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I have a classic 65 F100 with a 72 Gran Torino 302. I am kind of stuck on an issues here. While at cruising speed at random times, (more after cold start) I loose throttle. The engine bogs down. I can pump the gas/pedal to floor, but nothing happens. Ill pull to the side of the road and stop, then the engine picks back up again and runs fine. I just recently replaced carb 1404 with a new Edelbrock 1405, added fuel pressure regulator set at 4psi, newer performer 289 intake, added 1" 4 hole carb spacer, new fuel lines, new distributor (flamethrower ignitor 2), (has older master blaster 2 ignition coil), new plugs, new wires, new fuel tank, new Delphi mechanical fuel pump, new battery. Installed new negative lead on battery and new ground lead to frame. I also just rebuilt top end due to bad head gasket. Adjusted timing to 8 for initial, haven't set total yet. There is some sort of new noise, a howling sound (not whistle) (vacuum leak somewhere, not sure?), on drivers side of engine. I am having trouble pinpointing sound. My fuel economy is terrible as well. In 30 miles, I burn through a 1/4 tank. Engine starts just fine, idles great and runs good, except for the bogging down and fuel economy.
If it operates through the RPM ranges at slow speeds driving and upshifting just fine, Christmas’ suggestion of fuel filter makes most sense (fuel starvation) at higher flows.
The bad economy statement made me think it was running too rich at speed.
Does the motor run good speeding up and accelerating in 1st & 2nd ?
If it operates through the RPM ranges at slow speeds driving and upshifting just fine, Christmas’ suggestion of fuel filter makes most sense (fuel starvation) at higher flows.
The bad economy statement made me think it was running too rich at speed.
Does the motor run good speeding up and accelerating in 1st & 2nd ?
Yes. Awesome performance until 50 +. But it also chews through fuel while idling. Can practically watch needle go lower. I have an edelbrock 1404 that had issues and I will take it apart to learn how to fix the new one.
Just my two ... but the secondary's are opened by venturi vacuum, not to be confused with manifold vacuum, pulling against a spring. The weaker the spring the sooner they open. It's less noticeable in the lower gears because the carb transitions thru it's various circuits a lot faster. But I could be wrong. That happens all the time.
If ya got the time, one of my favorite carb tuning episodes .....
I was campaigning a dirt track Pinto with the stock 290 CFM Weber but the rules allowed us to run a 4412 Holley. 500 CFM. But I couldn't get that Holley to run up top in any way shape or form. Wildly rich. Fuel all over the place.
The clue came one day when I was showing a buddy how bad it ran. It was on the trailer at the time, hood and air cleaner off, and with that horizontal view I got from standing next to it on the trailer, I could see a good rev was producing a cloud of fuel and air and out the top of the carb! What the ?
Vibration. Being a "racecar" I had fabricated some massive steel motor and trans mounts that could not vibrate and release the energy being created by the crank at higher rpm. The carb, being the farthest object from the crank on a 4 cylinder, was taking all the abuse.
Bottom line. I changed the trans to a rubber mount and fixed the carb!!!
Here's a picture of the Evil Pinto, but don't get the idea I was wildly successful. That night was my single Main Event win in something like 65 attempts. I was 49 at the time ... but I sure felt like a kid!
Edelbrock dont like fuel psi 5 and above and even 5 psi has been known to cause flooding.
Have you replaced ALL rubber fuel line from tank to carb yet?
If not do so and please dont say "the rubber lines look good" as they go bad from the inside out and unless you are supper man you cant see that.
What you running for exh? From motor to tail pipe and how far back to the exit?
How old is the system?
Truck just back on the road after sitting and if so how long did it sit?
Old gas, rusty or dirty tank / fuel system and old hoses but that is not where I am going with this.
Truck sitting for a bit something could make a home it the exh system and plug it even more so if motor was out at that time.
Old exh system a muffler coming apart, baffle, can plug the exh system. Maybe not all the way but enough to only get to 50 MPH and "choke".
Sometimes hitting the bottom of the muffler with a mallet you can hear it rattle if so bad muffler. Could drop the exh system and go for a test drive too.
You said you are new to timing, how did you set the timing on the motor? Do you have a dial back timing light?
But before we get into that what IGN system you running, points or a kit to swap them out?
Now how did you set timing, what was the idle speed (auto or stick trans?) vacuum to the dist. pulled a & plugged?
Are you sure the timing ring did not slip on the balancer and it does show TDC when on TDC?
Do you have a vacuum gauge you can hook to the motor for tuning it?
I know its a lot I just through at you but each can be the cause of what you have going on and with a little testing, no money needed till you find the cause, you have things to check.
DO 1 THING AT A TIME AND TEST.
If you do 2 or 3 things at once and it gets worst or better what caused it?
Doing 1 thing and testing you can tell and if it did not help depending on what the change was you either put it back or move on to the next thing to test.
Good luck
Dave ----
The Edelbrock's secondaries are mechanically operated, with the air valve above allowing only the amount of extra flow that the engine needs. Have someone push the throttle slowly to the floor, while you watch the throttle linkage. You should be able to watch the the levers open both the primaries and the secondaries.
"just my two ... but the secondary's are opened by venturi vacuum, not to be confused with manifold vacuum, pulling against a spring".
Edelbrock dont like fuel psi 5 and above and even 5 psi has been known to cause flooding.
Have you replaced ALL rubber fuel line from tank to carb yet?
If not do so and please dont say "the rubber lines look good" as they go bad from the inside out and unless you are supper man you cant see that.
What you running for exh? From motor to tail pipe and how far back to the exit?
How old is the system?
Truck just back on the road after sitting and if so how long did it sit?
Old gas, rusty or dirty tank / fuel system and old hoses but that is not where I am going with this.
Truck sitting for a bit something could make a home it the exh system and plug it even more so if motor was out at that time.
Old exh system a muffler coming apart, baffle, can plug the exh system. Maybe not all the way but enough to only get to 50 MPH and "choke".
Sometimes hitting the bottom of the muffler with a mallet you can hear it rattle if so bad muffler. Could drop the exh system and go for a test drive too.
You said you are new to timing, how did you set the timing on the motor? Do you have a dial back timing light?
But before we get into that what IGN system you running, points or a kit to swap them out?
Now how did you set timing, what was the idle speed (auto or stick trans?) vacuum to the dist. pulled a & plugged?
Are you sure the timing ring did not slip on the balancer and it does show TDC when on TDC?
Do you have a vacuum gauge you can hook to the motor for tuning it?
I know its a lot I just through at you but each can be the cause of what you have going on and with a little testing, no money needed till you find the cause, you have things to check.
DO 1 THING AT A TIME AND TEST.
If you do 2 or 3 things at once and it gets worst or better what caused it?
Doing 1 thing and testing you can tell and if it did not help depending on what the change was you either put it back or move on to the next thing to test.
Good luck
Dave ----
Thanks for your response!
I installed a fuel pressure regulator today and dialed it down to 4 1/2. I also checked the little screen right inside the fuel inlet on carb (looks clean). I will road test it tomorrow morning to see if lowering psi works.
This is what has been done last month:
I just replaced everything fuel related, including new fuel tank. 2 new filters, fuel lines, etc. Carb is brand new, purchased last month.
Distributor= MSD Flamethrower 2 (new), MSD Blaster 2 Ignition Coil (older), no box.
Flowmaster exhaust with nice headers (not sure on brand for headers).
Timing= set mark at 0 tdc, (tdc is correct/hand cranked engine until #1 was at top) used timing light to set to around 8/9 initial. Did not set total timing yet. Idle speed is 600 rpm.
Adjusted fuel/air screws on carb with vacuum gauge and is steady.
It seems that the bogging started after I installed new carb. The old carb (1404 edelbrock) was pushing fuel through vacuum advance line into distributor diaphragm and It caused my truck to die.
I would bump the timing up just a little more to 10* or even 12* as long as you dont get pinging.
It sounds like that new carb may have issues.
I think I would try and rebuild the old carb and see how it runs with it.
Heck I might even put it on before the rebuiild and plug off the vacuum line so no fuel will come out of it.
If the truck run better, may not have the same power as no vacuum advance, then you would know its that new carb.
I have seen it posted some new carbs had a lot of junk in the bowl & passageways from when it was made and not cleaned.
That could be yours?
Dave ----
