Setting Timing

[reddawn222]

The TBI install is complete! A big thanks to all on IFSJA that have helped me crawl, then walk with this project. Not running yet.

I am feeling my way through some software learning curves today, but will be ready to start her up tomorrow or Saturday. I found my timing light, but in looking over the front of the engine it's not obvious where the timing pointer is...passenger or driver's side? There's not a lot of visibility on either side.

[FSJ Guy]

You'll want to disconnect the timing bypass wire first. Then start the truck.

You will have to shoot your timing light down the passenger side, avoid the fan () and get the light inbetween the triangle shaped hole in the lower bracket when it will hit the harmonic balancer and the timing marks.

Try doing it with a flashlight with the engine OFF. That way, you don't have to worry about the fan eating you.

It's not too hard once you know where to look, but no, it is definitely not obvious.

[reddawn222]

Thanks for the tip of looking with a flashlight with the engine off. I crawled underneath and used chalk to highlight the mark on the balancer.

Started the engine with the timing by-pass disconnected and can't see a thing with the timing light. But it must be close because it runs, albeit like poo. It was late this afternoon, losing daylight and I discovered other problems so will give it another go tomorrow.

[FSJ Guy]

What base timing are you using? The AMC doesn't run well at zero base timing.

[reddawn222]

I plan to run 10* BTDC as base timing to start out. Last night's snow has slowed me down today.

First, however, I have to fix a leak around the top of one of the injectors. It leaked on initial startup. I pulled the TBI and installed new O-rings top and bottom and a new top gasket but it leaked again when I was trying to set the timing.

[reddawn222]

I fixed the leaking injector that was plaguing me and got the base timing set at 10* BTDC. The engine will fire up and idle (roughly) at this point.

However, when I reconnect the timing -by-pass it idles down (lower rpm), spits, sputters, surges and dies. The main SA table in the BIN I choose as my base BIN is for a Chevy and the initial advance being applied by the computer is 20* and up at idle speeds. Is this too much, too little??? I've tried scaling it both up and down in small increments with no luck.

[Bill USN-1]

You have to pick one way or the other.
If you change the base timing from whats listed in the bin then you have to tell the bin what the new base timing is.

But I really don't understand the need to change the base timing from 0.
The only thing it is changing is the initial cranking timing.
As soon as you hit about 400rpm the ECM takes control of the timing and it will reflect what is in the tables. It confuses me to see people say that the engine doesn't run right with a lower initial setting.

Even the old duraspark system that AMC used, had a crank timing retard.
So it would operate just like this is. That's why it had a red and a white 12v input.

By setting the initial timing to 0 you actually help the engine to crank easier, especially in the hot weather.

Just because the factory used an initial timing of 10* does not mean it needs to be that way with the fuel injection.

[JeepsAndGuns]

Timing should be fine. I run somewhere around 23-24 degrees at idle.

Back when I first installed my tbi, I had a problem with it idleing just fine with the bypass disconnected, but once connected it would run rough and backfire badly out the exhaust. Turned out my "new" distributor pickup coil was at fault. I replaced it with a quality one after replacing pretty much everything else, and my problem got cured.

Also, make sure you have the wires from the dist pickup connected to the correct pins on the ignition module. I cant remember what the correct way was, but I originally had them hooked up backwards. But I think its purple wire to the "P" terminal, and orange wire to "N" terminal. I would double check on mine but its pouring the rain at the moment.

[FSJ Guy]

The reason I like my base timing at 10 degrees is that my motor does't like to idle at 0 degrees when I'm setting the base timing.

20 or so degrees at idle seems fine.

Did you do the voltage checks and set the TPS correctly? Then set the IAC (See Bill's setup procedures on Binder Planet). Ideally, you should do it with the engine warmed up, but you get get it close and then go set it again later.

[Bill USN-1]

The reason I like my base timing at 10 degrees is that my motor does't like to idle at 0 degrees when I'm setting the base timing.

But you only set the base timing once and then you never touch the distr again.
That's the whole point with EFI.

If you ever happen to go into get home mode where there is no timing control then the engine will operate at the base timing until 2000rpm and then the ignition module adds 20*.

If you start with a base of 10 then you will be driving at 30* which may be excessive even under light loads to get home.

Just more food for thought.

[FSJ Guy]

Oh the HORROR!! TBI isn't supposed to break, right?

I carry an extra ESC module. And coil. And PCM.

Since everything is so small and light, it's easy to carry extras.

[Bill USN-1]

If you offroad then no matter what system we run, we carry spares.
But for my drivers, I don't carry spares. The updated older vehicles are just as reliable as any new car. Unless you don't trust your work.


The whole point of upgrading to a newer more reliable system is to reduce breakdown and if you do, you can buy the parts anywhere.


It's the main reason I never went with an aftermarket system and stuck with factory parts.

[reddawn222]

I will check the wiring from the distributor to the ignition module to make sure they are not reversed.
EDIT: JeepsAndGuns said
Also, make sure you have the wires from the dist pickup connected to the correct pins on the ignition module. I cant remember what the correct way was, but I originally had them hooked up backwards. But I think its purple wire to the "P" terminal, and orange wire to "N" terminal. I would double check on mine but its pouring the rain at the moment.[/quote]

I checked my wiring and Orange goes to P on the ignition module and Purple goes to N. This is the configuration given in the sticky in this sub-forum for adding ignition control to Howell TBI. Can someone check and clarify the contradiction?

I guess I'm confused about how the base timing and ECM controlled timing work together. I'm thinking with a base of 10* and a spark advance table showing 20+* at idle, the engine is seeing over 30* total at idle, which seems excessive. This seems to be the same point made by Bill regarding limp home mode. Am I way off on this?

I have other BINs I can choose that have less advance in the SA main table as a starting point.

[Bill USN-1]

You really need to go back to the binderplanet FAQ's.
Read through the distr conversion FAQ and then the initial setup FAQ.

The P and N need to be verified prior to trying any tuning.
This is all discussed here. http://www.binderplanet.com/forums/s...737#post345737.

But if the distr rotates clockwise then normally the purple goes to P.


As already mentioned, if you change your base timing then you have to change the setting in the bin telling the ecm what your new base timing is. You can NOT just change the base timing of the distr and expect the timing to be correct.

[JeepsAndGuns]

Ok, double checked on mine and purple goes to the "P" terminal, orange goes to the "N" terminal.
So switch them around, then re set your base timing, it will be off.
And yes, base timing needs to be set in the bin file you are using. If you set it to 10*, then make sure you put that into the base timing paramiter in the bin. Otherwise the ecm will think you have 0* and give 20* at idle (or what ever the bin is set at), and if you have 10* base timing, you will actually be getting 30* advance at idle. So making the base timing and the setting in the ecm the same is very important.

[Bill USN-1]

Thanks for confirming all I said.
It's nice to have another input.
Didn't you set yours up and do all the installation and upgrades by following the FAQs I referenced already.

So if yours worked as I stated then his should if he follows the same procedures.
This isn't an IH/jeep thing.
It is basic installation procedures.

I have assisted more jeep and chevy guys then all the IH guys combined.
So I know the procedures work.

[Woodchomper]

Bill USN-1 wrote:

But I really don't understand the need to change the base timing from 0.
The only thing it is changing is the initial cranking timing.....

....If you ever happen to go into get home mode where there is no timing control then the engine will operate at the base timing until 2000rpm and then the ignition module adds 20*.

If you start with a base of 10 then you will be driving at 30* which may be excessive even under light loads to get home.

Bill, I'm in the camp with FSJ Guy in setting base timing somewhere around 10 degrees for the simple reason that in my experience AMC V8s do not run well at 0 degrees base timing. Additionally, usually when you add more cam you need to add more base timing.

In your example, if base timing is set to 0 degrees, and you get stuck in limp home mode, you will have 0 degrees of timing until 2000 rpm at which time you will have 20 degrees of total timing. So if an AMC V8 barely idles at 0 degrees I can't imagine how it will drive under a loaded condition until it reaches 2000 rpm. My guess is the vehicle would barely drive (stall like crazy) until you reached 2000 rpm.

In FSJ Guy's setup, with 10 degrees base timing, the engine will idle and will probably run well enough to allow you to limp home.

With an AMC V8, I feel 10 degrees base timing is a good place to start and the only reason to change it would be to add base timing if the engine windmills during starting or reduce base timing if the engine is hard to crank when warm.

This is just my opinion and so far has worked for me. Once, I did have a situation where I was 10 miles from home and had to use the limp home mode. If I remember correctly. 45 mph was about as fast as it would go but I did make it home.

Bill, I'd also like to take this opportunity to thank you for your service to our country.

[Bill USN-1]

You can set the base timing to anything you want or "feel" you need.
My concern with these types of discussions or bin changes is it has nothing to do with how the engine runs.

The original poster is a new guy to EFI so as he reads through the FAQ's on the binderplanet on how to install and set up the system, then comes back here and sees what he thinks is contradicting info, he's going to think he needs to do what the jeep guys say.

So without a real knowledge of how the system works he just bumps the base timing to 10* because that's what he read.

In reality, the only thing the base timing is going to affect is the cranking timing and get home timing.

A lower cranking timing is preferred for ease of starting. It was mentioned that if you have a cam you need more timing. Do you need more cranking timing with a cam? Did you bump the compression? How will that affect cranking timing when warm?

So then if we ever should have a failure that causes the system into gethome mode, the timing reverts to base till 2000rpm.
If we have an auto then the stall is normally 16-1800rpm. Now if we added a cam then we may have even up'd the stall.
The timing jumps to 20* at 2000 rom so that's not really and issue if all you need to do is get to the parts store or get home.

Now you you have a clutch, I'm sure if need you can grab a lower gear to maintain 2000rpm. Again, your just driving it to the part store or home.

There is a failure, the whole point of get home is just that.
It's not to allow driving for the next month till you get around to it.
if that was the case it would just fail and you would be walking.

So, for the new guys, if they actually got thru all this, there isn't a real need to set the base timing to 10*. It has nothing to do with how the engine runs under normal operation and is simply a personal preference.

Another misconception is trying to use the service manual setting and apply them to the EFI system.
Forget them. They have nothing in common and the engine needs to be tuned for what it likes.
You can put a stock 350 chevy chip in and run and drive just fine. But if you have this wonderful, tunable system then you should tune it to maximize your engine. Not the other guy with the same size motor as you. That will only get you close. (If he did it right to begin with)

I made it a practice to not post bins online because I see guys that just copy any bin they find and throw it in their chip and try it. Not a good way to go.

There was "jeep" bin that was being passed around that was pretty bad. But everyone was trying it.

I spend a lot of time writing this stuff because I spent so much time sorting thru all the bad stuff. I am just trying to keep others from going down the same path.

If a setting doesn't need to be changed then don't change it.

Bill, I'd also like to take this opportunity to thank you for your service to our country.

Your welcome. I am actually officially retired now after 28yrs. More time for projects!

[Woodchomper]

The original poster is a new guy to EFI so as he reads through the FAQ's on the binderplanet on how to install and set up the system, then comes back here and sees what he thinks is contradicting info, he's going to think he needs to do what the jeep guys say.

Bill, thanks for the great response. I have always said that there is no one size fits all for efi tuning and that is one the reasons I don't share or post bins. The beauty of these systems is the user gets to decide what they want to adjust based on what they think or "feel" their engine needs.

I actually got a chuckle over your statement on what the Jeep guy says. I totally understand where you are coming from and the intent of your statement so I didn't take it personal. However, this forum is filled with posts where mechanics and so called experts that have screwed up peoples Jeeps based on practices that have worked on other vehicles.

My AMC engines are usually modified (cam, pistons, intake, and heads) and what works for me may not work for someone else.

[Woodchomper]

Yesterday, I checked my timing and both the bin and the distributor are set to 6 degrees. Does this mean that it will always be 6 degrees? No, it just means that at this point in time that is the setting I chose based on how I feel.

For the record, at about 2 degrees, my engine will idle but it is very rough.