hey all, i am VERY new to this and I have some general tuning questions
and also 1 very specific one.

I've also posted this over at TunerPro and TunerPro RT - Professional Automobile Tuning Software since that is the software I'm using.

Let me start with the specific question:

1) Background, I'm tuning on a 87 TPI with a early 90's vette computer.
Some of the key ingredients are 350 ci., High flow heads (aftermarket plus being ported, 24/.lb injectors, TPIS intake, Corvette hot cam.

I've got Very strange data showing up in spark advance relative to reference pulse field. The data I'm seeing is arond 1700 RPM and high manifold pressure (87 kpa), currently showing a rich condition the spk_adv_rel2refpulse field has 23083 in it. I will mention also that around this same RPM/kpa there has been notable backfires/pops from the intake. Can anyone clue me in on what might be happening ?

I'm also reciving quite a bit of knock count, but am not sure if I should touch the spark tables until the BLM's are all dialed in.

Now on to my general tuning questions.

I've read some of the documents out there and this is my current plan of attack:

1) Start by adjusting the VE tables until BLM's are as close to 128 as possible ( I realize this is a time consuming part since I've already gone through 20 chips. ) I am assuming once this is done the car should run fairly decent.
a) Is it common practice to tune by the BLM or the INT ?
b) Is it common practice to smooth values as you go ?

2) Start to modify some of the PE related table values.

any comments or suggestions are appreciated !

 

Backfires, are usually the result of too lean or too much timing.

The other items have all been covered in detail in the stickies.

 

Hit the "Tuning Guide" up top and read it about 4 times and it will start to clarify itself.

Go slow, one thing at a time, take notes, if u dont know why you are changin something, try to find the answer first so you know what it will affect.

later
Jeremy

 

I have read some of the tuning guides (several times), I'm not denying that re reading them again might help ! I Just wanted to know if I was on the right track, and also if anyone has seen a value like that in the spark advance field (relative to ref. pulse). It looks to me like 23,083 degrees of advance. It threw me off since most values were 0 and some were less than 5.

I'm also concerned I'm not getting enough data points when data logging. I've been capturing Approx. 7,000 data points per drive (15 minutes or so). Sometimes I'm modifying values inthe VE table based on only a few points of data at a given RPM/kpa (should I have a minimun amount of data for a given RPM/kpa before changing values?)

Thanks in advance for any input ...

 

Just make sure the load is reasonable for what you're looking at. If the throttle is slightly closing, ie your going downhill, the load seen, vs AFR will be *off*. Stuff like that can be misleading.

 

That is exactly the type of advice I'm searching for. I think I understand the basic theory ... So, let me interpret your response:
Any values in my data log where the TPS% is 0 or TPS volts = .49 (closed throttle) are not values I want to be considering for making any adjustments
to the VE tables ?

Also let me bounce a scenario of you if you don't mind:
The other day I was in the garage and really wanted to do some tuning on my dad's street rod (this is what the motor is in). However, it was raining out so we didn't want to take the car out. I decided to play in the garage
by logging data that I thought would be useful in the lower VE table.
I fired the car and took it in 100 RPM increments from 1000 - 1600 (while it was in neutral) stopping at each 100 RPM increment to hold it steady for about 10-15 secs. I then repeated the entire process with the car in gear.
Does this seem to you like it would be useful data to analyze or would just plain "driving data" be better ?

... wish I had a dyno for those rainy days !

Thanks in advance.

 

What bin, xdf, & ads file are you using?

 

Tonight, I disabled PE per the advise of a local tuner, and did some data logging. When analyzing the data
I ignored the values that may be misleading (per Grumpy's advise). The BLM's were anywhere from 118 - 136. Usually in the trouble area (popping from the intake) the BLM's are around 130. I decided to narrow my focus and only change VE values for the BLM's of 136 and 134. Also I took about 20% advance out of the Main Spark Advance table in the trouble area: 1200 - 1800 RPM and 70-90 kpa.

I won't be able to log the results for a couple days, but I'll post them once I do.

Z69, I'm using $8d.xdf, 1227730.ads, .bin is custom (stock 350 .bin would not even start the motor). We were able to acquire a custom bin from a local tuner (also a member here), that had a similar setup. Same heads (minus the porting), same cam, stock intake w/Lg runners (we are using a TPIS intake), we also have a bored throttle body ( I believe 52mm), and larger injectors (which have been accounted for in the .bin. This .bin at least gave us a starting point. We've already made significant changes to the VE tables.
I've been exporting the logs to .csv format and importing it into an Access DB to do analysis.

 

I'm the "local tuner" and am also not sure what should be corrected to eliminate the excessive spark retard and popping through intake. But we're going to look at it more this weekend. If anyone wants to throw in some additional thoughts, please let us know.

On somewhat of a side note, we're both interested in knowing what tuning can be done to get back some of the lost torque after swapping from a stock TPI intake to the LT4 hot cam and miniram. Once the BLMs are good, is the majority of the tuning for the lost torque in the spark tables?

 

Thanks for your input to the thread, I didn't want to throw your name out there without talking to you first ...

As S10Wildside mentioned, we are interested in learning some tuning techniques that are beyond the tuning guides and VE tables. I really
believe that with enough time and data analysis we should be able to get this motor to run better than stock in all aspects of the operating range.

Any and all input is greatly appreciated ... what is that others are looking at after getting the VE's in align ?

See ya this weekend S10Wildside !

 

I don't know how well Mike follows the board, but the super_8dm2.ecu can be imported into TP from the TP sight. I've never checked to see if the 8D.xdf is based on the 8dm2 or not.

I've never notice a problem with the SA display in TP using that ads.
There is an aldl???.zip on moates IIRC that has the A100 file.
The A100 is the aldl definition for 8D. It can be used to check the math of your ads. Which has a few errors in it btw. But I guess that the aldl software in TP is involved in the funky SA displayed.

 

I'm not a stranger, but I'll admit I haven't kept up with the DIY tuning (or my S-10) since my I got busy with the Firehawk rebuild, marriage, new home, etc..... but I am having fun helping with the tuning for this ******.

 

Z69,
I'm assuming when you say "SA" you mean "Spark Advance" (sorry I'm still learning the lingo/abreviations), regarding the field "Spark Advance Relative to Reference Pulse", as I noted above.

In that case ... I wonder if anyone else here has seen this erratic data in the Spark Advance Display ? I'm guessing tuner pro's data logging is flawed in that something is occuring in the Computer that does not allow tuner pro to interpret the Spark Advance properly. Throughout the rest of the data this Spark Advance display seems fine, just lower RPM in Overdrive (1700 mostly) and high kpa (70-90).

Maybe this weekend I'll see if S10WildSide can log some data with another program (other than TunerPro) since the anomoly is reproducable.

 

We can work with DataMaster.

 

I seriously doubt it's flawed, chances are your ALDL definition file is bad.

 

We'll have more answers (or questions) after Saturday. The problem area is very reproducible, so we'll see what the data shows with DataMaster.

 

I've had plenty of reproducible aldl problems- that went away the next day....

 

The definition in the ADS for "Rel to TDC" (word 39) is ok and should be mult by 0.351600.
I haven't see a correct one for the other one (Word 41, Rel to DRP)
I have a note in mine that it is wrong and the formula has the same value.
I'll check a few others and see if there is a different value in any of them.
doesn't really matter, the value that works just includes your base setting.

Also the A100 is incorrect on the AFR calc.

 

thanks for the info ... interesting ?

 

Well, we had a very discouraging weekend ... see thread: https://www.thirdgen.org/forums/diy-...roblems-w.html

Although in addition to the laptop/connectivity issues we found several small mechanical and software config issues (some while S10Wildside was there some after he left ... it was a long day ... for me about 10 hrs !):

Mechanical:
1) Spark plug gap was set too large ... changed to 35 thou. from 40 plus.
2) Found a "cooked" (melted/cracked) plug wire on cylinder 8. Replaced with a temporary old one (new Taylor being made before next testing session).
3) Compression test showed all 8 cylinders at 120 PSI (had to rule it out, since we could hear a slight miss from the pass. side exhaust ... hence the "cooked" wire.)

Config changes:
1) injector flow rate changed to 24 from 27 (I guess there was some debate on how the injectors were rated at first ?)
2) initial advance changed to 6 degrees from 7.

All these changes didn't seem to make much difference, however we changed the PROM back to square 1 (the .bin acquired from S10
Wildside) and it was a considerable improvement. We also added the above config changes in for flow rate and initial advance. We still have a flat spot in that area, but considerably less popping from the intake ! We only could reproduce the pop a couple times (before we could just about make it pop perpetually ... you had to stab the throttle or completely get out of the throttle to clear it up).

Well, that's all I know for now ... Although we noticed a recent post ( I think it was March 06) on "Lean intake poping" regarding the AE table. I Will research that post a bit before making too many more changes.

Thanks all for you thoughts and input !