Re: My 440 runs like crap under load
[Re: Gusteve]
#377150
07/16/09 02:18 PM
07/16/09 02:18 PM
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Joined: Feb 2003
Posts: 10,232 Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,232
Someplace you aren't
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Did it ever run right with the current parts?
Change fuel and maybe the air filter if they have much age at all. I would change the fuel filter no matter what. Maybe one a clear one for a short time and see if any crud is getting sucked out of the tank, then change back to a steel filter when it is sorted out.
Wire the choke open to cut that out of the picture.
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Re: My 440 runs like crap under load
[Re: SomeCarGuy]
#377151
07/16/09 02:51 PM
07/16/09 02:51 PM
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Joined: Mar 2007
Posts: 5,660 Flint, MI
Gusteve
OP
I Love the Unicorn Song!!
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OP
I Love the Unicorn Song!!
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Flint, MI
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More info:
Carb is edlebrock. The car was last registered in '89, and I know it wasn't driven since at least 2001. So I have no idea if it ever ran right.
The base idle is real smooth, and I have decent vacuum, so I don't think it has any kind of cam in it. I think I'm dealing with a stock 440 that came out of a 1974 vehicle.
At quarter throttle, the car accelerates and runs OK. If I go from idle to 1/4 throttle, the car takes right off with a little wheelspin and no hesitation at all. If, at cruise (around 35 MPH), I go to half throttle, or WOT, it bogs. It continues to bog for as long as I have my foot in the throttle. It is not a case where it bogs down for a few seconds and then takes off. (i.e. - does not "buck and surge" as was asked above.
If I take my foot back off the pedal, and coast for a few seconds, I can then go back to 1/4 throttle and keep driving. Although at that point it starts to have a hard time at low RPM's. It wants to stall if I'm idling up the hill in my driveway back to the garage. I have to give it more throttle than I should to keep it running. (Hmm - sounds like a fuel issue after all).
Choke is a manual one. If it was sticking closed, I assume my plugs would foul, and they are not.
Vacuum advance is hooked up. I haven't yet tested to see where it is coming in, and how much.
So - sounds like: Check Fuel Filter Check Float Levels Recheck timing and advance.
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Re: My 440 runs like crap under load
[Re: Gusteve]
#377155
07/16/09 05:05 PM
07/16/09 05:05 PM
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Joined: Jan 2006
Posts: 957 Heart of Ohio
4boxers4
super stock
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super stock
Joined: Jan 2006
Posts: 957
Heart of Ohio
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I have seen ignition coils that are failing have similar symptoms as well. They would operate fine at low RPM's then start to flutter and have no power at higher rpm's.
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Re: My 440 runs like crap under load
[Re: 4boxers4]
#377156
07/16/09 08:08 PM
07/16/09 08:08 PM
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Joined: Mar 2007
Posts: 5,660 Flint, MI
Gusteve
OP
I Love the Unicorn Song!!
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OP
I Love the Unicorn Song!!
Joined: Mar 2007
Posts: 5,660
Flint, MI
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Thanks for the responses.
1) Not old gas. Tank was dry when I bought it. We had to winch it onto a trailer when I bought it cause it wouldn't start. When I got it home, and added gas, it fired right up. (And we all felt pretty stupid)
2) New coil (not that that means its good...) Its just some crappy aftermarket performance coil that I think I bought from Autozone.
3) Edelbrock carb was new. The previous owner put it on after he bought it in 2001, but the car was never driven. I suppose the float level is still suspect. Could be: carb was added in 2002, gas was added to the car, an then it sat for years. But - previous owner said he started it every 3 months or so and let it run for a while. He was definately a car guy (but he was a chebby guy that bought a mopar).
4) Don't get me started on arcing plug wires. I THINK I have the wires all safely away from the headers, but there are at least 2 plug boots that rest nearly right against the header. But - I suspect it would misfire all the time if that was the problem, not just when I get into the throttle. I know this is a future problem waiting to happen once I'm able to drive the car for more than a mile at low speed.
Last edited by Gusteve; 07/16/09 08:12 PM.
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Re: My 440 runs like crap under load
[Re: SomeCarGuy]
#377160
07/16/09 09:33 PM
07/16/09 09:33 PM
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Joined: Apr 2007
Posts: 1,261 ILL
mark7171
pro stock
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pro stock
Joined: Apr 2007
Posts: 1,261
ILL
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Check Accelerator Pump shot adjustment. Use one of the holes for the least amout of travel on the plunger and see what happens.
Smooth idle tells me vacuum is advancing and initail timming is at least close. Cause a stockish 440 loves more timming.
Last edited by mark7171; 07/16/09 09:34 PM.
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Re: My 440 runs like crap under load
[Re: Gusteve]
#377161
07/16/09 09:56 PM
07/16/09 09:56 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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accelerator pump shot tip in
live every 24 hour block of time like it's your last day on earth
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Re: My 440 runs like crap under load
[Re: DaytonaTurbo]
#377163
07/18/09 10:03 AM
07/18/09 10:03 AM
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Joined: Mar 2007
Posts: 5,660 Flint, MI
Gusteve
OP
I Love the Unicorn Song!!
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OP
I Love the Unicorn Song!!
Joined: Mar 2007
Posts: 5,660
Flint, MI
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I think this might be a combination of things, since the car was never really sorted out after a lot of work was done to it.
I changed the fuel filter, re-timed it (it was way off, for some reason), and did a major change to the carb throttle linkage. While messing around with things, it looked like at WOT that the secondary linkage wasn't being activated. (That was probably most of the problem).
Anyway, its way better now. I had almost forgotten that throaty sound when the secondaries kick in.
But, after a couple hard accelerations this car still won't idle. It idles and drives fine until I do a couple WOT pulls. When I slow down the engine just dies. No sputtering, just "done", as if I'd turned it off. It'll fire right back up, but unless I keep the RPMS pretty high it'll just die again.
This sounds fuel related to me, but I can't see why it would only do this AFTER a couple WOT runs. I haven't checked the float levels yet - going out to the garage now to do that.
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Re: My 440 runs like crap under load
[Re: DaytonaTurbo]
#377165
07/18/09 02:39 PM
07/18/09 02:39 PM
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Joined: Mar 2007
Posts: 5,660 Flint, MI
Gusteve
OP
I Love the Unicorn Song!!
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OP
I Love the Unicorn Song!!
Joined: Mar 2007
Posts: 5,660
Flint, MI
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Quote:
Is this 'new' edelbrock carb a performer series 750cfm by chance? Those carbs had some quality control issues from new.
That's exactly what it is. I just checked the float levels and they were way off. Drop was 3/4" too low, and the upper limit for fuel shutoff was also nearly a 1/2" low. The previous owner probably just took it out of the box and popped it on the car, without checking anything.
I also moved the pump rod up one notch just for the heck of it. I think I might be able to get away with another degree or two of timing, but I should probably do a test drive with the new carb changes first.
Except - it started raining. Darnit! It'll probably blow right over, but I live on a dirt road. Doing WOT runs in the mud is probably not a good idea.
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