Noel_z28

I did some research and turns out to be the thermal vacuum switch witch is the same as the ported vacuum switch ima go buy it right now and replace it hopefully thats the solution

miguelc561

I replaced mine. I actually have two. Did nothing lol

Noel_z28

Well mine looks pretty beat so ima go get it

Noel_z28

Worked for me buddy

miguelc561

Uugh lol. Ok guys i got new plugs. Wires. Rotor. Cap. Coil. All vac lines. Timing set. Thermal vac switch. Sprayed everywhere with carb cleaner. No leaks. Fuel pressure is 6psi. Im running out of hope. Car runs the same as when i started

midias

Did you bring it back to the guy who rebuilt the carb yet?

miguelc561

Yes i did today. He checked the voltage on the TPS and looked at the charts and said it was checkin out ok. He also looked for vacuum leaks and found nothing idk what else he did but said he didnt know what to tell me

Noel_z28

My only guess is your having the same problem i have as we speak since i did everything you did too, tell you this cuse this is the problem i found out check the pressure of your exhaust i have no sorce of air flow my catalytic converter is plugged lets see it that helps im about to take it off right now and see how it reacts, that should be the solution everything that suppose to be released is gettin sent right back at the motor once it gets to the cat due to the cat being plugged up make sense right

miguelc561

Ill try anything at the moment lol but wont i have to cut it off? Pretty sure it doesnt bolt off

Noel_z28

I just unbolted mine i went with straightpipes, make sure your timing is good tho after you get it done cause thats the main cause of the cat getting clogged up

Noel_z28

I fixed my timing to and it works like new again completly satisfied=D hope you solve your issue too

miguelc561

Did it work for you

Noel_z28

Yes it did thank god and thanks to everyone who helped

nater

hey I had the same problem a couple of weeks ago and it happend again late last week. i had done the same as you the week before it happened the frist time, and the car ran great for a few days then started missing and boging a lot, the missing was one of my plugs getting screwed up. the boging and not idleing, exactly as you explained it, was the little vacuum plug in the manifold behind the carb. from what i understand this is to hook up a vacuum advance distributor, but on our cars it is just a ruber plug. mine blew off(somehow) and then the car wouldnt idle could kinda idle if you gave it gas but still eventualy died. the second time the replacment fell off because i just use what i could find, i replaced it with better hose and it has worked great since.

miguelc561

So for you it was the cat and for you the vac line. Well my vac line is in there just fine but at least you found your solution lol i will try my cat

miguelc561

Well the cat did nothing lol just made my car louder. Guys after i work on it always after its cold its runs 100% then after a minute is when all the problems show up. It sucks cause everytime i replace sonething i think i fixed it and then i drive a little ways and everything comes back. I think my problem is im missing 45 cubes lol

miguelc561

My car also diesels after shut off if thats connected aaaannd when the car is under tow or going up hill i hear a rattling sound as if its a dead piston. But ive replaced everything....so my motor?

miguelc561

Am i being given up on? Lol

90camaro355rs

are you sure your timing is correct?

90camaro355rs

are you sure your timing is correct

90camaro355rs

didn't mean to post that twice, didn't see it post the first time

Joe Tag

iTrader: (4)

The rattling you hear is detonation, timing is too advanced. This is very damaging to the engine. Disconnect the black and tan wire from the distributor, set the timing at 6* BTC and go from there.
Dieseling is usually the throttle plates too far open. It allows the engine to continue to get gas and air after you shut it off, which is then ignited by hot carbon buildup in the cylinders. My guess is your mechanic did not properly adjust your carb after the rebuild. I recommend you refer back to Naf's post #19.

miguelc561

100% sure had a professional do it and he even taught me

miguelc561

Ouch didnt read that one lol ok i will check timing again tomorrow

1986 iroc z28

post a video of it running

dustin1984

Had same problem don't remember the tool but you plug a vac hose with it and it measures the suction. Loosend my distributor and turned it very slowly to the left or right it would then either idle worse and die or sound like a beast. Not 100% sure you have same problem but the only money it will cost to try is for the tool and maybe you can rent and return so wouldn't hurt to try. 84 firebird 2.8 v6 manual 5 speed

jwfirebird

iTrader: (2)

that sounds like vacuum advance, on electronic engines you have to set it as above

miguelc561

I gave up and simpky took it to the shop and told them its their problem now

Noel_z28

what did they tell you it was?? how much did they charge you??

miguelc561

They have been working in it for a week. They still have no clue lol. At least i know im not retarded now

miguelc561

Well guys. They have absolutly no clue they said they spent alot of time.working on it. Messin with things. They want me to get rid of everything computer wise. Basiclly new carb intake amd distributor but i already went that route amd it didnt help. So now im stuck. I dont know what to do. They said im running on all 8. Bout to write a letter to the president of gm lol

miguelc561

Ask him what he would do

Joe Tag

iTrader: (4)

He'd give you a brochure of the 2014 ZL1.

Noel_z28

lol write it haha, im pulling my motor out im just going to re do everything **** it, if i can why not right

naf

iTrader: (7)

Do you intend to put forth the effort necessary to fix it? Don't want to waste anyone's time.

Noel_z28

im actually pulling the engine out later on today to
i will be sending the motor out to get rebuilt, ill just go with a new carb and intake manifold

miguelc561

I think i will be taking everything out computer wise

Noel_z28

i hate wiring, these cars are a headache to fix but once there up and running there fun to drive

FtrSpeedy

I would try changing the distributor module and try running higher octane fuel, compression check cylinder. Does that engine have a knock sensor?

8Mike9

If you haven't pulled it yet, you may want to verify closed loop operation (scan tool) and search on how to set the MC Dwell...this problem sounds familiar from the past.

Noel_z28

thanks but i already pulled it out ima send the motor out to get rebuilt since ive been wanting to do it

jwfirebird

iTrader: (2)

seems like a waste of money, is it burning oil or coolant?

its likely something that will be resolved once you put an aftermarket ign and non emissions intake/carb on

miguelc561

Ok so basicly if i get a normal carb. Intake. Vacuum advance Distributor. And water neck and headers would that get rid of the computer? And most vacuum lines

Scorpner

iTrader: (4)

Not with a 700r4. You would need to modify it to run without the computer. FWIW, I replaced all of my vacuum lines before only to find out they were all leaking. I had to go to a different store to get tighter fitting lines.

miguelc561

How will i have to modify the 700R4 cause i think im going that route

Scorpner

iTrader: (4)

This thread should explain it.

https://www.thirdgen.org/forums/tran...ock-up-no.html

Scorpner

iTrader: (4)

I caught up with this later and quickly read through it so forgive me if I missed anything.

When the carb was rebuilt, did they check the throttle shaft bore/s? They can leak air causing issues similar to a manifold leak. The links below are for reference only so that you can understand what happens. I had mine done at a local carburetor shop. Could maybe try a little spray at that location to see if there is a change?

http://rmcavoy.freeshell.org/Q_Jet_bushings.html
http://quadrajetparts.com/rochester-...tion-a-19.html
Different car same deal:
http://www.vw-resource.com/air_inleakage.html

miguelc561

Yea idk guys. Tried alot of things. If i start her up cold. I have to give her gas to keep it on. Then itll idle by itself just fine. Then once its driven and warmed up it kreeps up to 1500 and the cars all over the place

miguelc561

Might as well do the manifold gaskets

miguelc561

Another thing to add. The breather guy off the valve cover that goes to the air cleaner is steaming. So im thinking she needs head gaskets and intake gaskets? I have no problem doig the intake. I just really dont wana pull the heads off