Engine idles great in park/neutral but stalls almost instantly when put into drive or reverse. Is this a carburetor or fuel issue? I changed the fuel filter but it didn't help.
What carburetor are you using?
Generally carb issue , lower vacuum , the power valve opens up or the metering rods rise & it stalls out , although I have seen the timing change in gear causing it to stall
Larry, 1st check for a vacuum leak
Then try backing off the idle screw & advance timing a couple of degrees.
Use a vacuum gauge to find max vacuum at idle & you may solve this issue.
Over exposed idle transition slots will cause one to stumble or die under load .
about half way down in this article
http://www.superchevy.com/how-to/45638/
Item #2 is a transition slot
(https://forum.e-bodies.org/proxy.php?request=http%3A%2F%2Fimage.superchevy.com%2Ff%2F9559852%2Bw640%2Bh426%2Bq80%2Bre0%2Bcr1%2Bar0%2Bst0%2Fp109594_image_large.jpg&hash=fcfe3a24ee7482a378c7c930586d3a18fafc4b90)
Quote from: Cuda Cody on August 06, 2023, 09:03:42 PM
What carburetor are you using?
I have a thermoquad 850
Wade.... I'll check for a vacuum leak first and then take it from there.
Chryco.... I'll check the carb and look for anything binding or loose.
This question should have been asked.
Did this problem all of a sudden show itself ? Were there any changes or adjustments done on the car before this happened ?
Transmission/torque converter ?
What Mopar Leo said. If you just installed a wilder camshaft and this started happening the car needs more initial distributor advance and the total advance limited.
If no changes were made and this just started happening it means other things, one thing to look for in that case would be a vacuum leak.
No changes were made....other than an oil change.
I'm thinking it could be a vacuum leak or possibly something lodged in the carburetor.
It started to do this last fall just before I stored the car.
Last month when I started it up from winter storage the engine ran perfect. I took it for a short drive and it didn't hesitate or stall.
It sat unstarted for about ten days, then 2 days ago after starting it up it started stalling when backing out of the garage, just like last fall. I changed the fuel filter, but nothing changed.
Other than the distributor hoses and the brake vacuum booster, where else could a vacuum leak be occurring?
Should I spray some carb cleaner around the base of the carburetor while the engine is idling?
Never spray anything flammable on your intake ! Just a fire looking to happen.
You are just looking for a change in RPM.
Use a spray bottle with water. Just look for an RPM drop.
Pull the spark plugs and inspect for fouling, etc...
Just for more info, what exactly are you running ? Stock small block, big block ? If not stock, what is the build combo and any trans mods done.
More details help make better diagnosis.
MoparLeo...I'm running a stock 1973 340 and nothing has been done to the 727 transmission. The spark plugs are 14 years old with 1,750 miles on them. I'll pull and clean them the next chance that I get. The timing was set 13 years ago at 36° at 3,000 rpms. It has ran excellent with that timing. Any other ideas to look for are welcomed.
I once found the hose to the PCV split at one end on some Mopar, cut off about 1/2-inch & reinstalled.
Also on a 90's Dakota that was running bad and stalling I tracked it down to a dirty PCV valve that wasn't closing completely at idle.
Don't recall any vacuum leaks otherwise... Tried spaying carburetor cleaner around on a couple of occasions & found it was getting sucked into the carb and revving up giving false indication.
Quote from: Hood on August 07, 2023, 06:39:56 PM
Other than the distributor hoses and the brake vacuum booster, where else could a vacuum leak be occurring?
Between the intake and cyl head. I had a leak there once on a 318. Can't remember for sure but I think back then - about 15 yrs ago - I used WD40 sprayed at each intake runner.
Base of the carb. Maybe check if the mounting nuts are snug?
Recheck your 14 year old tune.. Plugs and timing, carb adjust. Nothing lasts forever. Fresh fuel ?
Mileage is not the factor.
Today I spent a couple of hours troubleshooting. Pulled the plugs and cleaned them. They were in really good shape. Checked for vacuum leaks and I didn't find any.
Went for a drive and it ran great. Came home and it started to stumble slightly in park. And then stalled when put into Drive. I turned up the idle to around 900-950 rpms from about 800 rpms. The higher curb idle cleared up the stalling issue....so far.
I think I have some compromised fuel. So my next move is to add some dry gas to the tank eventhough I use Stabil every fall.
I sprayed some throttle body cleaner into the carb while running and also used small puffs of compressed air into the carb vent stacks and through the fuel line going into carb.
My mission is to burn through the remaining tank of gas, and hopefully my stalling will cease.
Quote from: Hood on August 14, 2023, 07:55:08 PM
My mission is to burn through the remaining tank of gas, and hopefully my stalling will cease.
These cars are custom built for that kind of mission...lol
I have trouble keeping the tank filled.....
Well it turns out that the Sta-bil that I have been using is from 2017 when I first bought it. Lesson learned on checking the expiration dates. It's safe to say that my fuel is un-stable!
I poured in a bottle of Royal Purple max clean and my stalling issues have been solved. This stuff worked very quickly.
So once I run this tank of old fuel down, should I consider using ethanol free gas? I usually use premium and I know that it contains ethanol.
I will be sure to use Sta-bil that is freshly dated and to buy only the smaller size verses the 32 ounce size. Out dated sta-bil is not effective.
Wow! Thanks for posting the follow up. I'm going to have to start using that stuff now that our govt. mandated ethanol in all our fuels including our previously "pure" 94.
A good reason for giving all pertinent info from the start.
After six months and sometimes sooner, modern fuels are kaput.
That is a good point; I am not so sure mine is all that "fresh" either. Guess I will be doing some driving to burn through some (maybe) stabilized fuel.
Quote from: Hood on August 21, 2023, 07:07:07 AM
Well it turns out that the Sta-bil that I have been using is from 2017 when I first bought it. Lesson learned on checking the expiration dates. It's safe to say that my fuel is un-stable!
I poured in a bottle of Royal Purple max clean and my stalling issues have been solved. This stuff worked very quickly.
So once I run this tank of old fuel down, should I consider using ethanol free gas? I usually use premium and I know that it contains ethanol.
I will be sure to use Sta-bil that is freshly dated and to buy only the smaller size verses the 32 ounce size. Out dated sta-bil is not effective.
Picking the right stabilizer is difficult. I did a lot of research and it's always different form one source to another. I like star tron for an every day driver, it's supposed to lubricate the fuel system and remove water and good for storage. Sta- bil is supposed to be better for long term storage. But who knows?
I'm still a fan of Sta-bil. But in my case it wasn't any good after the 2nd year of opening it. Sta-bil is good for 2 years.
My bottle of sta-bil was seven years old. So for the last five years I wasn't stabilizing my fuel during winter storage. It's a miracle my car even started and ran.
Summary....Don't buy Sta-bil in a quantity that you can't use up in two years. And if you have too much left over, dump it into your daily driver.