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

guy's with PCMForless inside please.

Old Sep 24, 2003 | 09:21 AM
  #1  
94Zpower's Avatar
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guy's with PCMForless inside please.

o.k I have pcm for less tunning and very happy with it but I have one question for those of you who have the 160 stat programmed in to your pcm... i got a check engine light the other day and I never noticed b4 so please tell me if this in normal, when ever my car is ice cold for example in the morning whem I start her up and let it run for even 10 sec both cooloing fans come right away! and we all know that there is no way for the engine to 160 in 10 seonds! could this be a temperature sensor problem or a pcm programming problem?? or is this normal?

I am getting the car scanned on the weekend but I would like to try to figure this out b4 because it's really bugging! other than that the car runs perfect not stumble or hesitation at all.

thanks
Old Sep 24, 2003 | 09:33 AM
  #2  
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After you scan the code, clear it, disconnect the battery if you have to. Then see if the fans still do that, because they shouldn't.
Old Sep 24, 2003 | 09:41 AM
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Is your check engine light coming on with the fans? The ECM will switch on the fans when it throws a fault code.

There are two temperature sensors. It's possible that one of the temperature sensors is faulty.

One controls the dash temperature gauge and is located right under the driver's side exhaust manifold.

The other temp. sensor is read by the ECM and is located on the front of the water pump housing.

Check out shoebox's website for some more info...
http://csce.uark.edu/~jgbertr/rb/4th_gen_tech1.html
Old Sep 24, 2003 | 09:56 AM
  #4  
95 Silver TA's Avatar
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If you check engine light is on and your fans come on, your car is in Limp mode. Which means you are loosing power too. Get it scanned and fix the problem. Make sure your MAF, TPS and other connections are connected securely.

Hope that helps,
Claude
Old Sep 24, 2003 | 10:05 AM
  #5  
94Zpower's Avatar
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Originally posted by i387
Is your check engine light coming on with the fans? The ECM will switch on the fans when it throws a fault code.

There are two temperature sensors. It's possible that one of the temperature sensors is faulty.

One controls the dash temperature gauge and is located right under the driver's side exhaust manifold.

The other temp. sensor is read by the ECM and is located on the front of the water pump housing.

Check out shoebox's website for some more info...
http://csce.uark.edu/~jgbertr/rb/4th_gen_tech1.html
when I start the engine the light stays off for a few seconds and then comes on...probably when the fans click on or that's what I think is happening , I 'm gonna check it at lunch by haveing a friend start it and I will check for the fans under the hood, because they are hard to hear from inside the car when the engine is running.lol

Thanks for the input guy's! I'll let you know hat happens.

Gary.
Old Sep 24, 2003 | 10:09 AM
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Ive never heard of "Limp" mode, what is that? My car is doing the same thing and i feel like im losing a sh!tload of power, but i think mine is related to my TPS because sometimes the car will stutter and miss then the engine light will come on for a few minutes and then it will go off. When i first got my tuning the throttle response was a lot crisper then before but now it almost feels like back to stock. Anyone had similar problems.
Old Sep 24, 2003 | 01:49 PM
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95 Silver TA's Avatar
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Originally posted by SnakeSkinner28
Ive never heard of "Limp" mode, what is that? My car is doing the same thing and i feel like im losing a sh!tload of power, but i think mine is related to my TPS because sometimes the car will stutter and miss then the engine light will come on for a few minutes and then it will go off. When i first got my tuning the throttle response was a lot crisper then before but now it almost feels like back to stock. Anyone had similar problems.
Limp mode is not a technical term...Its just my own personal word for it.

Let me try to explain this as simple as I can...
Say if your car is working perfectly (without any Check Engine codes). Its has a certain amount of timing.

Now if your car is not working perfectly (Check Engine Light mabee cause by bad sensor, loose connections etc.), the PCM will do a few things to prevent you from damaging the engine. It will pull out timing, kick the fans on to prevent any damage that overheating may cause and will warn you with the Check Engine light and I also believe it adds more fuel. This is what I and many other folks call "limp" mode. By adding fuel and pulling out timing, the PCM is trying to safegaurd the motor from any potential damage but pulling timing and having the motor run richer than normal will also KILL performance.

Hope that made some sorta sense,
Claude

Last edited by 95 Silver TA; Sep 24, 2003 at 01:53 PM.
Old Sep 24, 2003 | 01:52 PM
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I maybe have the answer to your question. I had pcm4less tuning about a year ago and I have the exact same thing. I have the 160 degree thermo and the fans come on instantly. I called Byran Herter and found out that they was a few bugs in that particular pcm flash file, so you might want to contact him and ask him about that
Old Sep 24, 2003 | 02:07 PM
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94Zpower's Avatar
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Thanks!

I will contact him after I get the car scanned.

but I have had the programming in since April with no Fan probs or lights until now? did yours do it right away or after some time ?
Old Sep 24, 2003 | 02:26 PM
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It may have been that way from the start but I honestly don't remember. It was quite a while before I even noticed that they were coming on that quickly.
Old Sep 24, 2003 | 02:36 PM
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Originally posted by 95 Silver TA
If you check engine light is on and your fans come on, your car is in Limp mode. Which means you are loosing power too. Get it scanned and fix the problem. Make sure your MAF, TPS and other connections are connected securely.

Hope that helps,
Claude

I'm with ^
Almost definitly not the Program.

Scan those codes, thats what they are there fore. Fix problem. No check engine light. Fans don't come on with light anymore.
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