engine problem

[lildebbie1111]

Hi everyone I HOPE SOMEONE CAN HELP ME . I HAVE AN 83 CAMARO WITH A 74 350 MOTOR I HAVENT HAD ANY PROBLEMS WITH IT UNTILL TODAY.THE RPMS DROPPED 300 AND THE ENGINES SHAKING ALSO SEEMS TO LOST POWER I PULLED THE PLUGS AND THEY ARE REAL DARK WHEN THEY USE TO BE LIGHT TAN IM THINKING IGN MODULE EVEN THOUGH THE DISTRIBUTOR WAS PUT IN 2 MONTHS AGO ANYBODY HAVE ANY IDEAS

[53 Chevy5]

you definetly have a fuel problem. did you check to see if your choke is opening up? what carb do you have on it?

[lildebbie1111]

I DID CHECKTHE CHOKE IT IS OPEN ALL THE WAY IT HAS A EDELBROCK 600 MODEL 1405 14 DEGREES IN ITIAL 34 TOTAL AT 2800RPMS 234 DUIRATION 496 LIFT 194 VALVE HEADS ROLLER ROCKERS PROFORM GEAR DRIVE PERFORMER RPM INTAKE

[Matt167]

Originally posted by lildebbie1111
I DID CHECKTHE CHOKE IT IS OPEN ALL THE WAY IT HAS A EDELBROCK 600 MODEL 1405 14 DEGREES IN ITIAL 34 TOTAL AT 2800RPMS 234 DUIRATION 496 LIFT 194 VALVE HEADS ROLLER ROCKERS PROFORM GEAR DRIVE PERFORMER RPM INTAKE

Check/ replace all fuel filters, if that don't work, check the fuel lines, run some fuel system cleaner through it, the STP high strength stuff.

[lildebbie1111]

THANKS GUYS I WILL CHECK THE FUEL SYSTEM I RUN 104 IN IT EVERY TANK BECAUSE ITS BORED 40 OVER WITH DOMED PISTONS

[docone31]

I just ran a post on that same carb. Are you running a Performer manifold with the carb?, or an LT1?
I went nuts with mine, replaced ignition, module, complete distributor. I readjusted the idle mixture over, and over. Each weather change, the van would run differently.
I am presuming you are not computer controlled, or you would not have that carb.
The HEI has an interesting quirk. The coil must be grounded or it fries the rotor. That is number one.
Second, as it sounds like my issue, check vaccum. You are probably timed to peak, so any drop in vaccum will make a big difference.
First, check air filter, obstructions in the air filter and intake portion of the carb. Second, check the power brake hose connection. It is in front between the idle adjust screws. Next, check the larger vaccum hose connection to the distributor.
If you have the performer manifold, you also have an EGR adapter, and carburator offset plate. Under the offset plate is a thin gasket. Above the offset plate is the 1" gasket. My carb had a gap caused by a thin washer under the right front stud. I am going to speculate, the 1" washer is the culprit.
My issue came on me suddenly also. I went nuts. I only found out my issue by trying to put a Q-Jet on to replace the Edelbrock.
I also had an idle screw back out on me. I had to take out the jet, put more tension on the spring and put it back.
To adjust you idle screws, turn them in to close, not hard, just closed. Open them out 1 1/2 turns. That should be your idle adjust point. If idle speed is too low, turn one out untill your engine goes to idle speed. Match with the other one. Using a tach, turn one untill the idle speed either goes up 50rpm, or down 50rpm. Match with the other one looking for the same gain or drop at your idle rpm. Same as a Q-Jet.
Also how is the torque on the manifold? Did you retorque the heads after 500mi?
Is your converter plugged? or plugging up?
Good luck, I know how frustrating that one is.

[drg84]

Lilldebbie, from now on try and back off the Caps Lock. Anyway, a few tips and tricks. To check for spark, pull your plugs and place then against the block. If you have a bright blue spark thats a sign of strong spark. Yellow, orange or none are all bad signs. Since you had a good burn on your plugs before, I'm going to have to assume that you have cleaned the plugs, gapped them properly and they are the correct heat range. It sounds like your either dumping fuel in it during acceleration(IE accelerator pump cracked a seal), you have too high of a float bowl or you have a severe vacuum issue. My advice would be to pull each line one by one, plug the port and see if your engine picks up. If this doesnt work, run your hand around the edges of your intake manifold and carb. Hope this helps.

[lildebbie1111]

Hi everyone.Itriedevery thing every one suggested.I have a nice blue spark on every plug wire.Itook the top off the carb,sprayed carb cleaner in every hole I could find. I took the cap off, cleaned it , checked for cracks, eliminated vacume lines one by one and it still dont run right. Think im going to see if a buddy has a carb I can try . If docone31 is out there tell me what you figured to be your problem was it the carb? And I have the perfomer rpm intake for the older chevy no cat no computer just the way they were built in 69 the right way drive it like you stole it

[lildebbie1111]

oh I almost forgot ten inches of steady vacume at 850 rpms

[lildebbie1111]

Its been that way since I built it and it ran like a bear Dont forget it has a very radical cam in it 496 lift 290 dur 104 lobe seperation

[jramshu]

Sure sounds like a vacuum problem.
Edelbrock suggests this:
1. Check for air leaks. Make sure carb and manifold gaskets are sealed properly. Make sure all unused ports are plugged.
2. Ceck ignition system.
3. Check choke adjustment.
4. Check carb fuel filter and/or in-line fuel filter.
5. Check float drop level.
6. Check for dirt in needles and seats.
7. Increase accelerator pump stroke.
8. Check float for leaks.
9. Check airhorn gasket.
10. Fuel pressure too low.
11. Check secondary latching device and rod for proper movement.


I know some doesn't apply to your situation but, these are from thr troubleshooting chart from a Edelbrock Owners Manual for 1403,1404,1405,1406,1407,1409,1410,1411,1412, and 1413.

[docone31]

Lil Debbie, the problem I found, was the washer caused part of the gasket to lift from the manifold making a direct vaccum leak. Ten inches is a little low for the street, especially in traffic.
As I put in my first reply, the brake booster vaccum line had vaccum flow, and the carburator effectively had a gap between the base, and gasket.
All I did was flip over the 1" gasket, torque to 40ft lbs, put a cable tie on the brake booster line, and it never worked better. The 1" gasket has steel bushings so there is very little crush.
I reccomend, removing the carb. You probably built it so you know where the vaccum hoses go, then just take a look see. Mine had a brown spot between the back venturi's, that is the EGR dump. The brown spot should have been dead center between the two back galleys, it was off center to the left rear.
She now runs like I designed it to. Power, fuel economy, and smoooooth. It is after all a 4 X 8 sheet of plywood upright with wheels.
I went from 3.23 rear to 2.73 posi. She cruises on the highway at 70 at 1600rpm.
check the base of the carb. Be careful retorqueing, it is basically a Q-Jet and over torque can crack the base.

[jramshu]

Are the plugs sooty? That is flooding isn't it, unless its oil. Still sounds like vacuum to me though.
Just athought but have you checked ignition timing?