Where would I find this in 8D?

I did a search... just not sure which table (or mutliple tables to pursue)

I think I have a spark retard issue for tip-in off Idle.

Basically, my fuel seems good, but it hesitates pretty bad until ~ 1500 RPMs or so.

Should I look at the Main SA?
Or
Idle Spark Advance Mult. Vs. MAP
or
Idle Spark Advance Retard Mult. Vs. MAP
or
IDle Spark Advance Retard Vs. RPM

If it is one of the Multiplier tables, what should the multiplier be? (e.g. multiplier .5 x Main SA table)?

Thanks
Or is my problem something else entirely?

 

Hey, I see that we're neighbors. I had the same problem with my rig for about 1yr. I recently bought a Romulator and now I almost have my system perfectly tuned. The fuel and spark combination at "tip in" can be very tricky to get right. Are you doing real time tuning? If not, you really should give it a try. You won't be disappointed.

 

No, I don't have any real-time tuning capability.

I am just using Tunerpro and Moates 852ECM program.

What did you do for your SA tables and tip-in?

The truck really runs a lot better in open-loop. I am just not sure why. I presume it's because in open-loop it is running rich. But I am not sure anymore.

I just got the computer-controlled distributor in, as before I was running a mechanical. So now it seems like it is really running WAY too advanced (spark).

I got better low-end (below 1500 rpm) response, but my power above that has really suffered, so I know I have a long way to go.

Should I even bother with the SA retard tables?

Or should I simply look at the Main SA at different KPA?

 

"Tip in" requires just the right amount of spark and fuel. It seems, in my experience, that tip in is more sensitive to the spark/fuel combination that any other driving condition. The tables I tweaked the most to get mine right are as follows:

1. Main SA table.
2. AE vs. %TPS
3. AE vs. MAP
4. PE Spark
5. %TPS threshold for PE
6. Main VE table.

If you can slowly open your throttle and it runs good from ~600-1500 RPM and your BLM is close to 128, then I'd say that your VE and spark is close enough. I'd start focusing on your AE. I've found that AE is not worth my time to tune unless I have real time tuning equipment. It's just too difficult to get right without RT tuning. Very small changes to AE can make big differences. The trouble with this is that it's very easy to overshoot your mark.

 

Even w/o real time tuning the AE is worth looking at. It can make or break things. If you get into detonation the retard will carry for quite a bit and can really slow you down when you go to accelerate. Its more difficult with the 7747, though, since the tps and map ae both carry for a bit so its some mixture of both. With a car its slightly more easy since the tps AE is there just to prevent the mixture from going lean momentarily after tip in. I was able to quasi-somwhat tune the MAP AE pretty much by butt alone since it had a longer duration then the tps and I could gestimate where I needed more by where it was bogging. The tps was trickier since I had no idea how much tps corresponded to where it was going lean. I wasnt able to figure out what delta tps corresponded to what untill I got a faster serial datalogging system. RT tuning wont help unless your running lockers or some other higher speed communications. Youll still be plauged by the slow ALDL. Even though I dont have one I imagine a WB-O2 woudl really help more then anything else as far as dialing in the AE. I can somewhat see it with the stock O2 but only when the engine is going lean.

Never had any experience with them but do some of the newer RT tuning systems implement faster serial communications?

 

I still use WinALDL for my data logging. But for tuning tip in AE, I don't even bother looking at the log data because, as you said, it's too slow. With RT tuning, I can tune tip in by the seat of my pants. I just keep tweaking TPS/MAP AE until it feels good at tip in.

 

Any other suggestions?

 

i started lean but not by choice so the bog/stumble occurs. i gradually increased AE(10%) PER BURN in both TPS and MAP until the car got better. it took much more than i expected. once the stumble reduced significantly i stopped the % of bump up. now i am taking it away but only in lower MAP areas not tps to see/feel the effect. . like it was said trying to feel the difference in the tip in as well as the hard accell areas by seat of pants. with the WB install coming soon i can see the affect without needing to sense it.

 

Thanks for the reply.

So you didn't need spark retard during AE???

You added fuel instead?

20 D of timing seems like a lot for AE at the 800 - 1200 rpm range...

I just want to be clear.

Thanks.

 

i am uncertain if ecu retards spark in ae. IOW i just left spark table stock and worried about lean all over so main fuel tables and AE corrections at first burn. i worked on main fuel and AE at same time getting my blms close to 128 or so and adding to ae on each burn. in fact still on stock tables for spark but that will change. no KC (ae or otherwise)so spark appears conservative and gains to be made.

 

If you stomp on it hard enough you're going to get spark advance (PE) not retard. On the 7747 you can set the %TPS threshold for PE and therefore limit when PE will occur.

 

that sounds correct (brennan). in fact i think i saw that table in TC. did not touch it.

 

Yes, I am aware of the PE. PE Enable is set for ~70% TPS in the '7730. I disabled it (set for 100%) so I would know what that I am only working in AE.

 

is disable of PE safe? i did that but only to get 3200-3600 fuel tables in line. i populated as many cells as i could and fudged the rest. drove car on level highway. then i reinstated it(PE) after the log.

 

That's my plan...

Traxion's post/sticky suggests changing PE to 85% to tune...
(Edit'ed my nhromyak after Grumpy's correction)

It's not my DD.


I suspect the others aren't replying because they keep telling me to change my drivers as I am running a TBI with the 7730 computer. But they can't tell me WHY (othre than 1/2 voltage to the injectors). It seems to work fine so far.

 

YOU'VE NEVER, EVER HEARD ME MENTION DISABLING PE WHEN TUNING!!. Just a raised voice, not really yelling.

If your going to quote people or infer credit please be accurate.

PE tuning needs done in a well defined manner, IMO, and nowadays with a WB. Especially for the new guy. Disabling PE in order to get stoich right, at WOT, is flirtting with killing an engine, IMO.

 

Sorry Grumpy, obviously I am mistaken...

I am not Disabling PE to get WOT tuning. I am disabling PE to get VE and AE Tuning....

Apparently, I am referring to Traxion' post about AE tuning the '7730 (NO PE).

"The last thing that you would want is to disable PE and then find that you are lean in the upper kPa values of the VE tables. This can cause severe engine knock which can lead to engine damage. With that said, I don’t necessarily disable PE. I change the point at which PE is engaged. In many of the stock BINs PE is engaged anywhere from 50% to 70% throttle depending on RPM. I change these values to 85% across the board."

Found it here:
https://www.thirdgen.org/techbb2/sho...threadid=39254

In Traxion's six post.

 

my point was the AE tuning. if you disable the PE to do AE that is dangerous. i disabled only to get the 3200-3600 and was on level road and snuck up on that rpm in 3rd gear(5 speed). i was only getting fuel tables in order(BLM) not AE/PE. i thought someone would chime in. they are watching.

 

I understand what you're saying Ronny. I also am aware of Traxion's post suggestion about being very careful.

Perhaps I am not sure what or when AE is used...

I thought AE is used when you're accelerating but not in PE (70%).

So how do you tune AE then if your not able to tune AE above 70% PE?

More interesting to note, how does AE get enabled? It looks like it is (or can be) a function of both TPS % Delta AND/OR MAP%Delta.

As I recall, AE with these two changes, like when I had my mechanical and vacuum distributor there should be spark retard when vacuum goes away... my current program does not show (nor do the logs show) spark retard when the vacuum goes low (hi KPA). For the most part, the Main SA is used during AE even under no (or less vacuum). Hence, the question...

Does anyone USE AE Retard?

Or is everyone relying on the MAIN SA?

Thanks.

 

this is beyond my knowledge but here goes. i dont have the constants in front of me but in that table any time the TPS registers a change of 10%-20%-30% at any TPS position quickly it invokes a pump shot of fuel based upon value in that table . this qualntity of fuel can occur over a short period of time instataneously or longer PS, as a lag. the MAP sensor also reads a change of pressure and it to provides a helping hand of PS again based on values in constants. . i am not certain if TPS/AE + MAP/PS= Total or they offset. not sure. it would seem TPS AE would come more quickly. not sure. this may not be on money but reasonably close.

 

thanks Ronny, I understand that... but what about spark.

Did you or anyone else work with the Spark Retard table?

 

I think I posted this before but here goes again.

the way I tune the VE cells for high kPa is as follows..

calibrate all the PE tables to provide a stable, static AFR. 12:1 seems convenient. (I use trax's AFR modifier but i think there are others). it's a combination of two tables i believe, PE enrichment vs temp and PE enrichment vs RPM. the two tables combined together determine PE AFR (well, more correctly, they determine how much fuel to add on top of the calculated fuel indicated by the VE table values).

So, I get it all up so that the computer thinks it's achieving 12:1. This of course isn't going to be what it is in the real world, but that's because the VE table needs fixin up.

So, I set the computer for 12:1, install the DIY WBO2, hook it into the ECM on an unused input (I think it's TPS2 or MAP2) and use the a variation of the published code hack to log the WBO2 in the data stream. Hook up diacom, find a nice hill to climb, and go for a drive.

When you analyze the data you've collected, you'll find that your AFR "errors" away from the desired AFR. Then you just correct the VE table and go for another drive. the goal is to (1) achieve a steady, unwavering AFR at WOT (which you'd expect, since you asked the code to provide a steady 12:1). This will make the overall curve for the 100kpa cells VERY good; and the actual accuracy for these cells pretty good too.

Another advantage is after the 100kpa VE cells are close to matching the real-world engine VE, you can use AFR modifier to easily and quickly change the AFR half a point up or down for performance testing to see what the engine likes.

if none of that made sense, here's the logic of my approach:

given: an accurate VE table, without other modifiers (PE, INT, BLM, etc.) should result in 14.7:1 (assuming using the ECM as GM intended it, closed loop, stoich ratio, etc.)

given: (directly from above): the 100kpa VE cells should result in 14.7:1 without any other modifiers (PE etc.)

given: we don't want to run the engine at 14.7:1 at WOT.

given: it's safe to run the engine rich at say 12:1 at WOT

theorize: IF the VE table values for 100kpa were correct, and IF these values were used with a known, controlled modifier (for example - a fixed 20% enrichment achieved through PE vs. temp table), THEN the observed AFR would be 14.7:1 enriched by whatever fixed amount we asked for.

thus. if we KNOW the observed AFR (with a wbo2 that we trust to be reasonably accurate), and if we KNOW what we've set up the ECM to give us for AFR, .... if the observed AFR varies from the theoretical intended AFR, the only place that could cause this error is the VE table itself.

I am of course disregarding the effects of incorrect injector size settings, the effect of AE, etc. I'm presuming a calibration that is otherwise reasonably well in shape.

this method works for me. I find a hill to climb (to reduce the rate at which RPM climbs), and disregard the first second or so of WOT data (to avoid any effects of AE). if any timing retard occurs during the WOT period, the AFR data is suspect and should be disregarded. When I first used this method, I found myself chasing phantoms all over the place because I was disregarding an occassional few degrees of retard (damn california heat and 91 octane crap fuel...)