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Re: measuring fuel pressure [Re: NHCharger] #2686057
08/09/19 02:31 PM
08/09/19 02:31 PM
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Aurora, Colorado
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With the Fuel, you want to measure the fuel delivery volume at pressure.
Easier to test with electric pumps, with a mechanical you may need a temporary fuel supply to be able to rev the engine with the mechanical pump disconnected.
You need to add some restriction at the fuel output to create pressure. If the pump is internally regulated, need to be careful to just bring pressure up to the regulated set point.
Setup fuel outlet into a empty gas can, and time how long it takes to fill to figure the fuel volume delivered.

This is just a static test with the car under zero G-Force.
You can also lift the cars front end to simulate fuel delivery under acceleration.

Re: measuring fuel pressure [Re: bee1971] #2686125
08/09/19 08:25 PM
08/09/19 08:25 PM
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Originally Posted by bee1971
Did issue get resolved ?

Thanx Scott




No. Have only dubbed around with it when I have time. A couple of things I recently tried.
Was wondering if I had some type of obstruction between tank and fuel pump. I took a two gallon container and strapped it to the 1" tube framing for the nosecone and ran a hose to the fuel pump, completely bypassing the tank and fuel line. Same issue.
I put a fuel pressure gauge on the car and taped the gauge to the windshield (that was interesting). The gauge fluttered a lot, not sure if it's supposed to do that. While under acceleration it fluttered between 5.5 to 7, smoothly out a bit at 50 MPH fluttering at 6-7. Once I stabbed the pedal it fluttered wildly between 2-7 with the engine just laying flat. (I have already installed two different fuel pumps).
My mechanic buddy wondered if I had an obstruction in the rubber fuel line between the pump and carb. Changed both hoses, same issue.


My Dad always told me, when setting goals " avoid disappointment, aim low".
Re: measuring fuel pressure [Re: fast68plymouth] #2686416
08/11/19 09:12 AM
08/11/19 09:12 AM
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Sobieski Wi
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Originally Posted by fast68plymouth
If the motor goes flat at 5200 in each gear, it’s very unlikely a fuel issue.

This would mean you could roll on the throttle in first, experience the flat line of power at 5200, and then right after the shift into 2nd, and the corresponding drop in rpm....... the motor recovers and pulls good back to 5200.

My experience has been this situation has always been an ignition or valvetrain related issue.
I suppose it “possible” it’s a collapsed muffler condition, but I can’t imagine that having the on/off switch-like affect you get from ignition or valvetrain problems.

Fuel supply problems usually manifest themselves as; the motor just starts laying down, and no recovery occurs until the throttle is closed........ fuel bowls start refilling, then you step back down....... car accelerates for a bit, then lays back down as the bowls start to empty.

With the XE cam, you’re certainly a candidate for a valvetrain issue.

Another thing, if it’s somethiing other than fuel, you should be able to run it hard through the gears(wot), and not experience any issues if you keep the rpms below the point where the motor lays down.
So, if yours lays down at 5200, you should be able to go thru all he gears at WOT and shift at say 5000, and not experience any issues.

If it’s fuel supply, you wouldn’t be able to do that.
You’d probably get about 1/3 of the way through 2nd and it would lay down.


Had it out yesterday for a little bit

Took your advice and ran it through the auto gears shifting manually at say 4800 Rpms to 5000 Rpms

Definitely not fuel pressure related as it never missed a beat through all three gears

Then get into that 5200/5400 Rpm range on some more shifts , and it falls on its face

Didn’t have a spare Mopar Ignition Control Module on hand or in the garage to change quick - My bad

Been running the Mopar Chrome Module for a decade or longer , but recently had a few issues with MSD Blaster 2 Coils (Two to bee exact) going bad at much lower RPMs , intermittent missing and going flat under light acceleration since this new motor

.8 MSD Resistor - Now running a Mopar Canister Oil Filled Ignition Coil that I had brand new in the box from the 90 s - Made in da USA Lol

It works - Zero issues at any lower RPM s

Anyways that’s it for now until I swap in a new ignition box I guess , I would of thought they either work or they don’t , another words fail completely

I see the Rev nnator is sold out back ordered

Mopar doesn’t make boxes anymore

4 second s flat sells a box

There is a Jegs 7500 unit

I should probably just throw some China jobber junk on there for now to see what happens at higher RPM s


1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: bee1971] #2686435
08/11/19 10:18 AM
08/11/19 10:18 AM
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So. Burlington, Vt.
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Have you checked the voltage at the coil while it’s running?
Checked voltage on the hot side of the resistor, and compared that vs the voltage at the battery?

Many years ago on my heap, I put in a higher rpm motor than I had run previously, which allowed some ign issuers to show up.

In my case I had lots of loss through the old factory wiring.
I peeled off some of the insulation in several spots and it was all green inside.

That’s when I went to a MSD 6A box...... since the power feed wires go direct to the battery, bypassing all the factory wiring........ and getting rid of the ballast.
I used the big yellow Accel Super Coil with it, which was already used when I got the car in 1981.

That being said, in my mind, it’s just as likely a valvetrain issue as ignition.

The pitfalls of fast rate hyd cams:
https://www.hotrod.com/articles/mopp-0510-440-engine-dyno-test/


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: measuring fuel pressure [Re: fast68plymouth] #2686988
08/12/19 06:47 PM
08/12/19 06:47 PM
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bee1971 Offline
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Thanx for the link - Great read on the lifters

Hopefully I won’t have to go down that road , no pun intended

Anyways

Won’t get back to the car until the end of the week , hopefully will have more answers then questions

Thanx again


1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: fast68plymouth] #2694082
09/03/19 07:00 PM
09/03/19 07:00 PM
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Originally Posted by fast68plymouth
Have you checked the voltage at the coil while it’s running?
Checked voltage on the hot side of the resistor, and compared that vs the voltage at the battery?

Many years ago on my heap, I put in a higher rpm motor than I had run previously, which allowed some ign issuers to show up.

In my case I had lots of loss through the old factory wiring.
I peeled off some of the insulation in several spots and it was all green inside.

That’s when I went to a MSD 6A box...... since the power feed wires go direct to the battery, bypassing all the factory wiring........ and getting rid of the ballast.
I used the big yellow Accel Super Coil with it, which was already used when I got the car in 1981.

That being said, in my mind, it’s just as likely a valvetrain issue as ignition.

The pitfalls of fast rate hyd cams:
https://www.hotrod.com/articles/mopp-0510-440-engine-dyno-test/


E Street 75 cc Heads - Angled Plugs

Came across this article and started with the spark plugs - They talked about toasted boots on #6 plus #8 later in the article

http://www.moparts.org/Tech/Archive/bb/Lobe.html

Never noticed anything on the plugs themselves or the spark plug boots for that matter , but once I looked inside the boots on #6 and #8
They where black - Went to pull the plug boots off and the metal terminals came with them

Serious heat issue and misfire with these two plug wires

Two new plug wires and those 1200 degree boot protectors , and I was off thinking for sure this was the issue - Fixed on the first day

Man what a difference overall , Smooth , Rpms come up fast , really fast , first gear all the way up to 5500 5600 Rpms shift into second

Engine feels Awesome , like I gained fifty horse overall

Second now coming up to 5200 5400 Rpms and it starts sputtering , PINGING like crazy



Cruise mode on the highway 3200 Rpms at 70 mph in Drive - Get in the gas to 5500 Rpms no problem

All day long in first to 5500 5600 Rpms then

Verified fuel pressure with gauge taped to my windshield - 4 to 5 psi at full throttle - Delphi mechanical stock 383 , verified pump rod at 3.22 “ factory original from 1971

Friends gave me a couple different ECUs and a new coil - Pertronix 40011 Coil - Jumped the ballast resistor

Idle 700 Rpms 13.5 volts to both sides of ballast , 13.5 volts positive side of coil - All wiring is fairly new and looks great
Volts come up to 14.5 with Rpms

Different ECUs no change



Obviously there is a huge difference between fuel pressure and fuel volume correct ?

I also pulled the valve covers - I wanted to check my rocker arm geometry and wear pattern with these Sealed Power rocker arms and shafts

Man I couldn’t bee happier - Rocker arms , comp cams push rods , spring retainers no rubbing , valve stems looked damn near perfect brand new after two summers

That’s where I am at - A much better running engine overall , all day long out of the hole in first to 5500 5600 , then falling off in second around 5200 5400 on a full run and PINGING like crazy

Thanx Fast 68 Plymouth for all your help

Last edited by bee1971; 09/09/19 08:14 PM.

1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: bee1971] #2694174
09/03/19 11:20 PM
09/03/19 11:20 PM
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Bend,OR USA
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Pinging tells me it is running out of fuel at that time, check the needle and seats size twocents
Try the next bigger to see if they are the restrictors or not scope wrench
Some of these gremlins will run you through the hoops finding and correcting them whistling You can lick them hammer up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: measuring fuel pressure [Re: Cab_Burge] #2694211
09/04/19 06:40 AM
09/04/19 06:40 AM
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Originally Posted by Cab_Burge
Pinging tells me it is running out of fuel at that time, check the needle and seats size twocents
Try the next bigger to see if they are the restrictors or not scope wrench
Some of these gremlins will run you through the hoops finding and correcting them whistling You can lick them hammer up


These Edelbrock s come with .093 Needles and Seats

They make or sell a .110 Needle and Seat

Float level is at 7/16” verified on both - One float was out of whack from the factory new when I opened it up


1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: bee1971] #2694616
09/05/19 09:26 AM
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Last edited by bee1971; 09/09/19 08:10 PM.

1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: bee1971] #2694626
09/05/19 10:05 AM
09/05/19 10:05 AM
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Fuel pressure is an indicated 4-5 psi........ while it’s experiencing a problem at high rpm?

If so, I’d probably rule out a fuel delivery issue.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: measuring fuel pressure [Re: fast68plymouth] #2694648
09/05/19 10:59 AM
09/05/19 10:59 AM
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Originally Posted by fast68plymouth
Fuel pressure is an indicated 4-5 psi........ while it’s experiencing a problem at high rpm?

If so, I’d probably rule out a fuel delivery issue.


The massive PINGING when it runs out of gas and falls flat at RPM


Thanx Scott

Last edited by bee1971; 09/09/19 08:09 PM.

1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: bee1971] #2694778
09/05/19 07:45 PM
09/05/19 07:45 PM
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How does you fuel pressure change between normal cruise or driving verses WOT.

I would guess that this pressure drop causes the the vaporization temperature to drop low enough on a hot day to cause the vapor lock. Throttle closes, pressure goes back up.

Re: measuring fuel pressure [Re: BSB67] #2695477
09/08/19 02:46 PM
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Originally Posted by BSB67
How does you fuel pressure change between normal cruise or driving verses WOT.

I would guess that this pressure drop causes the the vaporization temperature to drop low enough on a hot day to cause the vapor lock. Throttle closes, pressure goes back up.


I won’t know again until probably next summer , but it doesn’t fall off more then a few psi in this cooler weather at WOT


Last edited by bee1971; 09/09/19 08:07 PM.

1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: bee1971] #2695481
09/08/19 03:00 PM
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If it only bothers in hot weather, it’s likely just a vapor lock issue.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: measuring fuel pressure [Re: fast68plymouth] #2695489
09/08/19 03:17 PM
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Originally Posted by fast68plymouth
Fuel pressure is an indicated 4-5 psi........ while it’s experiencing a problem at high rpm?

If so, I’d probably rule out a fuel delivery issue.


5400 RPMs is about all










Last edited by bee1971; 09/09/19 08:06 PM.

1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
Re: measuring fuel pressure [Re: fast68plymouth] #2695492
09/08/19 03:20 PM
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Originally Posted by fast68plymouth
If it only bothers in hot weather, it’s likely just a vapor lock issue.


Yes and no , maybe LOL


Motor just runs flat out Awesome with everything I have improved on , especially finding those two bad spark plug wires


However 5,000 RPMs comes on really really fast especially on the highway running 3:91 gears








Last edited by bee1971; 09/09/19 08:06 PM.

1971 Dodge Charger Superbee
2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded
Siberian Huskies
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