here's a poser for you guys that isn't really answered in the archives. My car is missing under load. Starts and idles fine, goes down the road 1200 to 2000 rpm , no problems. as soon as i step on it or try to accelerate going up a hill. it misses about every second or two. I have checked the dwell = 26ยบ. plug wires are essentially new and not crossed or touching anywhere. all wires are pluged in snugly. I have a fuel filter (plastic see thru) that is slightly rust covered but there is no crud chunks visible in it. I did notice that it was empty when I looked at it running. I am going to change that out as it's probably due. I don't think that is the problem as the carbn has two float bowls full of gas. The miss starts almost immediately as I step on the accelerator. (Accelerator pump maybe?) Give me your guesses. Winner gets a hearty thanks and a bourbon on the rocks the next time I see you in a bar. I'm off to get a fuel filter. Thanks Bob___
Vacuum advance not advancing? Accelerator pump would be more obvious, it would stumble as soon as you press down the gas pedal. Is you vacuum to the dist. straigh from the carb or going through the ported vacuum switch on the t-stat housing?
I would go through and check Plugs, wires, cap, rotor, coil. I would have to be there to really know though, just doesn't sound like a fuel problem
got a timing light? Point it down at the timing marks and see if it advances the timing. Then remove the vavuum from dist. and cap it off and check with the light again. Should still advance some with the mechanical advane but not as much. If advance is the same then bad vacuum advance. If it dosnt advance without the hose on then the dist. mechanical advance is sticking.
Coil is failing. Or you have a fuel delivery problem, I would check the fuel pickup in the tank, Uphill missing tells me the sock has fallen off the pickup tube and you are starving for fuel...Good luck!!!
It's a brand new sending unit . 100 miles or so on it. I do think it's something electrical. I've got some things to check. I'll let you know. and hey, that's not well bourbon either.
Sounds elec.( Secondary ign ) to me, possible plug or wire! or even carbon track in distributor cap, Even new parts can fail or plug could have gotten cracked during install and spark could be going to ground under load. Don't sound like fuel prob. to me!
Take a timing light and clip it onto each plug wire one at a time. Watch the fash pattern when you rev it. if one spark plug is misfiring it will be noticable in the flash of the timing light. Lots of ways to use a timing light to diagnose ignition problems.
Bob You said the dwell is 26 deg. are you still using points ? If so check if the dwell is stays at or near 26 deg. as you raise the RPM from idle to 2000 RPM . If the dwell falls off or drops or moves all over the place the top end if your dizz. is worn out. Next remove the dizz. cap and see if you have side play in the upper shaft . If so replace or rebuild dizz. The dizz. shaft is 2 piece shaft . the lower shaft is in the case . the upper shaft set on the lower with bushing inside and is part of the mechinal advance. This bushing will wear with the side pressure from the points causing the dwell to drift all over the giving you a miss under a load. Let us know if it fixes the problem.. Jay
Good info Jay. I have gone through quite a few reman. disttributors because they did not replace the bushing or the plate was loose and the dwell was bouncing around under load. I returned 3 of them before I got one i liked for my 70 F-100.
my car is awesome off the line..get up to around 35 and above and whenver i got on it the car would miss all over the place. especially up hills! I had just done all the wires and everything else i knew was in top condition! i was completely confused as to what it was. I changed the jet size to a bigger one and then it completely fixed the problem. the jets were only a few bucks so you might give that a try. my car just simply wasn't getting enough gas to go uphills fast or take off when im already up on speeds. just another possibility for you to look into
I had a very close look at the wires yesterday. I found one of the metal connectors had gotten bent and was not getting good contact inside the dist cap. That fixed that problem. It still bogs down ,sometimes, under load but the missing is fixed. I changed t5he jets in rthe carb to the smallest ones I could get. I had a very rich running car. fouled plugs etc. That has stopped but maybe I'll got up 1 size and see if that stops. First though, I'l check to see if the accel. pump is working properly. I am saving this thread in my favs as it gives a LOT of good suggestions to current and future tuning problems. To whom do I owe that bourbon? I'll buy all of you one if we ever get to a bar. heheh
