pdbq

iTrader: (7)

Here's something that has been bothering me lately and now is of a greater concern. I actually now have the time to write about it and will explain it in the greatest detail possible.

Since I had the car, this problem seemed to have gotten worse each time I go to the drag strip. This problem seems to happen 80% of the time when I bring up the rpms to a certain level and footbrake off the line:

Back in December 2009, my car had full bolt ons and drag radials. Stock 12" converter.

1st pass: Staging with the shift lever on Drive, I bring up the rpms to 2000, footbrake and the car launches off the line in 2nd, I run a 9.0 @ 87 mph, 2.3 60'.

2nd pass: It is all good if I leave off idle. I run 8.40 @ 89 mph, 2.0 60'.

3rd pass: I bring the rpms up to about 1200 rpms, footbrake, I run a best of 8.28 @ 90 mph, 1.9 60'.

4th pass: I bring rpms back up to about 1800 to 2000 rpms, car does exactly the same thing in the 1st run.


Fast forward to October 2010:
With my new mods since May, (Torquer v2 cam, TSP Stage 2.5 heads, 3800 Vigilante stall, MT ET street slicks) here's what happened a few weeks ago:

1st pass: I do my burnout to heat up my MT ET streets which dead hook btw. 3rd light at the tree, I footbrake to 2500 rpms and launch the car. Shifter is in Drive. Once I'm off the line, my transmission immediately starts in second and goes from there. 60' = 2.3, 1/8th mile ET is 8.66, trap speed is 92 mph in the 1/8th. WTF? Why didn't it start in 1st?

2nd pass: I do the same routine as above, but this time, I let the car leave off idle. The car doesn't do the best ET and mph but I still end up running 7.9 @ 93 mph. 60' is 1.85. Of course, the 1-2 shift is PERFECT without footbraking.

3rd pass: Out of desperation, I try something different. Manual shifting. On my 3rd pass, I keep the shift lever on 1ST GEAR, footbrake and bring rpms up to 2500. I launch the car, and the transmission still starts in 2nd gear EVEN IF THE LEVER IS IN 1ST GEAR. WHAT THE ****??? I run about the same ET as I did my 1st run: 8.6 @ 92 mph.

4th and 5th passes: Desperately trying to find out what the **** is wrong, I do a 4th and 5th pass using my linelock to launch instead of the footbrake. Shift lever on Drive. RPMS were brought up to 2000-2200 and I end up running back to back 7.70s @ 94.5 mph, 60' 1.76. Dead hooking, absolute best passes of the night.

6th pass: Tried using the same exact routine stated in my 4th and 5th runs, except launch rpms are about 2700 to 3000 to try to take advantage of my 3800 stall. Like before, transmission starts in 2nd and I run exactly what I did on my 1st run. 8.60s @ 92 mph, 2.3 60'

Here's a little insight to the problem: Some people have told me that my posi could be going because occasionally, one tire will spin while I burn out to warm up the tires. Sometimes both tires spin, but it is usually one tire that spins a little more. Could a bad posi be doing this? Bad transmission shift solenoids or other electrical tranny issues? Please explain to me what could be causing this fucked up problem... Thanks!

ebk06

iTrader: (5)

Subscribing. Ive seen a few threads about this but havent seen any clear answers. Ill be running a similiar setup so im hoping you find an answer.

Could it possibly be a tuning problem?

pdbq

iTrader: (7)

I doubt its the tune because the tune was 100% stock back when I had bolt-ons at the drag strip.

pdbq

iTrader: (7)

TTT... Anyone else care to chime in?

pdbq

iTrader: (7)

TTT again...

pdbq

iTrader: (7)

TTT once again.

Heads-Up-Outlaw

Why do you think it is leaving in 2nd? Just curious. I have a little experience with 60e's by the way.

Have you data logged any of the passes where it acted up? How do you know it is dead hooking as opposed to spinning? Not doubting you... just curious.

I am going to doubt very seriously that the issue is inside your transmission. If it was it would either be commanded electronically, or it would be an issue with your shift linkage changing position of the shift lever when the body is torqued on the footbrake. If I were you I would data log it with H/P Tuners or EFI Live and have an experienced tuner or tranny man look at it.

yulluz2

iTrader: (1)

I have had the same issue and here is what worked sounds stupid but it worked on my car add 1 extra quart of trans fluid 4l60's are bad about sucking air under hard launch and immediately puts it to 2nd. the other thing is your TPS simple to change and fairly cheap. again worked on my car but don't know which did the trick for sure

pdbq

iTrader: (7)

I know it dead hooks in 1st gear from the few times I have cut mid 1.7 60' ets when I do my best passes. I hear or feel no tirespin off the line. Of course, if I could bring the rpms up even more with my loose 3800 Vigilante stall and launch off the footbrake, with the tranny actually starting in 1st gear, I'm certain that the 60' would be at least 1.65 from how hard those tires hooked when my friend borrowed them.

I definitely know when it is in 2nd gear when I realize that I've just completed the 1/8th mile with a boggy start, no shifts, all in one gear.

I know the shifter cable is solidly correct. I still have yet to datalog it... Hope I can figure this out real soon...

n.m.racer

What was the cause of your problem? My 60e is doing the same thing. Car is just a stock stall full bolt-ons. I can roll into WOT and rap up 1st gear but like the op's problem, footbreak launches into WOT and itll take off in 2nd gear. Sometimes even downshifts back into first.... for like 1000rpms.

Sorry to hijack but I want to know the problem

kevin87turbot

iTrader: (2)

What year model is your car? Do you still have the stock tune in the car?

RevGTO

iTrader: (12)

Limp mode. I had a similar experience. Here's a thread I started describing what happened to me: https://ls1tech.com/forums/automatic...nce-track.html Get the followig DTC's tuned out before you return to the track. I had a a lot of confusion because of bad advice ("replace the VSsensor"). I had to get rid of P0300, P0502 and I believe P0720 and 751 for my SS3600 converter to work at the track without going into limp mode. You can find the codes and their functions listed in this thread: https://ls1tech.com/forums/automatic...lush-more.html

ShortChevy

iTrader: (21)

I have somewhat of the same problem. i am pretty sure it is in the VB. Mine will just bang all the gears and run the 1/4 in OD, awesome. Every now and then it won't kick down on the highway either.

n.m.racer

I have a 99 T/A with just full bolt-ons and a simple tune. I thought it might have been limp mode but I still had TCC lock-up and it would take off in light throttle in 1st, I hooked up a scanner and saw it was comanding 1st gear at WOT but was launching in 2nd manually. Plus no DTC's anywhere.

The problem was definitely in the valve-body. I dropped the pan and checked the valves and noticed one had a little piece of crud in it restricting movement. Cleaned everything out and put a new valve in and the tranny has never felt happier. I recently just had the tranny out and rebuilt so it was probably just something in the new/old valve or something just got in there.

Thanks for the help everyone and I hope this can be used on some insight to others problems. VB's are a sensitive little piece of the trans.