Recommendations for ECM Fan Programming
Thread Starter
Instructor
Joined: Jan 2013
Posts: 140
Likes: 15
From: Carpentersville, Illinois
2022 C4 of the Year Finalist - Unmodified
Recommendations for ECM Fan Programming
I'm looking for recommendations to get my PCM reprogrammed for lower fan temps in the Chicago area. I have a 1994 LT1.
Last edited by NARDA1; Oct 3, 2023 at 08:27 PM.
Team Owner
Joined: Sep 2003
Posts: 25,420
Likes: 2,746
If you have a running car NOW you DO NOT want to surrender yours for programming to anyone that you DO NOT KNOW 'NO ONE'! Someone that can do PCM tuning/programming locally. You might quiz their credentials also! You DO NOT have an ECM - your car has a PCM, '94 is first year!
Thread Starter
Instructor
Joined: Jan 2013
Posts: 140
Likes: 15
From: Carpentersville, Illinois
2022 C4 of the Year Finalist - Unmodified
If you have a running car NOW you DO NOT want to surrender yours for programming to anyone that you DO NOT KNOW 'NO ONE'! Someone that can do PCM tuning/programming locally. You might quiz their credentials also! You DO NOT have an ECM - your car has a PCM, '94 is first year!
Melting Slicks
Joined: Mar 2002
Posts: 2,884
Likes: 767
From: Sligo PA
If you only want the fan temp to change you don't have to have the computer tuned. There are lots of nice fan controllers out there that are user programmable. You just need to add another temp sensor.
Or if you want to do more of a DIY solution there is a write up on the Arduino forums on how to use a temp sensor for a S10 pickup an Arduino nano and a relay card to run dual fans. Total cost of doing it yourself is around $50 if you can program an Arduino. Or you can copy the code on the post and use it.
Or if you want to do more of a DIY solution there is a write up on the Arduino forums on how to use a temp sensor for a S10 pickup an Arduino nano and a relay card to run dual fans. Total cost of doing it yourself is around $50 if you can program an Arduino. Or you can copy the code on the post and use it.
Racer
Joined: Sep 2001
Posts: 367
Likes: 93
From: Chesterfield VA
If you only want the fan temp to change you don't have to have the computer tuned. There are lots of nice fan controllers out there that are user programmable. You just need to add another temp sensor.
Or if you want to do more of a DIY solution there is a write up on the Arduino forums on how to use a temp sensor for a S10 pickup an Arduino nano and a relay card to run dual fans. Total cost of doing it yourself is around $50 if you can program an Arduino. Or you can copy the code on the post and use it.
Or if you want to do more of a DIY solution there is a write up on the Arduino forums on how to use a temp sensor for a S10 pickup an Arduino nano and a relay card to run dual fans. Total cost of doing it yourself is around $50 if you can program an Arduino. Or you can copy the code on the post and use it.
Melting Slicks
Joined: Mar 2002
Posts: 2,884
Likes: 767
From: Sligo PA
The fan settings are in the PCM on a 94. In order to have a switch do it you would have to wire into the fan relays, the best way is to change the temp in the PCM that you want the fan to come on at. Even in the 85 up you had to do it this way. If you had a Z51 with HD cooling there was a fan in front that used a switch, but the main fan was controlled by the computer.
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Melting Slicks
Joined: Mar 2002
Posts: 2,884
Likes: 767
From: Sligo PA
Here I'll post a link for a good one.
This one works well but I wouldn't use the thermistor that comes with it. I would get a temp sensor for a late 90's S10 pickup with a 4.3L. The S10 temp sensor has threads that are NPT and should thread into your cylinder head instead of the probe type temp sensor that comes with the kit. The newer LS style temp sensors are the same ohm range as the S10 but use metric threads so avoid those.
Using one of these allows the user to adjust the fan temp with a screwdriver. No PCM tuning required. The integrated relays in this controller can handle 70 amps total, 35 amps per fan.
If you don't have the ability or the equipment needed to tune your own PCM this is the easiest/most cost effective way to get this done.
This one works well but I wouldn't use the thermistor that comes with it. I would get a temp sensor for a late 90's S10 pickup with a 4.3L. The S10 temp sensor has threads that are NPT and should thread into your cylinder head instead of the probe type temp sensor that comes with the kit. The newer LS style temp sensors are the same ohm range as the S10 but use metric threads so avoid those.
Using one of these allows the user to adjust the fan temp with a screwdriver. No PCM tuning required. The integrated relays in this controller can handle 70 amps total, 35 amps per fan.
If you don't have the ability or the equipment needed to tune your own PCM this is the easiest/most cost effective way to get this done.
Burning Brakes
Joined: Aug 2023
Posts: 1,093
Likes: 35
From: San Diego
If you type into google, there used to be several companys that would reflash your ECM to do exactly what you want. Its been many years since I have done one. But, it was a simple flash program hypertech "Used" to have, pcmforless, and here is one
94-95 LT1 Corvette Performance Tune – Garrett Tuning
Should be simple to find a sponsor too on here.
94-95 LT1 Corvette Performance Tune – Garrett Tuning
Should be simple to find a sponsor too on here.
Racer
Joined: Sep 2001
Posts: 367
Likes: 93
From: Chesterfield VA
Yes but you will pay close to $300 and if you do not know what you are doing you can brick a discontinued PCM. I'm all for someone learning and doing it themselves but you have to be willing to pay the price if you screw it up as well.
Safety Car
Joined: Jun 2010
Posts: 4,564
Likes: 1,677
It’s not like you are throwing somebody in front of the NASA control panel. It’s a laptop and a cable. And if it gets bricked he can get a new PCM.
Race Director
Joined: Apr 2007
Posts: 11,153
Likes: 892
From: South Western Ontario
There is a program called flashhack that is about as good as you can get for not bricking the PCM.
Racer
Joined: Sep 2001
Posts: 367
Likes: 93
From: Chesterfield VA
I'm guessing you have not done this then. It is not difficult to someone who understands it but it is to someone who does not. And you can't just get a new PCM for a C4 of any year and especially the LT1 cars.
Racer
Joined: Sep 2001
Posts: 367
Likes: 93
From: Chesterfield VA
I am interested in what you just described, but to be honest, with a PCM that is discontinued and so difficult to get you are crazy to even attempt it with a free program that has the name hack in it or a cable bought of the internet. If the PCM were replaceable I would say it is worth the try but not in this case. Programs are quirky and its possible to even brick a newer ecm with HP or EFI live if you are not careful. For the life of me I would not attempt this on a C4 PCM because of their lack of availability and rebuildable status seems to be almost nil now. At least with LT1 edit it has been around for a long time and proven itself and it is stable.
Safety Car
Joined: Jun 2010
Posts: 4,564
Likes: 1,677
By guessing, you mean assuming and you assumed wrong. Not that I would expect anything less.
You don't NEED a new PCM. You can get a used one and program it.
Race Director
Joined: Apr 2007
Posts: 11,153
Likes: 892
From: South Western Ontario
I am interested in what you just described, but to be honest, with a PCM that is discontinued and so difficult to get you are crazy to even attempt it with a free program that has the name hack in it or a cable bought of the internet. If the PCM were replaceable I would say it is worth the try but not in this case. Programs are quirky and its possible to even brick a newer ecm with HP or EFI live if you are not careful. For the life of me I would not attempt this on a C4 PCM because of their lack of availability and rebuildable status seems to be almost nil now. At least with LT1 edit it has been around for a long time and proven itself and it is stable.
I didn't buy a cable, I use a FT232RL adapter board worth a couple of bucks from Ebay, because that's what you'd find inside a $50-$100 cable anyways.
You also can't even get ECM Edit anymore.
It appears you'd rather just rail against anyone doing it themselves vs following the current state of tuning for these PCMs.
Last edited by lionelhutz; Oct 12, 2023 at 04:58 PM.
Racer
Joined: Sep 2001
Posts: 367
Likes: 93
From: Chesterfield VA
Can you, please tell us where they are available since you know. Every company that rebuilds them is looking for cores on all of them from 90-96 and the 90-93 use a prom chip so there is no cables and flashing those, I can program the prom though, but the 94 and 95 PCM is the same and the 96 is all by itself. Every builder which you can count on a couple of fingers now is looking for cores. Most of the cores are bricked so that can't even be fixed because the items that are starting to go bad on them are proprietary to GM and are not available. So the risk of someone guessing at what they are doing is really a dumb idea, I was just trying to be nice earlier. Unless you are really in the need to have some lawn art then I would leave programming a 94-96 to someone that is familiar with it. Actually the same goes on the 97-98 cars as well, the PCM is done for them but luckily you can modify the harness to use a 99 PCM. The C4 guys don't have that option though so it is better to be smarter and not try to save a buck and end up creating a dead C4.