Today on my way home, I was getting in a long, empty road (it was 12.30 am) so I decided to get on it and see how it pulls, I got the pedal to the metal on all 3 gears, it pulled really hard and the acceleration was amazing! .. but the RPM was limited to about 4500 and it simply wont go beyond that, just like if I have a rev. limiter! .. it pulls really hard up to 4500 but it just stops there, could that be a valve float symptom? .. is it a fuel starvation? .. I need some analysis for that before I start taking things apart.
Egine will not go beyond 4500 RPM, what could be the cause?
- Thread starter Hamad
- Start date
mrvette
Phantom of the Opera
OK, so you in 4th or maybe overdrive, and engine just quits?? backfire any or just stop....somehow I suspect a fuel problem, the ignition would be fairly easy to prove out, is it HEI or points???
what are your ignition specs?? initial, mechanical, DPFI or carb, vacuum advance don't count at WOT...
:sos:
what are your ignition specs?? initial, mechanical, DPFI or carb, vacuum advance don't count at WOT...
:sos:
MYBAD79
Moderator
What you're describing "sounds" like vapor lock. Any details on the fuel system? Pump, fuel line, return line ?
The RPM will be limited to 4500 in all gears, no back fire or stumble, just it will stop there. I got a stock quadrajet with a Mallory magnetic breakerless distributor with vacuum advance (its connected). Timing is set at 10* at idle and 36* at 3000 RPM without the vacuum advance. It also has the stock fuel pump and the stock small filter inside the carb. inlet housing. I have few upgrades in the engine, like a 9:1 pistons instead of the stock 8.5:1 and the Lunati camshaft (specs on my signature) with open elemnt air cleaner.
Do you think that I may have a wiped camshaft lobe?
Do you think that I may have a wiped camshaft lobe?
Everything is pure stock '71 BB system. Today was a hot day (about 95F when I was on my way home) .. how can I verify that?
DeeVeeEight
Fast Pedalphile
Take the floor mat out from under the gas pedal.
SmokinBBC
Well-known member
So, at 4500rpm's it just dies, sputters, bogs? Or does it keep revving but won't go any further?
big2bird
Charter Member, Founder Bird-Run, Cruise-In Bird-R
Take the floor mat out from under the gas pedal.
Yep. Verify the accelerator gives full t-plate opening.
pcf_mark
Well-known member
- Joined
- Aug 22, 2008
- Messages
- 218
If it is a non violent ceiling (no popping, ratting etc) I am with the suggestion for floor mat or the throttle bracket slipped and wide open is only half carb opening. Or the air filter waaaay clogged.
SmokinBBC
Well-known member
Take the floor mat out from under the gas pedal.
Yep. Verify the accelerator gives full t-plate opening.
secondaries locking out?
It will just reach 4500 and wont go any further, just like it has no power to go. The accelerator linkage seems OK and the secondries sounds like they're opening, but I dont know for sure if they are fully openning. I will try to capture that in video and post it here.
TimAT
Addict, Cruise-In Bird-Run 1 Veteran
A load of bad fuel will do that too. That little filter in the carb will plug up right quick fast and in a hurry.
gr8vet
Well-known member
Do you have an old, stock Tach? Voice of experience, verify the tach is not stuck at 4500 on high side. Been there, done that........:cussing:
Good luck
tt
Good luck
tt