Hi all. I hope that someone has some advice for me on this. The car is a 2002 WS6 A4 with 48k miles. It has less than 500 miles on a circle-D 278mm 3200rpm stall, 228R cam, and headers.

Following initial tuning, I took it back to my tuner for some tweaks to the shift points (car was bouncing off the rev limiter in 1st gear at WOT). Following the tweaks to shift points, everything was fine for about 2 days.

Then, out of the blue, the car developed the following condition
1. At light throttle, it won’t shift out of 1st until about 4000rpm
2. At WOT, it never shifts out of first.
3. On kickdown from about 30mph, it downshifts twice (I think from 4-3, then about a 1/2 second later, it drops to 1st.) Before these problems, it just dropped to first without the interim step.
4. It will always upshift into 2nd above 20mph or so if I take my foot off the throttle completely.
5. I can get in all four gears manually with the shifter. I can also get it to shift to 2-3-4 automatically after I get out of first gear.
6. No codes are being thrown.

My tuner is out of town for about 2 weeks, so I don’t have a way at the moment to tell whether the PCM is ordering 2nd gear or not. (Unless there’s a way to add a custom PID to my phone’s “torque” app to watch that?). Using the torque app, I was able to see that the TPS seemed to be responding, although I don’t know if the percentages it showed were appropriate for how much I had the throttle open.

Any ideas? Is it even possible for it to be tune related if it was fine for 2 days after the tuning?

Thanks in advance for any insight.

 

faulty TPS will cause issues like this. Shifts are controlled by a few things, calculated load (as indicated by the MAF), TPS, speed, and RPM. If one of those is wacky shifting will be erratic. MAF issues usually cause overly harsh shifting. Speed or rpm issues should show in your gauges. Hence my suggestion for TPS first.

 

Ooh, it'll be nice if it's that simple. I actually have a potz ported TB will all new sensors sitting in my closet right now, but my wife snagged it and declared it a "birthday present", so now I don't get it until Wednesday, lol.

 

Just to further the comment by 01SSREDA4


My TPS when it went bad did exactly the same. Would not shift at WOT 1-2 and light throttle it would hold first until about 4000 rpm. It also would hold 3rd until about the same..

 

When my tps reversed output (weird I know) I only got a hanging idle but it seemed to shift ok. When the wife's dodge had a bad tps, it would hold shifts too long like yall are describing.

 

Ok, so I put in my ported TB (with new sensors) this morning.

The car still bounces off the limiter in WOT (at least in 1st WOT - I don't have anywhere to test 2nd really). At very light throttle, it shifts at about 3000rpm into 2nd (seemed higher before). It almost (maybe?) feels like it's shifting off of speed instead of RPM.

I think VSS is ok, because my speedometer is matching with my GPS.

I can get into all gears manually, and the shifts feel fine. Unless someone else has some thoughts, I'm thinking it's back to the tuner?

 

Did you calibrate the TPS?

Has to be 0.47-0.53 volts at throttle fully closed and no more than 4.71 at WOT. On aftermarket TB's this usually entails elongating the screw holes on the TPS which allows you to "clock" the TPS backwards and forwards until you get the required voltage. Voltage measured by backprobing the dark blue wire on the TPS connector and a good battery ground. If it's outside of those voltage specs then it can create weird problems such as yours and the pcm won't enter idle fuel cells at idle. If that checks out ok, then back to the tuner.

 

I would at minimum do the relearn procedure. Then try it out. Then before replacing any more parts i would visit the tuner with your concerns. Yes, the part throttle shifting is MPH based vs throttle input. So speed sensor and TPS must function for correct shifting.

 

I just did the TPS re-learn, and I tried to get voltages but I was having a rough time getting consistent readings with my cheapo multimeter.

I did watch it with my scantool app go smoothly from 0-100% as I manipulated the throttle. Is that effectively the same check or do I need to make sure of the voltages?

In any case, I'm 99% sure that the answer lies with my tuner.

 

Probe the purple wire with the red lead, black lead to chassis ground. Read DC volts. Should be get whatever idle is (less then 1 volt) to a max of around 4.6ish volts.

 

If the scanner is showing the throttle at 0% and 100% when it should be, and it is repeatable on every key cycle, then the voltage of the TPS must be within the right spec otherwise the reported throttle percentage wouldn't be correct.

 

Most likely yes. But isnt it great when you can PROVE it is.

 

I have a follow-up to this, now that it's springtime and the car is removed from storage.

It turns out that correct gears are being ordered at the correct time. What's really going on is it's not shifting into 2nd gear when ordered. What I thought was 2nd is actually it going into 3rd, right on queue. So I'm guessing it's probably the band (even though I do still have 4th).

I'll probably just take the opportunity to drop a Performabuilt transmission in it.

One question. Am I safe to drive it to where the work will be done or do I need to trailer it there? I'm asking because I plan to re-use the stall converter - it's got probably 300 miles on it.

 

 

No 2nd but every other gear sounds like a leak in the 2nd circuit. Maybe a bad seal on the 2nd servo. Not sure how easy it is for you to pull the servo, but it's something fairly easy to check.

 

It could be the 1-2 accum or the 1-2 shift solenoid too. Those might be a little easier to check than the servo.

 

 

96 z28 here and just like all of ya...my 4L60E won't upshot out of first until I let off the gas at 20 mph. Shifts into third but.....no overdrive. On the hiway car is at 3000 rpm because I can feel that the torque converter isnt locking up. Solenoids in the trans (TCC torque converter clutch, and PWM solenoid) are what I have been told is the problem. Plus..I have the SES light on. Code is a 1870 if I remember correctly which by definition...transmission slippage detected. I have the 3600 page factory service manual on PDF and well...I'm still driving this thing except no slipping any gear just shifting issues. hope this helps a little