Dieseling/Run on

[canadian357]

Does anyone know how to fix it? Its really, really starting to piss me off.

[Dr_Snooz]

Run a can of Techron through it. Then use nothing but Chevron 91.

[87roach]

Run a can of Techron through it. Then use nothing but Chevron 91.

Not everyone can afford running 91 octane.

If you have a manual there is a troubleshooting area for dieseling/run on, I don't have mine at the moment so I can't look and I'm not sure what it could be off hand.

[canadian357]

ahahaha, yeah, i'm struggling enough to pay for my 87 octane. and nope, no manual.

[Dr_Snooz]

Not everyone can afford running 91 octane.

I can dig it man. I totally feel you. Of course, the equation isn't as simple as it might first appear. Most people roll up to the gas station and see that premium is $0.20 more per gallon and assume the best value is the low-grade. Then they spend a lot of time trying to figure out why the car doesn't run right, why it hesitates, why it diesels, why it won't pass smog, why the Check-Engine Light is always on, etc. They get fleeced by crooked shops, buying all kinds of expensive repairs, when all they needed was good gas and a decent tune-up.

In the end, there's no substitute for proper maintenance using good fluids. You can't cheat the car, unfortunately.

Anyway, run some Techron through it and you should be fine.

[canadian357]

Techron will work with a carb?

[LxAcc510]

Does anyone know how to fix it? Its really, really starting to piss me off.

dont know how to fix. but when my diesels. say when you turn it off and it starts to diesel...turn the key bak to the on position. just a turn, not a crank. and it'll keep your engine running, rather than letting the distributor get wet with fuel. Because i believe thats how it happens. Fuel leaks into the distributor.

[LxAcc510]

Not everyone can afford running 91 octane.

If you have a manual there is a troubleshooting area for dieseling/run on, I don't have mine at the moment so I can't look and I'm not sure what it could be off hand.

What kind of manual? just an oem 1989 accord manual?

[LxAcc510]

I can dig it man. I totally feel you. Of course, the equation isn't as simple as it might first appear. Most people roll up to the gas station and see that premium is $0.20 more per gallon and assume the best value is the low-grade. Then they spend a lot of time trying to figure out why the car doesn't run right, why it hesitates, why it diesels, why it won't pass smog, why the Check-Engine Light is always on, etc. They get fleeced by crooked shops, buying all kinds of expensive repairs, when all they needed was good gas and a decent tune-up.

In the end, there's no substitute for proper maintenance using good fluids. You can't cheat the car, unfortunately.

Anyway, run some Techron through it and you should be fine.

wth do u mean by techron? sorry newb question. unless by that you're referring to just gassing up at chevrons

[Oldblueaccord]

dont know how to fix. but when my diesels. say when you turn it off and it starts to diesel...turn the key bak to the on position. just a turn, not a crank. and it'll keep your engine running, rather than letting the distributor get wet with fuel. Because i believe thats how it happens. Fuel leaks into the distributor.

No.


the car is actually running with out any spark ,hence the term diesel. Its caused by somethings wrong with the carb in general or too high of an idle to start with. Not a carb person but there should be a dash spot that holds the idle up when the igniton is on the lets off with the key off. or that give you something to search for.

Techron is fuel injection cleaner or fuel treatment additve to help clean out fuel systems. It will work on carbs just fine.


wp

[greentee76]

While these suggestions maybe all that is needed I would take the time to check your timing.
Just my .02$

[russiankid]

I have hard that it is caused by a rich mixture. Mine only does this when it is cold, which would be a rich mixture. If I let the car shut off from 1500 rpms while fairly cold it will diesel. I had some idling issues before and it would idle at 1500 rpms, once it was fully warmed up it wouldn't diesel.

[Ichiban]

My cheffy 350 would diesel for a minute or more after shutoff when the choke was stuck on. 2.7 MPG, yay. My Toyota 22R (10.75:1 CR) diesels after I shut it off hot, which is understandable, it has to run somewhat rich. Your carb should have a fuel cut solenoid that closes the idle circuit when the ignition is shut off, stopping the flow of fuel and eliminating dieseling. Check it to see if it functions at all. You could have other problems like stuck on choke, too high of a float level, buggered powervalve, or something else. I'm not a carb pro, but I've dealt with this problem before.

[Dr_Snooz]

Techron is a fuel system detergent. Chevron makes it and adds it to their gas. It's also available in their stations' stores and at AutoZone (or Kragen or one of those) right next to the STP Gas Treatment.

Plagiarized from Wikipedia (http://en.wikipedia.org/wiki/Dieseling):

"Potential causes
This condition can occur for a multitude of reasons:

-Built-up carbon in the ignition chamber can glow red after the engine is off, providing a mechanism for sparking unburnt fuel. Such a thing can happen when the engine runs very rich, depositing unspent fuel and particles on the pistons and valves. Similarly, non-smooth metal regions within the piston chamber can cause this same problem, since they can glow red. It has also been suggested that an improperly rated spark plug can retain heat and cause the same problem.
-A carburetor that does not close entirely can contribute to running once the engine is off, since the extra fuel and oxygen mixture can combust easily in the warm piston chamber. --Similarly, hot vaporized oil gases from the engine crankcase can provide ample fuel for dieseling.
-Incorrect timing.
-An engine that runs too hot or too lean may produce an environment conducive to allowing unspent fuel to combust.
-An idle speed that is too fast can leave the engine with too much angular momentum upon shutdown, raising the chances that the engine can turnover and combust more fuel and lock itself into a cycle of continuous running."

In general, dieseling indicates a dirty, poor running engine. I'd start with a can of Techron. If that doesn't fix it, l'd do a good tune-up if one hasn't been done in awhile.

Anyway, hope that helps.

[Bass Man]

Mine did that when I first got it... I just did the complete vacuum removal and fixed it right up!

[joshskillz]

Good thread. I'm having this issue myself

[NBS-Spike]

dont know how to fix. but when my diesels. say when you turn it off and it starts to diesel...turn the key bak to the on position. just a turn, not a crank. and it'll keep your engine running, rather than letting the distributor get wet with fuel. Because i believe thats how it happens. Fuel leaks into the distributor.

WTF!?!? Fuel in distributor = blown up distributor...SMH... Have you checked your timing?
The only reason you need high octane is high compression or advanced timing, both would add power and require 92 octane.
If everything is right, I would do what Dr. Snooze says ans Seafoam the hell out of it (maybe twice).

[InAccordance]

My question is; How would fuel even get into the distributor....?

What is your idle speed with everything off, engine warm, in park (if auto)?

I've had to fiddle with my weber to get the idle just right or it will diesel cause the idle is slightly too high.

Good chance though, old engine and carb full of gunk and carbon causing things to not function as they should. Clean 'er out.

[g.frost]

In order to diesel, there must be an ignition source (other than the spark plug) This is usually carbon deposits built up in the combustion chamber. Running rich can make these deposits build up fast. Cheap gas without detergent will too. A Bottle of PEA combustion cleaner like Redline SI-1 in a full tank of gas, and some spirited driving aka Italian Tuneup will usually cure.
If it's running rich, that needs to be fixed! Fuel dilution in the oil, carbon deposits, cylinder wash down, fowled CAT will all do serious costly damage.

[Dr_Snooz]

Update to this now 9 year old thread: Dieseling is usually caused by a vacuum leak or by having the idle speed set too high.