Can someone help me 85 Chevy c10 dieseling problem?

Question

I found a split hose to vacum advance and replaced ..now it diesels when I shut off, sounds like missing and hesitation, stalls at stop light.
have to hold pedal to floor to start.

it's in very good condition only 85,000 miles

Answer 1

First thing, check the timing. Try disconnecting the vacuum hose you replaced, or check to make sure you have it in the right vacuum port on the carb( the one that has no vacuum at idle). You can also turn down the timing a bit or get an adjustable vacuum regulator for the distributor. Dieseling is usually caused by one of 2 things- too much timing or allot of carbon buildup in combustion chambers.

Answer 2

Very old truck... there is something not allowing the throttle to close all the way. Possably another split hose allowing air in look at the vacuum tree between the carb and distributor. Ingnition timing should be checked and after the linkage is freed up idle speed set. Also on 4bbl carb look at the large vacuum hose middle front of carb for the pcv valve in the valve cover and replace the pcv valve.

Answer 3

Sounds like the timing was last checked/adjusted with the vacuum hose already leaking.

I would just reset your timing with a timing light.....or you could just set it by ear. Slightly loosen the bolt that clamps the distributor in place, start your truck and slightly turn in each direction until the engine idle smoothes out and sounds good to you. Tighten the distributor clamp bolt and take it for a test drive.

If you are due for a tune up, replce the distributor cap and rotor and check your vacuum advance canister for proper operation and freedom of movement.

Have fun (this is an easy fix).

Answer 4

yea sounds like the timing to me when you fixed the hose that allowed more vacum witch gives more advance!!!

Answer 5

someone adjusted your timing with the vac um hose leaking. now its not. get it checked.

Answer 6

it is a timing and/or carburator issue