FAQ |
Members List |
Social Groups |
Calendar |
Search |
Today's Posts |
#1
|
|||
|
|||
RPMs Dropping Under Moderate to Hard Acceleration
Hey Guys, appreciate your feedback on where to look next.
My car starts and runs fine under normal driving conditions and light acceleration. Especially after its hot, the car will stumble under moderate to hard acceleration. RPMs will drop by 1000, then come back, then drop if I hold my foot into it. Feels like the car is starving for fuel. Not sure if this is coincidence, but I just installed a new DUI distributor. Initial timing is 12 and I have no pinging. Thank you |
#2
|
||||
|
||||
If it happened right after you installed the distributor, I’d take a look at that.
More info needed: Did you replace a points system or a different HEI?
__________________
1965 Pontiac LeMans. M21, 3.73 in a 12 bolt, Kauffman 461. |
#3
|
|||
|
|||
I replaced an HEI with an HEI. I actually installed two different new DUI HEI distributors. No change in problem.
|
#4
|
|||
|
|||
could be a mild case of vapor lock. Considering this happens at moderate to high throttle openings when fuel need is at it's highest and again only when the car is hot, I'd look for an issue there myself.
When I was still running a carb (1407 eCarb) I would get similar performance as the heat built up in the engine bay. Most often if you popped the hood, you could hear fuel percolating in the carb.
__________________
-Jason 1969 Pontiac Firebird |
#5
|
|||
|
|||
I'd first check the gas filter.
Then make sure the tank vent is working like it's suppose to. Inspect all the short pieces of rubber hose where hard lines are hooked together. One at the tank, one where the hard line goes from the body to the subframe and the one at the fuel pump. |
#6
|
||||
|
||||
If the motor will rev cleanly out of gear to 5000 rpm when you mat the throttle open then you likely do not have a ignition problem, its fuel related!
I can't tell you how many times I have helped a guy who rebuilt his car only to have it do what yours is and at the end of checking out things it turned out the issue was the poor clamping job done on the furl line hose jumper back at the darn tank! In each of these cases the hose was tight enough to not leak, but it would suck air and since air is far lighter then fuel that's what the fuel pump sucks, air!!!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#7
|
|||
|
|||
sounds like a fuel problem or carb. does the carb have a choke? almost like the choke is closing and cutting the air flow...if its a q jet then the secondary flaps might not be openning all the way.
__________________
1970 firebird, 468, e heads, |
#8
|
|||
|
|||
What is the fuel pressure when the engine stumbles?
|
Reply |
Thread Tools | |
Display Modes | |
|
|