200 c.i. with auto trans rough idle problem

Altho it seems like fuel pressure probs I'm still thinkin there's some fruitful research at the below reference (the "Handbook" as well):

bubba22349":3tt2plue said:
There isn't much if any vacuum advance at idle and :unsure: Yes yours is a very common problem. Most newcomers to these early Ford six'es just don't understand how the distributor (LOD) and carb's (SCV) work together, it's not the same as the typical vacuum advance systems and requires some different testing. There is an excellent article that will help you in getting to know how they should work ( see below link) and then you will be able to figure out what's causing the problem. When everthing is right and in good condistion a 200 will idle smooth down to 525 - 575 RPM in drive many even lower. Have you done a compression test yet or tested the plug wire resistance? Good luck :nod:
http://www.classicinlines.com/Loadomatic.asp
Stock 1966 Ford Mustang tune up specs
Plugs are gaped to .034, Points are set to 39 degrees Dwell or gaped them to .025,
Base timing is 6 degrees BTDC with a Manual trans or 12 degrees BTDC with a Auto trans, Idle RPM in drive (AC off) 600 RPM (650) with Manual trans 525 RPM (575) with an Auto trans. Numbers in (575) are for engines with California Emissions.
Click to expand...
Still, a pic would help ID ur system.
Keep talkin ~
 
Hi, inspect the fuel line from the sender all the way to the fuel pump for a cracked hose, connection, pinch, etc. Good luck
 
Ran car today to check fuel tank. Started at 4-5 lbs pressure,after 10 minutes pressure dropped to zero.

Engine continues to run. Stopped engine and disconnected fuel line at pump...blew 20 lbs air pressure back thru

the fuel line to the tank..reconnected the line...still zero. ?????????? Put car up on ramps and checked every inch of the fuel line

for kinks or bad spots. Gas line and tank are almost new as they were replaced during restoration,so I found nothing there. Waiting now to burn enough

gas out to drop the tank to take a look inside. Car still runs...just WILL NOT run smooth at 600 rpm in drive. Must be 700 - 750 in drive.

Mystified...
 
I cannot get into the Classicinlines site using the link....the site keeps demanding a user name and

password and I can't find a path to set up an account. FEH ! I know my distributor is not the original

one. I don't think it has centrifugical advance because there are no springs on the breaker plate.

Vac advance works when revving the engine and watching timing light. There's no vac advance at idle.

There is no spark valve on the holley 1940 carb.
 
Hi, your car may not idle that low, but it should. I don't understand 0 fuel psi. You would run out of gas. Are you using an inline fuel gauge or a vacuum / fuel pressure gauge. What kind of vacuum readiing do you have. If you have low or fluctuating vacuum you need to look at that. Maybe some little problems are stacking up. Good luck
 
If you want to fix your problem, get a looser torque converter & contact me for a distributor that will fix your problems. What camshaft are you running???
First you need to fix your fuel pressure condition, V/R Bill
 
B RON CO":2k0ezd9p said:
Hi, your car may not idle that low, but it should. I don't understand 0 fuel psi. You would run out of gas. Are you using an inline fuel gauge or a vacuum / fuel pressure gauge. What kind of vacuum readiing do you have. If you have low or fluctuating vacuum you need to look at that. Maybe some little problems are stacking up. Good luck
Click to expand...

The fuel pressure gauge I'm using is placed inline just ahead of the carburetor. It is liquid filled and has fittings for hoses on each end.

On cold startup it reads 5-6 lbs. As the engine warms up pressure drops to zero and a very small amount of gasoline is showing in the
clear glass filter...fuel flow is just a little over a trickle. Last time I checked vacuum it was 13-14.
 
wsa111":kej2zc85 said:
If you want to fix your problem, get a looser torque converter & contact me for a distributor that will fix your problems. What camshaft are you running???
First you need to fix your fuel pressure condition, V/R Bill
Click to expand...
Can you explain what you mean by a "looser torque converter" ? Also what type of distributor would I use that has vacuum advance and
centrifugical advance? I have power steering and a DUI type distributor will not fit. I don't want to go to the expense of redoing the pump.

The camshaft is a COMP CAMS F65 260H-10. Part # 65-236-4. A mild performance upgrade from stock. It was in the engine
when I bought the car so I know nothing as to how it was installed or if all proper steps were followed by whoever installed it.

What carburetor would I have to use to replace the Holley 1940? Would a distributor change allow me to keep the 1940 ?
 
Hi, you need constant fuel pressure of at least 5 psi. And you should have more vacuum. Check every possible location for a leak with carb cleaner spray. All vacuum hoses and ports including the carb base and vacuum modulator on the transmission. I would temporarily plug the PCV and power brakes at the manifold and see if your vacuum improves. Maybe your lifters are set too tight. I think you have more than one problem, go after them one at a time. My guess is your fuel pump is sucking air, so I would redo the hoses just to be sure. Good luck
 
The last few days have been spent checking various parts of the car and engine.

Fuel lines are secure with no leaks or kinks in the steel line. Pressure gauge still shows 0 even with the gas cap off.
Installed a large,cheap,swap meet type clear fuel filter just in front of the carb. It holds more gasoline than the smaller stock one and seems to improve performance
a little bit. It still will not stay running under 650-700 rpm in drive. Believe I will have to invest in a new carburetor. Any suggestions ?

New set of spark plugs installed. Tested vacuum advance again...noticed it was retracting with a "click" when vacuum was applied.
Would not fully return to the normal position when released,had to move the breaker plate by hand..with a "click" when returned to normal position.
Did this consistantly.

Removed vac advance and discovered the plunger was hanging up on the diaphram housing. The hole in the housing and the lever were the SAME size,
and the lever would hang up when vacuum was applied. Hogged out the hole in the housing and now it works as it should. Set Petronics to .30, Timing to 14 BTDC.
Ran good at this setting. Upped the timing a little more...the pulley mark is now above the timing scale on the engine. Runs great at this setting with no detonation on premium gas.
The defective vac advance was hanging up...changing timing..changing idle speed..driving me nuts till found it.

My question is...Do engines with non-stock camshafts need MORE initial advance than when running a stock cam? There's a dramatic improvement in performance as a result of fixing the
vac advance and setting the timing about a 1/2 inch above the timing scale.
 
( I haven't been following for awhile but: )
these wrk well w/combined advance: 30 to 34*.
 
I'm running the same comp cam part number 65-236-4 ,
HYDRAULIC − Good for towing in 200-250c.i., mid-range torque and power. Smooth idle.
Hyd. , rpm range 1000 to 5000 260 260 / 212 212 / .440 .440 / 110°
with my 200 and a C4 trans and am kinda of having the same problem, idles fine , motor ran great on the dyno but when you drop it in to gear it stumbles and pukes on it's self. idle is set about 800 rpm's and if you choke it and get the idle up it seems to do better, used some carb cleaner and dont seem to have a vaccum leak. running on of the classicinline daytona unversal replacement 1brl carbs, at idle thou vaccum is reading only 12 but once you get about half throttle you'll get 20 on the vaccum gauge. checking the specs on the cam it gives a rpm range of 1000 to 5000 , timing is at 17 degree's had a recurve done on the dist by Faron Rhodes. I just finished the interior on the falcon so now working on getting the small stuff done and tuning it so I can drive, any suggestions would be helpful
 
Not OP:
idles OK?
wont run in gear tho?
have U set up the TV cable correctly?
ck on-line - some great vids!

Now back to OP - he can't get a good idle
Look in Performance Handbook (buy frm Matt at VintageInlines.com ~ $20 on-line, while waiting = go to free on-line source Classic Inlines Archive on any of our site's Index pages & locate ur carb there. )
Back later when you've gotten up to speed on the ins'n outs of the fuel system & ignition.
Follow bubba's suggestions on how to post pic and we can assist.
Hope 2 C U on a regular basis @ that point… U might not even need us if U look @ the 2 sources I've cited!
 
Never considered the TV cable,the book is going to be part of my library soon.

The TV cable on my car has about an inch of slack in it with the car in Park. 1-2 shift

is sometimes sharper than other times. How would this affect the idle when in drive?

Tore down the carb 2 days ago to readjust the float level.Discovered a small piece of

clear cellophane stuck in the inlet needle valve. Reset float to slightly lower,reassembled

the carb and I'm back on the road.Still idles rough below 600 rpm in drive.

Considering going to a nearby Electrical shop for an ignition check. I think the Petronix

may not be getting the voltage it needs.

Thank you guys for all the help you've sent my way. Will keep posting any progress I make.
 
To falkon...We are suffering from the same problem.Reading your post leads me to believe the
Camshaft may be what is causing it. This just guessing here,but my belief is that a carburetor needs
a certain amount of vacuum to operate properly (idle). If the pushrods are just a bit too long the valves
will not remain closed long enough to build required vacuum. This something I intend to check in the future.
This is just a theory on my part.Hope someone reading this can set me straight if I'm right or wrong here.

Another guess is that the power valve in my 1940 carb needs to see 13 to 15 inches of vacuum to remain
closed.Mine idles at 12 to 13 inches of vacuum.When set at factory rpm's in drive..my car will idle for about 8 to 10 seconds
before it starts to run very rough.Guessing that there is not enough vacuum to hold the power valve closed,
and it begins to dump extra gas into the engine.Engine smooths back out when placed in neutral.

I did not install my camshaft,bought the car restored.This is an area to explore for me to measure the valve
to rocker arm setting.

Was thinking about replacing my Holley 1940 with a Daytona Carb,but you have the same issue using one
of these. Says to me it's not the carb that is causing the problem. Going to have a Professional electrical
scopeout done in the near future.Running Petronix and the problem may lie there.
 
:unsure: You can always go to a power valve with a lower rated vacuum rating so it will close at a lower vacuum amount.
Good luck.Have fun.Be safe.
Leo
 
Woodbutcher....How would I go about finding such a power valve? Who would I contact to get parts for a Holley 1940 carb?

I realize these parts have to be somewhere in this country,but who has them,and are they sold by commercial interests or by

individuals who deal in these old carbs?

I would be very interested in trying this,as I believe this is my problem.

Thanks for the input,I will be checking this out.Will post progress.
 
my motor was built by a very knowledgeable old racer & engine builder so I know the pushrods are right we ordered specific length ones to match to the motor. I need to do some reading up on the adjustments for the Daytona carb thou. Also I do know it need good high teat gas from the dyno test, I'm at about 9 1/2 to 1 compression, got to fill the tank with some non ethanol with some race fuel and see if that helps, mine seems to be very cold natured to. Hope to get some time on it tomorrow
 
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