spudders at 1/4 Throttle

[CrazyMts]

Hello.
I'm new here, I found the web site a few days ago and I 'm thankful! I live in Montana@ 5270 FT
I have a 1984 Tercel 4wd wagon FED with an auto trans.with 148000 miles. I bought this car in 2000 been drive it ever since. I 've been having problems with for the last 5 years. The problem is that its spudder's at 1/4 throttle and when you go past that it runs ok not great just ok. I don't have a tach so when I set the timing at 5 degrees with vac unhooked and plug. I read it should be about 13 with averything hooked up. I checked for vac leaks and sprayed around the carb. The engine didn't race.

Where should i start to look for problems? The compression is 140 in all cyl. I'M selling it and had it on bozeman.craigslist on sunday 17 2013 because I didn't know how to fix it.

Any help I would be greatful.
CrazyMts

[TURTCEL]

Weclcome CrazyMts...these Tercs are great little cars but can definitely have some runnability issues.

As far as the timing goes it should actually be set to 10 degrees BTDC instead of the stock 5 degree recommendation. The factory timing was set for emissions reasons. These rigs are more responsive and have better economy and lower exhaust temps when running at 10 degrees BTDC. Sounds like the advance unit is working so prob no internal vacuum leak there. Double check it though by applying vacuum to each port to assure it holds vacuum. The 2 side by side ports need to be checked by plugging one and applying vacuum to the other to hold.

I would check the fuel filter and others as well to make sure they are all good.

Check the FSM for carb adjusting procedures as well to make sure all is good there too, easy to do. Check the float level throught he viewing glass on carb refer to FSM.

I had a leaking EGR valve that caused a little hesitation under low throttle and deceleration around 1800 RPM's. I removed my EGR system since we do not have SMOG testing where I live. You can't check for a leaky EGR valve at idle because the EGR only activates at higher RPM's. With the engine running take a can of carb spray and while running the throttle up by hand at the carb to 1500 to 1800 RPM spray the carb spray under the EGR valve at the diaphram body to see if there is a change in RPM's could have a leaky pintle valve too which would be a leak all the time as well. You can use an unlit propane torch with a hose on the end too like carb spray. Open it just a little on the propane valve and spray around to locate vacuum leaks too.

Check your spark plugs too.

I know there will be plenty of responses coming from some longer time members soon so pay attention to what they suggest, they have helped me greatly.

There is also the HAC (high altittude compesater) on these Tercs but I don't believe it is on your model.

Check the trans fluid level too. When was the last time the filter was changed. DLB mentions about an AT adjuster so look for posts on that too.

Good Luck.

Peace

[dlb]

hi crazymts. it's honestly probably not a big problem. vacuum leaks are a good place to start but spraying carb cleaner is not a definitive test. get a clean vacuum hose and attach it to each diaphragm—the vacuum advance unit at the bottom of the dizzy, the choke breaker, the throttle positioner, etc. suck on each one and make sure they hold vacuum. if they don't, ie if you can suck air through them, they are broken and need to be disconnected and blocked off, or replaced. also test the auxiliary acceleration pump, which is mentioned in the aux. sub-chapter of the emissions section of the FSM. the FSM is available for free here.

https://tercel4wd.com/forums/viewtopic.php?f=2&t=8103

next, make sure all the vac hoses are properly routed. use the diagram on the underside of the hood to do this. the hoses that go to the vac advance unit on the dizzy must go on the correct way; the hoses going to them supply vacuum at different times, and each port on the unit supplies a different amount of advance. next, make sure all hoses are securely attached and none are cracked, broken, or disconnected. check to make sure all the intake and exhaust manifold nuts and bolts are snug. do this with the carb mounting nuts too. any of these can wreak vacuum havoc with your system.

you might also check your float bowl level. this is mentioned at the start of the 'fuel system' chapter in the FSM.

does the car idle ok?

[CrazyMts]

Thanks for the reply's! I will run some of the test thats been suggested. I did download the FSM and was trying to figure out what to do!

CrazyMts

[TURTCEL]

You are on your way. Keep us posted on progress and be sure to keep asking questions.

Peace