Choke thermostat /RAGE

-
Nappa82

Nappa82

Well-Known Member
Joined
Feb 18, 2012
Messages
174
Reaction score
6
Location
united states
225 3.7 slant 6
holley 1bl carb


Would a faulty choke thermostat cause the car to die while at a stop light or stop sign? Fast idle screw is useless if the choke don't move haha. Everything else seems to be in tip top shape.

Grabbed a good carb off billgrissim today (Great guy btw). Installed carb, new plugs and reset the timing. Idles perfect now in P or in N. Soon as I place it in D I have to give it gas or it will die. No leaks to be found all vacs work fine. Car runs fantastic.

Any ideas are welcome at this point haha.
 
I think I would still suspect a vacuum issue, but the choke is easy enough to check. Just warm up the car and then unhook the choke thermostat and wire the choke open. If that doesn't solve the problem, you know you've got something else to check.
 
Sorry I haven't responded in a while. Everything is working ok so far for the past week. I started from scratch. Pulled the dist. realigned to TDC set the timing, dwell, idles and everything is now in working order.
 
To update, we first checked the Holley 1920 he had on the car. It looked fairly new, with maybe a rebuilder's label. A shot of starter fluid sped up and smoothed the idle, as did closing the choke. The idle adjustment was full out. The engine slowed down and shook in D. Seemed lean, just like my 69 slant always ran until I finally got a good carb. We put on the 1st Holley 1920 I had, and didn't seem any better. That one looked OK, but the idle screw seemed to stick too much into the bore. We then tried the almost new looking Holley 1920 I recently got at Ecology in SoCal. It still had the plastic cap on the idle screw to limit movement. It idled fine in D, though not as smooth as my 69 slant with its final carb, nor my 64 slant w/ a BBS. Not much adjustment was allowed on the screw and it seemed slightly better at the max rich. A shot of starter fluid didn't change the idle and closing the choke seemed to make it slow down, so seemed like the mixture was fine. He bought that one. I have never used either carb and don't know their histories.

However, the smooth idle went away later after a test drive. I originally checked the timing as 10 deg BTDC, which is fine. When I tried again, my clamp-on timing light would only flash occasionally on #1, but flashed OK on #2. I put an in-line spark lamp on #1 and the flashes seemed dim. The dwell was a bit high at 55 deg. I measured ~6 V at the coil (running), when should be ~8 V (recall). Looks like he followed thru on replacing the points and checking the ignition wiring. I suggested keeping an eye out for an electronic distributor. Re-routing and/or insulating the fuel line across the engine might be needed for those 110 F summer days in Sacramento.
 
Yes Bill thank you very much for the help and everything youve done for me. I did take your advice and set the points, checked wiring, replaced plugs and did a full timing on it. After tinkering with it and making sure the dwell and RPM's were good (Thank you for the meter for checking both of those it worked amazingly) everything runs great. New fuel filter on today and also a new air filter will complete the car for now I think. Havent had a chance to look into HEI conversion yet (Life is killing me right now) but I will be able to soon enough.

EDIT: Yea I suck at updating haha.
 
base timing at 10 degrees is the factory setting based on real gasoline. You'll need to jack the timing up and maybe lower curb idle afterwards.
 
Well well. Its been a few weeks. I have rebuilt carb, replaced carb, rebuilt that carb, changed plugs and wires, changed coil, replaced fuel filter, adjusted timing, adjusted fuel/air, valve adjustments, and messed with the choke. No vac leaks or any leaks of any kind that I can find.

While in P or N it idles fine. When placed into drive and the gas is pressed it will stutter like theres no fuel and die.

While driving there is a slight stutter like there is air bubbles interrupting the fuel flow. This is felt at a steady speed on highway or in town.

Stopping at a stop light or sign it will slow down and idle perfect. As soon as gas is applied it will die.

Gas peddle feels like it gives too easily. Sluggish acceleration. I can floor it and it will just gradually gain speed.

Could this be the fuel pump? Disconnecting the fuel line from the carb the gas that is in the line shoots out.

The car is very hard to start sometimes.

I can't wrap my head around what could possibly be causing these issues.
 
Heres a list for you. 1. intake leak 2 . fuel volatility 3 .water in gas 4 . clogged air bleeds or passages 5 . dist. vac. advance 6 . timing 7 .accelerator pump 8 . clogged idle transfer slots 9 . carb to large . Cross off the ones to know are right and consider the rest . My .02
 
To answer your first question ,YES .the bi-metal is overstressed [not exerting enough force to close the chock plate when the eng. is cold] or to it open it all the way when warm
 
This engine have a egr valve or other emissions components that could alter the fuel air mixture ?
The 3 cases of a off idle stumble/stall like yoy describe that come to mind... Failed accerator pump. If that initial shot of fuel isn't there...
Venturi bleed tubes dropped out of where they were staked in the pot metal. This one depends on how the car is built since not all are the same.
Small piece of crap holding the egr valve open just a little.
There are/were all sorts of NOX valves and other emissions components that casued a host of various fault conditions. Good luck.
 
Nappa82,

I know you changed the points, new plugs, and adjusted timing, but I still suspect something isn't perfect in the ignition because the #1 plug wire triggered my clamp-on timing light only sporadically when it was idling bad, whereas it flashed fine earlier when I initially checked your timing (and the engine was running smoother). Also, I measured the supply to the ignition coil a bit low (~6 V coil+ to gnd).

Did you try my suggestion of jumpering 12 V direct to coil+ next time idles bad? Only do this for 20 sec to see if it smooths the idle and use ~16 awg jumper wire. You can get 12 V from the alternator's big stud, right next to the coil. If that works, remove it and go upstream, jumpering 12 V to the upstream side of the ballast resistor (side with 1 wire). If that works, you have too much voltage drop thru the bulkhead connector, ignition switch, or dash wiring (very common problem).

Radio shack sells jumper wires, but some are too thin. You can make your own using alligator clips. I carry some in all my cars, which has saved me several times on the road.

To trouble-shoot fuel delivery, install a see-thru fuel filter to monitor boiling fuel. A small region of vapor at the top is normal, but if entirely vapor you know you have a "vapor lock" problem in the fuel supply. It that is OK, try a few shots of starter fluid down the carb barrel (keep head away) and see if it smooths the idle. That helped with your original carb, but not with the replacement one. I tried testing with propane, but by bottle was almost empty and/or it was too cold to get much flow.

He needs the correct clip to connect the thermostat rod to the choke. When he bought the car, someone had bent the rod in a semi-circle to "hill-billy" the connection. I didn't find a clip in my parts boxes. If a new thermostat, his has some type of sheet-metal insert in the exhaust well, so might be a bit special. That was a prior post about an exhaust leak there.
 
BillGrissom said:
Nappa82,

I know you changed the points, new plugs, and adjusted timing, but I still suspect something isn't perfect in the ignition because the #1 plug wire triggered my clamp-on timing light only sporadically when it was idling bad, whereas it flashed fine earlier when I initially checked your timing (and the engine was running smoother). Also, I measured the supply to the ignition coil a bit low (~6 V coil+ to gnd).
Click to expand...

Yea I haven't had time to mess with the ignition at all.

Did you try my suggestion of jumpering 12 V direct to coil+ next time idles bad? Only do this for 20 sec to see if it smooths the idle and use ~16 awg jumper wire. You can get 12 V from the alternator's big stud, right next to the coil. If that works, remove it and go upstream, jumpering 12 V to the upstream side of the ballast resistor (side with 1 wire). If that works, you have too much voltage drop thru the bulkhead connector, ignition switch, or dash wiring (very common problem).
Click to expand...

Its been idling great. The idle is fine at a stop as well. But as soon as I let off the brake it starts to die. Sputters and pouts then dies. Bum.. bum... bum. bum.... dead


To trouble-shoot fuel delivery, install a see-thru fuel filter to monitor boiling fuel. A small region of vapor at the top is normal, but if entirely vapor you know you have a "vapor lock" problem in the fuel supply. It that is OK, try a few shots of starter fluid down the carb barrel (keep head away) and see if it smooths the idle. That helped with your original carb, but not with the replacement one. I tried testing with propane, but by bottle was almost empty and/or it was too cold to get much flow.
Click to expand...

I just did this a few days ago and everything looks good inside. No garbage nor did I see any vapor.



He needs the correct clip to connect the thermostat rod to the choke. When he bought the car, someone had bent the rod in a semi-circle to "hill-billy" the connection. I didn't find a clip in my parts boxes. If a new thermostat, his has some type of sheet-metal insert in the exhaust well, so might be a bit special. That was a prior post about an exhaust leak there.
Click to expand...

Yup this is broke. Holding together with a wire at the moment. Thinking of just switching this to a manual choke.

Im going to go through the car again this weekend. Ill take all the offered advice and check them all for anything that might be out of place or off.
 
Is there anybody near you with a good-running carb you can throw on there, just to rule that out?

Also, that discussion about coil voltage sounds pretty good to me. I did the jumper wire trick on my road runner to rule out everything upstream of the ballast resistor; saved me from tearing out a bunch of things I didn't need to.
 
The culpret is usually a very loose timing chain. Take the dist. cap off and turn the crank back and forth . Watch the rotor on the distributor and see how far the crank moves until the rotor moves. I have seen this problem a lot and it is usually over looked. The slack usually kills the motor when put in gear.
 
I was leaning a bit more towards the intake gasket leaking (or maybe a small piece of it got blown out from a previous backfire)....or...if you have power brakes, maybe the power booster is sucking air. Having that many carbs on and still somewhat the same problem, sort of eliminates the carb, almost. I don't think fuel delivery should even be considered; if the fuel pump can deliver enough volume to get you up to speed, it's not the culprit. This sounds like a off-idle lean stumble, but as Bill said, bypass that ballast resistor and check that out. 6v sounds very low to me.....I thought it should be over 9 volts on the "+" side of the coil.
 
at idle in drive, your voltage is probably too low...

make sure all electrical connections to the alt, battery, ballast resistor, voltage regulator are clean and shiny and nothing is loose.

then... i bet you will have a smoother running idle while in drive.

by clean and shiny i mean using light grit sandpaper on the connectors where possible, sometimes you have to use a knife tip to scrape the tarnish off if you cant get to the connections with paper. also make sure the alternator is grounded well, and that your engine is grounded to the frame and to the firewall.
 
I've seen some pretty weird things go on when troubleshooting electrical......like getting an intermittent voltage supply, caused by just the engine torquing over when you take off at a green light!! The engine can move over just enough to wiggle a harness and give an slight interruption of voltage. Like Bill said, jumper wires are your friend! A few months ago, I had a weird ignition problem, so I got a voltmeter inside my car and drove around my city, watching the voltage on the "+" side of the coil......by using some long jumper wires coming up and out of the engine comp....and into the driver's area.

Unfortunately, it wasn't the culprit in my ignition problem. :(
 
also note that the alternator main charging wire in stock mopar electrical systems is LONG. it goes from the alt to the firewall (passing through an old connector on each side to get through the firewall). then after that connector it goes to a welded splice under the dash. then to the ammeter. then out from the ammeter back to the firewall. then through that connection back out to where it joins up with the starter relay and battery. that is a long distance with lots of connectors in between where you can have a failure. that's why a lot of people do the ammeter bypass and other connector retrofits like on the mad electric site. and again that's only 1/2 the circuit because if the alternator or block is not getting a good ground then you have double problems.

http://www.madelectrical.com/electricaltech/amp-gauges.shtml
 
Are you getting a nice stream of pump shot right of idle? may be a clogged shooter.. When you put it in D are you touching the gas or just the act of putting a load on the motor causes the motor to stumble and die? That sounds like a lean condition. put your hand over the air horn at idle..does the idle go up? That is a lean condition. The 1920 has an economizer valve in the bowl. they tend to get plugged up and stop working properly. A good soak and blow out helps. The BBS is supposed to be a superior carb but millions of 1920's were built and worked fine.....also valve adjustment is very important on a 6 for idle and driveablilty, adjust them after they get warm, no need to have them running.
 
This electrical is confusing haha. Going to go look for the jumper wire today and hook it up.

Now the problem in going from a stop. Driving down the street a stop sign approaches. I let off the gas and apply the brake and come to a complete stop. Everything is running perfectly. To go I let off the brake and start to push the gas pedal down and thats the exact moment it starts to sputter and then dies. If I am lucky a very very light push of the pedal will make it sputter but it will gain speed and I can go again.

The carb seems to be working just fine. I even rebuilt it and cleaned it all out. Getting a good strong stream pumping out of carb.

Will update once I can get out after work one of these days. Hopefully today I can take some time to go get the jumper or make one.
 
to me it sounds like an ignition problem . I went through the same thing on a galaxie . carb was full of junk from sitting ,rebuilt it adjusted the timing cleaned and set the points it helped but wast right still had a stumble and noticeable miss while driving and would stall sometimes taking off .
i put a points eliminator kit in the distributer timed it and wow it was like a totally different car .
if you can try one of the points eliminator kits, accel ,pertronixs, and a few others make them and they arent real expensive . Another option is a junkyard distributer out of a 73-76 slant
 
i have a feeling its a choke problem. do a quick test let it die when in drive then
pop the hood real quick,pop the air cleaner off and look where the choke is at.
 
here's a funny!?? sold my buddy my duster (yrs ago). ran perfect when he bought it, then had some of these "problems". cause: (after changing 3 gas tanks, etc, found a dead bug in fuel line that moved from strait part to bent part off and on.
 
barbee6043 said:
here's a funny!?? sold my buddy my duster (yrs ago). ran perfect when he bought it, then had some of these "problems". cause: (after changing 3 gas tanks, etc, found a dead bug in fuel line that moved from strait part to bent part off and on.
Click to expand...

HAHA!! Thats awesome. I just did slantsixdans fuel mod yesterday and checked all the lines. I also found a HUGE leak where the intake and exhaust manifolds connect to eachother under the carb. It wasnt there a few weeks ago but was probably starting. That will be fixed today.

New remflex gaskets going on today and then I will readjust timing and fuel mixture and report back. Hopefully this will fix my stalling issues.
 
You must log in or register to reply here.
-

Back
Top