When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
After rebuilding the engine the passenger side of the engine doesn’t want to fire with little to no throttle. When more throttle is given it begins to run normally. Revs high on start up burning remaining fuel in passenger side cylinders, fouling out plugs on passenger side.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
With the engine running pull the spark plug wires one at a time and replace them as you go and see which cylinders arent firing. It could be you have an idle mixture issue if its the cykinders that are fed by one side of the carb on a dual plane. I wold think that a poor fuel mixtuer would effect the end cylinders first. If thats not it or its inconsistant then I would suspect a distributor issue. EIther a bad cap or weak power getting to the coil. Check the power at low RPM versus Higher rpm. Could be a shorting apark plug wore that works better at higher rpm... lots of things it could be. You might have crimped a wire while tightening up a motor mount as well.
Last edited by Rescue Rogers; Jul 15, 2021 at 09:00 PM.
With the engine running pull the spark plug wires one at a time and replace them as you go and see which cylinders arent firing. It could be you have an idle mixture issue if its the cykinders that are fed by one side of the carb on a dual plane. I wold think that a poor fuel mixtuer would effect the end cylinders first. If thats not it or its inconsistant then I would suspect a distributor issue. EIther a bad cap or weak power getting to the coil. Check the power at low RPM versus Higher rpm. Could be a shorting apark plug wore that works better at higher rpm... lots of things it could be. You might have crimped a wire while tightening up a motor mount as well.
Weak power being an issue crossed my mind but it seemed strange that would be the cause of the whole bank not wanting to fire. But I don’t know for sure
Fuel mixture screws on the drivers side feed the following cylinders:
1 - 4 - 6 - 7.
Passenger mixture screw gets:
2 - 3 - 5 - 8
That has nothing to do with a bank of cylinders unless its a single plane Intake.
You have cyl 2,4, 6, 8 issues. The only thing they have in common is the head gasket & Intake gasket.
A weak coil or bad dizzy cap can not separate a bank of cylinders.
Take a vacuum reading first.
Last edited by HeadsU.P.; Jul 16, 2021 at 08:07 AM.
Ok. Mixture screw not likely kill off a whole bank of cylinders though.
Might be the passenger primary booster / jet. Then later, under throttle, the secondary boosters kicks in. Runs a little better?
Tell us about the carb model, age, last rebuild?
Last edited by HeadsU.P.; Jul 15, 2021 at 09:06 PM.
Engine idle was decent running only off of drivers side bank. When I give it throttle all cylinders will begin to fire perfectly. Does not seem down on power when in higher RPMs. Prior to rebuild engine idled great with all cylinders running.
Carb is a Holley 750 double pumper only has 3500 miles on it
Passenger side appears to be getting fuel as the plugs were coated in dark gas when I went to change the plugs. And engine surges upon start up burning residual fuel producing a white cloud from the passenger side pipes for a brief moment.
YOu have to determine if its the whole bank. I think if you were running on 4 cylinders the motor would try to shake it self apart
I agree...the likelihood of one whole bank cutting off is lottery odds.
Tell us more about this engine and post pics.
Take a timing light while running and run the clamp around each plug wire.....does it strobe? If they do then you have spark on all.....if not, then narrow down the individual cylinders and troubleshoot from there.
In 30 years, I have never seen a whole bank disappear....up to 3 cylinders on one side, yes....but never a whole bank. I have seen where two people lash one side of the engine and one guy screwed up......so do not rule out lash, you claim this is a rebuild so worth investigating.
Jebby
Last edited by Jebbysan; Jul 16, 2021 at 07:47 AM.
The engine is the original 1980 L48, it was rebuilt a few years ago with lots of upgrades. Due to a severe oil leak I lost most of my oil while driving and the engine began knocking so I parked it and pulled the engine. I rebuilt the engine with new bearings and had the crank machined, the knocking is no more, however the passenger side bank does not want to fire unless there is some throttle given.
The engine has the following:
-New Pistons
-Cam with .515” lift at valves
-New heads
-Edelbrock victor Jr. manifold
-Holley 750 double pumper
-DUI distributor with crossfire cap
-Roller rockers
From: At my Bar drinking and wrenching in Lafayette Colorado
Your plug wires are not in the right firing order - you have all the wires on one side of the cap going to one side of the engine, and all the wires on the other side going to the other side of the engine, and the distributor is not correctly installed or clocked in the engine.
The firing order of the distributor was taken into consideration and plug wires are connected properly. They are also in the same places they were before the engine was rebuilt.
The engine also runs fine in higher RPMs so I suspect that rotor placement is correct. And drivers side bank fires well at any RPM as well. I could be wrong about rotor placement though.
The firing order of the distributor was taken into consideration and plug wires are connected properly. They are also in the same places they were before the engine was rebuilt.
The engine also runs fine in higher RPMs so I suspect that rotor placement is correct. And drivers side bank fires well at any RPM as well. I could be wrong about rotor placement though.
That is not even possible based on the pictures you provided unless you have some weird cross fire side counter rotating flux capacitor distributor installed.
That Crossfire cap is very different then most people are used to. Since it essentially rearranges your (at least perceived firing order), I might think that it might be worth a closer look.
That is not even possible based on the pictures you provided unless you have some weird cross fire side counter rotating flux capacitor distributor installed.
Strange engine problem after rebuild
