Dieseling "After Run" Problem...

Ok i have replaced the cap, rotor, plugs/wires, both fuel filters, K&N Flat Piece Air-Filter, cleaned electrical components & it still likes to diesel! I am assuming the engine is getting too hot causing it to diesel. But why is it getting hot? What could cause this? Any Ideas? Please Help, Thanks

Close_Call

It's an 85 1.5 CRX....

Is it carb'ed?
Because if it is and it runs too fast,it will still suck gas in after you stop it,you got to find a way to slow the rpm so it wont do it no more.

2 possiblies:

1, the idle speed is to high as suggested by 89ssgti

2, there is excessive carbon build up in the head.

The 1st is easy to fix, you just wind back the idle speed to about 700rpm

The second requires de carboning the head. which if there is a lot of carbon in the combustion chamber as well could to really bad things to your compresion.

Iv known several egines with badly worn bores that were only maintianing compresion becuase of the carbon build up around the edge of the cylinder bore.
Any method of the cleaning the carbon deposits that dosnt involve removing the head will also remove these important deposists.

How would i go about getting the carbon out of the heads? Is there a cleaner or ? Also i believe my seconday jets are not kicking in (Yes mine is carbed!) how do i get them to function properly? Thanks Guys,

Close_Call

Either the idle speed is too high or the fuel cut soleniod is stuck open. The soleniod cuts off the fuel flow to the idle circuit when the key is turned off.

To test the solenoid:
Unbolt it from the back of the carb and ground it as far from the carb as possible (to avoid a spark, which could ignite fuel in the carb). And have someone turn the key on, but don't crank it or start it. The stick on the end of the solenoid should retract with a click and come back out as soon as the key is turned back off.

You can de-carbon the heads by dumping water :eek: into the air intake on the carb. I watched my step-dad do this once to my '85 Civic (1488cc carbed) and I am not sure it helped...turns out we had other issues, like a lack of compression due to bad valves/valve guides and such.. sometimes I would get backfire out of the carbeurator (why can't I ever spell that word?)
and the car didn't have enough horsepower to pull the car over 60 MPH (2700-ish RPM) under load.
So anyway...one of you has to control the throttle so the car won't die when you dump water in it...the water acts as a steam agent to help remove the carbon. too much water is bad tho, because water doesn't compress very well and can do bad things if you dump in too much. We used maybe a 32oz. cup (~ 1 liter) and poured it in very slowly (trickle) and in short bursts over many minutes. Again, I would recommend trying this with help from someone experienced in this area...I did this 8 years ago and was the assistant.
Good Luck.

Actualy using some automatic transmission fluid is best. find some way of hooking the bottle up to a vacume line and just let the engine draw it in.
But do this away from nosy neighbors etc, there will be a HUGE cloud of very smelly black carbon and burnt fluid.

The only problem with decarboning the engine is you may lose a lot of compression if the engine is old and has done a lot of miles.

I would look at getting the carb tuned properly, or if its not working properly get it rebuilt. (do it your self with a manual if you feel like a challange)

Originally posted by sastanley
...carbeurator (why can't I ever spell that word?)...
carburetor or carburettor :)