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If the carb sticks at WOT, it could be caused by gummed up throttle linkage, defective throttle cable, some kind of mechanical interference preventing the throttle from returning to idle (floor mats, etc), mechanical issues with the throttle linkage or related parts (air cleaner jamming the throttle, cruise control linkage, choke linkage, weak return springs)the list goes on.
If you throw the trans in neutral with the throttle stuck, the engine is going to rev up. If your relatively comfortable with your ability to steer the car with no power steering, if leave it in gear and shut off the ignition. You shouldn’t be able to turn the key completely off unless the trans is in park, so no worries about locking the steering wheel. You will be able to steer the car and use the brakes, just with more effort.
If if there is any doubt in your ability to safely steer the car with no power steering, put the trans in nuetral. Better to trash the engine than wreck the car, or yourself. Engines can be replaced much easier than bodywork (on the car, or your personal body!)
first, spray the carb linkage with lots of carb cleaner. Then work the throttle many times with the gas pedal. Look all the linkage over, look for anything that may stick or bind. If you don’t see anything obvious, get another more experienced set of eyes. Better safe than sorry
No, the TPS on your carburetor is quite basic. If your car surges to WOT then there is some binding in the throttle linkage or the carburetor. As Matt mentioned start with lubing the throttle linkage. You can also use carb cleaner to clean the exterior of the carb and the primary/secondary venturis.
No, the TPS on your carburetor is quite basic. If your car surges to WOT then there is some binding in the throttle linkage or the carburetor. As Matt mentioned start with lubing the throttle linkage. You can also use carb cleaner to clean the exterior of the carb and the primary/secondary venturis.
* I am equating 'surge' as being WOT, is this correct or are their two terminologies? I have already performed cleaning the carb on the exterior. Hesitant to lube the throttle with anything other than to clean with carb cleaner. I believe that from the information I've seen is that the secondaries are possibly the problem in WOT. How do I clean the primaries and secondary? This problem is almost non-existent but occurred years earlier intermittently on a very rare basis. I do not at all like the fact of being in the position with WOT. I just replaced the fuel filter as an outside shot, maybe unlikely but changed anyway. It is sort of a 'blue moon' thing; just in that light. If it were anything problematic, the issue would re-occur more often. Thanks and a response is appreciated. Again, I do not know anything of carburetor's, just not my line. To find anyone knowledgeable today is more than a task.
Last edited by synoptic12; June 24th, 2019 at 05:51 AM.
If the carb sticks at WOT, it could be caused by gummed up throttle linkage, defective throttle cable, some kind of mechanical interference preventing the throttle from returning to idle (floor mats, etc), mechanical issues with the throttle linkage or related parts (air cleaner jamming the throttle, cruise control linkage, choke linkage, weak return springs)the list goes on.
If you throw the trans in neutral with the throttle stuck, the engine is going to rev up. If your relatively comfortable with your ability to steer the car with no power steering, if leave it in gear and shut off the ignition. You shouldn’t be able to turn the key completely off unless the trans is in park, so no worries about locking the steering wheel. You will be able to steer the car and use the brakes, just with more effort.
If if there is any doubt in your ability to safely steer the car with no power steering, put the trans in nuetral. Better to trash the engine than wreck the car, or yourself. Engines can be replaced much easier than bodywork (on the car, or your personal body!)
first, spray the carb linkage with lots of carb cleaner. Then work the throttle many times with the gas pedal. Look all the linkage over, look for anything that may stick or bind. If you don’t see anything obvious, get another more experienced set of eyes. Better safe than sorry
* Thanks very much for the detailed info. I've checked everything and nothing seems to be binding, as well as the throttle cable having no frayed ends I can see. Sprayed the carb linkage and complete exterior of carb while using a toothbrush. The problem is to find someone that has knowledge with carbs, maybe easy for some, not me. I've seen the YouTube videos and do not care to waste my time. I just dumped a mechanic I've used for several years due to his limited knowledge and refusing to ever see or notice anything.
WOT = Wide Open Throttle. If you're driving down the road and the engine revs uncontrollably after actuating the throttle then the carburetor could be stuck at WOT due to binding in the throttle linkage or in the carburetor.
To clean the primaries and secondaries use your carburetor cleaner and spray it down the carburetor holding the choke open on the primary side and the air valves open on the secondary side. For now, clean it with the engine off as this is a SUPER fire hazard!
WOT = Wide Open Throttle. If you're driving down the road and the engine revs uncontrollably after actuating the throttle then the carburetor could be stuck at WOT due to binding in the throttle linkage or in the carburetor.
To clean the primaries and secondaries use your carburetor cleaner and spray it down the carburetor holding the choke open on the primary side and the air valves open on the secondary side. For now, clean it with the engine off as this is a SUPER fire hazard!
*Thanks very much. I did not use any carb cleaner down into the carb, rather outside only. As some have pointed out, spraying inside would cause deposits to move further down. When you refer to holding the choke open, is that with the butterfly 'open'? I'm not familiar with the air valves. I'll try to post some pics. Thanks very much.
1) Hold the throttle wide open.
2) Open the choke plate / secondary air valves.
3) Spray the venturi with carburetor cleaner.
4) Let the engine sit for 5 minutes before starting.
Don't worry about knocking stuff loose into the engine. Any gunk in the carburetor will be too small to damage the engine.
Thanks much. Is the 'red' primary and 'yellow' secondary? Sorry for my ignorance, but where is the venturi? Gumout states not to spray down the carburetor throat. A picture is enclosed whereby a video I have seen on YouTube states to spray the hole (White Arrow) while car is running. What is that hole where arrow is, and is that info correct?
* Could you place that synopsis in terms I can comprehend, WTO? Are you saying that moving the selector in Neutral could damage the connecting rods and leave the crankshaft damaged as well? If this occurs again and I shut the car 'off', how do I restart in traffic going about 70 m.p.h.? Thanks very much.
"I'm guessing the throttle was not WFO, at least not the secondaries if the engine survived running at no-load" > 'Please elaborate in terms I can understand. Thanks very much.
WOT = Wide Open Throttle
WFO = Wide ******' Open
WTO = World Trade Organization??? No idea.
"Stuck" throttle, or engine surge are not the same as WIDE OPEN THROTTLE. Even so, it could cause engine over-rev if the engine has no load (trans in neutral)
Originally Posted by synoptic12
* I found this piece which seems to relate to my issue:
Sudden Surge in Speed While Driving on the Highway
This is a particularly hazardous situation. What usually happens is that at high speeds, the butterfly valve inside the throttle may close up, and if the driver pushes on the pedal harder, the valve 'pops' open suddenly, giving the car an unintentional burst of speed. All of this happens if the sensor is unable to detect the closed position of the throttle.
*Could the TPS be at fault?
Possibly. Not likely. That advice is very poor. THERE IS NO "BUTTERFLY VALVE" in a carburetor. There's a choke plate, and throttle plates/throttle valve. They don't "close up" and then "pop open" on their own. But yes, a faulty TPS can cause engine surge.
Originally Posted by synoptic12
* I am equating 'surge' as being WOT, is this correct or are their two terminologies? I have already performed cleaning the carb on the exterior. Hesitant to lube the throttle with anything other than to clean with carb cleaner. I believe that from the information I've seen is that the secondaries are possibly the problem in WOT. How do I clean the primaries and secondary? This problem is almost non-existent but occurred years earlier intermittently on a very rare basis. I do not at all like the fact of being in the position with WOT. I just replaced the fuel filter as an outside shot, maybe unlikely but changed anyway. It is sort of a 'blue moon' thing; just in that light. If it were anything problematic, the issue would re-occur more often. Thanks and a response is appreciated. Again, I do not know anything of carburetor's, just not my line. To find anyone knowledgeable today is more than a task.
"Surge" is not WOT/ WFO. Depending on the amount of "surge" it could be a matter of timing advance or EGR operation, and not the throttle at all. I've had guys complain about the torque converter clutch engagement/disengagement as if it were an engine surge.
You have a computer-controlled engine. Time to connect a scan tool and look at the data stream. Also, when was the last time the engine had a proper tune-up (fresh distributor cap and rotor, spark plugs and plug wires, set timing, change all the filters--PCV, air filter, fuel filter, charcoal canister filter (if used) PCV valve, adjust idle mixture screws and/or mixture control solenoid, etc?
Mixture control solenoids used to be a high-failure item.
Originally Posted by synoptic12
Gumout states not to spray down the carburetor throat. A picture is enclosed whereby a video I have seen on YouTube states to spray the hole (White Arrow) while car is running. What is that hole where arrow is, and is that info correct?
Gumout's instructions are faulty. They were written by a lawyer, not a mechanic or engineer. Spraying down the carb throat is about 1/3 the reason people buy the product to begin with, along with spraying the various linkages and the outside of the carb in general. I know guys who have used aerosol carb cleaner to clean the internal passages of carburetor parts during a carb rebuild.
Originally Posted by synoptic12
Spraying down that hole does nothing but clean the choke tubes and choke housing, and only then if the carb has a hot-air choke. (Yours does.)
Last edited by Schurkey; June 24th, 2019 at 08:12 AM.
The venturi are circled in red. You'll see the primary venturi when you open the choke plate.
I agree with Schurkey, spraying crab cleaner down the carb won't hurt anything and is what it's actually used for. You can pull any codes on your ECM by shorting the A and B terminals of your ALDL (but that is a topic of discussion for another thread). A tune up (plugs, wires, distributor cap etc.) would definitely do your car good if it hasn't been done in awhile.
You can pull any codes on your ECM by shorting the A and B terminals of your ALDL (but that is a topic of discussion for another thread).
Pulling codes is not the same as reading the data stream.
Codes are often helpful. Sometimes, they're as helpful as the data stream. And don't listen to the folks who claim that there is no data stream on GM OBD-1 vehicles. There is--I used it often. You won't access it with a crappy code-reader, though. Takes a "real" scan tool. And the data stream on the early computer-controlled vehicles is not as extensive as the later fuel-injected OBD-1, and not anywhere near as extensive as OBD-II.
Thanks very much. You're surely adept on carburetors, more so than I. 'WTO' error on my part, meant WFO which is a term unfamiliar to me. I just performed a tune-up about 2-3 mos. ago. Replaced plugs, rotor, distributor cap, pcv, carb fuel filter, air cleaner. Did not change charcoal canister filter (unneeded). No timing, adjustment of idle mixture screws, etc. This is really in depth and too much for me. Your information is most appreciated. So, I do not have surge according to you as the WOT is the problem. I understand the difference now that you have expanded upon the difference. As to the photo depicting the arrow in which you state that 'hole' is to clean the choke tubes and housing contingent upon the carb having a hot air choke which my carb does, should I spray the hole with car running and will it provide any benefit?
I'll try cleaning the inside of the carb as suggested by you, wait five minutes and start. In the interim or after 'should I spray that hole' (White Arrow)? You did not make mention as to whether I should. In fact, I believe that the YouTube video showed 2 holes (one at each end) but I only see one on my carb. Again, I am very much appreciative of the assistance and courtesy you have provided.
The venturi are circled in red. You'll see the primary venturi when you open the choke plate.
I agree with Schurkey, spraying crab cleaner down the carb won't hurt anything and is what it's actually used for. You can pull any codes on your ECM by shorting the A and B terminals of your ALDL (but that is a topic of discussion for another thread). A tune up (plugs, wires, distributor cap etc.) would definitely do your car good if it hasn't been done in awhile.
Spray EVERYTHING on the carb with the carburetor cleaner. You can even use a toothbrush to get the gunk off of the throttle linkage and exterior of the carb. Don't do it with the engine running. As I mentioned it's a fire hazard. Plus, it will change the idle of your car and may wreck havoc on the O2 sensor or catalytic converter.
Pulling codes is not the same as reading the data stream.
Codes are often helpful. Sometimes, they're as helpful as the data stream. And don't listen to the folks who claim that there is no data stream on GM OBD-1 vehicles. There is--I used it often. You won't access it with a crappy code-reader, though. Takes a "real" scan tool. And the data stream on the early computer-controlled vehicles is not as extensive as the later fuel-injected OBD-1, and not anywhere near as extensive as OBD-II.
Spray EVERYTHING on the carb with the carburetor cleaner. You can even use a toothbrush to get the gunk off of the throttle linkage and exterior of the carb. Don't do it with the engine running. As I mentioned it's a fire hazard. Plus, it will change the idle of your car and may wreck havoc on the O2 sensor or catalytic converter.
* Thanks very much. Never cleaned the carb with motor running, ever. This is why I asked about that 'hole' (White Arrow) as to spray or not spray cleaner in there. A video stated to spray in that hole while vehicle is running. At this time, I'll clean the inside as suggested by the ever present Schurkey.
'WTO' error on my part, meant WFO which is a term unfamiliar to me.
WOT and WFO are the same thing. WTO is apparently a mis-spelling of WOT.
Originally Posted by synoptic12
'I just performed a tune-up about 2-3 mos. ago. Replaced plugs, rotor, distributor cap, pcv, carb fuel filter, air cleaner. Did not change charcoal canister filter (unneeded). No timing, adjustment of idle mixture screws, etc. This is really in depth and too much for me.
No problem, and the "usual issues" should already be handled with the work you've performed. Ignition timing should still be checked, though.
Originally Posted by synoptic12
'I do not have surge according to you as the WOT is the problem.
Other way around. The engine would not have survived being put into neutral at WOT/WFO. You maybe have a surge instead, which may or may not be throttle related, or even carburetor related.
Originally Posted by synoptic12
'As to the photo depicting the arrow in which you state that 'hole' is to clean the choke tubes and housing contingent upon the carb having a hot air choke which my carb does, should I spray the hole with car running and will it provide any benefit?
You should spray it. Unless there's dissolve-able deposits, there will be no difference once the cleaner evaporates and is burned in the engine. That hole is not a high-problem area--but what the heck, you've got the aerosol cleaner so you might as well.
Originally Posted by synoptic12
'I'll try cleaning the inside of the carb as suggested by you, wait five minutes and start.
OK.
This is really hard when we have no common basis for describing the actual problem. I'm fairly convinced the carb is not going to WFO. Whether the engine is surging is still open for debate. You would do well to describe how the vehicle runs and drives when you're having problems with it.
Last edited by Schurkey; June 24th, 2019 at 08:30 AM.
WOT and WFO are the same thing. WTO is apparently a mis-spelling of WOT.
No problem, and the "usual issues" should already be handled with the work you've performed. Ignition timing should still be checked, though.
Other way around. The engine would not have survived being put into neutral at WOT/WFO. You maybe have a surge instead, which may or may not be throttle related, or even carburetor related.
You should spray it. Unless there's dissolve-able deposits, there will be no difference once the cleaner evaporates and is burned in the engine. That hole is not a high-problem area--but what the heck, you've got the aerosol cleaner so you might as well.
OK.
This is really hard when we have no common basis for describing the actual problem. I'm fairly convinced the carb is not going to WFO. Whether the engine is surging is still open for debate. You would do well to describe how the vehicle runs and drives when you're having problems with it.
* I'm beginning to hate all cars. This is getting complex. The car runs excellent: 1.) No hesitation 2.) Good response 3.) Overdrive kicks in. The vehicle runs, again excellent; even when the problem occurs. i believe the problem is initiated by pressing on the accelerator quickly or activating the overdrive. Sometimes, the vehicle will increase power at speeds of maybe 55 and above, "Then the alleged WTO occurs" > at least this is the assumption I'm under. This is a rare problem as mentioned prior. Has occurred a couple of times a year or two ago: "Stopped for a year or more, then occurred last week". If I had the money, I'd probably have the vehicle looked at. And again, there are not many, if any knowledgeable people in the State I live. Too bad some of you guys are not here or me there. Thank you very much for the continued support.
* Just started. A tad, tad slow in starting. Raced the motor by increasing the idle several times. At one point, the throttle appeared to increase speed in not kicking down the idle. Shut down and restarted. Immediate start up, increased idle a few times and kicked back down good. Idle seems to be very superior and idle is much improved. My car is in the garage and my brother pulled in the driveway (my side). To ask him to move now presents a new issue. I'll have to wait to drive the car. Thanks very much for the excellent support provided by you guys. If there is anything I can be of service in this part of the U.S., contact me.
* I know not whether this problem will reoccur or if once the motor is hot the idle shall be the same. However, at this point, a huge difference. If the idle drops once the vehicle is run, could that be a hot air choke setting? All replies have been very much appreciated.
Just took the car for a fifteen minute ride, using the overdrive several times; much, much better. More so, the idle is much smoother in 'D' whereas before there was a little rough idle. Hopefully, the problem does not arise again. Thanks very much guys. I guess the instructions on the Gumout Carburetor Cleaner are not actually correct.
In addition, I changed the transmission fluid, filter, and gasket using Castrol Dexron VI overriding or in unison with Dexron II. Also, had the rear differential seal replaced, fuel filter, linkage spring and isolater (Bushing) replaced, new AC Delco fuel pump, new starter, new brakes and exhaust system, and valve cover gaskets replaced. I try to maintain the vehicle. Now, the tires are hard to come by 205/70R/14. Michelin, Goodyear, and Firestone have discontinued that model line. Going with the Uniroyal Tiger Paw AWR II. They arrived today but one tire has a DOT code of 2017 that I'm not accepting. The remaining three tires are August of 2018 which I'm hesitant.
My work truck has tires I bought prior to 2003 when I retired.
My beater Monte Carlo has tires Dear Old Dad bought years before he died. Maybe 2010-ish. They're crappy tires, but they were crappy when they were new, 'cause Dear Old Dad always bought the least-expensive junk he could.
My hot-rod El Camino has tires I bought in the 1990s sometime. I don't drive it much.
My work truck has tires I bought prior to 2003 when I retired.
My beater Monte Carlo has tires Dear Old Dad bought years before he died. Maybe 2010-ish. They're crappy tires, but they were crappy when they were new, 'cause Dear Old Dad always bought the least-expensive junk he could.
My hot-rod El Camino has tires I bought in the 1990s sometime. I don't drive it much.
June 24th, 2019, 03:21 AM
