Engine dieseling Help!!

GTSSportCoupe · Post by **GTSSportCoupe** » Wed Aug 11, 2004 10:13 am

My engine is driving me nuts. It is dieseling almost every time I shut it off these days. (did I mention I hate carbs?) It happens mostly when the ambient temperature is fairly warm (ie. at night it doesn't do it as much). If I run 91 octane, it helps a little bit, but not much. The engine is in excellent shape. It doesn't have carbon buildup and compression is good. Timing is set correctly. Air and fuel filters are good. Engine has a new thermostat and temperature is usually around half on the temp guage.

Anybody have any ideas on what the problem might be? I have to pop the clutch after I shut the car off to keep the thing from dieseling for very long. It must be hard on the engine. I don't have time right now to troubleshoot the hell out of the damn thing. I just need to know if there are a few basic things I could check.

Thanks for any help.

takza · Post by **takza** » Wed Aug 11, 2004 11:44 am

Using heated fuel, my car will run backwards if outside temps are 85F or above...this isn't dieseling though...it just bouces backwards and stops.

I'd check the manifold bolts, look for other vac leaks, and maybe try a different brand of gas. For the hey of it...try running with the EGR disabled to see if this makes a difference?

GTSSportCoupe · Post by **GTSSportCoupe** » Wed Aug 11, 2004 12:20 pm

Takza: Mine actually does exactley what yours does. When the temps are up outside, it will run backwards for a bit after I shut it off. I know it is backwards because if I let the clutch out while it is doing it, the car moves backwards even though it is in 1st gear. So this is ok? I'll try playing with the things you mentioned to see if it makes a difference.

thanks.

Thereminator · Post by **Thereminator** » Wed Aug 11, 2004 2:12 pm

Mine did that some if I shut~it~off while the fan was operating,but I think it stoped with the new radiator and lower temps.So theres another que for a different radiator,Nick.

takza · Post by **takza** » Wed Aug 11, 2004 5:40 pm

GTSSportCoupe wrote: Takza: Mine actually does exactley what yours does. When the temps are up outside, it will run backwards for a bit after I shut it off. I know it is backwards because if I let the clutch out while it is doing it, the car moves backwards even though it is in 1st gear. So this is ok? I'll try playing with the things you mentioned to see if it makes a difference.

thanks.

I thought my problem was due to the heated fuel. Not exactly something to build confidence? Since it doesn't happen except above 85F, I haven't worried too much.

Possibly it hasn't happened since I snugged up the manifold bolts? Not so sure I've seen 85F for a while either.

tercel4wdrules · Post by **tercel4wdrules** » Wed Aug 11, 2004 11:33 pm

When we first got that garbage engine it would also diesel but after we got the carb rebuilt a couple of years ago it hasn't done it in a while.

takza · Post by **takza** » Tue Aug 17, 2004 2:32 pm

GTSSportCoupe wrote: My engine is driving me nuts.Ã‚Â It is dieseling almost every time I shut it off these days.Ã‚Â (did I mention I hate carbs?)Ã‚Â It happens mostly when the ambient temperature is fairly warm (ie. at night it doesn't do it as much).Ã‚Â If I run 91 octane, it helps a little bit, but not much.Ã‚Â The engine is in excellent shape.Ã‚Â It doesn't have carbon buildup and compression is good.Ã‚Â Timing is set correctly.Ã‚Â Air and fuel filters are good.Ã‚Â Engine has a new thermostat and temperature is usually around half on the temp guage.

Anybody have any ideas on what the problem might be?Ã‚Â I have to pop the clutch after I shut the car off to keep the thing from dieseling for very long.Ã‚Â It must be hard on the engine.Ã‚Â I don't have time right now to troubleshoot the hell out of the damn thing.Ã‚Â I just need to know if there are a few basic things I could check.

Thanks for any help.

A colder plug?

Engine Speed and Load

"Increases in firing-end temperature are proportional to engine speed and load. When traveling at a consistent high rate of speed, or carrying/pushing very heavy loads, a colder heat range spark plug should be installed "

<a href='http://www.ngksparkplugs.com/techinfo/s ... country=US' target='_blank'>http://www.ngksparkplugs.com/techinfo/s ... ntry=US</a>

Plugs are US:

<a href='http://www.sparkplugs.com/results_app.a ... IA=1279155' target='_blank'>http://www.sparkplugs.com/results_app.a ... 1279155</a>

<span style='color:blue'>I see 3 types of NGK plugs in the same price range...wonder which is best? Could you say what you use in your car?</span>

GTSSportCoupe · Post by **GTSSportCoupe** » Tue Aug 17, 2004 4:36 pm

Thanks Takza!! I am actually using NGK plugs right now, although I'm not sure exactly which ones. I know they are the basic copper replacement spec'ed for the tercel 3ac engine. I think I'll get some better ones as you recommended. This could end up being a nice easy solution. Also, where my header meets my down pipe, one of the bolts broke off in the header when I swapped my new engine in; I have an exhaust leak there right now. I wonder if this exhaust leak is contributing to these problems? This is one of the things on the list of work I need to do to the car. (I'm still 'worked-out' from all the swapping I did earlier this summer). I'm having trouble getting excited about working on the car these days.

I gotta replace a wheel stud that I broke too

; this will also be a pain in the ass. My A/C/heater fan decided to quit the other day for no apparent reason too :huh: ...the breaker is ok... <_<

2wagons · Post by **2wagons** » Tue Aug 17, 2004 7:17 pm

Mt 87 wagon did the same thing too, it drove me to drinking, well at least drinking more :blink: . I suggest you check your main fuel cutoff solenoid on the carb-, it has the three wires- and make sure your idle speed is not set too high. Apparently these carbs have high vacuum at idle and can pull fuel into the carb. Also you can lean your idle fuel mixtue. The srew is directly beneath the main fuel cutoff solenoid, I think. The screw is a pain to reach, you have to get a screw drive over the top of EGR valve and reach all the way to the base of the carb :angry. I took a skinny screwdriver and cut aff the handle so it just fits right

. MY dieseling stopped after I set idle speed and leaned the idle mixture. OH, I also broke a stud

but it easily came out with a few taps from the hammer

arbskynxnex · Post by **arbskynxnex** » Tue Aug 17, 2004 9:16 pm

GTSSportCoupe wrote: My A/C/heater fan decided to quit the other day for no apparent reason too :huh: ...the breaker is ok... <_<

Is the switch in the "off" position?

Seriously though, check for voltage going to the motor, If you have it, you've got a dead motor, or something stuck in the blower wheel. I bent the shaft on mine out wheeling, I have no idea how, but it wasn't hard to replace, I even think one from a similar year corolla fit, but I'm can't remember. I'd also check the fan speed switch, probably first since it's easier to get to. All you should have to do is check for continuity.

takza · Post by **takza** » Wed Aug 18, 2004 5:04 am

GTSSportCoupe wrote: I'm having trouble getting excited about working on the car these days. I gotta replace a wheel stud that I broke too ; this will also be a pain in the ass. My A/C/heater fan decided to quit the other day for no apparent reason too :huh: ...the breaker is ok... <_<

I've ALWAYS got a list of things to fix and improve. Keeps me out of trouble? <_<

GTSSportCoupe · Post by **GTSSportCoupe** » Wed Aug 18, 2004 9:28 am

Haha!

Ditto.

Juando · Post by **Juando** » Wed Sep 08, 2004 11:26 am

it's always nice to see ppl have the same problems I do. My car does the rough shut-down sometimes as well...my guess is it is definately something to do with the carb because I recently had my engine completely rebuilt..and it still does the dieseling. Carb is about the only thing I have not replaced or rebuilt under the hood in the past 2 years.