88 ranger 2.0 "dieseling" when I turn it off

[1988RangerVance]

Hey guys, I have a 88 ranger 2 door 2wd with the 2.0 (manual 4speed w/od) all completely stock with 94k original miles (yeah I said it!!) when I turn it off when it's warm it diesels, in other words, it doesn't want to shut off. I've tried changing the idle speed and the choke. Any help would be much appreciated! Thanks!

 

[adsm08]

So you have run on (engine continues to run even though the key has been shut off, also called "dieseling")?

I am assuming you have a carb, since you said you messed with the choke.


Carb means mechanical fuel pump (no need for electricity), and key off means no spark. That means you have something else in the engine hot enough to ignite the fuel for a little bit.

The most likely suspect is carbon build up on something inside the combustion chamber, either the valves, or a piston.

Run some SeaFoam through the system to start. Might need to do it more than once.

 

[1988RangerVance]

Awesome thanks! I'll try Seafoam and see of that works!

 

[RonD]

With that low on the miles the engine was probably not warmed up very long each time it was driven, this causes carbon build up.
Carbon build up is common on "low milers", also cracked rubber seals, they dry out from lack of oil circulation if engine sits for long periods.

Yes, Seafoam, and take it on a few 45min.-1 hour drives preferably highway speeds, and make sure choke is opening all the way after 5 to 8 minutes, running rich brings more carbon build up.
Also 2.0l -2.5l engines tend to run cool, which is bad, if temp gauge is not getting up to 1/3 then replace thermostat, it could be stuck open, get the highest temp available, 195degF if possible, or 192degF
Engines running above 190degF run cleaner with better MPG

 

[ricardo93]

Run it really hard after you seafoam it too.. and do it like on a long stretch in a back road... get it screaming and watch the exhaust just pour out black smoke like a coal train and then go run on the highway