just got the mufflers done...............somtimes it shuts off, somtimes it doesnt

[down4thakrown]

just got 2 flowmasters 40's, now it idles fine at 600rpms in D and bout 1000-1100 in park. with the dist. at 8* advanced. but it still runs on after i shut it off. .like the timing is still to far advanced. could it be too retarded????

 

[diesel4me]

idle too high..

Either retarted OR advanced timing can cause "dieseling",but usually its the idle speed being too fast that encourages it more than anything else..8 degrees may or may not be the correct setting for your engine,depending in CID,year,etc..some years use 0 or 4 degrees for timing..and make sure you take the hose off the vacuum advance and plug it before timing it..

 

[down4thakrown]

i got a mallory unilite distributor, its a 350, witha 274 lift/duration cam and quadrajet. the distributor has a mechanicle advance.

 

[bigbadchev84]

check for vacuum leaks, that will cause high idle for sure and if its an automatic make sure the vacuum line didnt fall of the modulator on the tranny while you were installing mufflers, also if you shut the truck off while it is in gear it wont diesel.

 

[down4thakrown]

ill check when its in gear, im thinkin vaccuum leak too. when im drivin the idles is high when im movin until i hit the brakes then it drops when i start slowin down.

 

[down4thakrown]

ummmm......ok, well the first time i shut it off in gear it died, the 2nd it dieseled a little, the 3rd it started dieseling bad then the rpms picked up and started runnin almost normal, then i flick key on and off a couple of times as it came and went then it finally died.

 

[bigbadchev84]

did all this happen right after the new mufflers or was it before too? is your choke sticking? what if you jab the gas real quick will it idle down then? when you put it in gear step on the brake too you said your rpms go down to about 600? then turn the key off it should kill it everytime without dieseling...just a quick fix so everyone dosent turn around and stare in the parking lot.....but you shouldnt have to do taht at all when its running right

 

[down4thakrown]

it stayed dieseling for a while when i shut if off in gear. i got the choke wired up, so that isnt movin anymore. but i used a zip tie. i never checked before i got the mufflers but it runs a lot better with the mufflers. i only had it runnin with headers. this motor was just rebuilt and im still breakin it in. before when it had straight headers it would hardly idle if idle at all when the timing and idle screw where set at this. when i got it back from the exhaust shop it was idling at 1400rpms and 6-700 in gear. but this is the only way i could keep it runnin with just headers. im thinkin it has a vaccuum leak. maybe like and intake gasket on the inside??? whats the best way to find a vaccuum leak.

 

[down4thakrown]

i tried carb cleaner and ether but, i couldnt tell much of a differance. i was thinkin maybe the metal line has a hole or somthing, its pretty bent up and i think i have it backwards since its so bent outta shape. anybody have one lying around?

 

[diesel4me]

maybe..

I dont think that "racing" distributor is any good for street use--if it has only mechanical advance,you'll need to set the timing way advanced to make up for the lack of vacuum advance--that encourages dieseling..you'd get way better gas mileage and performance with an HEI with vacuum advance--the Mallory is set up for wide open throttle dragstrip operation,not street driving..my friend made the same mistake on his 62 Nova with a built 350,and he had dieseling troubles too,plus it cranked hard when starting,when it was timed to run good..your high idle speed has a lot to do with it too,but I would suggest a "normal" distributor--sell your Mallory to a drag racer who needs it!..

I use carb cleaner and the squirt nozzle to check for vacuum leaks around base gaskets and hoses--or I stick a length of rubber vacuum hose in my ear and use it for a stethascope!(a real one works better!)...be careful around plug wires--the black rubber hose is an excellent contuctor--getting HEI voltage thru your eardrum isn't fun!--its happened to me!

An internal vacuum leak is harder to find--sometimes if its the intake gasket leaking,you can hear it thru the valve covers with the oil filler cap off while its idling..( remove the PVC valve and tape over it, so you dont mistake the vacuum it has for a leak..)

 

[down4thakrown]

yea i thoght maybe the distributor had somthin to do with it. im goin to try to find a deal on a hei and try that. thx

 

[wegel11]

Try http://www.hotrodheaven.com/ for an HEI. I bought the CHEVROLET HEI DISTRIBUTOR w/3 yr Warranty and its runs perfect, also it was only $99.99

 

[diesel4me]

ok if you got $$$$$$

I'd go to a junkyard--I can get an HEI with vacuum advance AND a cap,coil,and plug wires for about 30 bucks in my area!.. ..new is always nice,but expensive...