Runs like a snail

[SteveS]

82 cougar with 200 ci engine, auto with 1946 carb.

My problems started with a failed emissions test for high HC at idle. I thought the float was hanging down. It was cracked so I replaced it. It had been running pretty crappy with hesitation and surging.

I replaced the float and got about 4 miles of really good running. Next day they same old hesitation and surging with the added engine stops running. The distractor is that when the engine stops pumping the gas pedal brings it back to life. I'm possitive the engine is not off but just gone to lower rpm. It's a bit odd to explain.

On a whim I went ahead and replaced the fuel pump. I'm not so sure how old the pump was but the new one did not affect the problem.

Any there's always fuel present in the carb and there's no problem with the accelerator pump. The engine runs great at idle and revs up with no problem.....until it's under load. This meaning the car actually moving and accelerating. Hesitation, what feels like misfiring and the ever present when I'm trying to drive a 25 or 30 or whatever steady state the engine feels like it's run out of gas for a few moments.

I'm starting to think Duraspark II problems.

Any comments?

 

[Frankenstang]

In the 'keep it simple' vane, have you changed the fuel filter lately? How about the needle and seat? The fact that you changed the cracked float and it seemed to help for a few miles would point to a fuel issue. Really sounds like junk/contaminents in the tank, filter, or carb (on the needle seat).

As far as high HC's go, does this have a catalytic converter, and is it in good shape?

 

[66 Fastback]

A few things to check.

Carb:
Is the float level correct?
Is the choke set and operating properly? Maybe it is sticking.

Ignition Timing:
Does the vacuum advance diaphram hold a vacuum and does it function properly advancing the timing?

Have you set the ignition timing properly?
There is a possibility that the harmonic balancer has slipped and the timing mark is not actually at TDC #1 cylinder any longer.


Vacuum Leaks? Check for leaks on the other hoses etc.
Does the engine have one of those thermo-vacuum switches that change the vacuum source after the engine coolant has warmed up? Are all of those lines in place and does it work?

EGR System:
Maybe it is not functioning. The valve could be sticking or the vacuum diaphrams could be leaking etc. This could cause some hesitation or pinging.

Plenty of possibilities.
Doug

 

[fordconvert]

Plugged cat converter?

 

[PaulS]

I am surprised that nobody has called out a problem with fuel contamination. Our gas is mixed with alcohol and if water gets into the fuel tank the water and alcohol separate out of the gas. Since it is heavier than the gas it builds up on the bottom of the tank until the pick-up is covered. Then you get "running out of gas" symptoms. Pumping the pedal richens the mixture enough to make a mixture that will burn - for a short time. Try draining some fuel from the tank into a glass jar - if it looks like water on the bottom and gas on top then you know what your problem is.

 

[SteveS]

Wow. All good advice. I have checked all these things multiple times and even changed the carb for a known good one and the symptoms remain the same. The EGR system has been taken all apart and inspected, cleaned and verified correct operation including the VDV (vacuum delay valve) working at 200 + or - 40 seconds.

The emissions inspection failed for high HC only on the idle test. It was 1020 ppm. This is when I discovered the cracked float. At 2500 rpm it tested at 38 ppm well within the 120 ppm allowable.

The reason I was thinking ignition is that the fuel system is correct to the point of the swapped carb, new filter, new fuel pump only because the Motor Manual had most of the symptoms covered by the fuel pump. I thought the volume was OK but maybe the pressure was too low.

And of course that as the saying goes 80% of carb problems can be attributed to ignition. I think I've done enough to the fuel system. I think the ignition is the last place to look. For less than $100 I can replace the whole ignition system. I just hate to throw money at a problem.

I don't regularly get defeated by this stuff. This problem has me stumped and that's why I was thinking ignition and hoped to get some ideas. At least I don't depend on the car for transportation. But I do have to get it solved by Nov 30th. That's as far as the registration extension goes. California doesn't take you off the road for a failure. They give an additional 2 months for repairs. As long as they get their (our) money they are happy.

 

[fordconvert]

Good point Paul. A friend was working on his boat the last few days and turned out to be water (or something non flammable) in the fuel. The glass test usually works pretty well.

 

[JackFish]

If you had water in the gas it would sputter a lot.
I have suggested adjusting the accelerator pump to you already.
Did you try that?
Another thing that can happen with these carbs is the idle enrichment valve can get sticky, or worse, the c-clip that holds it in can fall out..

 

[ludwig]

You know, in Ridgecrest, you have a lot of up and downhill driving, changing altitude, etc. Plus you have wider temp swings than down on the coast. All this pulls more air in and out of the fuel tank. I wonder if it is some kind of contamination in the tank due to condensation, i.e. water. The diagnosis would be a fuel additive to bind the water or the glass jar test. The solution would be to drain the tank and get a fresh fill up.

 

[SteveS]

I talked to Holley this morning. It seems that the carb I got is probably remaned by Tomco and that Holley bought them out. There were are some issues such as the vacuum port next to the accelerator pump linkage is wrong. I found this and fixed it. It also had a 3/8" heli-coil laying in the bowl and the mixture screw allows the engine to run whether it's all the way in or all the way out. Very strange.

It's going back and Holley promises to provide a better quality job since Temco in not in the picture anymore.

Then and only then will I be able to accurately troubleshoot the problem. If the fuel was bad, which I'm convinced it's not, it would run bad all the time and not just while driving. Plus the tank won't rust. It hasn't yet after 26 years. It was a daily driver up until March and the tank is always full.

They symptoms are the same with both carbs and it was a suddon onset of problems that is now getting worse. This weekend I'll to some exstensive troubleshooting on the ignition side. Either while waiting for a new carb or after I install a new carb. Whichever comes first.

I haven't had the chance to really look at the coil and ignition box and check voltages and resistances at all in the last two weeks. Either way it will be solved. I will be sure to post my findings but first I have to get past the carb issues. It's really a bugger to get a quality 1946 especially when I thought I was getting a Holley reman and turned out it was not at their admission. The paper work all looks Holley but apparently they used to sub out the work. They say they don't anymore.

There is NO alternative for this car in this state.

 

[LaGrasta]

forgive me as I only breezed through the post, but my guess is "advance".

 

[SteveS]

forgive me as I only breezed through the post, but my guess is "advance".

Advance is on the list. All I can say is the vacuum advance is working but who knows about the mechanical springs etc.

Once I get the carb squared away everything will get checked. I haven't had a new car in 17 years so these old ones aren't going to beat me!!!! I won't have it. I'll beat it....:deadhorse: :arg:

 

[66 Fastback]

If you are just looking to pass the smog test, retarding the timing may help. It would raise the temp and help burn the HC's.

But you still have drivability problems.
Since the fuel mixture screw seems to have not effect, is the curb idle screw backed out enough so that the throttle plates close fully? Are the throttle plates hanging up on something? Maybe they are not centered in the bores. Open throttle plates would make it so it is not running on the idle fuel circuit and adjusting the fuel mixture screw would have little effect.

Someone familiar with 1982 models may have to chime in, but did they also have throttle solenoids etc to help hold the idle speed up at idle or with the A/C on?

Just a thinkin' out on it.
Doug

 

[JackFish]

The helicoil inside it may have been from the rebuild.
It's pretty common to strip and helicoil the float bowl threads and I have found that the helicoiled remans become loose and fall out.
And loose vacuum fittings will obviously cause timing problems.

 

[SteveS]

Well it's boxed up and going back. Holley recommended an exchange. I also noticed that the bowl had drained itself in the last 48 hours in to the intake manifold.

It's definately part of the problem. I'm hoping for all the problem but I have a feeling that there's something amiss with the ignition module. I have to get the fuel system working first.

I knew I'd get spot on advice here. I knew I was jinxing myself buying new tires before the emissions test.

 

[fordconvert]

Ignition modules dont tend to sort of work. Most of the time they are like all 'digitial' things all or nothing. Exception would be heat issues causing them to die and then come back when they cool (for a while at least). Something you could check is the wires that come from the coil under the rotor and eventually go to the module (finned box on the fender). As the vacuum advance operates (when engine loads change) it rotates the pickup coil and flexes those wires. If you loose the connection there will be no signal to spark the plugs so engine begins to die which changes the vacuum signal and the broken wire may make contact again so it comes back. This was very common with GM because they used little tiny wires but could also happen to the DS2's with enough age and miles. You can hook a voltmeter between the orange and purple wires and flex the harness around also operate the advance with a hand pump and look for drops.

 

[SteveS]

Ignition modules dont tend to sort of work. Most of the time they are like all 'digitial' things all or nothing. Exception would be heat issues causing them to die and then come back when they cool (for a while at least). Something you could check is the wires that come from the coil under the rotor and eventually go to the module (finned box on the fender). As the vacuum advance operates (when engine loads change) it rotates the pickup coil and flexes those wires. If you loose the connection there will be no signal to spark the plugs so engine begins to die which changes the vacuum signal and the broken wire may make contact again so it comes back. This was very common with GM because they used little tiny wires but could also happen to the DS2's with enough age and miles. You can hook a voltmeter between the orange and purple wires and flex the harness around also operate the advance with a hand pump and look for drops.

You bet! I'll jump right on that. It is acting strange and until I get the carb correct I'll not know. But this I can do while waiting for the carb to come in. I hadn't thought of that.

Thanks.

 

[SteveS]

Everything under the hood checks or tests good. All wiring, all voltage, all resitance checks.

The tank is comming out this weekend to check for blocked pickup and screen.

Wish me luck.

 

[JackFish]

You should be able to remove the fuel sender without dropping the tank.

 

[66 Fastback]

I have checked all these things multiple times

Have you specifically verified that eh balancer and timing mark has not slipped? Does TDC indicated correspond to actual TDC compression stroke in #1 cyl?

How is timing set? With a light or vacuum gauge etc?
Doug