looking down the throttle bores...or is this a vacuum secondary carb? Couple other things.... -vacuum leak (base of pot,hoses, intake gasket) -main jets too small? -slightly less likely, but carbon tracking in cap can be a nightmare, especially if no visible tracks can be seen. [You're sick of hearing this...,but please dump those points as soon as possible.]
just a thought, but my 308 with 542 lift cam, and msd distributor, 6al and blaster coil is only about 37 at wot.
Timing lines on the balancer...What are the increments? I am guessing when I say 40 degrees. I have been assuming 2 degrees per small line. Either way, the issue is (almost) definitely related to throttle position, not timing. I can run it up to 5500 rpm without any issues or power loss, as long as I don't pass that point on the pedal where it gives up. I can also get it to SPAZ out at lower rpms, such as 3500 if I put the pedal down past that point. As for the blades, if I WOT by hand with the engine off, the front two are straight perpendicular (to the ground) and the movement stops. The rear two don't move, so is that "vacuum secondary"? Finally [I will dump those points as soon as I financially can!]
Intake gasket, as in manifold to head, or carb to manifold? Is it safe to do the unlit propane torch test? I have heard of it but never used it.
Couple this thread with your early shifting/new modulator thread, I'm betting you have a vacuum leak somewhere. WD40 works to find vacuum leaks, carb cleaner leaves less residue on the engine, but is *kinda* flamable... You can even take a water hose just very lightly spraying and go over all the gasket areas.
if the rear butterlies are not opening it is either a vacuum secondary or the rears are broken and not opening at all... and this would cause it to lean out so bad that it dies... check all the linkage and make sure it is all connected properly... assuming that it is a manual secondary carb my timing is set to 36* at 3000... initial... no idea.. maybe like 12*.... i dont have a timing light... don graham helped me when we met up.. maybe he remembers what the timing set to..
I called Edelbrock Tech Support, and he said they are NOT vacuum secondaries. He seems to think that the choke is sticking the secondaries closed. I can look down and see them staying closed, and he said that they should open up at WOT. Also, he said you cannot over-throttle the carb, as the linkages will stop all movement at WOT. Maybe they are just stuck closed and I need to just bump them loose. Kinda early for this new of a carb to be messing up. I might need to get a Holley sooner than I thought...
Also, timing-wise, what are each of the lines on the balancer worth, in degrees? If I am not mistaken, there are large lines and small lines, kinda like a ruller?
I had that problem with my points distributor when i was running one and beat my brains out trying ti find it. The breaker plate in the distributor was the culprit it is busshed in there and those were worn out and the advance curve would jump all over the place. You might check that pull vaccume on the diaphram slowly and check the plate for looseness as in advences and retards.
I will check that. OR just replace the entire distributor and points system... But I still "strongly" believe it is carburetor. Edelbrock tech says the secondaries should open when WOT with engine off. Mine don't. I stuck a screwdriver in there, and they move freely, just feel like they have a little counterweight to hold them closed. Backed the choke off all the way and still won't open when WOT. I think they are vacuum secondaries, despite what Edel-tech says...but I don't know the difference and I can't tell. Should I be able to make them open from the outside somewhere, some lever or rod I can move to make them swing? I am thinking that the linkage to them is broken or disconnected and I need to get in there and reconnect them. STManser...what carb do you have? Mine is Edelbrock 1406 (600cfm with no EGR and electric choke). IF yours is anything like mine, could you check and see if your secondaries open at WOT (engine OFF of course)? Or anybody else for that matter, I just know ST has a similar setup to mine. Grease, check your PMs.
Ratio...I don't give up that easily... Actually, I have really liked the Edelbrock, just a few problems with the fuel delivery, A/F mixture, WOT Can't justify getting a new carb until I have completely worn this one out. It only has 2000 miles on it, and should still be fine. Speaking of... My next carb...double pump or no, and why? I use the triangular Edelbrock air filter, that you take the element out, and wash by hand, and reuse. How much cleaner would the air be if I used a K&N round filter on my next carb? Sorry, hate to jack my own thread. :16suspect
