Topic: Holley Idle Circuit Adjustment

[Angela]

Going back through the entire discussion, I didn't see any mention of transmission work. That's the sort of information that could be really helpful in working through the problem. Is there anything else that you haven't mentioned? Perhaps it would be best to go back to the beginning:

    When was the last time the car functioned properly?
    What has changed since then? That includes elapsed time, work that's been done, exposure to unusual weather conditions - anything you can think of.

----> Sorry about that. I really thought I had explained the entire situation. The car has been in the process of being restored.... it has been apart and off the road for at least 15yrs. When was the last time the car functioned properly? At least 15yrs ago... it hasn't been assembled enough to attempt driving until recently. What has changed since then? EVERYTHING. Every single nut, bolt, washer and screw has been removed, restored and reinstalled. The transmission rebuild was farmed out to a pro, as was the engine machine work.

We've discussed the carb and transmission as main culprits in this thread. Pertinent to those two items, the entire tranny, including the TC, was rebuilt top to bottom. The carb was sent out to Pony Carbs (at least 5yrs ago, before the owner died) where it was replated and rebuilt. Since the very first day the drivetrain was installed in the car, it has behaved as described (stalling when shifted into ANY gear).

Let me know if the above description helps.

As far as I am concerned, I am looking for another valve body to swap in, before I even consider tearing half the car apart to get at the TC. Thus far I haven't been able to find another fomoco TC.

[WT8095]

Let me know if the above description helps.

Yes, it does. It gives a better view of the range of potential issues you could be dealing with. For example, if the car had run normally a year ago, and then the carb was rebuilt and the problem started, it would make most sense to concentrate on the carb, or possibly deteriorated gasoline. But this widens the scope to potential transmission issues.

The two most likely candidates are carb or transmission. It would help to narrow the problem to one of the two. (But don't rule out the possibility that there are problems with BOTH!) It's impractical to swap the transmission, but the carb is reasonably portable. Running your carb on another similar engine/trans combination, and/or installing a known good carb into your vehicle would potentially narrow the search. If your carb runs fine on another engine, you're probably dealing with a transmission issue. If your carb fails on another engine, you've got carb issues (but maybe trans problems too). You get where I'm going with this. Once you determine which system is at fault, you can start narrowing down to a specific cause.

[1967 eight barrel]

I still see no mention of checking the plugs for color. What not one single person has mentioned other than a possible vacuum leak is the fact FE intakes can be prone to leaks at the intake gaskets. If you mill the heads more than .020 the intake has to be cut as well. The Felpro performance intake set is also known for issues. They have been known to become soft with oil and get sucked into the intake ports when they become compromised, often leading to coolant/oil use. putting a 96lb intake isn't easy to get down right, as it's also easy to misalign or have the gaskets shift. Did you check the intake with a straight edge?
As for Pony carbs, I know of several who are less than happy with them as well. I won't bother with my experience here with the BJ/BK's for my vehicle.
I gather the rebuilt unit also sat around for several years. Pony claims they run them before they are shipped back to the customer, which would mean gaskets and the power valve may have been compromised because there was fuel run through the unit post rebuild.  Did you check the modulator for ATF? I have also seen the modulator diaphragm go bad, which not only leaves you with a vacuum leak, but they often suck ATF through the unit and back into the engine.
The diaphragm on the distributor can be checked easily. You can check it with a mighty vac. When you pull vacuum on the diaphragm, it should hold that vacuum until you release it.
As Dave mentioned, you have three circuits to deal with. Many possibilities, even thermactor control issues.

                                                                               -Keith

[Angela]

Keith - plugs are the correct color, sorry for failing to mention that. I checked them day #1 when the problem first exhibited itself. I'm not pulling the plugs again... :-) it's a nightmare to do in a 67 390.
As far as vacuum leaks.... I stated I have measured vacuum multiple times with a Lisle gauge....17 inHg...right on the money.... hence, *if* there's a leak, it's tiny IMHO.
Concerning the carb - like I said, the problem has been here since day #1.... so whatever the issue is, it's not from sitting. Frustrating!


WT8095: I agree with you in that it would be excellent to swap in a known good carb. Sadly, I don't own any other known good carbs. 

[1967 eight barrel]

I know your pain, Angela. I have a '67 GT500. The two to the left rear are the worst. If you're short, I am sure it's even more fun.. ( Yes, I am being sarcastic) I have had three back surgeries, so I understand from another aspect. 

I have seen many of the emulsion tubes get fouled with the crusty white remnants of fuel. I have two four barrels, and I learned very quickly that even though I am proficient at one, two changes everything.

If I were closer I'd volunteer to assist.

[WT8095]

As far as vacuum leaks.... I stated I have measured vacuum multiple times with a Lisle gauge....17 inHg...right on the money.... hence, *if* there's a leak, it's tiny IMHO.

It doesn't have to be a big leak to make a difference in mixture. It's worth the time to check all of the likely spots everyone has suggested, and it can be done inexpensively and without taking things apart. Honestly, this should be part of a preventative maintenance routine once the car is up and running - vacuum hoses crack and loosen up, diaphragms and gaskets develop leaks, etc. Could be a once a year or every other year sort of thing.

WT8095: I agree with you in that it would be excellent to swap in a known good carb. Sadly, I don't own any other known good carbs.

Yeah I didn't expect that would be an easy one to do. But it was SO easy for me to suggest!     

[Angela]

I looked for vacuum leaks but found nothing. Vacuum reading remains steady at 17 inHg.
I'm still searching for a valve body and torque converter.... So, in the meantime, I experimented with the carb a little more. Here's what I did:

Turned the idle mixtures screws IN 1/4 turn (which left the setting at 1 full turn out from seated position)
Started the car, feathered the throttle until the engine warmed up
Car would not idle.... stalled without opening throttle slightly. (the engine did idle with the previous idle mixture setting of 1.25 turns out from seated)
Turned the idle mixture screws back out to 1.125 turns from seated
Restarted car
engine idled at 850 rpm.
Attempts to lower idle from 850 cause the engine to stall
Idling at 850 rpm, I tried to shift into reverse. Engine stalls in 1 second
Idling at 850 rpm, I tried to shift into drive. Engine stalls in 1 second

I need a known-good carb to swap in and test. I have several good cores for this (390) application, yet I'm not good at rebuilding them. Anyone out there good at rebuilding these carbs?
Anyone have a known-good holley for this application they want to consider selling?

[67gtasanjose]

"For Testing Purpose Only", there are many, many carbs you could try and often times a "Buddy" close by has one available. Just make every attempt to not alter things while making this "test", use a flexible fuel line, leave the throttle linkage alone or build a temporary linkage, do not worry about the choke system, things along thos lines.
If your "test carb" does the same symptoms, maybe your thought on the transmission are more likely then. Personally, your description matches a carb problem but I cannot hear or "feel" what is going on with the car while typing on a keyboard.

[70cj428]

Hi Angela,
Haven't been spending much time on the computer recently, wondering how you made out....

A couple thoughts on the transmission...
The only thing I can think of (internally) that would cause a C6 to lock up when you put it in drive would be if the direct clutch was applied on when the trans went into low, which is possible with a valve body problem but REALLY unlikely, and the car probably wouldn't upshift normally after you got it moving. (you said in your first post that you could feather the gas and get the car moving, then it drove normally) Additionally, it would self destruct in short order...

You could have something wrong internally with the torque converter, but that would also be very uncommon with a C6, and it the converter was locked up, the car would probably stall almost instantly when you put it in gear. ( It sounds like it takes a second or 2 to die) I actually had that happen once with a C4 converter, the converter company found a nut inside the converter that must have fallen in before the converter was installed.

Is there any way you could post a video of it running , then stalling ?   As dumb as that sounds that would be pretty helpful.

I still thing it's a carb issue...

It's a shame that you're not near PA, I'm sure we could get you up and running in short order..

John

[Angela]

Thanks John. Hmmmmm, a video..... I could give that a shot.... not sure how well the sound might turn out. Interesting idea. To be honest, I suspect she stalls in 1 second or less..... it doesn't really idle for any length of time. I want to hold out hope that it's the carb or the valve body, yet it really seems like the torque converter is the culprit. I could cry. The thought of removing 100 bolts, the hood and a million other parts is just sickening. Trying to make it look like those parts were only installed once would be very difficult.

I think I should try posting a wanted ad for someone who could rebuild one of my other carbs. I have quite a few 9510-D and -B carbs... but they all need rebuilding and I'm apparently no good at it. Plus, I still cannot locate a 67 or 68 torque converter or a valve body. Ugh.

[carlite65]

this guy is supposed to be a holley guru. check him out.  joe bunetic

[ruppstang]

Thanks John. Hmmmmm, a video..... I could give that a shot.... not sure how well the sound might turn out. Interesting idea. To be honest, I suspect she stalls in 1 second or less..... it doesn't really idle for any length of time. I want to hold out hope that it's the carb or the valve body, yet it really seems like the torque converter is the culprit. I could cry. The thought of removing 100 bolts, the hood and a million other parts is just sickening. Trying to make it look like those parts were only installed once would be very difficult.

I think I should try posting a wanted ad for someone who could rebuild one of my other carbs. I have quite a few 9510-D and -B carbs... but they all need rebuilding and I'm apparently no good at it. Plus, I still cannot locate a 67 or 68 torque converter or a valve body. Ugh.

 
You do not need to pull the engine to change the torque converter. With a C6 a transmission jack would be a must. Good luck.

[Angela]

this guy is supposed to be a holley guru. check him out.  joe bunetic

Charles, very interesting. Thanks for the tip. I'll give Joe a call

Ruppstang, could you elaborate? I assume you're implying that one could alternatively remove the driveshaft and exhaust, then slide the transmission away from the engine, yes? Hmmmmm, I wonder how difficult it is to reach all of the bolts between the engine and transmission. I'll take a look and ponder this.... thanks.

[ruppstang]

Yes that is exactly what I am saying. It is done in transmission shops every day. You may be better of taking it to a shop that has all of the equipment.

[Angela]

Could someone please explain what could possibly fail (or be incorrectly adjusted) in a Holley 4150 such that it causes the symptoms I have described? My engine idles well and drives well (if you can keep it from stalling), yet immediately  stalls upon shifting into any gear. I simply do not understand what, specifically, carburetor problem would cause this symptom.

I spoke with Joe about having a second carb rebuilt, yet he warned me that any rebuilt carb is going to require adjustments on the engine, hence there's no way to ensure the engine will initially run any better than with my existing carb. Therefore, I want to understand the mechanism by which you guys think my carb is messing up all of my fun. :-) I just don't get it...

Help?