Kamaro

Hi all, I just completed a LS3/4l60E swap into a '71 Firebird, everything work very well except for this annoying issue, the engine will hesitate and eventually die when I put it in reverse, the tuner says that the ECU (E67) should know which gear the transmission is in, but since I'm using a FAST EZ-TCU transmission controller, I just can't figure out where to get that signal and to where it should be read in the ECU side. The strange thing is the engine would only do it in reverse only, its fine on drive.

What do you guys think about that?

Kamaro

Anyone?

mrvedit

The PCM only needs to know whether you are in Park/Neutral or in Reverse/Drive as it has a few different idle tables for each condition. Your shifter might be able to supply that.
Or your tuner could just copy the Drive table values to the Park/Neutral tables.

Is the engine stock or heavily modified?
Does it also die when you shift directly in Drive?
(Reverse uses higher line pressure which puts a tiny bit higher load on the engine.)

Also, why are you using the FAST TCU controller instead of the GM one?

Kamaro

The engine is a LS3 based 416 stroker with a 239/250, 113+3 LSA cam. It also dies when I move in reverse and stop, the idle would hunt and then die.

Which pin in the E67 needs to see the park/neutral signal?

I'm using the EZ-TCU because of the adjustability it has in it.

mrvedit

That is almost identical to my engine. The issue is less the Park/Neutral signal and more of a big-cam issue, which requires careful tuning. While I had my setup working well with my 4150-style intake and TB, I'm still struggling with the stalling problem with my new 102mm LSXR intake and 102mm TB. For now, I gave up running SD and just installed a 100mm MAF which has helped a lot. Of course, I'm an amateur tuner and a good pro tuner should be able to fix your problem quicker.

Tell us more about your intake system, whether you are running a MAF, what converter you have and whether you have wideband O2 sensor(s).

Sorry, I don't know the pin # on a E67.

IMHO, the stock GM TCU will have even more adjustability and of course better integration with the ECU. I assume you don't have HP Tuners or EFI Live?
Sorry, but for future readers, if you have an ECU, I would suggest spending the money on HP Tuners and a GM TCU (new or $100 on ebay) instead of any standalone trans controller.

If you or your tuner could post the tune here, I'm confident some of the experts here could give you advice.

I plan to work on the same problem on my car this weekend and if I learn anything, I will post it here.

In the mean time, give us more info.

Kamaro

I'm using a MAF tune using the stock GM LS3 MAF. The converter is a ATI with 3000 RPM stall. I'm using the stock GM O2 sensors but do have a 3rd bung used for a WB gauge on the dash. I ran a EZ-TCU mainly because I have a 2008 and ealier 4L60E which can't be used with the GM T42 TCM, I'm not even sure if any GM TCM would be compatible with both my trans and the E67.

one guy adviced me to use some sort of air straightener before the MAF (what we call a honeycomb plate), just because my MAF is so close to the air cleaner (about 2 in. away), which may cause air turbulence at the MAF.

In my area its so hard to find a real good tuner to work on a GM ECM, most of the guys here are working on Japan imports and almost all of them will use ECMs like AEM, Motec .. etc.

Please let me know if you find anything that may help, I'm so frustrated that I can't enjoy driving the car after working on it all that time!

mrvedit

Thanks for the additional info.
In what city are you?
GM sells Connect & Cruise packages that come with a 4L60E and TCU; that indicates that at least some TCU support the 4L60E.

joecar

If you're looking for an airflow straightener try this:

http://www.saxonpc.com/100mm-cells-for-100.html

cpd004

iTrader: (13)

Did you ever get this figured out?