93 ATX shifts at 4k rpm only

[SW SHO]

A friends 93 atx with the following mods...80MAF SShop CAI, underdrive pullies, K&N, gutted cats, chip (don't know from where..he said Vadim, but???)

Here's the diagnositc: EATC off, WOT and the tranny shifts right at 4k. You can hear the secondaries starting to open, but then it up shifts.

He'll stop, turn car off, then restart with EATC off, WOT and it'll go to redline in first shift to second, go to redline, then won't shift to 3rd until the speed drops. Then, come to stop try it again and the aforementioned problem occurs.

He has not read codes yet but will. He wanted me to see what you guys think in the meantime.

He doesn't have the stock chip to replace his aftermarket one, and i'm sure once the codes are available it may or may not give clues.

Any ideas?

 

[Bizzy]

My suggestion is to pull the 80mm & CAI and chip and see if the car shifts properly then. If not, then pull the codes and see what you come up with.

 

[SW SHO]

We don't have the stock chip, should we pull the MAF and CAI anyway?

What about any cruise control issues? I remember reading about the cruise control in ATX causing shifting problems? Is that possible?

 

[PAracer]

My first guess is that there is a problem with the chip or computer. Pull the chip and MAF first, then try swapping in a different computer. If you do not have the D4U1 computer, that is a wise thing to try.

 

[Bizzy]

SW SHO:
We don't have the stock chip, should we pull the MAF and CAI anyway?

What about any cruise control issues? I remember reading about the cruise control in ATX causing shifting problems? Is that possible?

To my knowledge, normally there isn't a chip in the computer. You can remove it by opening the glove box and sliding the connector right out. That is providing that Vadim's chip installs the same as Ted B.'s. Also, as with any electronic change, you'll want to disconnect the negative battery cable to avoid zapping anything. I think if you pull the MAF and CAI and not the chip then more than likely you'll have idle issues as the computer will still think the MAF and CAI are there.

There have been some issues where the VSS on the tranny has been an issue for shifting. So this is a possibility as well but I think when it's VSS related that shifting has been more erratic. I could be wrong on that.

Cover the add-on's first, they're the easiest things to take off anyway. Assuming the car ran fine before the addition of the chip/MAF/CAI, once the stock parts are put back on with the stock electronics it would be easier to tell if the VSS is the issue versus the chip/CAI. Meaning, if you put it back to stock and it shifts fine, then you eliminate the VSS as the culprit and can pinpoint that it's a chip, MAF or CAI problem.

You'll also need to reset the idle in the car as well.

<small>[ January 25, 2004, 11:46 AM: Message edited by: Bizzy ]</small>

 

[AutoSHO]

The chip in the car is an add-on chip. Removing it just defaults the computer back to its original factory program. You will also have to put in a good stock MAF because the 80mm will cause the car to run lean. Good luck!

 

[wheels]

I had problems with Vadim's program for the 93 atx. Shift problems - would only shift 1 to 2 at red line. It turned out that the PCM (computer) was the H3Z2. No one has a LPM program compatible with it. IF this is your problem the solution is to change the PCM to either H3Z (1st iteration of 93 atx) or use the 94/95 D4U1 PCM and is what I changed to. The D4U1 also has improvements for the shifting. You still need the LPM to be reprogrammed for either PCM change and to use the 80mm MAFS. You can have the new program increase the line pressure of the atx shift program, but it can be quite harsh and potentially damaging to the tranny. You should discuss your needs with the programmer.

BTW, the LPM has the "chip" as part of it and plug into the back of the PCM. As already mentioned, you access this through the dropped down glove compartment.

John W. (big_wheels was wheels)
93 atx
89 3.2

 

[SW SHO]

Thanks everyone. I'll post any progress.