Need refresher course in Tweecer basics, N/A tuning

[shomethe$$$]

I purchased my 2nd tweecer, so now I'm making logs, engine is stock 3.0L MTX except for y-pipe and 3" single exhaust, cone air-filter.

I attached a log of a WOT run, to my knowledge it appears to be running borderline lean, the HEGO values are in the red, so where do I start tuning.
2nd issue, the TPS voltage is too low, I've never opened so it's weird that its almost 1v off.


Step 1, turn KAM off, max value=0, min value=254

Step 2, do I start adjusting the scalars or go to the tables?
high slope= 27.4181 lbs/hr
low slope= 72.008 lbs/r
WOT TPS breakpoint= 2.19727 Volts

 

[shoclown]

are you able to tune in rpm brakets? or over all only?

 

[yamahaSHO]

If you suspect TPS voltage being low, replace it.

 

[shomethe$$$]

are you able to tune in rpm brakets? or over all only?

far as I know over all

If you suspect TPS voltage being low, replace it.

I checked TPS voltage with a voltmeter, idle is .70 Volts, WOT is 4.9 volts....so the TPS is fine, but the log says 3.777.., idle on log is .005......i'm fumbled myself???

 

[yamahaSHO]

far as I know over all

You can tune various ways with load vs RPM.

I checked TPS voltage with a voltmeter, idle is .70 Volts, WOT is 4.9 volts....so the TPS is fine, but the log says 3.777.., idle on log is .005......i'm fumbled myself???

I would skim over the manual again to make you have all the settings correct again as well as make sure you have all the updates from Josh.

Here is a WOT shot of mine: Double checking shows mine in the 3.7v range... I've never really paid attention to it though. I could go back over a log when I get home to see if it gets any higher.

On a side note, I hit about the same load at 5,400 RPM now that I've gone down in altitude

 

[rubydist]

Why is the ECT showing room temperature? The pcm will want to run open loop and rich until the coolant temp comes up or until the error timer expires (which on obd2 pcms is like 20 minutes, not sure about obd1), and if the sensor isn't reading right, it will be very difficult/impossible to tune the engine correctly.

 

[yamahaSHO]

I'm blocked from seeing that picture here at work... When I get home I'll take a look at it... It sounds like you may have to update and select the correct settings (possibly re-write/payload) for the TwEECer.

 

[Sho Amo]

how is 17* room temperature?

 

[shomethe$$$]

I don't know the tune is totally stock, I haven't fiddled with it, I've only been taking logs and clearly its very lean.

If it was a TPS, shouldn't it have thrown a code?
I just checked the TPS again, turning it slowing it is consistent from .75-3.8, then the ohm reading goes to OL and then goes from 4V-4.5V. Could this cause the lean problem?

I'm calling to see if anyone has it but no one can cross the number, says E9Tf-9B989
then BA-2E01A

 

[shomethe$$$]

I didn't payload ECT. Your only allowed 16 variables most of them are taken by the KAM and O2's.

 

[Kens1992mtxSHO]

I was about to say that he either didn't payload it or he just started the car.

 

[shomethe$$$]

changed the TPS, the voltage readings are the same although at idle it starts at .84V, and the break at 3.7 is still there with the new TPS... I don't know...the tweecer could or could not be reading the TPS correct....the voltage meter shows a different reading than that of the log...perhaps there could be a short.....i don't know...I've installed all the updates correctly.....could be the wrong TPS says E9TF-9B989-BA (can someone check there's please).......honestly i think the TPS is in working order, I'm trying to find out why its running lean on WOT

 

[Ishodu]

TPS voltage has always been max of 3.7 it seems to use a 0 - 3.7 scale rater than a 1-4.7.

 

[shomethe$$$]

TPS voltage has always been max of 3.7 it seems to use a 0 - 3.7 scale rater than a 1-4.7.

Thanks, you could of saved me $23, I had to check my logs from 5 years ago to find out the same thing, it never went passed 3.7 range, back to why it's running lean, idea's?

 

[sho_sc]

TPS voltage has always been max of 3.7 it seems to use a 0 - 3.7 scale rater than a 1-4.7.

Yes, the EEC reads the idle TPS voltage and subtracts from the actual reading. So, idle shows up as 0v (or 0.05 - 0.1) and WOT shows up as ~3.7 v. This is why it's not important with a SHO to keep the idle TPS voltage under 0.9v.

 

[Ishodu]

Try lowering injector high slope and see how it goes. I have been spoiled and have always used a WB o2 for tuning that. Hopefully your 02s are in good shape.

 

[shomethe$$$]

Before I start tuning this for N/A, could I have overlooked another problem? or is this the way SHO's run on stock programming?

I forgot to mention that I have the dual feed line system with a Mallory FPR, the autometer gauge reads 39 relative even at WOT, I'll order a DataQ so I can log that as well. So that should be in working order.

No drivability issues, no CEL, lambse logs are right around 14.6 during CL.

I've checked all my logs, it is always lean on WOT, could the big exhaust have caused a lean condition?

 

[Ishodu]

Normally the SHO runs pretty rich on the top end especially. What do your karmfs look like when your not on the gas to much? Is the MAF dirty? Or aftermarket?

 

[rubydist]

how is 17* room temperature?

Sorry, I was thinking 17C not 17F. Maybe in an igloo...

Before I start tuning this for N/A, could I have overlooked another problem? or is this the way SHO's run on stock programming?

I forgot to mention that I have the dual feed line system with a Mallory FPR, the autometer gauge reads 39 relative even at WOT, I'll order a DataQ so I can log that as well. So that should be in working order.

No drivability issues, no CEL, lambse logs are right around 14.6 during CL.

I've checked all my logs, it is always lean on WOT, could the big exhaust have caused a lean condition?

Doesn't the pcm command a more rich mixture at WOT? On the obd2 pcm, there is a tps count and/or mafs count that triggers the pcm to enter the WOT condition, and there is a table where you can command a more rich mixture based on engine speed - do you get to do that on the obd1 also? If so, you should be able to richen the commanded setting and test what result you see.

 

[yamahaSHO]

That's actually 0 degrees.