SOLVED?...What makes car run waaay rich...not carb or timing

[BIGREDRASA]

Just a long shot. Have you double checked the timing order? Could you have reversed two of the plug wires?

 

[Anonymous]

Have you checked the coil?

 

[Anonymous]

The carb has always ran rich.

If this is true, then you likely need to concentrate on the carb. It sounds like you are doing the fiddle with this and fiddle with that mistakes that we all can fall into. Before long, everything has been fiddled with and the engine won't run. Pick one item, verify it is within spec and move on to the next systematically. If it is running rich, I would check the float level, float valve and fuel pressure and make sure the idle mixture screw is set properly. If it is warm enough, make sure the choke plate is functioning.
Doug

Thanks for the help...

1) I installed a different carb and have exactly the same symptoms. Anything is possible but that makes me think it is not the carb? I am going to check the float on the replacement carb though. I was thinking that running the carb rich for years may have messed up the valves or whatever...Now if I change carbs it is to late because the motor is all plugged up with crude?

2) I will check the wires just to be sure I have the right order

3) I purchased and installed a new coil.

I think I ned to buy a vacuum gauge and a tool to do a compression test. I will report back with my findings. If anyone has any other ideas please share them.

I'm going to fix this car someday! I hope

 

[Asa]

ya know, just because you swapped carbs, it doesn't mean that the new one is correctly adjusted

66 Fastback is entirely correct, when troubleshooting something, you have to start from one direction and work your way entirely through to make sure everything is correct

and if everything is clogged, you can always seafoam the engine

 

[Anonymous]

I don't think that the port divider would totally kill the engine like that, it seems to me that it would still try to run on the other 4 cyls, but I could be wrong. Are the plugs wet with gas or are they just black with unburned fuel? Does the motor sound any different at idle than it did before this started happening? The next time you pull your carb off look on the bottom side and you should see a small slot cut in it, how much of this slot is showing? The slot will be on the inside of the barrel right where the throttle blade closes. I'm wondering if the idle set screw could be in to far causing the carb to pull fuel from the main fuel circuit.

The plugs were not wet with gas just covered with black gunk. The whole plug is black including the part that is supposed to be white (center part). All of the plugs were the same. There is still a normal space between the 2 parts that the spark jumps.

The top of all of the pistons were also covered with 1/8 inch or so of black gunk. I looked through the spark plug hole and scraped with a screwdriver. That can't be good right?

The motor sounds really good at idle. The car was running great before this and was a real happy camper. It runs good for a while when I first start to drive it. Actually just long enough that I start to think it may be fixed! Then it starts to back fire (pop pop ... in mufflers) and dies on decelration.

I will look at the slot in carb as advised. Never heard of this so I will check it out for sure.

Thanks!

 

[Anonymous]

What is seafoam?

 

[Asa]

http://www.seafoamsales.com/motorTuneUpTechGas.htm

basically, start the engine and let it warm up, unplug the PCV valve hose and stick it into the can
keep the throttle up so that the engine doesn't die and hydrolock

let it run till it stops smoking, then drive it hard to get the residual liquid/vapor out of it

 

[BUZZ]

From the way you describe the amout of crud inside the engine I'd give the seafoam a try, it'll help. The slot I'm talking about is called the transfer slot it is connected to the main fuel well from which the the idle air/fuel screw pulls its fuel to make it run richer or leaner at idle. If its opened to far at idle it can cause all kinds of tuning problems. If its adjusted properly it'll only show about .020 of the slot from the bottom of the carb.

 

[Asa]

if you don't want to spring for the seafoam, you can also try using water

fill a 20 oz coke bottle with water and follow the exact same instructions as above, should do the same thing

i've heard that the seafoam can foul the plugs too, so check 'em before and after treatment

 

[JackFish]

So the engine is basically gunked up with carbon and oil and crud?
I don't think a carb swap and a can of Seafoam is gonna do it.
If you drove the car everyday I'd recommend an AutoRx treatment:
http://auto-rx.com/
You can find out more about it here:
http://www.bobistheoilguy.com/forums/
But it takes 1000 miles to work, so maybe you might consider pulling the head for a hot tank, and cleaning the tops of the cylinders by hand.
I'm sure the oil pan would be gunked up too.
Perhaps a PCV problem?

 

[Anonymous]

If you start your car and then just let it idle for an extended period of time, until it warms up, what happens? If you pop the throttle at idle what happens?
What I'm wondering is, is your problem there all the time or only when the car is in motion?

 

[grocery getter]

the fact that it runs better cold sounds like a vacuum leak, it runs better choked. does it have a pcv ? if you have a lot of crankcase pressure it will keep the pcv open and cause these problems. oil build up and poor running. a bad pcv will also be a problem.

the power valve will also open up and dump fuel in.

 

[Anonymous]

If you start your car and then just let it idle for an extended period of time, until it warms up, what happens? If you pop the throttle at idle what happens?
What I'm wondering is, is your problem there all the time or only when the car is in motion?

Thanks for the reply. The car will idle fine. It only dies on deceleration at first and then starts to run real bad and barley makes it back. It dies, I start it and drive a bit then it dies again etc...

I do have an update though. I decided to go back to basics and have a closer look at the ignition system. I only have 5 volts at the + side of coil. I should be around 8 due to the resistor wire? Seems very low and could be the cause of appearing to run rich. I bumped the starter and could only get either 0 volts or 5.

I am going to hook a 12 volt wire from the battery and try to drive it a little like that.

I had to change the pink resistor wire a few months ago. It showed around 8 volts at coil and worked great after the change. If this is bad again I wonder why?

Any ideas...

 

[Anonymous]

What would cause a lot of crankcase pressure? It is a fresh rebuild with less than 10,000 miles probabley. I have changed PCV...

 

[addo]

Crankcase pressure can come from a damaged bore, or unseated rings. I reckon you really need to check the compression on this.

 

[grocery getter]

do a compression check and get a vacuum gauge. it's money well spent, you'll use them for years. also, you very well could have more than one problem.

 

[james singleton]

According to my Manual it list a couple of things that might cause "Oil Deposits" (wet, oily coating) on your plugs: "A COMMON CAUSE IS A PLUGGED PCV VALVE, OR A RUPTURED FUEL PUMP DIAPHRAGM"
If the plugs have "Carbon Deposits" (presence of dry, soft, black, sooty deposits) it lists the following possibilities: "STICKING CHOKE, CLOGGED AIR CLEANER, WORN BREAKER POINTS, RETARTED TIMING OR LOW COMPRESSION. IF ONLY ONE OR TWO PLUGS ARE CARBON FOULED, CHECK FOR CORRODED OR CRACKED WIRES ON THE AFFECTED PLUGS. ALSO LOOK FOR CRACKS IN THE DISTRIBUTOR CAP BETWEEN THE TOWERS OF AFFECTED CYLINDERS". Good Luck! Jim P.S. Keep everybody posted when you find out what the problem is/was!

 

[Anonymous]

For what it's worth, I have the same 67 Mustang that you do and I'm measuring 10 1/2 volts, at idle, on the + side of the coil and about 11 volts at higher rpms. Not sure what it’s suppose to be but 5 volts sounds low.

Also, I had problem, one time, which was somewhat like what you’re going through. Every time I stepped on the brakes, the car would act like it was going to stall out. I would pull over to the side of the road and the car would run great and would continue to do so until the next time I stepped on the brakes. The strange thing was I couldn't duplicate the problem in my garage. I guess I replaced just about everything that there was to replace, including a rebuilt carburetor and distributor, before I found it. What it was was a loose wire on the coil! The wire was attached to the coil via a crimped connector and the connector had expanded and the wire had become loose. Apparently what was happening was when I stepped on the brakes the wire would move slightly and lose connectivity and when I came to rest the wire would move back and I would have it again. Chances are if I had just done a simple wiggle test, I would have spotted right away!

 

[Anonymous]

Thanks again for all the help. I will keep you posted on my progress. I will be taking the afternoon off work and spend some time working on the car today.

I have a new PCV valve and new fuel pump.
Your loose coil wire must have been a pain!


I does seem that 5 volts at coil is way low. That would cause weak spark and the car to act rich? Obviously, I am hoping that is the problem. If I can figure out what is wrong then fixing it is the easy part. I spent a bunch of time last night checking all the connections and going through the ignition system with my millimeter. I checked for loose wires, plug wires firing order, coil resistance, plug wire resistance, etc.

My plan is drive it with full 12 volts to coil. If that does not fix it get vacuum gauge. If that doesn't locate problem do compression check.

If that doesn't locate problem sell car to neighborhood kid for $5.00...Just kidding!

 

[JackFish]

Maybe just a bad coil...