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Old 04-20-2002, 01:44 PM   #1
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car dropped a cylinder...why...HELP!!!

hey

I was cruising along the road, going home today, and some shmuck is doing like 10mph in a Kia POS.

so I floor it and pass him...as soon as the rpm drops down and im cruising again, I notice its running a little rough, so I pull over, and when the car is at idle in gear(800) rpm, it i running like Sh*t. it seems to have a severe miss.
Also, at idle in gear, the rpm is jumping around by about 100 rpm, it never use to do that.
I popped the hood, no obvious damage like burned wires or anything like that, also, I put it in park and the motor is shaking back and forth to all hell.

the car is not computer controlled, it is a Chevy 350 with an Edelbrock carb.

HELP Quick!!

Joshua
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Old 04-20-2002, 02:22 PM   #2
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damage to the valvetrain, distributor moved/slipped and timing is off, ....

i'd pull the valve covers and look for damage. I know of a stock 400 that got revved just beyond 5k and it bent two pushrods in the process.....

how high did you rev it when passing
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1991 Z28
L98/G80/G92/J65
LT1 injectors, DIY PROM, t-56, AS&M siamese runners, accel intake, F1 GS-D3's
* 14.46 @ 93.36mph, 1.98 60' 7/5/02 (stock)
* 14.89 @ 96.76mph, 2.51 60' 7/7/04 (T56, AS&M SS runners, accel intake)
...guess I need to work on that rear suspension!
1971 RS
406/4spd...a work in progress..
in the 13's @ 107mph without a posi, it's a start.
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Old 04-20-2002, 04:38 PM   #3
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At this point it could be anything.....before jumping to that big of a conclusion, do some checks....

Make sure the oil press/temp are good...

Make sure its firing on all cylinders....I pull the wires off my distributor & set them back on WITHOUT snapping them in (while the car is off)......then i start the car, and pull 1 completely off & see if the rpm changes or it smoothes out....if not, place it back on & move to the next one.

That usually tells you if you have a cylinder that isnt firing.

If you find a dead cylinder, check the plug 1st then the wire....

Keep us posted.
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Old 04-20-2002, 11:18 PM   #4
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I only revved it to about 3300 or so.

I pulled the VCs to check for valve train probs. but everything seemed fine.

so I drove it to my friend who is a driveability mechanic, we went out for a cruise...he basically beat the hell out of the car and ran it to the redline, and for some reason, it fixed it rite up!

He said before hand its cuz "i drive it like an old lady and the plugs foul out cuz the car never sees high rpm so they dont get hot enough"

I guess he was right, cuz its running stronger now than it has since I put this engine in it..
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Old 04-21-2002, 10:00 PM   #5
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Hmm, sounds fishy to me....plugs don't foul out en masse all at once moments after the car is running perfect....

not to be negative but I still think I'd check things out to be on the safe side....maybe a tuneup, compression check.... get the car on a scanner and see what the computer is doing...

fuel pump might be going bad (intermittent low fuel pressure), fuel filter starting to get clogged.....

good luck!
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1991 Z28
L98/G80/G92/J65
LT1 injectors, DIY PROM, t-56, AS&M siamese runners, accel intake, F1 GS-D3's
* 14.46 @ 93.36mph, 1.98 60' 7/5/02 (stock)
* 14.89 @ 96.76mph, 2.51 60' 7/7/04 (T56, AS&M SS runners, accel intake)
...guess I need to work on that rear suspension!
1971 RS
406/4spd...a work in progress..
in the 13's @ 107mph without a posi, it's a start.
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Old 04-22-2002, 09:10 AM   #6
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It may sound "fishy", but there may be some validity to the statement. Engines that are "grandma" driven - low RPMs, low loading, driven cold with no thorough warm-up, no highway operation - tend to accumulate deposits on intake valves. As soon as someone pushes the engine a bit, the deposits can break loose.

I had a Ford 200 inch inline six that ran like crap. It turns out that a chunk of deposits was broken loose from the back of an intake valve and stuck in the valve opening, holding the valve open.

It turned out the driver had neglected to put the transmission in gear and revved the H3LL out of the thing trying to move out of the drive-through lane. Backfiring, valve clattering, and smoking, it made it in for a look. After a compression test and hunch, the valves were cleaned from the intake side without even pulling the head (just the intake side), and large chunks were removed en masse. One was still lodged in the valve seat, holding the valve open.

You may have had something similar happen to you and the hard driving could have cleared out some of the deposits, explaining why it runs much better now (more intake flow).
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Last edited by Vader; 04-22-2002 at 09:22 AM.
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Old 04-22-2002, 12:43 PM   #7
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Damn Vader, you always have one of those "I never heard of that!" stories! Wild!

I knew a guy with a '91 Formula... he had problem after problem after problem... but my '86 had so few compared to his. I think it's because I "drove" the car- in the literal meaning, and the figurative "drove it hard" meaning. He babied the gas 95% of the time, and barely drove anywhere. He sold it with 45k on it in 2000. I think the poor '91 was depressed.
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Old 04-22-2002, 11:05 PM   #8
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thanx for the comments.

the car has no computer at all, anymore

The pump is almost brand new, its a Holley standard presure, I am absoultly sure that the fuel was not the problem.

the motor has about 11K or so on it.

Im pretty sure I need to change the plugs.

I also have never actully set the timing, cuz the balancer needs the marks welded to the center of the timing cover, but I bought a new balancer just last thursday, and when we get another warm day and I dont have work, I will be setting the timing and putting the new balancer on it.
I pretty much just turned the dist. to where it ran best and there was no knocking or pinging. hasnt given me any problems in the past, so I dont think its timing related.
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Old 04-22-2002, 11:05 PM
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