2nd & 3rd gear starts

[bluhaven]

I have an 05 GTO with a 2800 Vigilante converter. I have been having intermittent problems with 2nd and 3rd gear starts after a burnout at the track. It finally thru a PO722 code (output speed sensor circuit low input, old-immature) along with 2 PO300 codes. the DTC for the PO722 was already set to report no error but still did? I was also told to set code PO757 to report no error but its not shown on the list, any ideas? I'm not the tuner just trying to get some info to try and fix the problem.

Kevin

[bluhaven]

Anyone have any info?

Kevin

[BAD364]

Hi, I know it's an old thread but did you find the problem? When ever I do a big burnout, the car gets stuck in 3rd on take off. No codes shown.

[bluhaven]

I just got mine fixed, had to use EFILive to turnoff the codes off(not report) po722, po723, po757, po751. Hope this helps you because it been a real pita for me. This was on a 2005 GTO.

Kevin

[BAD364]

I just got mine fixed, had to use EFILive to turnoff the codes off(not report) po722, po723, po757, po751. Hope this helps you because it been a real pita for me. This was on a 2005 GTO.

Kevin

Those codes have all been turned off.
When this problem happens, the speedo stops working for a little while. Did yours do the same?

[bluhaven]

Those codes have all been turned off.
When this problem happens, the speedo stops working for a little while. Did yours do the same?

Now you have me worried, my speedo never stopped working. When mine 1st started doing this we changed to doing a 1st gear burnout and that solved the problem. We have since changed our converter from a 2800 to a 3600 and the problem came back. We have made about 10 passes in the car since we had the codes turned off. We race this coming weekend so I'll get back with you and let you know if the problem comes back. Are you running a high stall converter?

Kevin

[BAD364]

No you have me worried, my speedo never stopped working. When mine 1st started doing this we changed to doing a 1st gear burnout and that solved the problem. We have since changed our converter from a 2800 to a 3600 and the problem came back. We have made about 10 passes in the car since we had the codes turned off. We race this coming weekend so I'll get back with you and let you know if the problem comes back. Are you running a high stall converter?

Kevin

Yes it has a 4600rpm stall converter. I'm thinking it's a mechanical problem; but only happens at the track after a burnout, so I'm not sure.
I'll try doing a burnout in 1st gear next time, thanks.

[bluhaven]

There was a tsb that says to clean out the valve body because of debris, i did this just to make sure I'm covering all my bases. I really don't think it's a mechanical issue, since our converter change we have gone back to 2nd gear burnouts and the problem didn't return (yet).

Kevin

[BAD364]

I've been doing some reading on the net about limp mode 4L60/5's. Normally when you get a 3rd gear start combined with a non-working speedo, the transmission isn't getting power. Just dont understand why it loses power after a burnout.

I also found this from a list of common 4L60 issues. Do you know where I can find this VSS drop-off setting?

23. 3rd gear starts, can manually shift through all gears. When car has been turned off for a bit, then back on it will run normally.: VSS dropoff w/ Hi-stall converter. The rpms are too high, but VSS is showing no movement. Happens after a tire burning take-off. Doesn't store a code, will not throw a CEL (I've heard that it will store a code if it happens 3 or more times). Cure: Reprogram PCM for VSS dropoff.

[bluhaven]

We raced this past weekend, made 9 passes and no problems. Doing a 2nd gear burnout. If I learn of anything else I will post back. I hope this can get figured out. What kind of car do you have this in?

Kevin