4th Gen ('81-'88): Random Shutoff
#1
Random Shutoff
So i blew a head gasket a few weeks ago in my 85 Monte. It has the 4.3 262 v6 in it. Ive just finished rebuilding it. Whenever I drive it, I can drive for about 5 minutes with no problems, but the car will suddenly turn off with no warning. Sometimes when it turns off, it starts to sputter a little bit. I got the timing adjusted by ear as well as I could, but I dont think thats the problem. Does anyone know what could be wrong?
#2
How long has it been since you changed the fuel filter?
Could be that your choke is stuck, dirt or water in fuel, bad fuel pump.
How long does it take for it to start back up once it stalls?
When does it stall? Idle, on acceleration, on deceleration? Is there a pattern, other than after about 5 minutes, to the stalling?
Could be that your choke is stuck, dirt or water in fuel, bad fuel pump.
How long does it take for it to start back up once it stalls?
When does it stall? Idle, on acceleration, on deceleration? Is there a pattern, other than after about 5 minutes, to the stalling?
Last edited by P343; 02-23-2015 at 06:29 PM.
#3
Ive had the car for two months, so I havent changed the filter yet. Where is it located? Im not sure about dirt, but it starts back up right away. Theres not really a pattern as far as i can tell.
#5
The fuel filter is attached to two pieces of hose near the carburetor and one end of that hose is attached to the carburetor. Should look something like this
If you change it, there is an arrow that indicates fuel flow. The arrow needs to go TOWARDS the carburetor. Now if you already knew that, please don't be offended. I just know some people who have put them on backwards. Your fuel filter will be your cheapest potential fix, so might as well start with the cheapest first!!!
If you change it, there is an arrow that indicates fuel flow. The arrow needs to go TOWARDS the carburetor. Now if you already knew that, please don't be offended. I just know some people who have put them on backwards. Your fuel filter will be your cheapest potential fix, so might as well start with the cheapest first!!!
Last edited by P343; 02-23-2015 at 05:38 PM.
#6
BTW welcome to the forum!! If you can take a pic of your engine, that would be helpful as we can see what kind of carburetor you have, etc. Take the air filter off before you take the pic and I think you can post the pic in your garage or photo album
#10
TBI's are beyond me..sorry. I found this from another source "Try to prove what it's losing.
Sometimes if you can't find the cause of something like this, or the failed part, you have to come from the opposite mindset....sort of diagnosing backward.
So to start off, is it losing fuel or spark?
If it fires right back up, you know it's not spark (at least it's a real good indication that it's not spark).
If it only does the problem once it's warmed up, you know it's not spark (again....or at least it's a good indication that it's not spark related).
When you write in for help, take extra time to be very clear about the description. Use words and phrases/sentences that convey exactly what's going on. It helps others help you faster, and more accurately.
For example, here's what would be better....
It runs fine when cold, but once up to operating temurature, it'll die unless I give it gas when stopped for a traffic light or stop sign. It accelerates fine, and is fine and normal running down the road.
Anyway, back to your issue.
Let's say that it's a fueling issue. That can mean 2 things a) it's not getting enough fuel b) it's getting too much air
So if we're pursuing this line of thinking, what controls the amount of fuel that the engine gets at idle? More importanly, what controls the amount of fuel that the engine gets once it's warmed up?
Same thinking process for what controls the amount of air getting into the engine, and in this case, you also think about what's attached to the intake manifold that can leak air into the engine. EGR valve, IAC, Brake Vacuum Booster, Dash vent controls, transmission controls, PCV valve, etc.
My suggestion would be to set the ignition timing to factory spec, hook up the timing wire, and then pursue the issue. You may have a failed computer, and that's why, when the timing wire is hooked up, the engine runs so bad. I'd certainly get on ebay and buy a computer for it and use it to test and rule out, or cure the problem. Same with the oxygen sensor if it's not been replaced, or the new one is some cheap China junk "
Here are some links that might lead you in the right direction.
tbi 305 1991 pickup stalls when put into gear - Hot Rod Forum : Hotrodders Bulletin Board <--Click
305 TBI stalling off highway ramps and approaching stop lights <--Click
Sometimes if you can't find the cause of something like this, or the failed part, you have to come from the opposite mindset....sort of diagnosing backward.
So to start off, is it losing fuel or spark?
If it fires right back up, you know it's not spark (at least it's a real good indication that it's not spark).
If it only does the problem once it's warmed up, you know it's not spark (again....or at least it's a good indication that it's not spark related).
When you write in for help, take extra time to be very clear about the description. Use words and phrases/sentences that convey exactly what's going on. It helps others help you faster, and more accurately.
For example, here's what would be better....
It runs fine when cold, but once up to operating temurature, it'll die unless I give it gas when stopped for a traffic light or stop sign. It accelerates fine, and is fine and normal running down the road.
Anyway, back to your issue.
Let's say that it's a fueling issue. That can mean 2 things a) it's not getting enough fuel b) it's getting too much air
So if we're pursuing this line of thinking, what controls the amount of fuel that the engine gets at idle? More importanly, what controls the amount of fuel that the engine gets once it's warmed up?
Engine coolant temp sensor">Engine coolant temp sensor" /> Engine coolant temp sensor">Engine coolant temp sensor
that feeds the computer, the wiring from that sensor to the computer, the Oxygen Sensor, it's wiring, the TPS and its wiring, the fuel pump, the fuel filter.......etc.Same thinking process for what controls the amount of air getting into the engine, and in this case, you also think about what's attached to the intake manifold that can leak air into the engine. EGR valve, IAC, Brake Vacuum Booster, Dash vent controls, transmission controls, PCV valve, etc.
My suggestion would be to set the ignition timing to factory spec, hook up the timing wire, and then pursue the issue. You may have a failed computer, and that's why, when the timing wire is hooked up, the engine runs so bad. I'd certainly get on ebay and buy a computer for it and use it to test and rule out, or cure the problem. Same with the oxygen sensor if it's not been replaced, or the new one is some cheap China junk "
Here are some links that might lead you in the right direction.
tbi 305 1991 pickup stalls when put into gear - Hot Rod Forum : Hotrodders Bulletin Board <--Click
305 TBI stalling off highway ramps and approaching stop lights <--Click