Hot Rod Forum banner
61 - 80 of 120 Posts

·
Registered
Joined
·
4,239 Posts
Figuring out a carburetor problem is a lot easier then trying to understand women and there problems. Been married 21 years and still can't figure things out with my other half at times lol. Keep working at it and don't give up. Its times like this that it will give you a heck of a lot more experience and in future times when problems arise you will be able to figure them out a lot easier and tune even better.

Trust me when I was 18 years old I did not know even how to adjust the idle on a carburetor let alone troubleshoot one. I only knew how to check and fill fluids and that was it. It took me a lot of years and reading and experience and to a lot of folks helping me on here that has led me to where I am now.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #63 ·
Figuring out a carburetor problem is a lot easier then trying to understand women and there problems. Been married 21 years and still can't figure things out with my other half at times lol. Keep working at it and don't give up. Its times like this that it will give you a heck of a lot more experience and in future times when problems arise you will be able to figure them out a lot easier and tune even better.

Trust me when I was 18 years old I did not know even how to adjust the idle on a carburetor let alone troubleshoot one. I only knew how to check and fill fluids and that was it. It took me a lot of years and reading and experience and to a lot of folks helping me on here that has led me to where I am now.
i'm not saying i have women figured out; i certainly don't. What i'm saying is that based on my history, i have an easier time getting someone to go to bed than fixing cars. And that's saying something......
As we will find out in a sec.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #64 · (Edited)
Anyways, back to the problem:

It has worsened:
Replaced pickup coil with an AC Delco unit because i tested the one in there and the OHMS went all over the place as i moved it back and forth----to simulate vacuum advance. They still stayed within spec----500-1500 OHMS but they did move wildly as i rotated the pickup and i heard that the OHMS reading should stay put when you move it. This likely had nothing to do with original problem as after i replaced this pickup coil, the engine did start but would not stay running below 1000rpms---which was the original problem.

Replaced Coil and module with AC delco units. Then replaced all 6 plugs with new delco R43T's:



i can get a better picture if necessary. Plugs 4, and 6 has gas on them, plug 5 was oily, but all three have dried up by now.

The engine now will not start.

Now keep in mind that after i replaced the pickup coil, the engine did start and run. There is no need to remove or reposition the distributor to change out the module or coil so the distributor IS NOT out of position or out of time, and the plug wires are all in the correct order.
And i'm getting spark, at least thru the wires as indicated by the in-line spark tester. As the engine did run before changing the coil and module, it's likely that spark IS getting to the plugs.

Starting fluid didn't work.

i think at this point, we should list causes from most likely / or root cause, to the next likely and so on and so on.

OR, if we want to continue with the "it could be this," or "it could be that," approach this is fine too. Don't get me wrong, i appreciate any and all help. In that case,let's list ALL and ANY possible reasons why the engine won't start.

Remember, If the problem is not solved by July 9th, then i'm quitting cars and going back to women.
(Note: i will suspend time for transit----for example fedex screwed me over as i was supposed to recieve the coil and module on friday, but did not recieve them until yesterday. And fedex is a subject for another thread....)
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #65 ·
P.S.
It has been 2 months and 64 posts and the problem is not only not solved, but it has gotten worse.

Part of me DOES NOT want the problem solved; i'm sort of like Charlie Brown---i get a neurotic pleasure out of NOT solving the problem. i want to see how long the thread can be stretched to try to get a non-computerized carb and distributor engine running, just to see how messed up things can get----sort of like a trainwreck.

This is sort of like neurotic entertainment for me in an unhealthy way.
 

·
Registered
Joined
·
14,319 Posts
It really sounds like either fuel pump or ignition.

Most common to worn throttle shafts is you cannot get the idle speed down unless you cut off the fuel flow as it is getting sufficient air around the shafts. Given new Q-Jets haven’t been made since dinosaurs roomed the earth your unit is most likely a rebuild so unless it was a shop that bushes the throttle shaft bore it is as old as the carburetor was newly made.

I’ve had carburetors that just died, never could find the cause, repetitive cleaning, micro inspection and kit rebuilding never exposed or improved the problem. Replacing the carburetor solved the problem immediately so it wasn’t fuel delivery, ignition or cam ot it’s timing set problem. Of those that did this they were Holley’s and Q-Jets, I can’t remember a Carter now Edelbrock, or Ford 2100 or 4100 series doing this. That said a long time ago a woman I was dating had an early 1980’s Ford station wagon that every now and and then would just stop running when sitting out a traffic light. It had fuel and spark but would not run till it sat for a few minutes then it would fire up and run fine till next time. She traded it for a Honda. So some of these problems are essentially unsolvable, in the case of the Ford in question, hours of inspection in the shop where of course it was running never exposed the problem. You would need the shops resources with you at a traffic light when it quit. By the time you had it towed to the shop, it would start up by simply turning the key on start and away it would go. So it’s hard to fault find when the fault isn’t displaying.

Now back at your problem with a time element for recovery, this speaks strongly to fuel supply and or ignition. This would include tank venting and weird things like some object being drawn into the fuel pick up which could range from a cigarette filter in the tank to a flex line that the interior has a peeling surface that reduces to cuts off fuel flow to where once the forces are removed eventually corrects itself. A pressure test with observation when this happens may reveal this. Idling with a functional hot spot under the plenum might cook the fuel out of the bowl flooding the engine and requiring a cool down and cylinder venting to get a restart.

This also fits a heat sensitive ignition module and or the timing sensor if your distributor separates these functions.

Oily spark plugs do not dry out but fuel wet plugs do.

A common SBC vacuum leak which includes making oily spark plugs is the intake gasket leaking on the valley side so it is not visible. This is really common where the block has been decked, or the heads milled, or aftermarket parts of head’s and intake are used where fitments, machined angles, and tolerances stack to allow gaps in sealing the intake to the head’s. Another common one
especially where screw in rocker studs are used is vacuum leaks into the ports around the threads of the studs. Valve guide to stem clearance is another problem especially with bronze guides.

Bogie
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #67 ·
It really sounds like either fuel pump or ignition.

Most common to worn throttle shafts is you cannot get the idle speed down unless you cut off the fuel flow as it is getting sufficient air around the shafts. Given new Q-Jets haven’t been made since dinosaurs roomed the earth your unit is most likely a rebuild so unless it was a shop that bushes the throttle shaft bore it is as old as the carburetor was newly made.

I’ve had carburetors that just died, never could find the cause, repetitive cleaning, micro inspection and kit rebuilding never exposed or improved the problem. Replacing the carburetor solved the problem immediately so it wasn’t fuel delivery, ignition or cam ot it’s timing set problem. Of those that did this they were Holley’s and Q-Jets, I can’t remember a Carter now Edelbrock, or Ford 2100 or 4100 series doing this. That said a long time ago a woman I was dating had an early 1980’s Ford station wagon that every now and and then would just stop running when sitting out a traffic light. It had fuel and spark but would not run till it sat for a few minutes then it would fire up and run fine till next time. She traded it for a Honda. So some of these problems are essentially unsolvable, in the case of the Ford in question, hours of inspection in the shop where of course it was running never exposed the problem. You would need the shops resources with you at a traffic light when it quit. By the time you had it towed to the shop, it would start up by simply turning the key on start and away it would go. So it’s hard to fault find when the fault isn’t displaying.

Now back at your problem with a time element for recovery, this speaks strongly to fuel supply and or ignition. This would include tank venting and weird things like some object being drawn into the fuel pick up which could range from a cigarette filter in the tank to a flex line that the interior has a peeling surface that reduces to cuts off fuel flow to where once the forces are removed eventually corrects itself. A pressure test with observation when this happens may reveal this. Idling with a functional hot spot under the plenum might cook the fuel out of the bowl flooding the engine and requiring a cool down and cylinder venting to get a restart.

This also fits a heat sensitive ignition module and or the timing sensor if your distributor separates these functions.

Oily spark plugs do not dry out but fuel wet plugs do.

A common SBC vacuum leak which includes making oily spark plugs is the intake gasket leaking on the valley side so it is not visible. This is really common where the block has been decked, or the heads milled, or aftermarket parts of head’s and intake are used where fitments, machined angles, and tolerances stack to allow gaps in sealing the intake to the head’s. Another common one
especially where screw in rocker studs are used is vacuum leaks into the ports around the threads of the studs. Valve guide to stem clearance is another problem especially with bronze guides.

Bogie
Thanks. However, wouldn't the ability to idle at 1000 or above [if i keep my foot on the gas or if the carb is on hi-step /choke still engaged, (assuming i can manage to get it started at all at this point...)] indefinitely indicate that is is likely NOT fuel or spark that's the problem?

Also, since i've replaced everything in the distributor, likely this rules out that the module/coil/pickup coil on the HEI only works at 1000rpm and above?

The only thing i can think of at this point is the idle tubes or something in the idle system of the carb is screwed. But how could BOTH passages get plugged in just one night?
 

·
Registered
Joined
·
3,881 Posts
bypass the fuel in the tank, either gravity feed the carb or put supply to pump in some fresh fuel. Remove a plug wire and lay it on the engine, spark should easily jump an inch or more. Check voltage at the distributor with key on and while cranking.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #69 ·
bypass the fuel in the tank, either gravity feed the carb or put supply to pump in some fresh fuel. Remove a plug wire and lay it on the engine, spark should easily jump an inch or more. Check voltage at the distributor with key on and while cranking.
Can you give me a little more detail on how to do the spark check thing: You said remove plug wire. Does this mean with no spark plug etc.?
 

·
Registered
Joined
·
4,239 Posts
I one time chased my tail trying to find out and issue once to where I checked everything imaginable and could not figure out why my engine would not run very well and had the carb on and off several times thinking it was that as I checked that I was getting spark and the distributor had not moved and it started up and would idle but not like it normally would and seemed down on power on the lower end and at slower speeds and just did not run right.

I kept checking everything and I finally thought I will check my timing to verify and when I checked it I was supposed to see about 29 degrees give or take a hair and behold I only read about 16 degrees. It was then I checked my vacuum line going to my vacuum advance and it was fine but I seemed to not have any vacuum advance timing. I hooked up a vacuum pump gauge and it would not hold the vacuum advance canister so I knew it was shot and replaced it and all was good.

I know this might not be your problem as your having a hard time keeping it to run or stay running. The main thing is I never had a vacuum advance canister go bad on me before and that was a first time for me like a few other things just like recently with carb issues as well that never happened before and blew me away and was not easy figuring out at first.

I would perhaps make a check list of each section of each area and leave nothing out such as a bad vacuum hose being cracked or dry rotted and maybe letting in air somewhere or a vacuum leak somewhere in the system etc and just go down the list and start checking things off in fine detail. If after all things have been exhausted I would then maybe perhaps take the carb off and inspect for warpage on the throttle body area and in the shafts like Boogie said and see if perhaps something is getting through etc. If that be the case you can buy a bushing kit with the reamer for not too much and some time and patience you can fix that all good if that would be the case.

I have had tiny vacuum leaks before that caused me some very hair pulling experiences and took me a while to find it. Also a R43ts is a very cold plug and normally for an everyday driver a R45ts is about normal and that is what I used in the past on iron heads regardless of factory or aftermarket is yours is that style of plug.
 

·
Registered
Joined
·
3,881 Posts
is the engine flooding while running?
Do you see lots of fuel leaving the booster?
Either the fuel is bad or there is too much of it.
You said it won't hit on ether? Flooding seems likely.
 

·
Registered
Joined
·
143 Posts
DB Where are you located!?

I still think need to start with simple basics, compression, spark and fuel.
Like others have said a simple gravity tank.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #75 · (Edited)
is the engine flooding while running?
Do you see lots of fuel leaving the booster?
Either the fuel is bad or there is too much of it.
You said it won't hit on ether? Flooding seems likely.
1) i don't think the engine is flooding while it's running. Of course i don't know what the hell i'm doing, so it could be. But my hunch is no.

2) i just got it to start run a few minutes ago. (i think it had flooded due to the unsuccessful starting attempt i had earlier today) i do not see any nozzle drip etc. However, the original problem still exists----the engine won't run below 1000rpm----unless i keep my foot on the gas.

So, i think we can eliminate ignition or bad gas. On top of that i put in new AC Delco pickup coil, module and coil which were all probably a waste of money. The only consolation is that i'm more comfortable working with HEI distributors.
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #76 ·
DB Where are you located!?

I still think need to start with simple basics, compression, spark and fuel.
Like others have said a simple gravity tank.
East coast---DC/Balto.

i think we can eliminate compression, spark and fuel, as the engine does run, just doesn't stay running below 1000rpm unless i keep my foot on the gas----which is the original problem.

On a quadrajet, Are the throttle blades supposed to be completely closed at curb idle, or just very slightly open?
 

·
Registered
Joined
·
143 Posts
Throttle blades just slightly open, like a turn to turn and a half on idle screw on side of carb.

Sorry I am not in DC area to help

Have you checked for vacuum leak at carb base
 

·
Registered
Joined
·
254 Posts
Discussion Starter · #80 ·
Throttle blades just slightly open, like a turn to turn and a half on idle screw on side of carb.

Sorry I am not in DC area to help

Have you checked for vacuum leak at carb base
Yes. i will check again, but i don't think that is the problem.
 
61 - 80 of 120 Posts
Top