My engine seems to be dieseling once i shut it off and after it shuts down it backfires thru the carb...this happens only when it diesels....i have tried different degrees of timing running it down -4* up to 16* and no difference...right now its advanced about 4*....no matter what i seem to do it wants to diesels like every 3rd shut down...and yes i dissconnect the vacum advance and plugged it...

thanks chas
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o and one last thing the car is running very rich which will be fixed soon...

 

What carb? What is your idle speed? Why is it running rich?

 

(2) holley 1850 600cfm vacum sec...

idle speed is ~800 it jumps a lil bit with the cam...

running rich from the dual carbs...

 

do u have an electric fan?

 

yup..its a dual fan set-up...its on a toggle switch as well

 

the fan motor is still turning generating electricing and still firing the ignition. Turn the fans off before you turn off the key and you should be good.

 

it does it whether the fans are on or not...i have to turn them on to bog the motor to lower the rpms to shut it down to get it to not diesel...most of the time it diesels more with the fans on...i have tried to run lower idle but it will stall out or have no vacum so my brakes dont work...that reminds me i have to get a vacum canister...

 

if its not the fans it could be a variety of things:
Timing
Too hot or too lean motor
Too high an idle
Too hot of spark plugs
Carbon buildup
the butterflies on the carburetor arent closing

 

timing is at 4*...what would be a good timing degree?
def not to lean...
idle is at 800rpms according to autometer gauge...
spark plugs are stock...

my guess would be carbon build up...the car runs major rich...when it was advanced to 12* u could see carbon deposits on the ground next to the tailpipe...i think i might pull the plugs and look at them...my guess is that they are fouled up with carbon pretty bad...i think i might have to tear it down this winter and rebuild the top end...

not sure what u mean by butterflies?...if u mean the metering plate that looks good and shuts fine

 

4* isn't advanced enough, but the reason you can't run more advanced is because your running too rich (rich=retarded lean=adcanced timing). your spark plugs probably are fouled. You'd have to fix this situation first but its going to be hard to do since your trying to run a tunnel ram with too big of carbs

 

I figure that i am going to put a primary 35 jets in each of the carbs to lean it out...

would the tunnel ram be the reason for low idle vacum pressure...

im not sure could be causing it...no leaks b/c the idle stays put and it doesnt rev high...

 

what are you using the car for? If your trying to run a tunnel ram on the street just don't, they're horrible on the street, they are good for high rpm race motors. You don't have the gears for it anyway. I'd swap to a good dual plane intake. If your still hell bent on using it id get some smaller carburetors, or you could try blocking off the secondaries. But it wont ever be near as good as a good dual plane intake.

 

right now just a daily driver to and from class...during the summer i was taking it down to the strip but it still ran like crap...i want to get a new intake and run just the single carb...but right now money is tight with school expenses and such...i want to make it more street friendly, plus i like the jaw drop effect from the ricers that pull up next to me....

 

its good for show or race, but as you can already tell they suck on the street and don't make for a good daily driver. I'd scrounge up the 200 bucks for an edelbrock performer rpm intake, (sell your tunnel ram and extra carb!) and bolt on one of the carbs till you can get a better carb. Used holleys or edelbrocks are pretty cheap. Stay with vacuum secondaries either a 650 or a 750 holley or edelbrock will work good. Itll run better, get better gas mileage and probably make more power.

 

i was looking at the weiand stealth air strike intake manifold...i believe its a high rise but the only problem is that i will need a new hood to cover the intake and carb...would u recommend a DP or vac?...lots of poeple have told me DP arent worth the hassle but some people swear by them....

 

the air strike will work well too, I like the eldebrock though but theyre almost the same thing. Don't go with a DP your heading down the same road you did with the tunnel ram. Stick with VS for the street and you'll be much happier. Edelbrocks are great street carbs too, though im a holley man. Like i said a holley 3310 750VS carb would do you good or even a 650. 750 or 650 edelbrock would be good too.

 

alright ill look into a 750...wouldnt a 750 be a lil over carbed i was thinking around a 650...but i guess i can always jet down...

 

a 750VS carb won't be too big because it's a VS they only flow as much air as the motor needs. If its a mild 350 then a 650 would work fine as well. You don't want to overcarb it though or else youll have the same problems again. You might have to experiment a little, sounds like you want a holley though, so I think a 3310 will work fine. They've been on anything from 289s to 454s