Hitting a wall at 4K

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Lars

Lars

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I'm had an issue crop up on my 70. Whenever I hit 4K rpms (any gear) it stumbles pretty hard like its got a rev limiter on it. I initially thought it was an ignition problem until I pulled the plugs and saw that they were kinda white. I am running one of those clear parts store universal filters and I noticed a little bit of rusty looking junk in it. When I pulled it out and cut it open there really wasn't anything to speak of in it. I put a new filter on it and it didn't help. Still has the factory tank and lines in it, is it possible that the little filter assembly in the tank has collapsed on me?

Thanks
 
Are you running the stock mechanical fuel pump? I had something similar a number of years back, turned out my fuel pump was bad...it could keep up just fine below about 3800 RPM, but just would not deliver the fuel well enough above that.
 
Comp cam, comp springs, very low mileage (less then 10K). Running a Carter strip fuel pump.
 
I had a very similar issue with my Duster a couple years back. I made two passes at the drag strip. Both times I had the car floored, over halfway down the track the car completey bogged out. Like it just ran out of breath. I thought it was going to stall. I asked about on this forum and suggested replacing the stock sending unit in the tank. The sock filter gets clogged when sitting for a period of time without being started. I know my car sat for a while at some point. We replaced the stock fuel tank and sending unit. The problem is gone. No more related issues.

Hope this helps.
 
Try an Autozone cheapie, if that cures it, the carters make nice conversation pieces. Thats what mines been delegated to8). On my Cuda you can take a flash light and see the sock, straight shot down the filler neck. These probably get destroyed by siphon hoses jammed into it. Socks are cheap enough, and I would blow the line out before assembly. hopefully thats all it is. good luck.
 
7duster4 said:
I had a very similar issue with my Duster a couple years back. I made two passes at the drag strip. Both times I had the car floored, over halfway down the track the car completey bogged out. Like it just ran out of breath. I thought it was going to stall. I asked about on this forum and suggested replacing the stock sending unit in the tank. The sock filter gets clogged when sitting for a period of time without being started. I know my car sat for a while at some point. We replaced the stock fuel tank and sending unit. The problem is gone. No more related issues.

Hope this helps.
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mopar head said:
Try an Autozone cheapie, if that cures it, the carters make nice conversation pieces. Thats what mines been delegated to8). On my Cuda you can take a flash light and see the sock, straight shot down the filler neck. These probably get destroyed by siphon hoses jammed into it. Socks are cheap enough, and I would blow the line out before assembly. hopefully thats all it is. good luck.
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Yeah, the car has sat for about the last two months without being started. It actually sits a lot, but its been fine up until a couple of days ago. Thanks for the ideas guys, I'll check it out. :)
 
A shorted out aftermarket tach will cause this problem also. It will apear to work fine.
 
I had a similar problem with my dart. Turns out it was the short piece of rubber tubing that runs from the tank to the metal fuel line was dry rotted and cracked and was sucking more air thru the hose than fuel. Replaced that and my problem went away.
 
11sec-cuda said:
A shorted out aftermarket tach will cause this problem also. It will apear to work fine.
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I did just put an Autometer tach in it right before this started too. hmm

second chance dart said:
I had a similar problem with my dart. Turns out it was the short piece of rubber tubing that runs from the tank to the metal fuel line was dry rotted and cracked and was sucking more air thru the hose than fuel. Replaced that and my problem went away.
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I never have changed those lines out, they are almost 40 years old, I'll check that too.
 
Lars said:
Yeah, the car has sat for about the last two months without being started. It actually sits a lot, but its been fine up until a couple of days ago. Thanks for the ideas guys, I'll check it out. :)
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I had the same thing happen to my car. It was the fule pump. Car sat for to long and all the rubber dried out and went bad on me.

Good luck
 
dusterdon said:
If your spark plug gap is too wide for your ignition it'll do the same thing.
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They were at .028 and I bumped them up to about .036.

Burntorange70 said:
I had the same thing happen to my car. It was the fule pump. Car sat for to long and all the rubber dried out and went bad on me.

Good luck
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Ugh, I hope not, I finally got it to stop leaking from the fittings. :p
 
Well I've decided to drop the tank, however its full of 93. :p So I pumped about 5 gallons out into a gas can, and I'm going to have to drive my 5.0 or something all week until its almost on empty, and then transfer the fuel from the Dart to it. While I was pumping the gas out of the Dart into the can I noticed the filter on the pump setup started catching a lot of black junk in it, so I imagine that's what's causing my problem (at least I hope so).
 
Got it fixed. After dropping the tank, pulling the sender, finding that the filter sock was cracked and no replacements could be found. I put the sender back without it and I monkeyed up a filter just to the outside of the tank. That didn't fix it. So I disconnected the tach, didn't fix it. As I was reconnecting the signal wire to the tach I looked across the engine bay and saw the ignition module. It looked fine but I decided to swap it with one of my spares. Bingo, pulls like a raped ape till I can't bear to look at the tach anymore. Wish I had thought of that before I got covered in 40 years worth of grime and dirt.
 
mopar head said:
Glad to hear you gotter whooped, Wonder if old one just lost good ground. Year 1 sells socks.
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I'll probably wait, I see Mancini sells sending units with 1/2 lines already built in, I might get one of those since I plan to upgrade the lines here in the future.
 
Good deal, Lars. The info presented on this thread should go into everyone's memory bank.
 
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