Rookie here with Vacuum issues possibly more.

How-to's and repair secrets for your 4WD can be found here. Have a question? Ask it in here!
trailerparkzero
Member
Posts: 35
Joined: Fri Jan 11, 2013 11:11 pm
My tercel:: 1983/85 halfbreed and a beastly 84
Location: San Diego, CA

Re: Rookie here with Vacuum issues possibly more.

Post by trailerparkzero »

Its tempting to disable the EGR but I pretty sure thats not my issue right now.
I have a lot to report learned a lot of things lately bu I think I have even more questions then when I started.
Well guys and possibly gals here it goes. I pulled the carb and rebuilt because I just wanted to check everything out but it might not have been absolutely needed. I am great at loosing stuff so I decide to take a long and trusty method and labeled each assembly per the FSM in in its own ziploc bag.
I found that my secondary throttle diaphragm was about half full of oil. How it got there I have no idea. Maybe it happend before I replaced the bad pvc valve. I also found that when I installed my aap diaphragm i somehow missed a hole and pinched it over. THat why it leaked until I tightened the crap out of it.
Another rookie move I found that I have myself to blame for is 3 misrouted vac lines. This is why im not going to label anything the next time i do something like this again. Labeling is only good if its right before you do it.
I put it all back together and the car ran better but it is still having unsteady idle issues and I can here it pinging sometimes and it only pings when its running poorly.
ITs way better but it still seems like a vacuum leak. I set it to 8 or 9 hundred rpms and the its fine for a little and it will sag down and run ruff. Sometimes the idle adjust dosen't seem to change anything. or if i turn it up its like the problem that caused it goes awway and the idle is set too high.
I know this wouldn't cause pinging but I wanted to check the few cut solenoids because i didn't do that when I had the carb off.

Can somebody clear something up for me? when the car is turned off does that short the fule cut solenoids to ground? Because I measure a dead short to ground when the car is off. I thought i was being clever and i tried testing the sol when the car was off with it in circuit. Well it worked but it made a loud arc and that how i found it. I hope I didn't toast anything, it seems ok because when I switch the car over to "on" I measure 12V on each solenoid.
Some day im going to stich all the pages of the schematic together so i can get a real understanding of the electrical system.

I just cant seem to figure this out and i tempted to seek out a good mechanic any chance anybody can recommend one in the southern california area?

Well working on my car i thought of a great invention. A grease proof tablet case with a hook on it so you can hang it from your hood and use the FSM. I would buy a tablet if something like this existed.
User avatar
dlb
Highest Ranking Member
Posts: 7447
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

Re: Rookie here with Vacuum issues possibly more.

Post by dlb »

good job on rebuilding the carb, and fixing the misrouted vac lines. it's surprisingly common. i think lots of professional mechanics probably made that mistake too. it's very easy to get mixed up.

what makes you think your idle issue is not your EGR? if it's 30 yrs old and has not been replaced or even cleaned out, you can bet it's chock full of carbon buildup which would likely prevent the pintle shaft from sealing. i would try it just to eliminate the possibility.
User avatar
Petros
Highest Ranking Member
Posts: 11941
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Rookie here with Vacuum issues possibly more.

Post by Petros »

most of the mechanics out there were not even born when this car was new, so you will have a hard time finding someone familiar with this car and the fuel system. I think you are better off just working your way through the systems yourself and fixing it. It will cost less and you are more likely to find it than a mechanic unfamiliar with this car.

One solenoid cuts the fuel supply off when you turn off the engine to prevent run-on, the other cuts it out when you down shift or let off the gas so you do not suck extra unburned gas into the engine. If either one was not working it would not run properly at all, that is not your problem.

engine speed cycling is an vacuum leak, if it only happens at low speeds it is likely a small leak. did you check the manifold bolts when the carb was off? it is easy to retighten them. they sometimes work loose from the temperature cycling of the intake/exhaust manifold.

check and double check the routing of the vac lines, their condition and any other possible source of a vac leak. You can test for vac leaks by spraying "Gumout" brand carb spray cleaner around the carb and vac lines, intake manifold, etc. and the engine speed will increase when you hit the spot with the carb cleaner where the leak is located.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
trailerparkzero
Member
Posts: 35
Joined: Fri Jan 11, 2013 11:11 pm
My tercel:: 1983/85 halfbreed and a beastly 84
Location: San Diego, CA

Re: Rookie here with Vacuum issues possibly more.

Post by trailerparkzero »

Thanks for the encouragement DLB and i dont thinks it is the EGR because I put in a new one in from amazon about a month ago.
FOUND IT!
Rookie move number 20 something. How to use and interpret a vacuum gauge. scenario 16: "if you get a reading that is steady and strong but the vacuum rises when accelerated you have the gauge on the wrong side of your break booster check valve. Rook!"
After that I hooked up the gauge at the disabled HIC line. it was shaky and was creeping around slowly. so I searched and searched, found another misrouted line and it still was not good. I realized that i could push on the throttle and lower the rpms. The trottle was not going all the way home. Then I realized that the extra spring that came on the carb from petros needed to be on there. I'm Derp! solved the high idle problem! This car was missing this from the day I got it. and I tried hooking it up like petros had it on the spare carb but it moved like junk but then I saw it goes on a piece of metal not on the carb it was just there to keep track. Thanks Petros. It still showed a vac leak and would rise in idle sometimes so I thought I would clean the linkage on the shaft and when I hit it with carb cleaner the rpm would change.

It's for sure leaking from the primary trottle shaft on the back of the carburetor but I tightened it and it only seemed to get worse. Anybody have any luck trying to seal this back up. It makes sense why this car would run on now.

Whats funny is before I found this today my camping buddy said I should take it to this shop by his house. told me its some old Asian guys wo are always doing on all kinds of work on cars. They have a $30 eval charge. So I said why not and took it in. THey asked "what year is it" 85 "does that have a carb?" Yes "Sorry we dont know how to work on that"
Ha!
Well i'm glad they didn't! I went to my friends and was showing him my problem and I told him about the test and how I cant find it with the carb cleaner tric. Then I showed him the trick and hit the shaft and we both looked at each other. DING!
User avatar
Petros
Highest Ranking Member
Posts: 11941
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Rookie here with Vacuum issues possibly more.

Post by Petros »

when companies re-manufacture the carbs and the shaft is worn out they usually drill it out larger dia and put a bushing with a seal in it. If you are equipped to do this it is not too difficult, but it is easier usually just to find a used carb with a good lower throttle body and swap it out. You might try a temp fix of just putting some silicone sealant in the throttle shaft bore to see how it works. It till not last too long but you can see if there is much difference in driablity. Usually, my own car included, you just live with a slight leak and allow it to idle around 900-1000 rpms.

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
Post Reply