Top-End Problem
#1
Top-End Problem
I have a 1965 conv. with a 289 2 barrel. I am having some top end issue I cannot figure out. Please HELP!!
The car idles on only four cylinders, and it is the four that are “fed” from the driver side barrel. The four on the passenger side barrel will not fire at idle, BUT when I gun it and actually drive the car, I feel like all of them are firing (but obviously can’t check then.) Also- when I spray carb cleaner into the passenger side barrel, the engine revs and seems to be firing correctly. Intake manifold gaskets not believed to be the problem. We have had the carb on the bench and it seems to be working (the jets are weak, but gas is going where it is supposed to.) Is this a vacuum problem? Could it be the intake manifold? Please someone give me some things to check see what’s causing this. Thanks! Doug in Athens, Georgia.
The car idles on only four cylinders, and it is the four that are “fed” from the driver side barrel. The four on the passenger side barrel will not fire at idle, BUT when I gun it and actually drive the car, I feel like all of them are firing (but obviously can’t check then.) Also- when I spray carb cleaner into the passenger side barrel, the engine revs and seems to be firing correctly. Intake manifold gaskets not believed to be the problem. We have had the carb on the bench and it seems to be working (the jets are weak, but gas is going where it is supposed to.) Is this a vacuum problem? Could it be the intake manifold? Please someone give me some things to check see what’s causing this. Thanks! Doug in Athens, Georgia.
#2
OK, THE DRIVERS SIDE OF CARB FEEDS THE PASSENGER CYLINDERS AND VISE VERSA. REMOVE THE IDLE MIX SCREW FROM THE OFFENDING SIDE OF THE CARB AND SPRAY CARB OR FLAMMABLE BRAKE CLEARER IT USING THE LING THIN NOZZLE.
REINSTALL SCREW. BOTH SCREWS SHOULD BE AROUND 1 1/12 TURNS OUT ON A STOCK CARB OR AROUND 3/4 TURNS OIUT ON MOST HOLLEYS.
IF THAT DOES NOT FIX IT AND THE VCARB IS STOCK THEN REMOVE THE METERING BLOCK IN THE VENTURIS. IT IS HELD IN BY A BIG SCREW IN THE CENTER.
POKE A STRAND OF WIRE FROM A PIECE OF SMALL ELECTRICAL WIRE THROUGH ALL THE HOLES INCLUDING THE LITTLE SPRAY NOZZLES.
USE THE LONG SPRAY CAN NOZZLE AND BLOW THEN ALL OUT INCLUDING THE LONG BRASS TUBES.
NOW STICK THE NOZZLE INTO THE 2 HOLES ON BOTH SIDES OF THE CARB BUT DO NOT SPRAY THE CENTER SCREW HOLE.
REASSEMBLE AND SET IDLE SCREWS. IF ONE OF THEM DOES NOT AFFECT THE IDLE THE IDLE CIRCUIT ON THAT SIDE IS STILL PLUGGED.
REINSTALL SCREW. BOTH SCREWS SHOULD BE AROUND 1 1/12 TURNS OUT ON A STOCK CARB OR AROUND 3/4 TURNS OIUT ON MOST HOLLEYS.
IF THAT DOES NOT FIX IT AND THE VCARB IS STOCK THEN REMOVE THE METERING BLOCK IN THE VENTURIS. IT IS HELD IN BY A BIG SCREW IN THE CENTER.
POKE A STRAND OF WIRE FROM A PIECE OF SMALL ELECTRICAL WIRE THROUGH ALL THE HOLES INCLUDING THE LITTLE SPRAY NOZZLES.
USE THE LONG SPRAY CAN NOZZLE AND BLOW THEN ALL OUT INCLUDING THE LONG BRASS TUBES.
NOW STICK THE NOZZLE INTO THE 2 HOLES ON BOTH SIDES OF THE CARB BUT DO NOT SPRAY THE CENTER SCREW HOLE.
REASSEMBLE AND SET IDLE SCREWS. IF ONE OF THEM DOES NOT AFFECT THE IDLE THE IDLE CIRCUIT ON THAT SIDE IS STILL PLUGGED.
#3
Barnett468- Thanks - this gives me a few things to check this weekend. In checking the "firing" valves - there are 2 on each side that are working, 2 that are not. If it is accurate that driver's side barrel feeds all passenger side valves, I have a different problem, or additional problem. (hell - maybe I have a couple of pairs of plug wires in the wrong order) We wired the stock carb (both jets) and media blasted the thing in and out when we had it out of the car. I appreciate the advice very much and will let you know how it goes. Thanks again. Also- I should have put it in original question, but I could run passenger idle screw all the way in with no change, and doing that to driver side killed engine completely.
#4
I am suspicious of your findings because I am under the impression that there is no way a 289 could run for any length of time on only one bank of cylinders let alone idle....period.
how did you arrive at this conclusion?
Despite this I also believe it it a carb issue.
could you tell us the make of the carb?
Could you please provide photos of engine and distributor and plug wires?
-Gun
how did you arrive at this conclusion?
Despite this I also believe it it a carb issue.
could you tell us the make of the carb?
Could you please provide photos of engine and distributor and plug wires?
-Gun
#5
Check firing order again. 1- 5 - 4 - 2 - 6 - 3 - 7 - 8.
The cyl numbers are on the intake.
Do I get a complimentary set of beautiful artisan designed faux wood handled steak knives with decorative paper doilies now?
#6
Please provide a credit card so we can bill for the proper 'shipping'. Western Union also available.
Last edited by racer_dave; 03-27-2014 at 08:07 AM.
#7
OK- I am obviously neither a mechanic nor a photographer, but I have attempted to upload some pics. The "4 Cylinders" belief is from pulling the plugs from the distributor one at a time and not "detecting" any appreciable change in engine performance with my five senses (I know - not exactly science down here in Georgia). The wires with a yellow drop of paint are the 4 I think to be going to the "not firing" valves. Which seem to be the middle two on the driver side numbered 7 and 8 on the IM, and the front and back cylinders on the passenger side, which I cant read because of the crud on the engine. Before anyone starts - this car sat in a barn since 1991 and I haven't gotten around to cleaning it yet...
Cant help with knives or doilies, but if you need a divorce in Georgia, I will cut you a great deal....
Doug
Cant help with knives or doilies, but if you need a divorce in Georgia, I will cut you a great deal....
Doug
#8
you had all 4 wires off at once or did you replace them directly after checking to see if it made a difference.
What I see is the potential for lots of small dirt particles in the fuel
What I dont see is a fuel filter.
If the engine runs well you say at higher throttle settings its a safe bet the idle circuit is plugged up
But before you get into rebuilding the carb put an inline fuel lifter on the soft line from the fuel pump that runs to that hard line...unless its hard line all the way to the fuel pump then there should be a piece of soft line from the from the fuel pump to the fender apron. replace that softline with a nice new one and put the fuel filter in there.
Then remove the idle screws and spary them out with carb cleaner and try again...
THe cylinders that you think are not firing remove the spark plugs from those cylinders and take photos of the spark plug...the part of the plug that goes into the engine is what we want to see...
Im guessing on multiple issues here
-Gun
What I see is the potential for lots of small dirt particles in the fuel
What I dont see is a fuel filter.
If the engine runs well you say at higher throttle settings its a safe bet the idle circuit is plugged up
But before you get into rebuilding the carb put an inline fuel lifter on the soft line from the fuel pump that runs to that hard line...unless its hard line all the way to the fuel pump then there should be a piece of soft line from the from the fuel pump to the fender apron. replace that softline with a nice new one and put the fuel filter in there.
Then remove the idle screws and spary them out with carb cleaner and try again...
THe cylinders that you think are not firing remove the spark plugs from those cylinders and take photos of the spark plug...the part of the plug that goes into the engine is what we want to see...
Im guessing on multiple issues here
-Gun
#9
Hi Gun- This survivor sat in a shed in the Ga Sun for 23 years. The gas in the tank / lines / carb / was roughly the consistency of molasses (what was not dried hard that is) I replaced the pump, tank, hard line, and filter, and the filter is actually there, just lower and out of the pics.
The 4 wires were off one at a time, with no noticeable difference in idle, and then replaced before the next one was removed.
I will take off the passenger side idle screw tonight and work on it.
Also- Plugs and points were replaced before initial starting of the engine - so I think the four "not firing" will look pretty much like a new spark plug - still any reason to pop them, or just keep focus on idle screw for now?
I really appreciate the feedback!!
Doug
The 4 wires were off one at a time, with no noticeable difference in idle, and then replaced before the next one was removed.
I will take off the passenger side idle screw tonight and work on it.
Also- Plugs and points were replaced before initial starting of the engine - so I think the four "not firing" will look pretty much like a new spark plug - still any reason to pop them, or just keep focus on idle screw for now?
I really appreciate the feedback!!
Doug
#10
if plugs and points were replaced then no there is not at this time a need to remove a plug...I figured that the plugs looked like the rest of the engine and if fowled could prevent a cylinder from firing as well.
another test would be to check the temps of exhaust headers best with a non contact temp gun...Or by using small drops of water. Start the engine and see if any of the headers are running very cold see if drops of water boil or not or with the temp gun. if one header boils a drop rapidly and one does not that is an indication of a dead cylinder.
I think the carb will need to be fully disassembled before you can locate the blockage but try the idle screw first.
That said I also still think its a plugged idle circuit.
-Gun
another test would be to check the temps of exhaust headers best with a non contact temp gun...Or by using small drops of water. Start the engine and see if any of the headers are running very cold see if drops of water boil or not or with the temp gun. if one header boils a drop rapidly and one does not that is an indication of a dead cylinder.
I think the carb will need to be fully disassembled before you can locate the blockage but try the idle screw first.
That said I also still think its a plugged idle circuit.
-Gun