Printable View
Some times not all the time my 327 still wants to keep running after i turn it off. what could be cousing this to happin? the timing off? ummm or the carb. loading up and still shooting fuel down into the engine or what? So what can i do? if you need any specs on the engine i'll get them to you.
Cd
Since you identified it as an intermittent problem, and assuming it's a modified engine (?), I'd check to see if there's bind in the throttle linkage or carb shafts, maybe the return spring. Sounds like the throttle plate (s) not shutting all the way. Could be you're on the edge of the octane requirement of the engine too, but the intermittent brings that to question. Timing, and temperature are also potential contributors, but I'd start with the carb/linkage.
ok, ya the engine is modified its bored .060 over and has a 3 stage over rv cam in it. 600cfm carb. brand new. im running 87 octane at the monent. it also has the vette heads on it big valve 350 heads. the performer rpm intake.
I will check the carb and see if it shuts all the way or not, thanx for you help bob.
cd
Your engine is heivily modified engine and your running 87 octane? you should be running 89 or higher. you should also replace your carb with a 650cfm carb and you should be good.
the carb is jetted at 690. had to jet it back down to 600 because it was getting so much fuel it wasn't burning it all so i was getting soot. i will try running on 89 im running 87 with booster.
thanx Cd
CD667;
Hey, if your engine wants to keep on running after you shut it off, that means you are taking it too easy while you are driving and all that energy is bottled up. Hehehe!
Anyways, the problem could be one of several.
A) your idle is set too high, it should be 800 rpm at idle if it is a standard and 900 if it is an automatic.
B) your compression is too high for the gas you are using.
C) it is running too hot.
Or you've got carbon deposits, sharp edges, or too hot a spark plug all of which can get hot enough to ignite the fuel and keep the engine running.
Since this is so intermittent my suggestion may not apply, but not turning off can be from an electric fan back feeding the ignition or from a alternator that need a diode in the line to prevent back feed to the ignition system I have had both give me problem. On my 327 with an electric fan the engine seems to run on till the fan comes to an stop. This is a new project and will be on a seperate relay that I hope will prevent this. Ed ke6bnlQuote:
Originally posted by CD667
Some times not all the time my 327 still wants to keep running after i turn it off. what could be cousing this to happin? the timing off? ummm or the carb. loading up and still shooting fuel down into the engine or what? So what can i do? if you need any specs on the engine i'll get them to you.
Cd
i got a cluch fan on mine with a 192 dre. in it
nice looking 327
MSD ignition Boxes sometimes cause run-on, that is if you have one installed!
My Ford was doing the same thing after a rebuild, Mine disapeared after going to a cooler plug.
Might not be the correct fix but it worked in mine!
what do the plugs look like?
the plugs are clean its running a little on the warm side. i mean there is sings of them getting hot but nothing major
what streets said about the throttle stop is usually what causes that problem on all gm cars in the seventies and up, but from the pic it looks like your running an edelbrock and I love those carbs I have never had that problem with them unless your fuel pressure is through the roof and its flooding out the vent or something I doubt its that if its a holley it they always piss out the vent tubes even with good needles and seats and proper fuel pressure. You can check this by taking the air cleaner off making sure the choke is open and just shut the engine off it you see a bit of smoke or haze from the carb after its off you know somewhere raw fuel is leaking down in the intake. As far as cheap tests
I would try cooler plugs and better fuel cheap start to find out what the problem is may be even a cooler thermo stat would help too if its running hot any idea on compression ratio forgive me if I am blind and didn't read it also how often or hard do you drive if you said it was running fat and sooting up carbon deposits could be doing it either being hot and igniting the fuel and or raising the compression ratio. Some say you can burn them out by gettin it on the road but the best way is to either take it down and decarbon the combustion chamber some with will say leave it together and use the walnut shell blaster which I know is a gm thing or may be a healthy shot of Seafoam in your fuel tank may clear some of that up. hope this helps...I have never heard of the backfeeding ignition one but I have had problems with aftermarket ignition doing all sorts of things I never would have checked that...hmm the fan spining made enough power to keep the engine running? I heard this somewhere else before weird oh well.
thanx guys for all the help i will try it. i have looked down the carb after the engine stops and i can see some haze coming up. i think the compression is around 10.25 to 11 psi.
I'm with tech inspector... the only time i ever had dieseling was thru heat...its a common misconception that it can be many other things... but it is worth checkin the temp...you say its a lil hot...how much is a lil?...colder plugs, new 'summer' thermostat,decent pump gas,maybe even some heatwrap on yer exhaust down pipes n manifolds etc are all inexpensive ways of tryin to fix this..the throttle stop thing is a poss but... the most common cause for it IS heat..i worked on all kinds o engines from 4 bangers to RB211 jet engines and the same can be said.... heat is the devil..
my 55 was a real pain in the ass, it used to diesel when i used it..i ignored it like a dork fer hella days...then i sat in traffic one day and the thing got sooo frickin hot under the hood that the petrol vaporized in the fuel lines...so i jus sat that like a dumb ass tryin to cool em down... try the easy fixes first....use good gas etc.... check ya ignition also etc... jus my opinion but, its a case of the usual suspects.. yknow :)
ok i know the engine runs around 192 to 193 that is coming from the top of the manfold, im running 350 big valve heads and headers with a 3 stage over rv cam on 89 oct. pump gas. lately it hasn't been giving me any trouble on some times not all the time it does it.
thanx cd
what are the combustion chamber size for the heads you run?
What are the cam specs?
Then I will let you know if you need 91 octain or if yur good on 87.
oh yes.
plus head gasket and piston specs.
If you please.
im running a 3 stage over rv. i can't remember the specs on it it came with the edelbrock proformer. i got the metal shim head gasket. .060 over pistons. im running the big valve 350 heads i do believe they are 194cc. i think.
cd
I had the same problem with my 327. I retarded the timing and put smaller jets in the 600 carb I had on it. Ran like a champ after that and shut off and stayed off. Bart
Quote:
Originally posted by CD667
Some times not all the time my 327 still wants to keep running after i turn it off. what could be cousing this to happin? the timing off? ummm or the carb. loading up and still shooting fuel down into the engine or what? So what can i do? if you need any specs on the engine i'll get them to you.
Cd
Most of the time its as simple as the timing being to far advanced.
Thanx for all your guyes help. Just to make sure that its not my timing. how can i check it with out a timing light just by the sound of the engine or what? it wants to raps up fast once i got it to where it can hit about 40 in 2nd gear in an 81 pick-up with a 4 speed. 1st is to low of a gear but i bet you all know that. but now i can get to 30 and its tacking out. so is the timing to far advenced? or what. sorry i just keep asking qustions.
Cd
ok i bet this is going to sound stupid but when you do it the engine has to be running right?
ok thank you streets just wonted to make sure