Engine "dieseling"; help with vacuum stuff

[87DXHatch]

For some reason, now that it has gotten warmer outside, on and off my engine will "diesel" when I turn the car off (In otherwords, the engine winds down but then sputters some more and shakes the car).

When I put it in park I know immidiately if it will diesel or not because if my RPM's are at 800-900 I'm safe but if they're at ~1500 its dieseling time. BTW, there is no in between, it's either one or the other (900 or 1500).

My car is carbed and I have heard some people talk about a "vacuum leak." What exactly is a vacuum leak, how do I check for one, and more importantly how do I fix it once I find it?

Thanks in advance

[GreenMachine]

My car did this before, after i got my carb tuned by a friend it was much better.
Searching for vacum leaks is a bitch, but just take your airbox off and look for any tubes not connected or with cracks. Good luck with that. But with my expeirence it was the carb that needed adjustment

[hondaisthebest]

What is your idle speed when you are in park or neutral?
If its more that 1250 its normale to dieseling.

Your idle speed in park suppose to be at 900-1000 and drive at 750-800. To put in gear at more that 1250 is not very good for your tranny and engine mounts.

A vacumm leak can be a cracked vacum line or a bad pcv valve.
To find a vacum leak you need a propane or starting fluid.
If you dont have any idle problem i thinks its not a vacumm problem.

[locknload68]

Get a can of carb cleaner and clean the carb. Then take it and spray all around the vacuum hoses. If you notice a jump in RPMs when you spray around a hose, look for a crack or such int hat area.

[87DXHatch]

My dad has some carb cleaner, what do I spray with it? If I'm 100% warmed up the idle is ~1000 park and ~750 drive.

[ACCORD EX]

spray inside the carb and on all linkages that you see ! ( do it when cold engine and wait for a couple of minutes afterwards ! )





MIKE

[87accordlxph]

Originally posted by ACCORD EX
spray inside the carb and on all linkages that you see ! ( do it when cold engine and wait for a couple of minutes afterwards ! )





MIKE

LOL! Mike likes his Carb cleaner (O2 sensor safe though, right?)



-Mike