miguelc561

305 700r4 1986 sport coupe 100% OEM with 87k miles. Im literally about to sell my car for 1000 dollars and go carless for awhile. Ive.lost all hope. My car wont stay idling unless i give it gas. And when im trying to go it will sufficate or flood i cant tell. 100% rebuilt carb by a professional. All brand new vac lines in the correct places. New thermal vac switch. Its just so eratic. Any.suggestions?

midias

Sounds like you need to go back and visit that professional

Check fuel pressure

oreobadr

Could possibly be a vacuum leak and you could try advancing the timing a bit that usually helps to keep the car running to solve the problem

Ozz1967

iTrader: (4)

Check the vacuum, should be, stock, near 20". When your rev it up, should ve 22-25".

Plug all ports on the carb and intake except say, brake booster, if it stays running, you have a leak. If it doesn't, unplug one port and check the vacuum, anything less than 16 will give you issues.

Check your fuel pressure. Carbed fuel pressure should be 5-6psi. Any more and you risk flooding the carb.


Since the car dies when you give it gas, could be the secondary tension is too loose. Causes the secondaries to flop open, flooding the intake with air, causing a a stumble and it to die.

Have you looked over the Q-jet troubleshooting guide on the site here? It'll give you some ideas where to look.

miguelc561

So the servuce light finally came on and it says for me to check the thrttle position sensor. Could that be my only problem?

Ozz1967

iTrader: (4)

It's possible. Won't know until you change it.

miguelc561

Yea nothings working ive invested so much time and money into this one problem in about to call the scrapper

92g92

Why not go efi?

90camaro355rs

scrapper is no way to deal with an issue, patience my thirdgen owner, there are people on this site that will help if you are willing to listen!

miguelc561

Im all ears lol. New tps and messed with the voltage. Whole new carb. Messed with all adjustments. My cars telling me cylinder 1 is running lean and the o2 says that also. 99% sure i dont have a leak in my manifold. My car starts up fine after 5 seconds it tried to die and i have to constantly give it a small anount of gas to keep it on. And two foot it at stop signs. When i give t about half throttle it stumbles all over its self. All vacuum lines i checked and no leaks and correct places

miguelc561

I dont go efi cause of money lol im 17 and my first year owning this was great. Second i git all hese problems. The money i had to make it a 5 speed has been dumped into this one problem

midias

Welcome to the life associated with owning cars.

Take it back to the mechanic who rebuilt the carb

Did you check timing? Did you check fuel pressure? Did you mess with the idle speed screw NOT the idle adjustment screws.

miguelc561

Yes. Fuel pressure has not been checked and i dont have a timing light and spent my last few dollars on having the carb rebuilt and buying vacuum lines and what not

miguelc561

To measure fuel pressure is it just a small gauge i can buy? I have a whopping 50 bucks till i get paid again

miguelc561

Also my car diesels when shutoff and sounds like.its missing or maybe its cause its running so lean at driving speed. those point back to timing but i swear either im crazy or when i give it a small amount of gas i can hear the vacuum leak with the hood popped up. But all the hoses are new and clamped. So ill.try the soapy water experiment when i get home. Idk this things got me running in circles. And the fuel pump would make sense but i put another carb on my car while this one was being rebuilt and it ran ok except of course i was getting all kinds if codes and my mpg was horrible and i also had to two foot that one

jwfirebird

iTrader: (2)

soap is for tires, the vacuum sucks in air so you need to use something that will not hurt the engine, carb cleaner. let the engine idle, use something to block the throttle open so it stays steady if it wont idle, then spray the carb cleaner at suspected areas and listen for the engine to change pitch. suspect areas would be carb base gasket, intake manifold gaskets, any sensors on the manifold, vacuum lines and tubes, etc.

get use to your car sucking your money. its how you learn. we probably all have been there. at least you have the internet for ideas mine was all hard earned "stupid tax"

miguelc561

Yea i didnt think about that. So thanks for that info. Basiclly it come down to timing. Vacuum and fuel delivery?

jwfirebird

iTrader: (2)

every time i had lean codes, poor idle, and general poor running it was a vacuum leak. there are a billion places it can on a 86


just noticed i said vacuum lines and tubes, meant to say lines and tees.

naf

iTrader: (7)

electronic q-jet?

have your attempts to adjust the curb idle speed with the set screw failed?

Count turns out on the Idle Air Bleed and Idle Mixture Screws. Record where they are and if not near 4 turns out on each, try setting them there for now. While you're there pull out the IAB and inspect it. Insert a small rod into the opening, or one of the slots next to it, and you should be able to click the MCS up and down. Travel should be 1/8".

Disconnect every vacuum line at the carb and cap each one. With the motor running, reconnect each. If one of them causes the idle to change-chase that one down for a leak. Don't forget to check the fitting behind the carb on the manifold.

TPS bad won't cause a poor idle, it can cause an intermittent high idle, in that the ECM may keep the throttle kicker engaged.

You can carefully fill the float bowls on the q-jet through one of the vent holes. It should idle for a minute or two from the fuel in the bowl alone. If the problem persists when you KNOW the bowls are full, you can rule out fuel pressure as your primary problem.

miguelc561

Yes i believe its a e4me? Not sure if thats right lol. Ive been Around alot of carbed cars and mine for aure has the most vacuum lines. Quite ridiculous. But i will try that in an hour or so and will tell you feedback and my buddies got a timing light so we will also check my timing

miguelc561

Well everyone who just heard my car says its got a dead cylinder is what it sounds like and we cant get a reading on the timing for some reason and its hooked up on #1

miguelc561

Alright well the timing is just fine and all my problems are still here. Vacuum is fine. Voltage on tps is fine. All these guys are sayin i got a dead cylinder and idk what it is

jwfirebird

iTrader: (2)

check all your plugs, the ones that are dead will be wet and carbony looking

midias

how old are the plugs and wired?

Pull the wires one at a time, if pulling one does not change anything then that cylinder is not firing.

miguelc561

Is it the plug itself? Or distributor or wires? I feel like i wont know till i replace it

jwfirebird

iTrader: (2)

when you figure out what cylinder it is you can swap parts to a good cyl to see if the problem follows.

midias

you could inspect for damage and measure the wires

jwfirebird

iTrader: (2)

measuring wires doesnt tell you that much, most wires when they start to age the dielectric starts breaking down and leaking power to metal near them. an ohm meter isnt going to tell you that

naf

iTrader: (7)

If I were on a budget I would pull all of the plugs and clean them and use some light sandpaper on the electrode and ground strap, re-gap and reinstall. I'd inspect the cap and rotor and if the wear was light, I'd clean and re-install. If the wires were in any way suspect I'd suck up the $15 for a new set from RA.

Do not fiddle with the carburetor in any way until you KNOW the ignition system is tip top.

miguelc561

Ok i pulled each if the wires one my one and i dont think there is a dead cylinder but maybe one with a weak spark or something i swear i can hear it detonating

miguelc561

Guys would ignition really let my car run fine for a short while and then all of a sudden stumble on its self and have an eractic idle and stall itself

Ozz1967

iTrader: (4)

Yes, if a spark plug wire was shorting to the headers/manifold it would stutter bad, possibly killing it. Erratic idle, in my experience, is usually a symptom of electrical or vacuum issues.

miguelc561

I want to convince myself its vacuum cause it gets a little better once the car warms up but then again i replaced most of the lines. At least the important ones going to the carb. So i might just buy new plugs tomorrow cause they are kind of old

miguelc561

Wires*

Ozz1967

iTrader: (4)

Do the cap and rotor as well. IF the cap goes bad, it causes spark-scatter inside the cap which could cause a misfire.

miguelc561

Well its got a new cap and rotor now and checked all wires. Were good there but the car still runs the exact same. Its so inpredicable on the idle. It will.run ok for a sec then i rev it up and it slowly goes down until it dies

jwfirebird

iTrader: (2)

still sounds like vacuum issue to me, you test it like i posted?

miguelc561

I will when i get home. I thought i ruled it out cause i replaced all the lines but im also thinking its vacuum

miguelc561

Could it be the idle air bleed? I have yet to touch it cause i dont want to drill out the little guys holding the cover

miguelc561

After fiddling with my car it seems to run ALOT better when i barely push the choke down with my hand like it runs how it should. Is there an adjustment i can make to wear it doesnt open so much? Cause the choke in the carb is new

miguelc561

Or is that cause of the vacuum leak

jwfirebird

iTrader: (2)

does it do it if you push down on the carb without touching the choke?

jwfirebird

iTrader: (2)

im not real familiar with the stock quad TBO, there may be an adjustment to the choke that needs done, or if you push on the carb you might be making the base seal properly and thats fixing the vacuum leak

miguelc561

I am all out of starting fluid blake cleaner and carb cleaner so tomorrow ill make a trip to advanced. BUT good news guys. I swear right as my car is dieing i can literally hear my car shorting itself and its right by the number 1 cylinder that my car was running lean. I dont work tomorrow so i plan on fixing this once and for all. Ill look everywhere for leaks and replace my wires and hopefully will discover something. I really do appreciate your guyes help. My main thing about owning a thirdgen is that i have all these people to help me out. Just for a short while im selling my car to get a bike. Ill buy another third gen but not the base model sport coupe.305 auto like mine. Its gotta be a 350 ttop 5 speed wont settle for anything less. Itll be hard to find. Why are manuals so rare with thirdgens?

midias

good luck, also there are no factory manual trans 350 cars

miguelc561

Yes im aware lol which i think is dumb. Isnt cause the trans dont hold up to it?

midias

it was more about having to recert for emissions

jwfirebird

iTrader: (2)

you are better off getting a good solid body with whatever engine and making the car you want. the stock 350's werent anything special. a t5 or t56 and a crate 350 or 4.8/5.3 or ls engine has 50% more power and everything but the crate 350 will be much more fuel efficient

Noel_z28

did you figure it out im stuck with the same issue-_-

miguelc561

No. Im loosing mind