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  #31 (permalink)  
Old 07-20-2010, 12:33 PM
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get in the habbit of shutting if off in gear, then put it in Park. That will stop the dieseling.

but you run the risk of forgetting to put it in Park.

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  #32 (permalink)  
Old 07-20-2010, 12:57 PM
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Okay I'll start shutting it off in gear.

Last edited by kyle86; 07-20-2010 at 01:22 PM.
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Old 07-20-2010, 04:30 PM
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Shutting off in gear works pretty good. I also hooked up a fuel filter inline with my pcv to see if oil was getting in that way. sure is. I'm going to build a catch can and then pour some seafoam down the carb to try and loosen up anything in there.
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  #34 (permalink)  
Old 07-20-2010, 04:37 PM
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Oil migrating thru the PCV iinto the intake manifold will defiantly make it ping knock and run on. Oil in the combustion chamber is not good.

The valve cover oil baffling under your PCV is missing, mislocated directly over a rocker arm or just poorly designed. Typical of most of the pretty aftermarket valve covers.
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Old 07-20-2010, 10:12 PM
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Quote:
Originally Posted by F-BIRD'88
Oil migrating thru the PCV iinto the intake manifold will defiantly make it ping knock and run on. Oil in the combustion chamber is not good.

The valve cover oil baffling under your PCV is missing, mislocated directly over a rocker arm or just poorly designed. Typical of most of the pretty aftermarket valve covers.
The baffeling is in there, must just be a crappy design. I got the cheap auto zone dress up kit. I'm hoping this resolves the issue. Regardless the engine will be a lot better without oil leaking in. I hope the seafoam breaks up the crap that's been burning in there.
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Old 07-21-2010, 10:28 AM
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kyle,
there ARE cleaning detergents in the gasoline,,,it won't take many hwy miles at all to get the chambers back to "normal" clean (with the pcv corrected if testing shows "is" a problem)...

the problem with dumping a bunch of stuff down the carb is it is ALSO going to wash the cylinder walls clean where the carboned oil helps seal any scratches to prevent blow by...
(increase the blowby= just that much more crap that doesn't burn is going to constantly get sucked up by the pcv to cause problems)...

Shell was recently selling/promoting a "super detergents" premium (that was for real),,,just dose it with that or any better brand gas...

products like seafoam can open "pandora's box"...

catch can=all you need is a 12-16oz screw top jar with a fairly sturdy plastic lid (peanut butter jar?)...
drill 2 holes thru the cap spaced well apart just big enough that you can "stuff" the hose ends (one from the pcv/other to the carb) thru the holes and get just a decent air seal is all that's needed....
with the hose to the carb ending closer to the lid so nothing does get picked up....
a couple of zip ties/hose clamps/whatever on the hoses just to keep them stable....
plan "B" for a wimpy cap,,,use whatever is on hand fittings combo to get just a half way decent air seal at the cap....

do the test drives with the pcv plugged into the rear and then front cover holes,,,,the engine is tilted toward the rear,,,virtually all the oil drains back thru that rear hole so there is alot more splash back there....
................................
just food for thought and just for the idea:

your intake and convertor are both wrong for a 284 cam...
you won't/don't get what a 284 cam can deliver unless you have correct/matched power band motor parts like a victor jr open plenum and 1.75" headers (and higher stall and very deep gears so it stays in the power band)...

change to a just slightly less duration cam dramatically opens up the tuning options for all kinds of better driving performance....

darn good chance that a lesser cam will/can make more peak power than the 284 is now with that 5200rpms max intake (and be happy with the 2300 stall)...
(with your car weight,,,there won't be enough motor difference {10HP?} you can feel,,,and smarter to strip weight to get free HP anyway)
there won't be a 1/2 seconds difference at the strip (probably .2)....

apparently this is your every day driver car so a favorite Max Keith (a HR member) quote come to mind:

"ALOT more gooder is not necessarily more good"
.....................
(overlap some with another thread sorry guys)
re: vac gage
go borrow one or more buddies vac gage's (or ask at a garage),,, so you can side by side check with a tee fitting for reading variations/calibration accuracy compare with yours...

I chose that inexpensive $40 vac gage mounted on my column in the pic because the black face and white block type script matches the original dash script!!!

tested it against my lab calibrated gage that reads to a 1/10th Hg,,, it is off by .5Hg but consistently off over the whole scale so it's plenty good,,,I just do the correction add in my head...

in your case:
can't work around that 2300 stall drag problem killing the Hg at idle in drive completely...
"but"
it is possible your gage is reading off calibration at low Hg range (it's just a spring/diaphram inside and they are not linear and drop it just once onto concrete can mess it up)...

simple and smart to confirm (say) 8Hg in drive is 8Hg by just trying another gage...

cross your fingers,,,50/50 it will read 10Hg on another gage with 13 in park,,,5hg drop is alot at 1k idle,,,and even 9 is better than 8 with the motor warmed up....

Last edited by red65mustang; 07-22-2010 at 08:49 AM.
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  #37 (permalink)  
Old 07-21-2010, 12:13 PM
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Thanks Red65!! That makes me feel better. The cam may be a little large, but it's actually pretty streetable. Lots of low end torque still, and decent street manners. A step down would prob have been a better choice, but I kind of like the racy idle. Plus it trapped 107mph weighing 3650 shifting at 5500rpm so it can't be too mismatched. I hope this pcv oil can fixes the problem.

Last edited by kyle86; 07-21-2010 at 03:15 PM.
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  #38 (permalink)  
Old 10-01-2010, 10:13 PM
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Okay well it's been over 2 months now and I still can't get rid of the dieseling and I think it's getting worse even though the outside temps have cooled down significantly. The engine won't diesel when it's not warmed up. I have tuned the carb so that both the primary and secondary slots are evenly open, around .020 and look like little squares so I know it's not the carb.

My dad said he thinks since it was smoking a little out the exhaust before and now it doesn't smoke it all, that it could possibly be getting more compression than it was causing the dieseling. I'm running 93 octane gas so I don't understand how it's possible. My static compression calculated to 9.9 and my dynamic calculated to 8.1.

Also I can't run more than 30* of total timing without it getting into detonation at WOT or pinging off part throttle tip in. Before I was able to run 34* and before that 36* so it seems like carbon could be building up or something.

I am thinking this has to either be a "hot spot" or carbon stuck in the combustion chamber. I've caught probobally 1/3 cup of oil in the pvc catch can the past 2000 miles. I think the only/last option I have is to try to clean it out with either seafoam or the water method some people here have mentioned. I'm so frustrated. I've been shutting it down in gear for the past 3 months and even then sometimes I can hear it trying to run-on before arresting. If anyone here has any other advice please post up.
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Old 10-01-2010, 11:14 PM
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Hi sqzbox. I think that is because one reason your gas octane is 100-101. There are other reasons but I cannot explain it very well. I keep on researching it.
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  #40 (permalink)  
Old 10-02-2010, 08:29 AM
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Quote:
Originally Posted by kyle86
Okay well it's been over 2 months now and I still can't get rid of the dieseling....
If you are willing to do an easy experiment, I may have a solution for you.

Before starting the engine, completely close the throttle blades by backing off the idle screw so the engine will require you to keep your foot on the throttle to stay running.

Warm the engine up completely, so that when you shut it off it should diesel.

As you are about to shut off the engine, just as you turn the key to "OFF", release the throttle completely so the throttle blades will shut completely and see if this stops the run-on.

What you want to try to duplicate, is how a key-switched idle speed solenoid (shown below) would function- that is, when the key is on and the engine running, the solenoid extends to become the default idle stop. When the key is turned off, the solenoid retracts and will allow the blades to fully close exactly when the key is switched off- and that's what you want to duplicate w/how you let off the throttle at the exact same time you turn the engine off.

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Old 10-02-2010, 09:38 AM
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Fix the valve covers.
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  #42 (permalink)  
Old 10-02-2010, 06:05 PM
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Cobalt, I believe is right on the point there as ignition timing has nothing to do with dieseling once the key is turned off . As for having to back off the timing more than before to avoid pre-ignition, I'm not sure on that . I wish I could remember the application on the electric idle solenoid, but I do remember GM ran a lot of them .
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Old 10-02-2010, 09:09 PM
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ok, I just poured about 25-30 ounces of water down the carb, then I put some sea foam through it then shut it off a couple of times. Now I'm about to change the oil. Seems like it's running kind of funny. Still dieseled a little. I'm going to run it on a road trip tomorow about 150 miles. If there's any carbon in there, that should have got it.
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Old 10-02-2010, 09:19 PM
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Quote:
Originally Posted by adantessr
Cobalt, I believe is right on the point there as ignition timing has nothing to do with dieseling once the key is turned off . As for having to back off the timing more than before to avoid pre-ignition, I'm not sure on that . I wish I could remember the application on the electric idle solenoid, but I do remember GM ran a lot of them .

If I remember correctly, GM used the solenoids to allow the throttle blades to close at shutoff to prevent deiseling. The runon was caused by RETARDED ignition timing for purposes of emission controls. This is what I said way earlier in this thread. If you retard the initial you have to open the throttle more to maintain the desired idle speed. Open throttle = runon. ADVANCED initial allows for the throttle to be closed and prevents runon. I have to laugh when people need 50+ responses to the question or problem and then ignore the advice. RETARD THE CAM TO MFG RECOMMENDATION. And advanced cam will close the intake valve sooner which raises the cylinder pressure, which CAN promote detonation and runon. If all else fails, I'll bet the intake has an internal vac leak. Pull the intake and reseal it.
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Old 10-02-2010, 10:08 PM
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Simple question that from a modern day drivabilty guy that don't see much none computer operated stuff anymore..

Does the rig have a vacuum advance? If not, seach timing 101 on the net

Yes, timing can cause run-on. High combustion chamber temps will burn a mixture even when no spark present. A richer than stoich mixture creates a hot flame front, from my understanding. If the timing is late, it will not burn all the fuel in the chamber. You would have left over fuel for next fire event, even with ignition off, and high cylinder temps.
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