Acceleration hits a dead wall
- Thread starter 72smallairparticler
- Start date
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Charrlie_S
Well-Known Member
On a slant six the eccentric is ground onto the cam as a lobe. If it is worn out the cam needs to be replaced. That said, I would not discount the possibility of a bad replacement fuel pump (even several).A few years ago I ran into this problem on a 318. Multiple bad pumps from several different sources. I did a "band aid" repair, to keep the car usable. About 2 years later I got another pump, and that one was fine. Just had to wait untill all the defective pumps got out of the system.
Back to the original program.
Check the fuel pump pressure, and also the volume. Put the hose from the fuel pump into a container, and crank the engine. The pump should flow at least 1 pint in 30 sec at idle. To check pressure install a "T" fitting between the pump and carb, and connect to a pressure gauge. At idle should have between 3 1/2 and 5 lbs.
Back to the original program.
Check the fuel pump pressure, and also the volume. Put the hose from the fuel pump into a container, and crank the engine. The pump should flow at least 1 pint in 30 sec at idle. To check pressure install a "T" fitting between the pump and carb, and connect to a pressure gauge. At idle should have between 3 1/2 and 5 lbs.
72smallairparticler
Well-Known Member
Yeah good point. I noticed the other day that the fuel gauge stopped getting a signal for where the fuel level is. I was planning on putting in a new clean tank and fuel send unit as a mental checkpoint to ensure the whole fuel delivery system is completely new and uncontaminated.
72smallairparticler
Well-Known Member
Yep - just installed one so that I could get a solid metric on what the fuel pressure was at. Looks to be at 3.5lbs at idle after just starting it up.
Good call on the cam lobe wear. I have no idea how many miles are on this 225.
So my question is ... is 3.5lbs of pressure enough? I notice when I punch the throttle the pressure doesn't change (not sure if it should though)
If I was to install an electric inline pump like this one before my gauge, maybe that would be a quick low-budget test for the fuel pressure issue?
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TT5.9mag
Two atmospheres are better than one
Thanks for that. I wasn’t sure.
TT5.9mag
Two atmospheres are better than one
3.5 psi of fuel pressure is just enough to make it idle. Probably Not sufficient to drive normally. My opinion is that is low. And volume would be a bigger concern. If you could drive it and watch or video the gauge I bet it drops as you try to accelerate
Have you measured fuel pressure yet?
TT5.9mag
Two atmospheres are better than one
Post 29
dirty white boy
50 yr old Juvenal delinquent
3.5 at idle should be fine but id think it should go up with rpm to least 5 lbs by say 3000 rpms... but im no expert!
Dartswinger70
Well-Known Member
theres a spec for the carb if its a carter probably no more than 7 psi max but thats a guess look it up.
72smallairparticler
Well-Known Member
Alright, installed a new fuel pump. Now I’m getting 5psi at idle.
Test drive - same result, doesn’t move faster when jammin the gas down.
I don’t know a way to capture the psi at the gauge while driving but it sure is an odd issue
Test drive - same result, doesn’t move faster when jammin the gas down.
I don’t know a way to capture the psi at the gauge while driving but it sure is an odd issue
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just check that your heat riser valve is not stuck closed or has fallen off in the head pipe .yes it a long shot but have seen it happen.
72smallairparticler
Well-Known Member
Yeah waiting on new tank and pickup still
72smallairparticler
Well-Known Member
Just checked it, it moves freely still and has the small lightweight spring on it still.
72smallairparticler
Well-Known Member
I’ll give that a check tomorrow and see - it is worth checking for sure since it’s got a new electronic distributor that went in when I converted things to the HEI ignition. That and my vacuum pressure to the distributor from the carb.
He could see that with his timing light.
72smallairparticler
Well-Known Member
Nah, it's for sure not the distributor leads. Car won't even start when they're flipped and it starts/idles like a champ. Somehow managed to bust my timing light bulb in the old Sears timing light so the chase continues.
TT5.9mag
Two atmospheres are better than one
It may not start with the leads flipped from where you have them now because the initial timing is so far off. When you flip the leads you have to retime it. You will know right away when you get your light hooked up.
TT5.9mag
Two atmospheres are better than one
With the distributor leads flipped (wrong way) it is easy to time it and get it to run and idle just fine. When you accelerate the phasing (rotor to cap alignment) quickly goes out of whack and you loose time especially with vacuum advance. With the leads oriented correctly, you won’t loose phase. But you do have to re set the initial to see the difference.
72smallairparticler
Well-Known Member
Ok i'll give it a try
slantsixdan
=..=
72smallairparticler
Well-Known Member
yeah definitely not a fuel issue. I got a new bulb for my timing gun and started the car up. no timing marks were visible during idle so the leads are definitely flipped.
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