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

[Anonymous]

Hello. I'm really hoping you guys can help. My 67 mustang 200 is running very rich. So rich that it is dieing on deceleration and after it warms up it won't really run at all. I have wired the choke open and even switched carbs (1100) to see if it was the carb. I have advanced the timing also with no luck. I changed the plugs today. No help. I have been all through the car. New fuel pump, points, no vacum leaks.

I have no idea what to do next.

I'm thinking it may be a valve issue? The motor has less than 10,000 on a rebuild. Any ideas? I'm stumped. I have been all through the ignition system. It is running very very rich. It has a backfire on deceleration and then dies. Not a loud backfire but the kind that is in the muffler. On deceleration...pop.. pop...pop...then die. It idles fine. It is a manual trans....

Any ideas? Help!! Thanks much...

 

[BUZZ]

If its running rich it really can only be a carb issue, thats what controls your fuel flow. It sounds like you have timing or ingition problem to me.

 

[addo]

So, lets look at some basic issues:

1. Can you do a compression test on it, both wet and dry?
2. Can you check the timing with a light, and note its advance per 500RPM?
3. Can you tee into the fuel line and test pump pressure at various RPM?
4. Can you hook in a vacuum gauge and drive around a little?

 

[Anonymous]

So, lets look at some basic issues:

1. Can you do a compression test on it, both wet and dry?
2. Can you check the timing with a light, and note its advance per 500RPM?
3. Can you tee into the fuel line and test pump pressure at various RPM?
4. Can you hook in a vacuum gauge and drive around a little?

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Thanks for the replies.

1) I have not done a compression test. ( I guess that should be next?) it is a fresh rebuild so I don't want to believe it is something major!

2) I have checked with the timing light and confirmed vacuum advance
etc.

3) I have not checked fuel pressure but I did buy and install a new fuel pump just incase.

4) I do not have a vacuum gauge. Maybe I need to get one?

Thanks again....

 

[66 Fastback]

Fuel pump pressure too high?
Float level set too high?
Stuck float or trash under seat of the float valve?
Carb adjustments?
Are plugs fouled?
Hotter spark plug range needed?
Just some thoughts.
Doug

 

[pedal2themetal45]

I wouldn't be tairing the motor up yet..
I think your having carb or timing probs.
1) have you set the float level?
2) have you adjusted the air/fuel mixture?
3) If you changed points did you recheck the timing? changeing the point gap well change your timing
4) what did you gap the points at
5) did you gap the plugs before the install
6) What is the timing at idle
7) what is the idle set at
8) how did you check for vacuum leaks
9) plug wires good?

Did this all come on fast .. what was the car doing when you first had the prob?
As stated earlyer a rich condition can only be caused by blown power valve (in the carb) float to high and flooding out the carb. float to high can be check by running the motor shut it off and look down the carb and see if there is fuel dripping down the carb or is there a cloud of vapor in the carb..

Hope this helps
keep us posted
tim

 

[Anonymous]

Thanks for helping...I will answer your questions below.



Fuel pump pressure too high? Don't know...but I just installed a new pump hoping the old one was bad. No different.

----------- I put on another carb and no different at all-----
Float level set too high?
Stuck float or trash under seat of the float valve?
Carb adjustments?
----------------------
Are plugs fouled? Thay were...put new ones on today...no different

Hotter spark plug range needed? Don't know..but drove fine with same plugs for long time.

Just some thoughts.
Doug


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I wouldn't be tairing the motor up yet..
I think your having carb or timing probs.

1) have you set the float level? Put on different carb...same


2) have you adjusted the air/fuel mixture? Yes, a bunch

3) If you changed points did you recheck the timing? changeing the point gap well change your timing ---Yes I did many times

4) what did you gap the points at ---What was in the manual. Can't remeber right now

5) did you gap the plugs before the install ---Yes

6) What is the timing at idle I was running 14 seemed to help a little. lowered it to 10 today. No different

7) what is the idle set at -- by ear...many diferent settings. no different

8) how did you check for vacuum leaks ...By eye and ear...not many hoses and stuff on this car

9) plug wires good? Yes...not to old. Although, that is one thing I haven't changed in my pathetic attempt to fix the car! I guess I might as well give it a shot!

Thanks! I really appreciate the help....What do you guys think??

 

[66 Fastback]

I have had problems with floats hanging open when first installing a carb on a car. So the fact that the carbs were changed out does not necessarilly rule that out. And the float leave should be verified.
I have a dual carb car that is over-carbureted for street driving. I installed a MSD box and it cured the misfires and keeps the plugs clean. It is kind of addressing the symptons but for over 10 years I have not had to change the point or the plugs.
Are you adjusting the fuel idle screws at all when you are swapping out the carbs?
Doug

 

[fordconvert]

Here is a handy tool that anyone working on a pre 95's ish car should have. Yes you can do better but for the occasional use diy'er it has many uses. Most parts stores will have set like this. This one comes from:

http://www.harborfreight.com/cpi/ctaf/d ... mber=92474

Its a vacuum gauge, hand pump (useful for testing things like advance), plus it has that can or sucking liquids (not just brake fluid).

 

[JackFish]

I had a similar sounding problem. Found a small piece of wire stuck in the carb's inlet needle valve, holding it opening.
Also, what is the weather like where you are? I'm just wondering if there might be a chance you have some water in the gas.

 

[gtm1086]

plugged or restricted Exhaust.

 

[Anonymous]

Thanks for the help...

I'm in the bay area CA so the weather isn't too bad. I am tempted to drain out the gas just incase. I did put a bottle of water remover stuff in the tank. I have not been able to drive the car though because of the dieing.

I don't think it has a plugged exhaust. I am running Clifford header with dual pipes out. Thanks for thinking outside the box though...

I will get a vacuum gauge as shown looks good. Maybe it is the distributor? Could the distributor cause this condition on deceleration? I am running a load- o -matic with scv carb...

Here is what I will try next.

1) Take off top of carb and check flout. Although as mentioned this is a different carb and it has -- exactly -- the same symptoms as the old carb. The carb I am using is off a good running 170. Bought it from a guy doing a v/8 swap on 65 Falcon.

2) Try driving with air cleaner off. Maybe more airflow will have some effect?

3) Purchase and use vacuum gauge...

4) Maybe drain gas? What a pain....

Anybody have any other ideas? I will report back with findings....

 

[JackFish]

The water remover is all you needed, I wouldn't worry about the gas.

 

[Anonymous]

Just a thought, what's the condition of your harmonic balancer? Maybe the outer ring has slipped and your timing mark is not where it should be.

 

[Anonymous]

I think the harmonic balancer is ok? I did try and time the car by ear to see if I could get it to run better with no luck. Of course, then it screws up the carb idle mixture settings I guess so who knows?

How do I actually check the balancer? I know about removing number one spark plug + finger over hole to find exhaust stroke. Then what am I looking for?

Sorry if it is a dumb question....not really much of a mechanic I guess.

More of a remove bad part put on good part type of skill level!

 

[Asa]

I think the harmonic balancer is ok? I did try and time the car by ear to see if I could get it to run better with no luck. Of course, then it screws up the carb idle mixture settings I guess so who knows?

How do I actually check the balancer? I know about removing number one spark plug + finger over hole to find exhaust stroke. Then what am I looking for?

Sorry if it is a dumb question....not really much of a mechanic I guess.

More of a remove bad part put on good part type of skill level!

remove #1 and turn it over until you get to the compression stroke, there should be a mark on the balancer right next to the timing indicators
and i usually get the end of a coat-hanger and use it to poke inside the cylinder to verify that it is all the way up, if you're unsure if it's the compression stroke you can remove the valve cover and see if the valves are both closed

 

[ludwig]

I just poked my finger in the plug hole and turned until there was pressure. Pulled my finger out, pffft, and stabbed the dizzy. You can jockey it back and forth from there.

 

[Anonymous]

I'm starting to think it may be a plugged exhaust. I have a Clifford Header with port divider. I have had the same 1100 carb and exhaust for over 5 years. The carb has always ran rich.

Has anyone ever had an exhaust block up at the port divider? I hate to take of the header but...

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I did confirm that the distibuter points to #1 as it should on compression stroke...

 

[BUZZ]

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.

 

[66 Fastback]

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