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thats cool

I've always thought about installing a VSS on the Atlas 4spd which has provisions for a speedo (currently capped off). I've noticed that when 'wheeling (all that it does) and you are lugging the engine it will sometimes have a high idle for a brief period after the 'lugging' is over. Imagine it being under load then clutching it: the idle will be a bit high for a few seconds, then back down to normal. I've often wondered if a VSS would help with that.

This looks helpful. It is using a BB throttle body, so there may be some differences.

Blake wrote:thats cool

I've always thought about installing a VSS on the Atlas 4spd which has provisions for a speedo (currently capped off). I've noticed that when 'wheeling (all that it does) and you are lugging the engine it will sometimes have a high idle for a brief period after the 'lugging' is over. Imagine it being under load then clutching it: the idle will be a bit high for a few seconds, then back down to normal. I've often wondered if a VSS would help with that.

IAC relies heavily on VSS, so do many other things in program. Throttle follower behavior is another.
For a trail rig probably not big deal to not run VSS, on a street rig, driveability would suffer in several ways.

I have a simplified wiring diagram for TBI posted somewhere on here. Has helped several folks with install/questions/etc.

babywag wrote:

Blake wrote:thats cool

I've always thought about installing a VSS on the Atlas 4spd which has provisions for a speedo (currently capped off). I've noticed that when 'wheeling (all that it does) and you are lugging the engine it will sometimes have a high idle for a brief period after the 'lugging' is over. Imagine it being under load then clutching it: the idle will be a bit high for a few seconds, then back down to normal. I've often wondered if a VSS would help with that.

IAC relies heavily on VSS, so do many other things in program. Throttle follower behavior is another.
For a trail rig probably not big deal to not run VSS, on a street rig, driveability would suffer in several ways.

I have a simplified wiring diagram for TBI posted somewhere on here. Has helped several folks with install/questions/etc.

yup, that is pretty much what I've always thought.

But it's sooooooooooooo low on the priority list that it will simply never get done. My TBI runs fine. Although I'm gonna dig into the choke settings late this summer. I don't wanna derail this thread, but mine flat out dies upon a COLD startup now. It didn't used to do that. But as we've already discussed, I have 100% no clue on how to tune TBI (properly) and I'm confident that I have some really wacked out settings in my .bin

My '88 has been low priority for 3-ish yrs. lol just now getting back @ it, so yeah understand the low priority thing!

Anyway here's the diagram...
http://www.fsjnetwork.com/forum/viewtop ... =35&t=5099

dodgerammit wrote:Install dizzy at 0* base timing and start from there.

The VSS is useful should I want cruise control, though, right? Stock soup can is inop.

I never said to use zero degrees base timing. :- )

I have always used at least 10 degrees base timing. When I tried to use zero base timing, my engine would idle horribly when trying to set the initial timing.When set to 10 degrees, it was much happier.

You MUST program your base timing into the ECM, too. IIRC, It's labelled as initial timing in most of the definitions.

The VSS has NOTHING to do with your Jeep cruise control. But I like running the VSS anyway, for improved drivability.

Can you still get the 2PRS from JTR? They were discontinued for a while, I thought. Maybe they're back....

Ethan, if a guy is using a stock ASDU prom he cannot time it to 10*.
That would give 36* of timing @ idle once running, and too much timing everywhere else.

If yours wouldn't idle timed @ 0*, and
stock timing table, should've idled/run fine.
26* @ idle that way, something else was wrong.

Ethan lives at 5200 feet....

FSJ Guy wrote:

dodgerammit wrote:Install dizzy at 0* base timing and start from there.

The VSS is useful should I want cruise control, though, right? Stock soup can is inop.

I never said to use zero degrees base timing. :- )

I have always used at least 10 degrees base timing. When I tried to use zero base timing, my engine would idle horribly when trying to set the initial timing.When set to 10 degrees, it was much happier.

You MUST program your base timing into the ECM, too. IIRC, It's labelled as initial timing in most of the definitions.

The VSS has NOTHING to do with your Jeep cruise control. But I like running the VSS anyway, for improved drivability.

Can you still get the 2PRS from JTR? They were discontinued for a while, I thought. Maybe they're back....

I live at 1100 ft, so I'll play with timing once I get to that point.
According to their site, it is available for $101

babywag wrote:My '88 has been low priority for 3-ish yrs. lol just now getting back @ it, so yeah understand the low priority thing!

Anyway here's the diagram...
http://www.fsjnetwork.com/forum/viewtop ... =35&t=5099

Thanks for that! I've saved it.

Blake wrote:Ethan lives at 5200 feet....

OP doesn't, and is talking about running stock prom/tune.

OK. I didn't realize that the OP was NOT going to do chip programming.

In my post, I did talk about programming the bin for the base timing. :- )

If you're going to use a stock ASDU bin, you will have to hook up the GM EGR function AND the VSS in order to prevent it from throwing codes, right?

Honestly, however, I would recommend getting the Burn2 that will allow you to burn chips and program. It's not that much more $$ and IMHO will prevent lots of headaches. But as they say, YMMV.

Actually, I probably will tune, and plan on it. But just a tune to delete codes or set the parameters out of range of throwing the code and fine tune the setup to my engine. Still, I don't plan on anything extravagant. In fact, I may just see if a basic stock style 360 .bin is available once I'm closer to actually doing this. Get a basic bin that should allow my engine to run decent enough, then fine tune from there.

I have nothing but time right now, so I want to thoroughly wrap my head around the concepts, directions I can take, and understanding needed before diving in.

Ethan, In some other post you said if you did it again, you would get Burn2 and something else due to simplicity/expense. Care to elaborate?

What you've described is what I do when I "tune". I delete some error code checks or simply adjust the parameters so they never engage (such as EGR). The ASDU fuel map is pretty darned good for our engines. 360 versus 350. Pretty similar displacement. The timing will have to be adjusted. The OEM timing table in the ASDU bin is really weird, IMO.

Yes, I originally got the AutoProm (And still have one). It allows tuning on the fly. No swapping of chips. Just send a new bin to the AutoProm, which is connected to your ECM.

HOWEVER, I found that I had to pull over, stop, and re-adjust my bin anyway, so it was not a big deal for me to burn a new chip, pop out the old chip and insert the new one and drive off again. So, I would recommend an ALDL cable for datalogging, either DIY or one from Moates or other sellers and a Burn2 for chip burning.

The only advantage of the AutoProm for me would be if I had a partner and one person drove, the other person reprogrammed. THEN it would save time and even then, it would only be worth it if I was in the business of tuning peoples' vehicles. It's a nice device, but it just wasn't completely necessary for me.

BTW, having lots of time is good! I read and re-read tons of articles, writeups and threads before I dove into it. And I had an advantage of already having a working (Howell) system to hack into.

I want to thank Babywag for this link on another thread. http://www.ifsja.org/forums/vb/showthread.php?t=161925

So, if I'm understanding correctly I can:

1: Rotate advance plate and achieve the same result as the harder set screw method

2: Kill 2 birds with one tap. Wouldn't I be able to lock out the advance weights AND lock down the advance in the correct phase with ONE screw?

What I love is everything would be completely reversible should I desire to take it back to original fueling.

Nevermind. Went back and looked at Ethan's links on his page. Total brain fart.

The advance weights are under the plate that is under the pickup. Looks like 1 tap per bird.

Still, drilling and tap work would be easiest for me.

Two words:

Tack weld

You won't go back to carbs. Ever.

I know I won't, but should something happen to the Jeep, wrecked or sold, I could pull my efi stuff off and let it go. It has happened before.

You can always drop another distributor in there *if* you ever need to sell it.