Pinto Car Club of America

Welcome to FordPinto.com, The home of the PCCA => General Help- Ask the Experts... => Topic started by: stinsonj on June 01, 2010, 11:29:44 AM

Title: Run-on problem (Dieseling)
Post by: stinsonj on June 01, 2010, 11:29:44 AM
I have a 1975 ford 2.3L engine out of a pinto and am having run-on issues.  When i turn the key off, it continues to run for about a second or two.  Its not really a huge problem but definently an annoyance and im not sure if any harm is being done to the engine.  From what ive read, at least with diesel engines, crud can build up in the engine and become hot enough to actually ignite the fuel even when everything is turned off.  Anyone else ever experienced what im dealing with??  The engine is usually running at about 195 when i turn it off.

Also, my engine is only running "good" when the timing is as far advanced as the distributer will allow (way out of spec).  If i adjust it to spec (i think around 6 degrees advanced) it runs like crap.  Any thoughts??
Title: Re: Run-on problem (Dieseling)
Post by: dga57 on June 01, 2010, 11:36:54 AM
I don't know why this works, nor whether it will apply to your vehicle, but my 1983 Ford F-150 with 300 cid 6 cylinder will do that whenever I run Regular gasoline.  No problem with Mid-grade or Premium.

Dwayne :smile:
Title: Re: Run-on problem (Dieseling)
Post by: Fred Morgan on June 01, 2010, 02:13:15 PM
Having it advanced that far will give you that problem when shutting off, you need to up octane. Do you notice under a load go full throttle are piston's rattling as in ping or knock. What is happening is fuel is exploding not burning due to low octane or and to much advance on timming. Throw some AV-gas in there that will give you 115 performance that should clear it up.  Fred
Title: Re: Run-on problem (Dieseling)
Post by: lugnut on June 01, 2010, 03:09:43 PM
How fast is your engine idling?  Try slowing it down a bit to see if that helps.
mike
Title: Re: Run-on problem (Dieseling)
Post by: CHEAPRACER on June 02, 2010, 12:32:14 AM
Quote from: lugnut on June 01, 2010, 03:09:43 PM
How fast is your engine idling?  Try slowing it down a bit to see if that helps.
mike


100% agree. And check you idle mixture setting to make sure it's not too lean.
Title: Re: Run-on problem (Dieseling)
Post by: 78txpony on June 03, 2010, 11:45:47 AM
Carbon buildup is one of the popular contibuting factors.  A hot running engine is another.  The latter can be caused by lean mixture or improper timing.  Using a 180* t-stat can help, too. 

My 2.3 idles at 1100 and has carbon buildup and gets regular gas but a 180 t-stat - it has not dieselled for many years.  I am surprised it has not...

I rented a new 18' Bayliner with a 3.0 Mercruiser a few weeks ago and the first time I shut it off, it dieseled for about 10 seconds or so - even putting it in gear failed to help.  I thought it would never quit! 
Title: Re: Run-on problem (Dieseling)
Post by: 78squirewagon on June 03, 2010, 07:52:02 PM
Mine was doing the same thing a couple of weeks ago and I put a bottle of Lucas fuel injector cleaner in the gas tank. Now it has stopped so I am guessing the carb was gummed up pretty good. Of course the gas that was in it had been there since March  ;D It could have also been the Staybil that was in there
Just to be safe, I am going to run a bottle of Lucas at every fill up or close to it.
Title: Re: Run-on problem (Dieseling)
Post by: pintoguy76 on June 04, 2010, 12:54:18 AM
My 76 does that when its hot out sometimes. I put in premium fuel and the problem goes away. I have the timing set to spec. The engine will not idle smoothly at less than 1000 to 1100 rpm so i cant slow it down any.  I tried all the methods of decarbonizing the combustion chambers (stream of water down the carburetor to "steam clean" the chambers, as well as a stream of auto trans fluid down the carb which is supposed to clean the carbon up too. Then of course Ive revved the crap out of the engine trying to blow the stuff loose so if it is carbon buildup then its some tough stuff.

I've been driving this car since I was a new driver, teen drivers aren't nice to cars. I cant tell you how many lives that engine must have, Ive been pretty mean to it over the years.  Sure cant kill it tho. I'm grown up and nice to it now.  Anyways, the point is that it shouldn't have any carbon left  in it :D lol and it still runs on. I think its the combination of our crappy gas that they make today and the 9:1 compression along with the non computerized fuel and ignition systems.

My only solution Ive found is to run higher octane fuel.
Title: Re: Run-on problem (Dieseling)
Post by: Pinto5.0 on June 06, 2010, 12:13:56 PM
Try retro-fitting an idle stop solenoid on your carb. They are cheap & should fix the problem. When you turn the key on it will power up & set your idle where it needs to be. When you turn the key off it will close the butterflies of the carb & stop the run on. This is what they were invented for.....
Title: Re: Run-on problem (Dieseling)
Post by: powderblue76 on June 08, 2010, 10:57:35 AM
When it is warm (90+) out, my will do it now and then.
Having an automatic, I shut it off in gear.
Then shift into park.
(Don't forget that last part).
Title: Re: Run-on problem (Dieseling)
Post by: 1975PintoMPG on June 08, 2010, 09:06:34 PM
If the timing belt is in need of replacement it will do that and is, in my opinion, your most likely problem. Your car only runs with the distributor advanced to the max because the belt is probably screwed. Running super will only cover it up. Dieseling isn't normal on a properly running/maintained engine and ignoring it will end in the engine not running any more because the belt will jump teeth on the sprockets, the belt will shread, the belt will come off completely, or it can cause possible cylinder detonation from being so off-timed which can cause major internal engine damage.

Pinto 5.0 may also be right if I'm not, though it doesn't explain your timing issue. The idle stop solenoid is easily checked to see if it is working and your carburetor should have it on it. It's got a wire going to it and is located near where the throttle cable/lever is. Pop the hood, locate the solenoid, note where the plunger that engages when power is supplied to it is, turn the ignition to on and see if the plunger moved. If it didn't you need a new solenoid.
The plunger on the solenoid should move freely in and out by hand when the ignition is off and it should be pushed out when the ignition is on.
Title: Re: Run-on problem (Dieseling)
Post by: dga57 on June 08, 2010, 11:44:25 PM
You may well be right that running premium gasoline is only covering up the problem (I'm not a mechanic and quite frankly don't know), but if that's the case, it has been "covering up" the problem in my truck for nearly twenty years now, without issue. 

Dwayne :smile: