Another thing that easy to do is pull each plug wire one at a time and see if you find one that doesn't make a difference if it's connected or not. If so, that cylinder isn't fireing for whatever reason.
Good tip, I do that too... And yes, she knew what she was getting when she buckled up with me down the road to Buickville!:3gears:
You can ohm test the wires with a voltmeter. that will let you know the condition of each wire:beers2:
I was having issues with my car back before it was on the road and I thought it was not getting any spark. I pulled a wire and asked my friend to crank it over. It worked all right :shock: next time I'll just use a metal rod and lay it against the block
My buddy Cosmic likes to hand someone the plug wire, say "hold this" and crank the starter. Works great in checking for spark. Maybe not so great in other ways. (Girls tend to be REAL funny!) JB
It's running, haven't had much time to put any miles on it lately, work and weather haven't been cooperating. I did notice a bit of a hesitation, so I am going to pull the plugs again and see if they're fouling, could all be stemming from my qjet. The carb was rebuilt over the winter, and I expect that the jets/metering rods aren't optimal for the car at this point. I'm looking at getting a wideband for the car, so I can get the carb dialed in. I'll keep ya posted!
Hey all, finally had some time off work and started tinkering around on the car. Went for a drive, not running great still. Doesn't idle properly, sounds as if it's going to stall - idle set around 700 rpm. Hooked up a vacuum gauge, bounces between 6-9". I pulled all of the plugs, they were all pretty dark except cylinder #1 which was a light-medium brown. Did a compression test, everything was between 165-175 PSI, didn't do a leakdown test since it looks like it's making solid compression, and I don't have a leakdown tester. I put out a heads up to some friends to see if I can get my hands on a functioning carb to try out, might help me eliminate the carb as being a problem at least. Beyond that, all I can think of is to go through the ignition again... any other tips?
Are you sure you dont have a vacuum leak somewhere? Also is that 700 rpm idle in gear or in park? Good luck to you.:TU:
I've checked and double checked all of my vacuum lines and ran a propane bottle in the pcv valve, around the intake and carb with no change. The cam was degreed when we installed it @ 5* advanced I was playing around with the carb and when I crack the secondary air flaps open a touch, it smoothed out and stopped puffing out the exhaust, so I figure it's over-fuelling.
Are you using a Holley carb? Have you set the idle mixture screws to get highest vacuum at idle in gear? It sounds like the engine is strugling to idle due to a rich condition.
Craig, Certainly sounds like it is pig rich. I assume by now that you have put fresh gas in it and you aren't running on an E10 that is more than 3 months old. If we are talking about a Q-jet, make sure there is no nozzle drip. Are the idle mixture needles responsive? If not, you may be running on the mains instead of the idle system. If the idle speed screw is too far in, the carburetor will start to idle on the mains, and fuel will drip from the nozzles in the center of each venturi cluster. If that is happening, advance the base timing and close the throttles as much as possible. You can also stick a small screwdriver down the vent and make sure the power piston is being held down by engine vacuum. With 5 or 6" of vacuum, it is probable popping up, and pulling the primary rods out of the jets. When the plugs get fouled, the vacuum level will drop as the engine runs worse and worse.
Yeah it's a Qjet, she smells pretty rich - fresh fuel as of a week ago 92 octane. I used a piece of wire to push down on the power piston and it didn't seem to move or change the idle so I'm guessing the vacuum is enough to keep it down. I'm going to pull the carb off tomorrow and have a look and see what's happening mechanically before I start changing rods/jets. I had a thought that maybe the secondary throttle blades are open a crack which is pulling fuel through. When I crack the air flaps a tad on the secondaries, everything smooths out and the vacuum comes up to about 10" steady, no fluctuation. I'll check for nozzle drip tomorrow morning before I take the carb off. If the secondary throttle blades are closing up properly, any suggestions on where I should be at for jets/metering rods? Carb is off a 73 Olds (7043250)
If you have been running on old fuel, that will be a problem right there. I had a problem with fuel that was 7 months old. It fouled out all my plugs, but the engine ran with the MSD. It smelled pig rich, and smoked out the pipes at idle. Vacuum was low. Lots of guys said they never had a problem, but that was mine. I drained the tank and replaced it with fresh fuel, changed my spark plugs, and everything returned to normal. The carburetor was NOT FLOODING, but the fuel was not burning right in the cylinders. With the engine off, try pushing down on the power piston. You should be able to push it down, and then it should spring back up when you let it. If you suspect nozzle drip, temporarily advance the timing and close the throttle as much as possible by backing out the idle speed screw. See if the idle mixture needles are responsive. Can you make the engine run rough, or stall by turning them all the way in?
Fuel should be OK, I have had a few fresh tanks through it already this year and I have put in new plugs since the winter fuel was in it. I noticed that the car drinks the fuel back pretty fast. Checked out the primary nozzle when I first started the car this morning, I noticed a few small droplets falling in when the car was cold. Idle is around 800 in park. With the primary air flaps wide open, the secondaries closed tight, it runs really rough, and the mixture screws don't seem to have any impact on how it runs, backed all the way out or turned all the way in. Vacuum bounces from 5-9. However, when I allow the secondary air flaps to open up to the lockout lever (lets a small amount of air through) the vacuum comes up to 10 steady and the idle smooths out. With the secondary air flaps cracked a touch, there is no nozzle drip at full operating temp. Idle mixture screws didn't seem to change anything. The power piston had some movement when the car was off, but when I started it and put a screwdriver down there to make sure it wasn't moving, it caused fuel to come up the vent tube and stall when I put any force on the screw driver. The exhaust makes me smell like I took a gasoline bath, and my eyes are kind of burning. I'm trying to get my GoPro camera charged up so I can take a video of it idling with the secondary flaps shut and with them cracked open a touch.
