75 New Yorker Hesiatation

Wildbunch02

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Hello everyone, I recently purchased a 1975 NYB and I am having some drive-ability issues that I hope I can resolve with everyone's help. I consider myself a little bit more than a novice, more of a parts changer. I really would like to be able to diagnose better since guessing at what to buy next is hit or miss and becomes expensive.
The car has a 440 with a Carter TQ. It is fairly easy to start, but when its warm it hesitates when I put it in gear and try to take off. I have to pedal the gas to keep from stalling, and she takes off fine. When cruising if I accelerate it will bog then take off, sometimes I hear a slight backfire before she accelerates.
The car was represented as having been collector owned and driven very infrequently. The mileage shows 47000, although I suspect that is not correct.
The engine sounds good, and the car definitely has been maintained.
The TQ has a tag on it which states that it has been rebuilt 10/14, I don't know by which company.
Things I have done, New cap, Rotor, Plugs. all seemed fine, plugs were rj14yc and the tips looked tan.
I checked for arching wires by spraying them with water and looking for archs at night, none found, wires look fairly new anyway.
I checked timing, its at 8b.
I replaced metal fuel filter with clear one, no dirt observed.
I checked fuel stream going into carb by pumping accelerator linkage and looking into primaries, engine had not been started yet, and I had two strong streams.
I fiilled fuel bowl through fuel vents with carb cleaner, seafoam, and techron while engine running, no change.
I did a smoke test through line from power booster, and I also sprayed intake and all vacuum lines with soapy water while engine was running, no leaks found.
Any help would be appreciated, Thanks, Eric
 
Try adjusting the secondary air door a bit tighter. Say 1/4 turn. There's a tool for this thats very helpful.
 
Ok, where would I find this adjustment? And what does the tool look like and where can I buy one?
Thanks for your help, Eric
 
I found a video on you tube dealing with this adjustment. Can this be done on the car, or will I need to remove it? The video mentioned something about being careful to loosen it slowly because something may come loose inside, I guess I will re-watch it several more times.
Thanks for the Help, Eric
 
Hello everyone, I recently purchased a 1975 NYB and I am having some drive-ability issues that I hope I can resolve with everyone's help. I consider myself a little bit more than a novice, more of a parts changer. I really would like to be able to diagnose better since guessing at what to buy next is hit or miss and becomes expensive.
The car has a 440 with a Carter TQ. It is fairly easy to start, but when its warm it hesitates when I put it in gear and try to take off. I have to pedal the gas to keep from stalling, and she takes off fine. When cruising if I accelerate it will bog then take off, sometimes I hear a slight backfire before she accelerates.
The car was represented as having been collector owned and driven very infrequently. The mileage shows 47000, although I suspect that is not correct.
The engine sounds good, and the car definitely has been maintained.
The TQ has a tag on it which states that it has been rebuilt 10/14, I don't know by which company.
Things I have done, New cap, Rotor, Plugs. all seemed fine, plugs were rj14yc and the tips looked tan.
I checked for arching wires by spraying them with water and looking for archs at night, none found, wires look fairly new anyway.
I checked timing, its at 8b.
I replaced metal fuel filter with clear one, no dirt observed.
I checked fuel stream going into carb by pumping accelerator linkage and looking into primaries, engine had not been started yet, and I had two strong streams.
I fiilled fuel bowl through fuel vents with carb cleaner, seafoam, and techron while engine running, no change.
I did a smoke test through line from power booster, and I also sprayed intake and all vacuum lines with soapy water while engine was running, no leaks found.
Any help would be appreciated, Thanks, Eric
Try turning your accelerator pump to a richer setting.
 
Ok, I will check on YouTube for a video on this.
Thanks, Eric
Maybe this will help. I'm not familiar with tq's, but on most Carter's it is a simple adjustment of the connecting rod to preset holes.
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Also check for vacuum leaks at the carb/intake area. You can do that with carb cleaner while the engine is running. If there is a poor seal, the idle will increase as carb cleaner reaches the affected zone.
 
Also check for vacuum leaks at the carb/intake area. You can do that with carb cleaner while the engine is running. If there is a poor seal, the idle will increase as carb cleaner reaches the affected zone.
Ok, I sprayed evrything withsoapy water withe engine running, I didnt hear any changes in idle
 
Ok, I sprayed evrything withsoapy water withe engine running, I didnt hear any changes in idle
Unfortunately, the water won't tell you much. The reason carb cleaner works is because you increase the fuel/air ratio; thus increasing (or bogging) idle speed.
 
Failed or stuck vacuum advance can cause a nice flat spot or sag.
Unfortunately, the water won't tell you much. The reason carb cleaner works is because you increase the fuel/air ratio; thus increasing (or bogging) idle speed.
Ok, I will give it a shot tomorrow with carb cleaner, just trying not to start a fire, thanks again
 
Your accelerator pump may have given up the ghost as it were.. Pull off the top of the carb and see if the pump cone is intact, these tend to either get to the point they reverse on part of the circumference or get a void along the circumference of the pump piston cone. They do not pump that way.
If the accelerator piston is intact, check your float level, if it is set too low poor performance will result. Back-firing thru the carb is a symptom of an excessively lean mixture. As you are uncertain if the vehicle mileage is accurate, check the timing chain for excessive play. Do this by having a helper rotate the crank shaft back and forth with a breaker bar on the harmonic balancer nut from the TDC mark. If you have more than 10-12 degrees before the distributor starts to move, you have a timing chain that has excessive play and needs to be replaced. Excessive play in the timing chain will result in back-firing thru the carb and poor overall performance.

If your vehicle has an EGR valve, it could be stuck in the open position. Also check the heat riser to be sure it moves freely and is not stuck.

Dave
 
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Your accelerator pump may have given up the ghost as it were.. Pull off the top of the carb and see if the pump cone is intact, these tend to either get to the point they reverse on part of the circumference or get a void along the circumference of the pump piston cone. They do not pump that way.
If the accelerator piston is intact, check your float level, it it is set too low poor performance will result. Back-firing thru the carb is a symptom of an excessively lean mixture. As you are uncertain if the vehicle mileage is accurate, check the timing chain for excessive play. Do this by having a helper rotate the crank shaft back and forth with a breaker bar on the harmonic balancer nut from the TDC mark. If you have more than 10-12 degrees before the distributor starts to move, you have a timing chain that has excessive play and needs to be replaced. Excessive play in the timing chain will result in back-firing thru the carb and poor overall performance.

If your vehicle has an EGR valve, it could be stuck in the open position. Also check the heat riser to be sure it moves freely and is not stuck.

Dave
Thank you, I appreciate your knowledge, and I will be checking these items over the next few days.
 
You're on a Snipe hunt looking for a cure while keeping your Thermoquad.
Pitch it into the dumpster and bolt on an Edelbrock.
 
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