2QUIK6

I really had not noticed this before until I finally went to the track this past w/e with the new heads/cam setup...its actually been installed for 6+ months, but finally thought I had all the bugs out..

I dyno tuned it up to 349rwhp up to 6k rpms..its stock bottom end.
But at the track, it pulls great thru 1st and 2nd gear (A4), hits 5800rpms at the top of 2nd, shift to 3rd and drops the rpms to 3700...and by the time I hit the traps in the 1/4 its only up to 4400rpms

Its almost as if the convertor locks when it shifts to 3rd, but the TCC indicator is not set on at that time according to my scan data log. I've tuned the TCC lock tables so that it doesn't come on till over 100 mph in 3rd to see if it loosened the rpms up any but to no avail.
The 1/4 times really suck for 349rwhp, barely cracking a 13.8 at 98mph.

Its falling flat in 3rd gear at wot with hardly any pull at all in 3rd. Runs great elsewhere.
Has the cam specs in sig for the '95 TA and LE ported heads with stock valve sizes. 2400 stall convertor...stock 3.73 gears

VinceTrifecta

Have you tried running the track with the gear selector in both drive and overdrive?

2QUIK6

I think I tried it both ways may have left it in 4th the last time since it was never shifting to 4th by the end of the 1/4. No difference. Seems like I have it programmed to not shift to 4th until somewhere just over 100mph at 100% TPS.

Hmm... but it does almost seem like its shifting from 2nd to 4th gear. I'll take another look at my log when I get home.

TobyZ28

I had the same symptoms as you twice, once because of a dying fuel pump and once because of a bad coil!

VinceTrifecta

Yeah that's what I was wondering - is it skipping 3rd gear? From your trap speed (98) vs. rear axle ratio (3.73) vs. RPM (4400), it *sounds* like you are in 3rd gear, though.

For it to skip 3rd gear like that, it would mean the 2-4 band isn't coming off at the 2-3 shift for some reason. That could be caused by a mechanical or electrical condition. However, if you tried it with the gear selector in drive and it is still skipping gears, I think that points strongly to a mechanical problem.

2QUIK6

The coil and opti for that matter are new, MSD coil, stock replacement opti. Fuel pump was replaced with a Walbro about a year ago, but its not showing to be lean...well, maybe it was at the track...but previously road testing it with a wibeband hooked up it wasnt going lean...but I'll need to hook it back up to see if thats still the case now...
I was able to reproduce the issue it on the street yesterday.

Thanks, I'll see what I come up with later this week.

2QUIK6

Since I was able to duplicate the problem on the road yesterday, I'll try it again with the selector in just (D) to make sure when I hook the wideband back up to it to test the fueling situation mentioned above.

It may not be skipping 3rd but it sure as heck feels like the convertor is locked when it shifts since the rpms drop so far on the 2-3 shift.

2QUIK6

After reviewing my scan logs some more, I found an indicator showing what the gear selector was set at during the runs at the track...it was in 4th the first pass, and in the 3rd the rest of the time...and it made no difference.

I see it shifting at about 5700-5900 rpms and it drops to around 3500-3800 at each shift when at 100% TPS.....below 4000 is way out of the torque range for this cam after reviewing my dyno pulls....I need to try to keep the rpms up at least 4k or more.

So I'm going to raise the shift speeds at WOT by about 4 mph or so which will raise the rpms by about 300-400rpms.
I'm also going to hook the WBO2 back up on both sides and see whats going on there... I think a bad coil or ignition spark would show up in the lower gears when it revs high and under more load so hopefully this will shead some light on what the issue is.....if it picks up alot in the 1/4 by changing the shift points I know that was it although I'm not comfortable revving the stock 95k short block that high all the time.