Narrowing it Down...TURTCEL

[TURTCEL]

So I got the Terc back yesterday from the shop after taking it in to get the carb fine tuned for the higher elevation that I live at here in Idaho, as well as the timing checked. The mechanic had issues getting the car not to have slight hesitation under light acceleration.

I had just replaced the carb, EGR valve and dizzy with a new vacuum advance. The mechanic got the carb all dialed in and running great on that end and the reman dizzy in and timed correctly as well. But, after that it was still hesitating. He checked the new EGR valve and said that it was opening during light acceleration which was at the wrong time causing the car to run bad.

He plugged the line going to the EGR with a metal bb and said that the issue went away. I picked the car up from the shop and it seemed to run pretty good.

Before I changed the 3 parts the car seemed to be very peppy and had no symtoms like the ones described. But, right after installing the new parts it ran great and then the next day I could barely get it above 25mph. It felt like the choke was stuck on. After the adjustments and EGR block off I figured it was ok. The car now runs well but seems like it has less power than it did before and has a slight "miss" sensation on light acceleration still. Also, it sometimes feels kind of like it has a power-band like a motor cycle. It is very slight but almost goes from smooth acceleration to instant extra power and get up and go. The timing is set and carb adjusted. Seems to me like the car feels a little boggy almost like it is a little too rich. Eventhough the exhaust smells ok with no scent of unburned fuel. The car idles great and starts from a stop just fine. Only seems to happen at light acceleration or heavy footing the gas pedal. The Terc fells like it is dragging dead weight (checked brakes and they are not dragging). Any thought from the master minds?

Peace

[xirdneh]

i have had some wierd experiences with 3A carbs
my friend had a bogging on acceleration problem with his tercel
i put another carb in it (i re-built it) that did not solve the problem
tried two more home re-built carbs with no luck
the fourth carb worked and i have no idea why

on another tercel that bogged on acceleration it turned out the ball bearing under the accelerator pump had popped out
there is a "G" clip that holds it in

last but not least on another tercel that bogged on acceleration there was about 1/4 teaspoon of water sitting in the chamber behind the primary jet (screw)
when the top of the carb is removed and a few parts and screws removed you can look down there

oh yea, just remembered another
on one car that hesitated on acceleration but not a full bogged
i had left out the accelerator pump spring

[TURTCEL]

The carb I got was from Guaranteed Carbs out of Florida. It is the second one from them. The first one had a leaky throttle shaft so they sent me a warranty carb to replace it. The mechaic said he got the carb all set up just fine.

It doesn't seem to be a carb issue other than it may need to be leaned out a little or maybe the timing was set back to 5 degrees when the shop replaced the dizzy. Just seems like it lost a little pep more than anything.

I will have to do a fuel mileage check too since who can ever really bank on the sender being good on these rigs.

It has also only been in the mid teens for the daytime highs and down to the negatives at night. I have been told that these carbs tend to be a little bit of a pain at really low or really high temps outside. Could this also be a factor? The shop obviously adjusts the carb inside where it is warm and then it goes out into extreme cold...could it be too rich?

I live at 4000ft above see level too...could the HAC be a possible culprit? I am going to go buy a vacuum pump today so I can just start testing all the vacuum components in the system one by one.

Thanks for the advice on the carb, I have found through experience that even new parts can be the problem...case in point my new defective EGR valve.

There are also no vacuum leaks (had a smoke test done) and all vacuum lines are confirmed to be correct.

Peace

[Petros]

Carburated cars tend to have trouble in both very cold and very hot conditions. Once the engine warms up however it should run fine as long as you are not getting any carb ice forming. Is your heat riser (which draws hot air off the exhaust manfold) working properly. this would be real important in very cold conditions.

Another issue might be the ethanol blend fuel we get might be making it run poorly in very cold weather. these cars were not designed to run on ethanol and I notice mine runs better when I can find pure fuel. You might check out pure-gas.org and see if they list the filling station near you that sells ethanol free fuel.

[TURTCEL]

You have very good points Petros...I will check the heat riser tomorrow. If I remember correctly the heat riser should be closed when cold and open when warmed up, correct? I should be able to watch the door open when heating up and close if vacuum hose is disconnected. Could I use a vacuum pump to test the heat riser as well?

I have been running premium fuel in my car since I got it but I don't always have time to get non-ethanol fuel. We have one station in town that sells it but they are only open till 5 and closed on Sundays. I try and make it a point to always fill up there. But my last 2 tanks have unfortunately not been from there though so that may have something to do with it.

I just checked my fuel mileage after filling up and I was only at 18.5 mpg. I have had the car at the shop being worked on so lots of idle time, it's super cold out so takes longer to warm up, and obviosly will be running richer now because of the cold. I am not scared by that number, right now. I restarted my odometer and wil recheck my mileage on next fill up. I have a feeling that all the factors that have been going on have played a big part in the bad mileage numbers.

Before getting into the EGR system I rechecked the timing from the shop and it was at 5 degrees so I reset it to 10 degrees and reset the idle to 800 RPM's. This seemed to get rid of the dogginess on acceleration that I was having but I am still have a slight hesitaion under light acceleration at lower speeds.

I just replaced the EGR valve the other day and since right after then the car started running absolutely horrible. The shop that fixed it put a bb in the EGR line to keep it from opening. It did not do this with the factory EGR valve that I took off which was completely plugged. I figured the new EGR valve was defective so I cleaned my original EGR valve and put it back on...figured this would solve the problem (I checked the EGR valve with a vacuum pump and the diaphram is good. The car ran better with old/cleaned EGR but then very shortly after that it started running very chuggy and boggish again. i replaced the vacuum hose with the bb blocked hose and the car now seems to run fine. Still a little hesitation during light acceleration at low speeds but not bad at all.

I replaced the TVSV with a new factory Toyota part about 2 months ago. I checked the check valve and it is good. I also checked the modulator filters and they were clean. I have now looked at the FSM section on the EGR valve (fed,MT). I will check the modulator's air flow and make sure it is not in backwards and working properly.

I see the process for testing the TVSV and was curious if that part, the modulator, or gas filter could be the issue. What does the gas filter do and how can I see if it is bad? What are the symptoms I would have if any of these componente were bad?

It seems like the issue I am having is in the EGR system. Does anyone have any experience with this system as far as similar situations that they were able to fix? I would love some advice on this. I know a lot of guys just disable the EGR but I would prefer to have everything working if possible.

Peace

[TURTCEL]

So I really narrowed it down this time...another bad carb. This is the second carb that I have gotten for the Terc from Guaranteed Carbs. The second one being my original that they rebuilt and sent me as the warranty replacement. Turns out that the throttle shaft leaks on this one too.

I spray just a tiny shot of carb cleaner right at the throttle shaft and the ca goes from a nice smooth idle to dead. It kills it instantly. I even disconnected the throttle cable and was able to get the RPM's to change by lightly moving the throttle shaft. Both carbs were said to be rebushed on the throttle shafts and checked...checked?

This has become a "slightly" frustrating situation since I have now removed the second carb and the Terc sits without her heart. I need a transplant! I am going to call Guaranteed Carbs tomorrow and see what the situation is on now the second bad carb in less than a month from them. I understand these carbs are tough ones to get a good working unit in rebuilt condition,but seriously.

How good is Nationals reputation? I would appreciate as many feedback responses from any Tercer that has used them personally or knows someone who has. I really like the lifetime warranty at such a good price but I am considering other options.

I would also like to get opinions on Weber conversions. I live in the high desert in southern Idaho at around 4000 feet elevation. My concern is that I live up pretty high so the amount of higher elevation travel is less than the lower elevation trips. I know Weber makes a nice conversion for these Tercs as long as you don't have to deal with emissions. We live in an area that does not require SMOG so I would be ok there. I have heard that these carbs need to be jetted for the elevation of your main area and that major changes in elevation would require jet changing if long term stay woud be in a different area to aquire maximum performance.

The elevation change I would see on average would only be around 2000 feet. How woud the Terc tend to run with a Weber under these conditions? Anything special I need to know about the conversion process?

I have seen threads in the repair manual section and repair section that I will be reading over to help in my decision. I just would like some present day feedback and any new findings on the Weber conversion that would be helpful to know about before buying...if I do.

Thanks again Terc mambers.

Peace

[dlb]

lots of frustrated peeps go the weber route. i don't know how it would be in high altitudes but i believe you could just swap the jets to accommodate for that. do a search here for what weber jets to use at high altitudes.

when i first got into tercs, i had a few carb issues that i couldn't figure out with my lack of knowledge or experience (in hindsight, i think i had a faulty EGR and low float level). my buddy prompted me to get a weber so i went for it. i loved it at first but after a while, i regretted it. even though my weber was brand new, i still had a few issues with it over the course of 2 or 3 years and for how much it cost to buy and ship it up here, i don't think it was worth it. also, i love the simplicity of the stock carb emission. yes, it's a lot of hoses to stare at but once you familiarize yourself with them and understand what each thing does and how it does it, you realize how bone simple vacuum systems are, and the sheer poetry of how all those systems work together. i also totally support using emission systems to decrease driving pollution.

on top of all that, i've learned that i personally love the KISS mantra—keep it stock, stupid. i know petros is going to tear me a new one right now but i really do love everything stock. it makes it so much easier to find parts when things go wrong, or if you break down somewhere away from home and have to have a garage do work: explaining various mods to dubious mechanics makes a bad situation worse. since i swapped that one weber on, i've encountered numerous stock carb problems but none that i couldn't eventually lick, and i think that's important too. i like learning and improving my abilities to problem solve with this kind of stuff.

in short: my advice is to stick it out despite the frustration, but do whatever feels right for you. best of luck in whatever you choose.

[Petros]

If you can get the stock set up working properly it is a much better system for the high altitudes and extreme temp (both high and low) where you live. It is a very reliable system but you have to replace all of the suspect components (it is over 26 years old on your car after all). I suspect the weber would be frustrating since when it works right for one condition it would be out of whack for the others. I recommend you work though the issues and stay with the stock set up.

If you had a highly modified engine, and you did all your driving in a places where the extremes were not as far apart as where you live, the weber would not be a bad option (though it is a much more costly option than keeping your current system).

[TURTCEL]

Well I have no idea why...exactly, but pretty sure I got the hesitation issue figured out.

I called the tech line at Guaranteed Carbs and talked with a really knowledgable older guy named Jeff. He is their tech/mechanic of the shop. He really knew his stuff about the Terc carb set up and components. He had me do some adjusting and testing of the carb that was on the car (the second carb). He told me that the hesitation was prob from running too lean and also that the HAC or one of the fuel solenoid might be bad.

I did not have any of these runnability issues with the first carb they sent me...just a leaky throttle shaft. Jeff told me that there will always be some leak because it is a bushing not a seal and that in order to compensate for the shaft leak is to richen the mixture and the leak should lessen. I could not get the second carb to adjust smooth while driving and all my components checked out good.

I finally just bolted the first carb back on and adjusted the mixture a little richer and low and behold the runnability issue completely went away. The only hitch was that I used a different base gasket than the one that is called for. I used one that Guaranteed Carbs sent me that has 2 seperate holes for the 2 barrels and a couple extra holes that do not cause any issues with sealing once mounted. The only real difference is that the original gasket has one large opening for both barrels. The car runs great...but I won't say it is fixed since everytime I do it seems to have a problem.

The one concern I have now since I just took it on a nice long highway speed test drive and unless I have the heater on high the temp guage rises to the top of the little thermometer symbol on the temp guage and then will lower if I turn the heat up to high. It never got this hot before this with this carb originally or with the second carb.Only since I used this different gasket. I see that there is an electrical connection that is on the carb spacer that goes to the PCV system. Does this sense heat? Could I have possibly compromised the system with this gasket? Since this gasket is different could it be causing the temperture rise? It has only done this since the gasket change. The temp seems to rise higher in 4th and 5th gear but lowers at slower speeds.

My EGR is also disconnected...would this cause any heating issues?

I have the correct gaskets ordered for the car and they will be here tomorrow morning. I am going to replace the gasket with the correct one in the morning but I am curious to know if the wrong gasket could be my temp issues?

Peace

[Petros]

Neither of those issues will cause it to run hot. When you turn on the heater and the temp drops it is an indication of limited cooling capacity, that means either your radiator needs to be flushed or boiled out, or the thermostat is going bad (not opening all the way). If your t-stat is more than 2 years old, or of unknown age, replace it now with a good quality one (that would be in the $16-20 range, not the $6 cheap one). The cheap ones are often junk right out of the box, and they cause the temp to fluctuate and they fail early. not worth the trouble.

Also a weak lower hose that constricts when the engine is a high rpm (from the pump sucking coolant up it), you check it by watching the rad hose when you advance the throttle to over 3000 rpm.

[TURTCEL]

Cool. Thanks for the info on the carb gasket. So, should I just leave it alone since it is running really good right now, or should I put in the correct gasket?

The car had a new radiator (looked fine inside) and water pump installed 2 years ago and I just flushed and replaced all the coolant right before winter this year. I also installed a new factory Toyota Tstat at the same time.

The car never did this earlier today while working on it and test driving. It only happened after I put the last carb on it and took it for a drive. Where is the normal operating area on the temp guage? It only got up to the bottom of little thermometer symbol before that. Maybe I bumped the temp sensor wire loose...I will check that tomorrow.

I noticed that the coolant will go into the overflow but not completely back into the radiator after the car cools down. It was only 19 degrees outside today for a max and has been averaging that for the last few weeks so very cold outside. Could I have an air bubble in the system? Could that be why the temp guage goes up and down even without turning the heat on? I noticed that the coolant was to the top of the cores so maybe needed a little added. It also has a new cap. I thought that if the coolant didn't return back into the rad that there was some type of leak somewhere. I had a pressure test test at the shop 2 months ago and all was good. What else could it be if these all check out ok? I will check that lower hose tomorrow too, thanks Petros.

The fan comes on when it should too, so that is all good.

Peace

[dlb]

warmed up temp should be around half or just under on the temp gauge.

no need to mess with the gasket. it has nothing to do with the engine temp.

when the engine is cold, check and fill the coolant in both the rad and the overflow bottle. it's possible there was an air pocket in the system. when I fill rads, I burp both hoses to try to get as many air pockets out as possible but I still usually find that I need to top the coolant up once or twice after taking the car on a few good drives.

most likely the temp sensor wire got bumped. it is at the front of the head. might be a good idea to pull the wire off and clean the tab that it slips on to.

[TURTCEL]

Yeah, I did clean the sensors and tabs when I did the coolant...hope it's just a loose wire. I am just surprised that it did this all of the sudden. I don't want to overheat this baby so I am gonna tackle this issue tomorrow as my priority.

Peace