2nd gen stumlles and puffs black smoke
 

was out replacing a bad TPS in my car and after i installed it and adjusted it i fired it up. ran perfect for 2 min them suddenly started stumbling and puffing smoke. it is very rough while idle. any help would be great

sounds like a cigarette smokin drunk

seriously tho, black smoke is a sign of a rich fuel mixture... if a mixture is too rich it will make the engine stumble

double check that the TPS you installed it working correctly and check for fault codes...

Note that TPS adjustment must be performed with the engine at operating temp.

haha quit smoking two years ago. i have checked TPS with no luck.

anyway to pull codes myself i dont have access to reader???

ok so i went out and made a code reader and found out that i am not throwing any codes.

could it bad be bad oil control rings ? depending on how bad they are gone, it would smoke alot during startup, oil consumption would be increased, and the higher your engine is revving the more it will smoke (high revs especially)

only way to fix this is rebuilding the engine.

the other thing you'll want to check out is your pcv valve and make sure its working properly. (if you still have one on your car)

i could be wrong though, i am assuming black smoke = oil, but it could be gas

I am not 100% sure if its gas or oil but i think its gas. I get a bit of a gas smell around the car. Not sure but is my best bet to pull intake off and try cleaning it and reInstalling it???
Dont want to do but i think i running out of ideas.
I not sure if i am hurting anything if i run it. I not driving it because it is shakey.

maybe a bad mass air flow sensor ? you can basically go through process of elmination to figure outs whats wrong, but im sure youll be able to figure out the problem if you're determined to.

ok well pulled off my TB and notice the top two barrels in the dynamic chamber were blackish rusty kinda color. the bottom looked clean but my flashlight was dead. is this bad???

im not 100% but i think if its black thats carbon and usually indicates you're running rich (too much gas going through). So if you're running rich something is causing the engine to get too much gas/not burn all the gas, you need to figure out whats causing it to get too much gas, could be a few different things.

Bad adjustment on tps, fouled out spark plugs would be on the top of my list of things i would think would cause this problem.

Check the tps adjustment if you know how, and take out the plugs and give them a look, if they're all black, have black gunk on the ends you should replace them.

What year is this car?

You shouldnt have carbon buildup in your intake manifold fwiw. Lol. Unless your flux capacitor has a short from pin 2a to 3b. Thats just dirt. What year and model?

ok well i already did plugs they were black and burt up. TPS was checked. its rough getting up to temp when its just stumbling. is it bad to just let stumble its way up to temperature like that???
also found that i have a vacuum line with check valve that goes from therma wax to solenoid on to of TB that is broken and i need to replace

If the vacuum hose runs to the Double Throttle Diaphragm on the front of the throttle body then just plug the hose before the brocken valve. This hose would have vacuum on it til the engine warms up so if it is creating a vacuum leak then obviously you should take steps to correct the issue.

yes that vacuum line with a little green chack going to Double Throttle Diaphram valve i need to replace. do i need valve or can i just use vacuum hose??? i think i might have broken this when removing intake from TB.

Chances are really high that the diaphragm is inoperable so you can just cap the hose before the broken plastic piece.

Ok thank you. When i get home today i will finish cleaninTB and reinstall it. Hopefully with some luck. Thank you all for help

ok so cleaned up and reinstalled my TB with some luck. when it started she went right up to about 3000 RPM and worked its way down and bounce around a bit(but no stumble or smoke). so i let it idle till it was warm so i can check TPS. after i adjusted TPS started it up again and i got an idle from 1200-1600RPM. i could not get rpm below that.
could my BAC have anything to do with this??? i checked resistance and it was out of spec. was 13.8 ohms should be 10.7-12.3 ohms.

did you try lowering the idle via the idle screw on top of the throttle body ?

W/the car idling use the throttle linkage at the front of the throttle body and press upwards on it and see if this drops the rpm down to a normal level. If it drops to a sufficient level then the problem could be a function of an improperly set throttle cable, the cruise control cable is too tight, the Fast Idle Cam is not working properly or unmetered air is entering the throttle body by mistake. You can always disconnect the electrical plug to the BAC to see if that changes the idle speed but it is doubtful that the BAC by itself is the cause.

W/the BAC plug disconnected you can hold a ground to one of the BAC's terminals and then place battery voltage to the other terminal and the solenoid should click each and every time. If it does click then chances are it's not stuck in the open position.

Ok well i tried to get RPM down with idle screw, linkage and checked my throttle and cruise cable. It hit me this morning that when i put intake back together i think i didnt tighten clamp behind AFM. That is most likely wherei am leaking air. Gotta check when i get home.

Will also check my BAC with the 12 volts. Thank you you guys are AWSOME!!!

The Idle Adjust Screw is for minor adjustments as it shouldn't change the overall idle speed by very much and certaintly not by 500 rpm. And jumpering the Initial Set Coupler would come close to shutting off the BAC if it were working properly.

Ok i went back to my intake and tightened it up then started her up. It slowly sputtered its way up to 2000 RPM. That all it wanted to do. There was a bit of smoke when it was sputtering up looked dark not sure black or blue. Not much time lastnight so i will go back at it today. Just dont know why i have an all new issue

Does the idle change at all when you press upwards on the throttle linkage? Have you checked the CAS position to see if the timing is set properly? If it's off then the rpm can be higher than it should.

Timing. Post #3, 9 and 16,

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/new-13b-first-start-loud-boom-timing-question-978911/