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Topic: Engine Bogges Down

in Forum: C3 Engines


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Engine Bogges Down (1/10)
 8/8/09 3:39pm
Jeffm
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Sebago Lake, ME - USA

Vette(s):
1978 Silver Anniversary L82 4spd (M21) Red Leather. Pace Car is in the hands of a new caretaker.


Joined: 2/15/2007
Posts: 964

On my '78 Pace Car if I give it a work out and go through the gears (4 speed) when she gets up to about 3000 rpm in each gear the engine starts spurting and skipping and bogging down. I only put a little over 100 miles on her since I picked her up a couple months ago and she just turned 20K so I think she just sat a lot without being run.
Gas filter maybe? or what? My mind is pretty simple when it comes to the engine.
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Engine Bogges Down (2/10)
 8/8/09 5:25pm
Gunslinger
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Frederick, MD - USA

Vette(s):
1969 convertible L71 427/435 4-speed black interior


Joined: 9/8/2003
Posts: 3398

It could be the gas filter...the one at the carburetor or the gas sock over the pickup in the gas tank.  The gas itself could have turned into varnish from age.

The distributor module could be bad as well.  Just because the car has few miles doesn't mean parts don't go bad from age.  The same goes for the plug wires...they could be breaking down.

Does the engine start sputtering at 3000 rpm's when you have it in park and rev it, or only when under load of torque while driving?

The car may be in need of a complete tune-up, including fuel line flushing and combustion chamber cleaning, plug wires, distributor cap and rotor, etc.
Engine Bogges Down (3/10)
 8/9/09 2:02pm
Jeffm
Former Member

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Sebago Lake, ME - USA

Vette(s):
1978 Silver Anniversary L82 4spd (M21) Red Leather. Pace Car is in the hands of a new caretaker.


Joined: 2/15/2007
Posts: 964

Today it died on me. headed out and after a while it started the spurting and bucking. couldn't get it up over 25 mph and it would die and coast to a stop. It starts up after a little cranking and then the same thing. Got a ride home from a nice guy that stopped and went back with my trailer. I'll have to see what I can figure out or take it somewhere.
Jeffm2009-08-09 11:03:37
Engine Bogges Down (4/10)
 8/10/09 10:56am
VetteSpecialties
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Mounds View, MN - USA

Vette(s):
70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe


Joined: 5/24/2007
Posts: 1031

My first guess would be a fuel problem, most likely fuel pump.  It sounds like it runs out of fuel, and the problem is getting worse.  A check with a fuel pressure gauge would be a good idea.  And of course, a partially plugged filter would show the same symptoms.

Good Luck
Larry 
Engine Bogges Down (5/10)
 8/10/09 12:27pm
aceintheholeLifetime Member
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Manteca, CA - USA

Vette(s):
1978,two tone,Metalic Rootbeer & gold 1975 L48 4 speed


Joined: 11/20/2005
Posts: 3623

[QUOTE=VetteSpecialties]My first guess would be a fuel problem, most likely fuel pump.  It sounds like it runs out of fuel, and the problem is getting worse.  A check with a fuel pressure gauge would be a good idea.  And of course, a partially plugged filter would show the same symptoms.Good Luck, Larry  [/QUOTE]
 
Yep, fuel would have been my first guess also. I would just like to add, when a car gets this old and your not getting enough fuel at rpms, before buying a new pump, remove the rubber boot around the fuel cap and look at the 2 short fuel lines to the right of the filler neck. If they've never been replaced, they most certainly need it. It will be obvious if they're cracked up. And if you do replace those lines, be sure to return the little alignment bracket to it's intended position or the new lines will stress out prematurely from being offset.


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Engine Bogges Down (6/10)
 8/14/09 12:30am
1sty2000
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Menasha, WI - USA

Vette(s):
'79 Corvette completely restored (body on). 400 C.I. new engine, 80's style read bumper, new chrome side pipes, new interior. I have learned a lot & I am having fun!


Joined: 8/13/2009
Posts: 4


_popupControl();  I just went through almost the identical issue. My engine kept bogging and every time I would try something different it would help for a few miles then it would do it again. I changed the plugs, plug wires, had the carb. adjusted, etc. Then about a week ago I went through the ATM to get money out and it started bogging real bad. I had been putting it in neutral all the way home and was only a few blocks away. As soon as I put it in gear and pulled through the ATM it died. I turned it over for a minute or two and it finally started. I pulled into my driveway and as soon as the idle dropped again it bogged then died. I finally got it started again the next day and heard a ticking much like a lift but faster. I went around the engine trying to find it and I finally did. It was the PCV valve that goes into the valve cover. I pulled out from the valve cover and it still ran bad but as soon as I pulled the valve from the vacuum hose the idle went right back up and it ran great. I went down to the parts store and picked up a new one for $1.99 I took in yesterday and my mechanic adjusted my timing, carb. etc but the main cause of the bogging was a plugged PCV valve. the problem is I changed it out last year as a routine thing and I am wondering why it plugged up so fast. It may be from like the post above mentions, not driving the Vette much. I only had it on the highway 2 times for longer road trips this year otherwise it has been mainly city driving except hopping on the highway as a short cut.

 
Best of luck,
 
Jeff
 
PS- I have a 400 crate engine and my Edelbrock valve covers only have one breather hole and I do know some if not all stock 350's have 2, one on each side. Please correct me if I am wrong. Thanks.


 

Engine Bogges Down (7/10)
 8/14/09 10:56am
Gunslinger
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Frederick, MD - USA

Vette(s):
1969 convertible L71 427/435 4-speed black interior


Joined: 9/8/2003
Posts: 3398

If your PCV is clogging that fast, it often comes from excessive blow by in the crankcase.  Blow by is usually caused by worn rings or insufficient ventilation.

Are you saying your valve covers have the PCV in one cover and a breather on the other or no breather on the other side?  If you have the breather on the opposite side, that should be sufficient.  If you have no breather, just the PCV, then you need a breather installed.  

Some small blocks have three openings in their valve covers, depending on year and model...breather/oil fill, PCV and a vent tube taking valve cover fumes back to the air cleaner to be reburned.

Those Edelbrock valve covers are made to have additional holes drilled.  

If you have a breather and are still having a clogged PCV, have the rings seated in that crate engine?  You need to determine the cause of that so you don't develop serious problems.
Engine Bogges Down (8/10)
 8/14/09 10:41pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20126

Does sound like a fuel problem ,but...don't rule out a failed/failing ignition module, or coil. I would first check the fuel pressure, and go from there.
Also, check your oil...smell it...see if it has a strong gasoline smell. The fuel pump diaphragm could be ruptured, dumping raw fuel into the engine that should be going to the carb. On cars that sit for long periods of time like that, this is a real possibility...


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Engine Bogges Down (9/10)
 9/4/09 4:40pm
Jreis
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Rumson, NJ - USA

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1982 Corvette (current) 1987 Coupe 4+3 (past) 2003 Z06 (past)


Joined: 8/15/2009
Posts: 12

 

Jreis2009-09-04 13:41:07
Engine Bogges Down (10/10)
 9/4/09 5:36pm
anips
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe


Joined: 8/9/2002
Posts: 784

don't forget the mech. adv. weights mite be stuck'
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