351W popping @ 4000 rpm

[Blackpony]

What valve springs are you running? had a similar issue with a 347 couple years ago, and turns out the springs were too weak. replaced them with a correct set and problem went away. just a thought

[5.8mont]

What valve springs are you running? had a similar issue with a 347 couple years ago, and turns out the springs were too weak. replaced them with a correct set and problem went away. just a thought

Not sure, but i had the heads rebuilt and the guy checked the springs. I thought it might have been the problem it was having over 6000rpm but I dont think it would cause this.

[turbostang]

If you're using a single in tank pump and a V1 S trim on a Windsor, say no more. You're likely running out of fuel pump. If you had a guage you could see, you would likely see the fuel pressure dropping at high RPM, especially considering 60# injectors.

[5.8mont]

If you're using a single in tank pump and a V1 S trim on a Windsor, say no more. You're likely running out of fuel pump. If you had a guage you could see, you would likely see the fuel pressure dropping at high RPM, especially considering 60# injectors.

It's a 340lph pump it should be far more than I need. I dont get why that would intermitent. Every other time i punch it the car will run perfect.

[5.8mont]

I swaped my autolite plugs and ran a ground to the case of my computer. The computer is still sitting in the floor board from having it tuned. I test drove the car and it acted up for the first minute or two then ran perfect for about ten minutes then started doing the same crap, but at around 5200rpm.

[turbostang]

It's a 340lph pump it should be far more than I need. I dont get why that would intermitent. Every other time i punch it the car will run perfect.

You're using a cheap chinese imported fuel pump and can't tell us if the fuel pressure is rising 1:1 all the way to redline, but you're sure it's not the pump?

Having said all that, if the problem truely moves from one RPM range to another - I'd be looking at the pickup in the distributor. If it's not 'right', nothing will work. FWIW, I just replaced one in a BRAND NEW MSD distributor because the car wouldn't start every time.

The pickup is responsible for every single event that the computer uses to keep the car running - both fuel AND spark.

[5.8mont]

You're using a cheap chinese imported fuel pump and can't tell us if the fuel pressure is rising 1:1 all the way to redline, but you're sure it's not the pump?

Having said all that, if the problem truely moves from one RPM range to another - I'd be looking at the pickup in the distributor. If it's not 'right', nothing will work. FWIW, I just replaced one in a BRAND NEW MSD distributor because the car wouldn't start every time.

The pickup is responsible for every single event that the computer uses to keep the car running - both fuel AND spark.

Yes the pump is a pos, but I said the pumps flow rate is more than I need. You made it sound like just because I only have one pump its got to be the problem.

Is there any way I can test the pickup? It would piss me off a bit if they replaced mine with bad new part.

[Sleeper]

You really need to get a gauge on it and see what its doing. This is your next step, and then borrow another distributor and coil to test.

[5.8mont]

Yeah I do, ill try to move the gauge some time this week.

[turbostang]

Yes the pump is a pos, but I said the pumps flow rate is more than I need. You made it sound like just because I only have one pump its got to be the problem.

Is there any way I can test the pickup? It would piss me off a bit if they replaced mine with bad new part.

Yes, I did - but i was under the impression it's a 255lph.

Either way, as much bad luck as I've had with chinese import stuff, I'd seriously look into it.

I don't know of a way to test the pickup, but a new one is only 20$ I think. You just have to dismantle the distrubutor to get it out.

[5.8mont]

Yes, I did - but i was under the impression it's a 255lph.

Either way, as much bad luck as I've had with chinese import stuff, I'd seriously look into it.

I don't know of a way to test the pickup, but a new one is only 20$ I think. You just have to dismantle the distrubutor to get it out.

I will be looking into the pump. Where did you find the pickup for sale? MSD wouldnt sell me just the parts and I cant find them anywhere else.

[turbostang]

It's a stock replacement part for a 5.0 mustang.

[5.8mont]

I dont know why I thought it would be a special msd part. Thanks though

[turbostang]

That's what you'd expect from a ~300$ distributor!!

[5.8mont]

The car never has trouble starting, but one thing I noticed yesterday is the car would run like crap if the 6AL box was deleted. It would stutter and iddle rough, then run smooth when I added the box back in the system.