Cold starting issue
10-15-2014, 04:46 PM
#1
Cold starting issue
Since I got my 82 pickup, it has required the use of starting fluid for cold starts. Once I start the engine from cold, I have to keep my foot on the throttle for about 3 minutes, sometimes longer, until it will hold idle on it's own. Once warm, it runs and drives great.
PO said the choke just needed to be adjusted, so I looked up the procedure in my thick comprehensive Chilton manual. I'm pretty sure I found the right one for my truck. It has a cool spring electric choke.
I did first fully open the throttle which did close the choke flap. That's been happening every time I go to start it, since doing this doesn't make it start right up- I tried. But I wasn't sure if it was supposed to be closed even further than this, as there is still some air space around the flap. So I thought adjustment may have still needed to be done.
The plastic housing on the choke unit on the back of the carb had a metal bracket around it with 3 fastening points. The top two had tiny wood screws and 2 washers each, the bottom point had a rivet still in place. So someone's been in here before. I was able to bend the fastening bracket back after unfastening the tops screws to get the plastic housing off. I was unable to see how the springs were originally positioned around the tab that actuates the choke flap, but one thing seems certain: that flap is as far closed as it can go when I open the throttle all the way to engage it.
The next step of choke adjustment is to make sure it is turning off when the engine warms up. If not, I'm supposed to bend something. It had been a good education session after a long day of work, I was tired of working on it under a small clip light, so I decided to call it a day and button everything back up.
Since I wasn't sure how the two thermostat-like springs were supposed to be positioned to the choke flap actuator tab, I went intuitively: the one that has an open hook that seemed to pull in the direction of closed was of course going to go around the tab in that direction, and the more round spring that ended with a loop was also decided to go around the tab. Once I closed that up, I went to start the truck.
I was hoping for an instant start and that the last person in there had assembled it wrong, but I got a second place prize. I didn't have to use starting fluid. A whole lot more pedal pumping and cranking than I'd liked to have done, but it did start without ether. Yesterday when I had tried to start it that way, it was lots and lots of cranking and pumping with no sign of starting, had to use ether like before.
It did sort of run too rich for a while. I thought I'd assembled it in such a way that it kept the choke on too long or permanently. The exhaust started to burn my eyes. But it did stay idling after starting without dying, even though when I blipped the throttle it bogged a little each time, well after the amount of time I used to have to keep my foot on the throttle. But when I got in to drive to the store and then home, it ran and drove perfectly fine. When I got home (5-10 minute drive), I opened the air cleaner to find that the choke had opened since warming up all the way, so was at that point operating normally, even if too slow to close. The times of having to keep my foot on the gas never had a too-rich condition, so seemed unrelated to the choke. Also, whenever I started it with ether, it only had to warm up for a few seconds before being able to be restarted (it didn't ever need another spray of ether after having been started with some) although this still always meant having to keep the foot on the throttle until fully warm.
My 83 has always needed to have the gas pedal pumped 3-6 times before starting, but then it always starts strong and usually stays running- if not, a well-timed blip of the throttle will keep it running past the hiccup that usually kills it until it warms up another 30 seconds. But that's probably a different kind of problem. But that has been one I could live with day to day. But this need to have a can of ether all the time in hand and get out and spray it and nurse the throttle is something I'd like to get sorted out ASAP.
PO said the choke just needed to be adjusted, so I looked up the procedure in my thick comprehensive Chilton manual. I'm pretty sure I found the right one for my truck. It has a cool spring electric choke.
I did first fully open the throttle which did close the choke flap. That's been happening every time I go to start it, since doing this doesn't make it start right up- I tried. But I wasn't sure if it was supposed to be closed even further than this, as there is still some air space around the flap. So I thought adjustment may have still needed to be done.
The plastic housing on the choke unit on the back of the carb had a metal bracket around it with 3 fastening points. The top two had tiny wood screws and 2 washers each, the bottom point had a rivet still in place. So someone's been in here before. I was able to bend the fastening bracket back after unfastening the tops screws to get the plastic housing off. I was unable to see how the springs were originally positioned around the tab that actuates the choke flap, but one thing seems certain: that flap is as far closed as it can go when I open the throttle all the way to engage it.
The next step of choke adjustment is to make sure it is turning off when the engine warms up. If not, I'm supposed to bend something. It had been a good education session after a long day of work, I was tired of working on it under a small clip light, so I decided to call it a day and button everything back up.
Since I wasn't sure how the two thermostat-like springs were supposed to be positioned to the choke flap actuator tab, I went intuitively: the one that has an open hook that seemed to pull in the direction of closed was of course going to go around the tab in that direction, and the more round spring that ended with a loop was also decided to go around the tab. Once I closed that up, I went to start the truck.
I was hoping for an instant start and that the last person in there had assembled it wrong, but I got a second place prize. I didn't have to use starting fluid. A whole lot more pedal pumping and cranking than I'd liked to have done, but it did start without ether. Yesterday when I had tried to start it that way, it was lots and lots of cranking and pumping with no sign of starting, had to use ether like before.
It did sort of run too rich for a while. I thought I'd assembled it in such a way that it kept the choke on too long or permanently. The exhaust started to burn my eyes. But it did stay idling after starting without dying, even though when I blipped the throttle it bogged a little each time, well after the amount of time I used to have to keep my foot on the throttle. But when I got in to drive to the store and then home, it ran and drove perfectly fine. When I got home (5-10 minute drive), I opened the air cleaner to find that the choke had opened since warming up all the way, so was at that point operating normally, even if too slow to close. The times of having to keep my foot on the gas never had a too-rich condition, so seemed unrelated to the choke. Also, whenever I started it with ether, it only had to warm up for a few seconds before being able to be restarted (it didn't ever need another spray of ether after having been started with some) although this still always meant having to keep the foot on the throttle until fully warm.
My 83 has always needed to have the gas pedal pumped 3-6 times before starting, but then it always starts strong and usually stays running- if not, a well-timed blip of the throttle will keep it running past the hiccup that usually kills it until it warms up another 30 seconds. But that's probably a different kind of problem. But that has been one I could live with day to day. But this need to have a can of ether all the time in hand and get out and spray it and nurse the throttle is something I'd like to get sorted out ASAP.
Last edited by zombie_stomp; 10-15-2014 at 07:02 PM.
10-15-2014, 06:09 PM
#2
Another example of symptoms:
I just went to the store. Since I had gotten home and sat around playing around on the internet for a while, the truck had a chance to cool a bit for an hour or two. I was pleased that it started up pretty easily with only a tiny bit of pedal pumping, and stayed idling without having to stay on the gas pedal at all. I went right back to the store.
I was inside for about 5 minutes and came back out and I had to crank the engine twice or three times as much and lay on the gas pedal to keep it running. If I had stayed on the gas pedal a while and sat in place, it probably would have 'warmed up' enough to stay running without having to stay on the gas pedal, but I went ahead and started driving. The intersection was clear so I didn't have to stall at the stop sign and restart it, I was able to just roll through. But about a block later, once cruising, I pushed in the clutch to let the engine idle and see if it died, and it did not.
So at about the three minute mark of having been running, it stayed running, regardless the temperature it had maintained. It seemed to be about the amount of time it had been running instead of the temperature now. But that is incongruent to the amount of time it spent not running/cooling down when I came home and hung out for a couple hours.
One would almost just want to rebuild the carburetor and see what happens, if nothing else just to clean it and find out more about how it works or what might be clogged. But when it is warmed up and running, the exhaust smells so clean and perfect that it must just be some small auxiliary component. The carb is doing it's job when the engine is good and hot, and runs way more clean and lean than my old '83. There's got to be some circuit or component that is just not working in the early startup phase.
Also maybe noteworthy is that there is an aftermarket catalytic converter, and the original o2 sensor has just been cut. I've never figured out how the little emissions control module works on these trucks or what it does, or how it does whatever it does, but I thought it was worth mentioning that I saw it exists on this truck as well as my '83.
I just went to the store. Since I had gotten home and sat around playing around on the internet for a while, the truck had a chance to cool a bit for an hour or two. I was pleased that it started up pretty easily with only a tiny bit of pedal pumping, and stayed idling without having to stay on the gas pedal at all. I went right back to the store.
I was inside for about 5 minutes and came back out and I had to crank the engine twice or three times as much and lay on the gas pedal to keep it running. If I had stayed on the gas pedal a while and sat in place, it probably would have 'warmed up' enough to stay running without having to stay on the gas pedal, but I went ahead and started driving. The intersection was clear so I didn't have to stall at the stop sign and restart it, I was able to just roll through. But about a block later, once cruising, I pushed in the clutch to let the engine idle and see if it died, and it did not.
So at about the three minute mark of having been running, it stayed running, regardless the temperature it had maintained. It seemed to be about the amount of time it had been running instead of the temperature now. But that is incongruent to the amount of time it spent not running/cooling down when I came home and hung out for a couple hours.
One would almost just want to rebuild the carburetor and see what happens, if nothing else just to clean it and find out more about how it works or what might be clogged. But when it is warmed up and running, the exhaust smells so clean and perfect that it must just be some small auxiliary component. The carb is doing it's job when the engine is good and hot, and runs way more clean and lean than my old '83. There's got to be some circuit or component that is just not working in the early startup phase.
Also maybe noteworthy is that there is an aftermarket catalytic converter, and the original o2 sensor has just been cut. I've never figured out how the little emissions control module works on these trucks or what it does, or how it does whatever it does, but I thought it was worth mentioning that I saw it exists on this truck as well as my '83.
Last edited by zombie_stomp; 10-15-2014 at 06:14 PM.
10-16-2014, 04:04 PM
#3
You can download the factory service manual from a link in my signature. It has a lot of information on the stock carb and it's choke. The factory carb had a 5 "step" choke. Step 1 is full choke, idle around 2000rpm, them it will slowly step down as it warms up. I believe the choke breaker will slowly apply more and more vacuum as the engine warm. But the FSM will get into great detail on it.
10-17-2014, 02:42 PM
#4
Thanks for the link, I'll download that now.
Another thing happened that makes me think it's not the choke: it randomly died even after being fully warmed up. Then it did the thing where I have to hold the gas pedal down before it would idle on it's own.
Maybe I should just remove the carburetor after getting a rebuild kit just in case I find anything... well, needing to be rebuilt. At least a base gasket.
The truck came to me with no air cleaner gasket, so all kinds of crap had been getting in underneath the air cleaner. I'm surprised it ran as good as it did, minus the cold starting issue(s). So I wouldn't be surprised if I found something clogged inside that was causing all this to happen.
Another thing happened that makes me think it's not the choke: it randomly died even after being fully warmed up. Then it did the thing where I have to hold the gas pedal down before it would idle on it's own.
Maybe I should just remove the carburetor after getting a rebuild kit just in case I find anything... well, needing to be rebuilt. At least a base gasket.
The truck came to me with no air cleaner gasket, so all kinds of crap had been getting in underneath the air cleaner. I'm surprised it ran as good as it did, minus the cold starting issue(s). So I wouldn't be surprised if I found something clogged inside that was causing all this to happen.
10-17-2014, 06:38 PM
#5
I would advise you to get a rebuild kit and give it a shot. It's really fun to do an the FSM has all kinds of stuff on taking the carb apart. One of the most critical things during he rebuild is getting the float set just right if you put in a new float. Pay close attention to that.
10-18-2014, 12:54 PM
#6
Thanks, I think I will rebuild the carb first and a little later rebuild the engine too. I might just go for a new float, as weird and unknown as the problems with the carb are.
Anyone know what kit should get, or what the differences between the two shown at Rock Auto would be?
http://www.rockauto.com/catalog/x,ca...,parttype,5964
Edit: I think it may just be a different manufacturer of the 2 kits. I'll probably go with the extra $1 to ensure quality. I had a throttle cable from rock auto have the wrong inner hole size and had to modify it myself.
Anyone know what kit should get, or what the differences between the two shown at Rock Auto would be?
http://www.rockauto.com/catalog/x,ca...,parttype,5964
Edit: I think it may just be a different manufacturer of the 2 kits. I'll probably go with the extra $1 to ensure quality. I had a throttle cable from rock auto have the wrong inner hole size and had to modify it myself.
Last edited by zombie_stomp; 10-18-2014 at 01:09 PM.
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10-26-2014, 01:46 PM
#8
I got the carb out and started cleaning. One difference I noticed between this 82 and my 83 is that it is missing the fast idle vacuum diaphragm. That may not be critical, and surely wouldn't be causing it not to start cold. Also the butterfly valve on the drivers side seemed to be just plain stuck closed. I'll find out more as I proceed...
10-31-2014, 09:10 PM
#9
I rebuilt the carb and it has a lot more power than before. It stays running without having to keep my foot on the gas like before. The problem with starting cold still remains though: no matter how many times I pump the gas pedal starting from cold, it will only start after an absurd amount of cranking. I haven't used starting fluid yet after rebuilding, just cranking a whole lot. I'm almost about to start investigating electrical matters since it has been rigged to having an aftermarket coil and the lead to the o2 sensor has been cut...
11-02-2014, 09:25 AM
#10
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Have you replaced the fuel filter? Tried slightly different settings with the slow speed/idle fuel adjustment? Do a complete check for vacuum leaks imo. I have my choke set way back so wont even think to choke till i'm around freezing, but i'm in so. cal. Starts great with one to two pumps but have to hold the gas for half a minute if freezing. I like the motor to idle low so as not to wear on clutch & shift easy, just my way.
Last edited by g3bill2; 11-02-2014 at 09:29 AM.
11-02-2014, 10:43 AM
#11
It has been mostly better since the rebuild but today again randomly not wanting to start cold somewhere in the middle of cold/hot. Can't tell if it's flooding or starving, seems like flooding.
Tell me about the slow speed/idle fuel adjustment, I've looked through the Chilton and need to print the FSM or at least parts of it. I have adjusted the idle, and would think of adjusting the fast idle but the diaphragm for that is missing. I can kind of tell that it isn't a huge deal that it is missing, it just needs more careful throttle application and stalls a lot easier during the first three minutes of warmup. So tell me about the slow speed fuel adjustment.
Fuel filter appears to have been replaced very recently. Float bowl levels always seem good running or before starting. Adjusted float to specified levels of movement durin rebuild.
Tell me about the slow speed/idle fuel adjustment, I've looked through the Chilton and need to print the FSM or at least parts of it. I have adjusted the idle, and would think of adjusting the fast idle but the diaphragm for that is missing. I can kind of tell that it isn't a huge deal that it is missing, it just needs more careful throttle application and stalls a lot easier during the first three minutes of warmup. So tell me about the slow speed fuel adjustment.
Fuel filter appears to have been replaced very recently. Float bowl levels always seem good running or before starting. Adjusted float to specified levels of movement durin rebuild.
11-02-2014, 10:56 AM
#12
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How about the fuel lines? My old 83' had some bad fuel line and would lose fuel and need to be primed to get it running, but once running it would run fine and there was never any noticeable fuel leak. My bad fuel line was under the hood but there are lines all the way back to the tank that can be replaced.
11-02-2014, 11:21 AM
#13
Was the line clogged or something? Something is definitely wrong here, I'm having to fight with the throttle to keep it running right now, and other times it will maintain idle. I don't think it's starving for fuel though, I think it's getting too much as it smells rich right now while it's doing this. Maybe the choke is staying on too long. It would benefit from having the fast idle diaphragm and hot air intake reinstalled to start with.
11-02-2014, 01:29 PM
#14
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idle adjustment at bottom of carb but guess thats ok. I dont have a diaphram for the throttle either, its there but not connected, might have been incase of a/c? if your talking right side of carb? think there one on valve cover side but thats hook up and called a choke breaker?. still sounds like vacuum leak somewhere? who knows without being there....too much crap in these smog motors. 
ps. i have the '82 repair manual and thats been great, if you can download it?
i found a cheaper haynes manual '79-83 models and use that while in garage so dont get grease on the big one.
Wonder also if you have that spring in the right place in the choke? and did you check to see if the element was heating up...might have a bad electrical connection?
ps. i have the '82 repair manual and thats been great, if you can download it?
i found a cheaper haynes manual '79-83 models and use that while in garage so dont get grease on the big one.
Wonder also if you have that spring in the right place in the choke? and did you check to see if the element was heating up...might have a bad electrical connection?
Last edited by g3bill2; 11-02-2014 at 02:01 PM.
11-02-2014, 01:44 PM
#15
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Nope it had some cracking where it connected too the barb. It allowed the fuel to drain out of the line because of the vacuum lose or whatever. I replaced the lines and fixed it right up. It didn't seem to leak out, it just reseeded back into the fuel system.
11-02-2014, 02:06 PM
#16
The fast idle diaphragm is on the passenger side near the idle adjustment screw. It was also on my '83. It's on trucks without AC, usually AC gets a throttle boost from an electrical solenoid since it's usually an electrical signal relay that kicks on the compressor anyway. So what that vacuum diaphragm does is it helps the engine idle higher during warmup to keep it from dying. Once warm, you can blip the throttle and it releases the fast idle. I don't think it's really the problem.
Just a while ago, I got in the truck and started it from cold. It just about fired right up but had to restart it, and it did the bog/stumble/die if I didn't keep on the gas, but only until the end of the short city block I was on. When I was posting earlier, it was having a major meltdown case of those symptoms. Other times I will start it, and it will run fine like a well-tuned truck.
So it's got this intermittent rich/ doesn't want to idle condition, also with varying intensity. It also seems worse with engine temps between cold and hot. Since cleanin and rebuilding the carb, it's at least gotten more consistent and starts from dead cold more reliably, but is generally unreliable and unpredictable.
I want to know where some of the parts besides the electrical choke coil are that have to do with enrichment and temperature sensing/temperature control of the choke parts. This has been frustrating previous owners for quite a while, it seems like a lot of the things done seemed to aim to solve this long-term problem, such as the electrical choke coil housing being hacked into, head scratching commenced, and then they jammed some wood screws where the rivets were without fixing anything. As far as I can tell, there's nothing mechanically serviceable in there, which is probably their reason for riveting it closed.
Just a while ago, I got in the truck and started it from cold. It just about fired right up but had to restart it, and it did the bog/stumble/die if I didn't keep on the gas, but only until the end of the short city block I was on. When I was posting earlier, it was having a major meltdown case of those symptoms. Other times I will start it, and it will run fine like a well-tuned truck.
So it's got this intermittent rich/ doesn't want to idle condition, also with varying intensity. It also seems worse with engine temps between cold and hot. Since cleanin and rebuilding the carb, it's at least gotten more consistent and starts from dead cold more reliably, but is generally unreliable and unpredictable.
I want to know where some of the parts besides the electrical choke coil are that have to do with enrichment and temperature sensing/temperature control of the choke parts. This has been frustrating previous owners for quite a while, it seems like a lot of the things done seemed to aim to solve this long-term problem, such as the electrical choke coil housing being hacked into, head scratching commenced, and then they jammed some wood screws where the rivets were without fixing anything. As far as I can tell, there's nothing mechanically serviceable in there, which is probably their reason for riveting it closed.
Last edited by zombie_stomp; 11-02-2014 at 02:24 PM.
11-02-2014, 03:28 PM
#18
I looked over the carb diagram in the book, and noticed the rectangular box thing on the carburetor called the thermostatic valve. Now that sounds like something relevant to my cause. Well, whatever the contents of the empty rectangular hole on my carb, I just found it. And I'm afraid it may have been letting crap in the small hole but any amount of time I've had it rebuilt for is nothing compared to how long it had been run that way. Now for the same reason I have to ask why they removed the fast idle diaphragm, were they actually trying to solve this original condition by taking things off? I just don't want to search for this part in vain if there was nothing wrong when it was removed I it doesn't heavily affect or change the original condition. The biggest problem? Where do I get random parts of a whole carburetor?
11-02-2014, 04:18 PM
#19
Actually, the carburetor may not need that thermostatic valve to be correct. I set out on e-bay to try to find one to buy but just came across a bunch of Chinese Aisin knock-offs that are BRAND NEW, and don't have that part, and have the same hollow casting as I have with a hole that is most likely plugged or leads to a dead end, which I now presume again to be the case with mine.
I could buy one of those carburetors and run that, but if the problem persists, I'd have to start over, outside the carburetor. I was pretty thorough in my rebuild.
Since I only did the rebuild as best I could, and don't fully understand how everything works, there is the possibility that some passageway didn't get completely blasted clean, although I did use compressed air. There may have been holes or jets I didn't know how to further disassemble that I shod have, but that would have been special techniques. There were a few ball bearings provided that I have no idea where they would have gone, and they are I a plastic Baggie along with the gasket to what would have been the thermostatic valve, if my carb were so equipped.
This is getting to be one of those trucks whose only hope to run right again may be to do away with all the smog plumbing, or I get super nerdy, keep it all original, and slowly learn how all the systems work and restore it to original, and eventually, through meticulous testing, find the fault in the huge, cryptic system. It's like the algebra of auto tech, translated from Japanese. There are all these, "if this and that times this and that value are this and that times x, TJs and the other should be calibrated. If not, disassemble a for 4 hours and the. Bend tab one 12.5mm to the left, reassemble, and check again...."
I could buy one of those carburetors and run that, but if the problem persists, I'd have to start over, outside the carburetor. I was pretty thorough in my rebuild.
Since I only did the rebuild as best I could, and don't fully understand how everything works, there is the possibility that some passageway didn't get completely blasted clean, although I did use compressed air. There may have been holes or jets I didn't know how to further disassemble that I shod have, but that would have been special techniques. There were a few ball bearings provided that I have no idea where they would have gone, and they are I a plastic Baggie along with the gasket to what would have been the thermostatic valve, if my carb were so equipped.
This is getting to be one of those trucks whose only hope to run right again may be to do away with all the smog plumbing, or I get super nerdy, keep it all original, and slowly learn how all the systems work and restore it to original, and eventually, through meticulous testing, find the fault in the huge, cryptic system. It's like the algebra of auto tech, translated from Japanese. There are all these, "if this and that times this and that value are this and that times x, TJs and the other should be calibrated. If not, disassemble a for 4 hours and the. Bend tab one 12.5mm to the left, reassemble, and check again...."
11-02-2014, 04:30 PM
#20
I went on rock auto and noticed that they had remanufactured carburetors for $300 as opposed to the Chinese knockoffs for about $180 shipped. I'm pondering if that's worth the difference in price, or if I could just swap some of the plastic linkages and such from the original (I noticed the Chinese units have some plastic linkage parts) and come out with something just as good in every other way. Not sure where else to test, in NC, smog testing of this year will be over, I could meanwhile de-smog everything and strip it down to basic and skirt the inspections a while. Not sure if such a drastic measure will be necessary just yet, I'm just hoping where to test next. Or it an hour at the mechanic's would be one well-spent getting them to tell me what may be wrong, if I can duplicate the conditions.
P.S. The second part in the pic looks almost like the fast idle diaphragm, but I don't think it is. It's listed with what I think are basically choke breakers. But if it is a diaphragm in question, whose membranes can fail, why would it not be available? The rebuild kit had several such diaphragms replacements!
P.P.S. I'm headed to a salvage yard soon for some wheels, and might be able to pull one there.
P.S. The second part in the pic looks almost like the fast idle diaphragm, but I don't think it is. It's listed with what I think are basically choke breakers. But if it is a diaphragm in question, whose membranes can fail, why would it not be available? The rebuild kit had several such diaphragms replacements!
P.P.S. I'm headed to a salvage yard soon for some wheels, and might be able to pull one there.
Last edited by zombie_stomp; 11-02-2014 at 04:42 PM.
