At wits end......

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mycuda

mycuda

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Try to make it short.
84 318 police edition engine. Approx. 80k miles. Rebuilt 727 trans from member,stock conv.
Proform electronic ignition 8mm wires. Put mild cam, headers, action+ weiand intake, 650 Proform mech. sec. Compression is average of 120 lbs. in all cylinders. Hooker 1 7/8 headers.
stock fuel pump 3/8" line to engine.
Runs great all day 3/4 throttle.
WOT stumbles/no power
Ive had timing advanced to 53* total advance, and down to 25* total advance. No Difference.

My last guess is springs floating after 4000 rpm. Any suggestions on springs for hydraulic cam?
Ive done this a FEW times before in my lifetime. Its f****** pissin me off.
What do you think??????




Thanks and Merry Christmas.

Dave
 
P4452761AE purpleshaft

268/272 duration
450/455 lift

thanks.
 
Is this happening at WOT at only higher RPM's (like 4k or 5k) or even at lower RPM's and WOT, like at 2k to 3k?

Stock Carter replacement type fuel pump is spec'd at 25 GPH, which is around 250-275 HP..... might be fuel limited, regardless of the 3/8" line. Do you have the actual fuel pump model?
 
Fuel starvation is the first thing that comes to mind. I think I would start with a Carter, Holley or MP performance mechanical pump. Assuming Your Carb is good.
 
Put mild cam, headers, action+ weiand intake, 650 Proform mech. sec.
.
What do you think??????
Click to expand...
Did it do this before the parts were added or is this a build from scratch? As said, at what RPM does it act up at WOT? and does it do it at all RPM's? when you stomp it does it hesitate then straighten out or does it continue to stumble until you go back to 3/4 throttle ? Check rotor phasing. Holler back with any news
 
Thanks guys, probably doing it at 3000rpms at first.
but lay off pedal and go again fine till engine winding up to higher rpms.

Thanks, Dave
 
It did this with 340 torker manifold and 650 holley also after all adjustments possible.
 
mycuda said:
Thanks guys, probably doing it at 3000rpms at first.
Click to expand...
Then more likely fuel than springs...especially since it did it with another carb. A coupla checks I would do:
- measure the fuel pressure at idle
- see how much pumps into an open can in 30 seconds of cranking
- start engine cold then stop it, and then remove the fuel line to the carb to see if there is residual pressure in the line; a good outlet check valve should hold pressure for many minutes
- run it WOT to stumbling for a few seconds, then immediately close the throttle and shut off the ignition and shift into neutral at the same moment so the pumps stops right away; drift to a stop and see if the fuel in the bowl is at the right level

Have you cleaned the fuel tank and sock on the fuel pickup? You could just have a bunch of crud restricting the flow.

But what DO you have for springs? Stock cam and lifters?

Possibly ignition related and could be anything that makes a weak spark:
- Wrong spark plug gap
- Weak coil
- Wrong ballast resistor
- Poor wires
But you would probably see other issues with weak spark so that seems least likely.
 
Stock springs im assuming.
New Pro form carb... did it with holley also
did it with other torker manifold, now weiand action +.
Like I said, runs great up to 3/4 throttle, then sputters like you unhooked 2 plug wires.

Thanks Dave
 
Be careful with this. If it is a lean issue, you can ruin a good engine. Melt a piston real easy.
sounds like a fuel delivery issue. :burnout:
 
Veryfy TDC and timing, also did you check your rotor phasing? Floats set correctly? Do the obvious things first.
 
my truck did this, plugged fuel filter! $3 fix. Then I learned the electric fuel pump was barely working on top of that, so another $21. It would idle all day and actually run alright on the slow streets but once I got it onto the freeway, BOG! had to feather it to the offramp and it would pick up again, only to bog again. Id do what nm9 says, bog it and cut it off, then check fuel level.
 
pishta said:
my truck did this, plugged fuel filter! $3 fix. Then I learned the electric fuel pump was barely working on top of that, so another $21. It would idle all day and actually run alright on the slow streets but once I got it onto the freeway, BOG! had to feather it to the offramp and it would pick up again, only to bog again. Id do what nm9 says, bog it and cut it off, then check fuel level.
Click to expand...
Lol- I Thought fuel filter too.
 
Pull out your fuel sender and inspect it , also blow out the fuel line from the sender to the pump. What are we working on ?
 
I had a problem just like this and found out the 2 distibutor wires were backwards coming from ignition box.
 
Sounds like crud/filter/socked-line/all of the above.
Like Pishta said get a new filter, and before you put it on blow out the lines (even if it's with just a bike pump and rubber tube jammed in there, believe me it works lol). And put it after the pump, especially if it's one of the clear flow jobbies.
 
69 Dart project.

Had tank out earlier this year, cleaned out, sender also.
I'll blow out line back to tank tomorrow.
Try new fuel pump, go from there.

Keep you posted.
Thanks
 
What distributor? Was it used on the earlier package too? I'm leaning towards ignition issue too.
 
Proform mopar electronic ignition box,
ballast, distrib. With msd blaster coil.

I myself don't believe a fuel issue.

Original voltage regulator but charges
alternator fine?

Got to be electrical under load.......
gonna swith ballast, coil, cap rotor
 
mycuda said:
Proform mopar electronic ignition box,
ballast, distrib. With msd blaster coil.

I myself don't believe a fuel issue.

Original voltage regulator but charges
alternator fine?

Got to be electrical under load.......
gonna swith ballast, coil, cap rotor
Click to expand...

Have you used the dizzy before? If not I would check rotor phasing, maybe throwing spark between 2 terminals. Also double check tdc and make sure your marks line up on the damper, if damper slipped timing is off and can cause it miss
 
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