ilovefords31

1986 f-150 with feedback carb. 4.9 I6. Automatic 3 speed. The other day I decided to replace the gasket for the push rod cover. When I finished, I decided to also pour a half of a can of seafoam directly into the carb. while it was running. I then shut it off and let it sit for about 15 minutes and then drove it for about 2 miles to burn out the seafoam. Everything was fine until the next morning. When I tried to start the truck it kept stalling unless I kept my foot on the pedal, and the idle is low. I turned the low idle screw in all the way, and it still doesn't touch, which I assume is because the throttle is being help open by the solenoid.

What I've tried:


So I tried taking off the spark plugs to see if they were fouled, but they were not. But to remove any doubt, I changed the coil, plugs, and wires. Timing was checked and set about one year ago not that I suspect that. New air filter also. But it has to warm up very well before it smooths out and it never smooths out to where it was before the seafoam. Also I replaced the coil with a Accel super coil, and it did not work, so I returned it and got another one the same just to make sure it was not faulty. Still no better. Also messed with the idle mixture and that did not do anything. Checked all the hoses for cracks, and I did not see any, but most of them are less that a year old though anyway.


So could someone please tell me what the hell I did to my truck?????

Matthew Burr

whats throwing red flags for me is that the solenoid is extended and holding your throttle open enough that the idle screw isnt making contact, and yet the idle is low and stalls. so if the throttle is that far open and it is idling slow then you have a combination of vacuum, and misaligned choke issues. i would find someone that actually has experience working on those carbs and have them figure it out or possibly just replace the carb.

ilovefords31

Yeah I forgot to mention the carb is only 1 year old I replace it straight from the carter website. But I don't know how to adjust it. But this just started happening. After replacing the carb a year ago the truck was running fine until a few days ago. I replaced the pcv valve the other day and poured a third of a bottle of gummout straight into the carb throat and it evened out the idle greatly, except it stills stalls at cold startups. I ordered a new fuel filter today and I am trying that next. I think the smog pump is on its way out though it is squealing a low idle. Could that have something to do with it? Also the system is fully intact on this truck as far as all solenoids, and hoses. It was never messed with and it is all routed perfectly as far as I know. Except the orange hose at the bottom passenger side of the carb. It just hangs there. There was a small rusted pipe that came off and I don't know where from because it was rotted and broke in half before I got the truck 4 years ago.

ilovefords31

However I got to say I have NOT been able to get the choke to work right until the last few weeks before this started. It seemed to be better. Before that it would not open enough to start the truck if it was driven only a mile or two. I would have to hold it open while someone else turned the key or it would flood. But as I say that was straightened out about three or four weeks ago. I was so happy because I was dealing with that for the last year since I bought the new carb.

Matthew Burr

something a lot of people dont know or never realised is these carbs have a cold choke setting. before you turn it over press the gas pedal all the way to the floor once, then dont touch the gas pedal at all while turning it over. this closes the choke for the first start up on a cold day. depending on how cold it gets (close to zero or below) you may need to let it sit and cool off before starting it again. like a quick trip to the corner market, you may have to leave it running, or else it would be a pain to get started again. but you should not have messed with any of this stuff when you got it from carter, it should have been bench tested and set to spec before you ever got it.

Matthew Burr

that orange hose is the exhaust gas return pipe. it's intended to pull exhaust fumes back into the intake in order to warm the entire engine up faster. if it's disconnected it makes cold starts/restarts a pain in the rear

ilovefords31

Do you by any chance know where it connects? I can't seem to find it. Your right, I should have left the adjustment alone. When I installed it, I started the truck for about 30 seconds to make sure it was alright, then shut it off for about 1 minutes, tried to restart it and I couldn't, so I assumed the choke was supposed to be adjusted once on the engine so I adjusted it. Then a couple months ago I put it back to where the factory had it when I got it, and it was running awesome until last week when I put in the sea foam. Now it is horrible until it is warmed up. But if I could find where the orange hose hooks up it would be a great help because I could get a new pipe for it and at least that might help. Because even the heat pipe that goes into the choke broke off the exhaust manifold, so I just got it tightly jammed against the hole so it will still send heat up to the choke, which it seems to do pretty good. I burn my hands on it whenever I touch it. So if you could direct me to where the other (Orange) hose heat pipe goes, I would greatly appreciate it!

Matthew Burr

well, it's not absolutely necessary to have it, it's nice if you are consistently using the vehicle in freezing weather, but still usable without it. so what are the range of temps you get where you live?

i'm kind of wondering if maybe the seafoam knocked loose a bunch of gunk and clogged up your O2 sensor and maybe even the catalytic converter.

double check that the O2 sensor is still wired up. if its not then connect it and try running it again, if it is then this:

try temporarily removing the solenoid thats holding open your throttle and see how that affects it. if it runs better then replace/delete the solenoid it's only purpose was to keep the engine from stalling when you come to a stop and take your foot off the pedal too quickly.

next, verify that the solenoid on the side of the carburetor is still wired, if the original connector doesnt exist anymore then swap the connections if they are swappable, i would even pull it off and spray it good with carb cleaner to make sure it's clean and operable.

if all this fails to improve it running, i would temporarily gank all the vacuum hose and cap them off, maybe try one at a time and see if any one of them improves the operation and then you know which one is causing the issue.

remember if it's cold out there (shouldnt be this time of year unless you live in the arctic) then you need to set the choke before you turn it over.

ilovefords31

Thank you Matthew, I will try all of these things and report back. Right now where I live we are getting around 60 F in the morning, and highs of 100F at night. But the only thing that is very suspicious to me is that it was great until I seafoamed it. And now the pollution pump sqeals like crazy at idle. But I was thinking around the same things you mentioned though. The o2 and the cat. I think I don't have to have the cat anymore or the o2 but I didn't want to eliminate them out of fear it may make it run worse not having them since the computer will look for certain outputs from them. I truly appreciate that you are helping me though you are the only one who is. Sorry I took so long to get back to you last night my leaf spring broke and I was up all night fixing it. So I will check those out tomorrow and get right back to you!

Half ton

I have a 1982 f-150 302 v8 automatic and on cold start i pump my pedal a few times while the engine is cranking and it starts right up but at a higher rpm for a few minutes and i hit the gas pedal quickly and it goes to a slower but sstill cold high rpm until my gauge reaches a notch above the cold line and i hit the pedal again and it slows tto the warm operating rpm round 750 rpm.