LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

why does my car have a split personality?

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Old Jun 10, 2004 | 09:10 AM
  #1  
JoshGuitar's Avatar
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From: Bugtussle, PA - a suburb of Pittsburgh
Angry why does my car have a split personality?

I went to the track last night, everyone was running a bit slow because of heat and humidity...I was running 13.9 - 14.1. Then on my last run of the night, I did a nice smokey burnout to get my ET Streets nice and warm, then when I took off I had no power...it felt like I was at maybe 1/4 throttle, and it wouldn't above 2500 RPM or so. Ended up running an 18.x and getting slaughtered by a ford escort . After my run, I changed back to street tires (the car was off while I changed tires) and left, and everything seemed to work fine then.

A similar thing happened last year, but the "low trac" light had come on during my burnout. I ran a 17.x that time. I don't think the low trac light came on this time.

Thing is, according to my owners manual, my car could have traction control, and that's what the low trac light means. However, I don't have the traction control button mentioned in the manual, and I definitely don't have the big honkin' traction control module on my valve cover.

Is there a different form of traction control on the 94's that only affects ignition timing and fuel? If so, how do I disable it, just pull a fuse or something along those lines? Or could there be some other issue with my car?
Old Jun 10, 2004 | 11:29 PM
  #2  
OBE1 95Z28's Avatar
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You might of had the knock sensor kick in...it can take 12+ degrees of timing out of your engine thus killing your speed. Get the car scanned for knock.
Old Jun 11, 2004 | 12:23 AM
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I know there is no traction control system that takes out timing and fuel to control traction. My low trac light comes on all the times when doing burnouts and such. You may want to get it scanned or use some data logging software to see what is going on and if you are getting some knock or what not.
Old Jun 11, 2004 | 08:06 AM
  #4  
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would the knock sensor take out enough timing to make that much of a difference? I always figured it would make you lose a few HP, a tenth or 2, whatever...but when this happens, it seriously becomes ridiculously underpowered. Like I could out-accelerate it pedaling my Huffy. Does knock compensation make that big of a difference in power?
Old Jun 11, 2004 | 12:49 PM
  #5  
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To my knowledge, no 94's actually got a traction control system. If they did, it would be the same as the later years and you'd see the big box sitting over your drivers valve cover.

Are you sure it is the "LOW TRAC" light that comes on when you do a burnout? On mine, with a line lock, the "BRAKE" light comes on during a burnout, because of the unequeal pressure in the front and rear brake circuits.

In the event it really is the "LOW TRAC" light, on a car without TCS, it would mean the ABS system has kicked in.

The PCM can only pull 15deg of advance. That is not going to keep you from going over 2,500rpm, nor cause you to run an 18.0. It sounds like the heat is affecting something, which would leave the IC module and the Opti optical module as possibilities. Both of those would affect power and max RPM.
Old Jun 11, 2004 | 01:02 PM
  #6  
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If you don't have the TCS switch, then you don't have traction control. The "low trac" light is still there and will light in low traction situations, but it's just an iformation light. However, I don't recall 94s even having the option of TCS, I thought that started in 95 (but I could be wrong).

Also, the ECM will not pull out enough timing to cause that kind of a difference no matter how much knock it sees.

Unfortunately, I don't have any suggestions on what could have been causing the problem.
Old Jun 11, 2004 | 01:08 PM
  #7  
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the only time the low traction light should come on is under heavy braking? at least thats the way it is on my 94
Old Jun 11, 2004 | 01:16 PM
  #8  
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The "low trac" light can come on under various circumstances, the most common is under heavy braking when ABS engages. You can also get it under wheelspin conditions while driving at a steady state (i.e. if you hit a bump big enough to create wheelspin) or under hard acceleration.

From the fourth gen f-body FAQ:
Q: Why does my "Low Trac" light come on intermittently?

A: This light usually comes on as a result of abrupt changes in speed or road conditions. This could be from slamming the brakes or simple changes in road surface where the speed sensors detect some slip or moderation in the speed at one or both of the rear wheels. It's only a problem if the light stays on or comes on very frequently.
Old Jun 15, 2004 | 08:42 AM
  #9  
JoshGuitar's Avatar
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From: Bugtussle, PA - a suburb of Pittsburgh
I replaced the ICM prolly a year ago. When it went before, it just went. I was on my way to work, the car stalled, and wouldn't start again til I replaced the ICM. If it's the opti optical module, I assume I'd need to replace the whole opti, eh?

Since it's a sporadic thing like that, any bright ideas on how to diagnose which one of those it might be?
Old Jun 15, 2004 | 11:19 AM
  #10  
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my low traction light comes on anytime i hit anything more than a small bump in the road.
Old Jun 15, 2004 | 03:08 PM
  #11  
CamaroSS30thAnn's Avatar
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From: NY...what a bad place for a nice car
dude im having the same problem....im getting angry with my car.....do u get any lights....then go off after this happens...i do so it doesnt store a code....
i dunno what it is and im not really happy with my car
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