Jeep with chevy 350 misses at high RPM

[mrbrophx]

I have a 1985 Jeep CJ7 with a Chevy 350 four barrel. The CJ ran great till the electronic fuel filter stopped working. I have replaced it with a Holley Red Electronic fuel pump. Every since I have replaced the fuel pump it has misses at high RPM.
I have rebuilt the carb, changed the wires, replaced the fuel pump, timing chain and still misses.
A Mechanic thinks its not getting enough fuel. I am at wits end.
I am wondering if I need a different fuel pump, if the fuel tank should be drained and a new sending unit installed.
Any advise or help would be appreciated.
thanks

 

[Hedgehog]

What is high RPM?

 

[Scooter402]

What is high RPM?

x2.

High RPM to someone like me would be 7000+.


High RPM to some others might be something like 3-4000.

My first inclination before I even finished your post was fuel starvation. But, a Red pump should keep up with your 350, as long as it's not too hopped up. Where do you have your fuel pump located?

My second guess is your ignition module. You can actually pull that and take it down to your local Advance Auto (or maybe Auto Zone, but I can't stand any of them around me) and have it tested. If the module tests out good, the magnetic pickup could need replacing. What you didn't tell us, however, is what kind of ignition system you have. If it is a factory HEI (un-upgraded), they do tend to cut out at about 5K or so.


Long story short, a little more info could help.

 

[mrbrophx]

The fuel pump I located the fuel pump closer to the tank. If I am driving in second and I get up to 25 MPH it starts missing like crazy, I shift to third it will start missing at 35.
the mechanic thinks it is fuel starved.
As far as the ignition, it has a Mallory distributor. It has the smaller distributor to fit. Plugs are under the headers.

 

[Old Dog]

Have you tried putting a fuel press. gauge on it to see if your running out of gas?
You should be able to tell if it's running out of gas or if the ign. is missing it would feel totally different.
We still have no idea what rpm your talking about. Since you have not filled out your jeep profile we don't even know what Transmission ., gears, or tires you have to help us figure out what RPM you might be talking.

 

[harleydragon]

the red holley is rated at 97 gph and 7 psi..the fuel inlet to the pump should be the lowest point in the fuel system..restriction or too small lines could be the problem if in fact it is starving for fuel

 

[mrbrophx]

Heck I didn't know you could write a profile! the RPM is around 4-5000 when it begins to miss.
BTW it does have a Mallory distributor and I have replaced the coil too.
I will see if I can put a gauge to see if I am getting the pressure.
All I can say is it is really pissing me off cause the jeep has ran so well for ten years without any problems at all. I have had two mechanics and they can't seem to fix it either.

 

[Hedgehog]

So, what happened near the end of the 10 good running years? Was it just a break down in your fuel pump?

 

[Barry2]

When my engine with an HEI dist. started that, replacing the little winding/coil way down in the distributor under the backing plate cured the problem, now it will crank to 7 grand without missing a beat, Leastwise that's what it took to fix my missing problem.