So I replaced my old Edelbrock 1406 with a brand new Edelbrock 1406 and now the stupid thing diesels like hell when I shut it off, makes me look rather foolish. I had it idling at around 1000 so I turned it down to about 700, still does it. I have a 305 with an Accel ignition system, etc. Any suggestions, someone mentioned a different type of spark plugs, is that viable and if so what should I try? Thanks!

Do you have an anti dieseling solenoid?

I'm not familiar with the Edelbrock carb but two things usually cause this, throttle plates not closing enough(too much idle or AD solenoid improperly adjusted or malfunctioning)or too much timing.

Dieseling can be caused be too high an idle speed, malfunctioning carb solenoid, timing, thermac valve malfunction, or high operating temperature. The Edelbrock may not have a solenoid so that could be eliminated as a cause. Idle speed may require 5-600 at operating temp. Timing is always a question. Good luck!

Dieseling can be caused be too high an idle speed, malfunctioning carb solenoid, timing, thermac valve malfunction, or high operating temperature. The Edelbrock may not have a solenoid so that could be eliminated as a cause. Idle speed may require 5-600 at operating temp. Timing is always a question. Good luck!

Damn timing. A friend tells me you can't trust a timing light on an old motor, you can just get your baseline then the rest has to be done by instinct. Does anyone know of any information online I can read about adjusting the timing on my 305? Thanks!

Some guys say to set the initial timing with a light. Next, drive the car until it comes up to temp. Then, at a very low speed, kick it to wide open throttle. At peak efficiency, you should hear just a rattle or two of spark knock during open throttle. Worth a try. A little experimenting and adjusting, but free!

Ok, I've heard all the shade timing methods and have even used a few myself, BUT, GET A LIGHT AND USE IT!!!! Anybody can get one close enough to run by ear but that doesn't mean it's right.

That's the only sure way to know where you are for sure so you can advance or retard it to a point that works. Even if you set it by "ear" you can use a light to see where it is and know exactly where to put it back once you have it dailed in and you won't have to play with the distributor all the time if for some reason you take it out and have to reset it!!!

Preferably get one that has the advance dial so you can check the initial as well as total advance. A valuble tool for dialing in your engine.

Some engines are very sensitive to minor timing changes, especially with todays "lead free" fuel. And trust me, you don't want to see what kind of damage timing advanced too much can do, don't ask me how I know!!! 8O

Of course a light is a necessity. I never met a person who could properly time an engine without one. Only a buffoon would attempt to do so. However, if the original timing does not provide acceptable performance and efficiency, it is entirely appropriate to take additional steps to achieve satisfactory results. Then, when efficiency and performance has been attained, put your own timing mark in place for future reference.

First the dieseling--you may have a vacumn leak and are compensating for it by opening the throttles plates too much at idle. Or the idle speed and idle air mixture screws are maladjusted. The factory recommended timing is rarely optimum for max performance. Usually the initial timing is too little and the maximum timing comes in too late. Shoot for max 38 degrees at 2600rpm with initial timing at 10-14 BTDC with the vacumn advance disconnected for testing.

Look mine did too. I was experiencing a lean condition. I had to re-jet the carb. Also the MSD Ignition setup come with a diode that you could need to install in the altenator on the small wire that goes to the light. What happens sometimes with the MSD ignition is that there is enough juice being passed back through the ignition system through the light in the dash to make the MSD work. They include the diode in the HEI Kit.

So its eather a lean condition with the carb, remember they are generically calibrated to work with "Most" engine set ups but really they do have to be dialed in.

Or

Its possible that the ignition is getting power and just keeps on running. The information that came with my MSD kit talks about this a lot.

I don't know much about timing but I hooked up my timing light to the drivers side frontmost spark plug cable and this is what it looks like, does this provide any info?

http://www.mardens.com/misc/elky-may-32-2004.jpg

Also, how the hell am I supposed to get at the bolt to loosen to adjust the timing. I am assuming it's the one way underneath the distributor.

Is this still the stock 305 setup? If so on an 85 the ECM should be controlling the timing. I didn't think there was a way of adjusting the timing.

Hey Poltergeist, I made the same comment in a post earlier and some on this forum disagreed with me. To prove to myself that the ECM controlled the timing, I intentionally set the timing on my 86 to 17 degrees BTDC and drove the truck. Then I set the timing at about 10 degrees ATDC and drove the truck. In both instances, I kicked it hard (WOT) from a dead stand still and could detect no difference in the way the engine ran. If that is not proof positive that the ECM controls the timing on a stock engine, I don't know what does. By the way, I set the timing back to the original setting after the experiment.

Is this still the stock 305 setup? If so on an 85 the ECM should be controlling the timing. I didn't think there was a way of adjusting the timing.

It came with a V6 originally so the 305 is not stock and I don't think there is a computer controlling anything anymore.

if you email edelbrock or go to their site . you can tell the tech guys what is happening and they can tell you exactly what the problem is and how to fix it . i got the thunder series carb from edelbrock and the tech guys were great with my questions . now the engine idles great and has lots of power compared to my old q-jet . these guys live for this stuff so give them a try .

if you email edelbrock or go to their site . you can tell the tech guys what is happening and they can tell you exactly what the problem is and how to fix it . i got the thunder series carb from edelbrock and the tech guys were great with my questions . now the engine idles great and has lots of power compared to my old q-jet .

When I first bought the carb (about a month ago) I called their "hotline" and the guy was baffled why it would do that. He said it's probably the timing, carbon deposits in the motor, or too hot a spark.

On my '84 (305/4bl) I replaced the original computer controlled carb with a Holley 650 when the original gave up, so there's no computer control of the carb. The computer lit up the check engine light and set timing to some limp home mode (also does not lock up the converter). It would occasionally diesel on shutoff. I was able to reset initial timing from TDC to 10BeforeTDC without causing pinging. The car runs much better, but also the idle speed increased due to the initial advance. That allowed me to adjust idle mixture one more time and close the throttle plates to get idle RPM back in line. Now it doesn't diesel.

Regarding the discussion above--a timing light is certainly essential, but when you have modified the engine be prepared to make some changes from the stock settings. Then note what works so you can set back to that setting.