ecm

[diesel1456]

Hi just a quick question, i have an 89 c4 conv. Where is my computer chip located and is it a big deal to unplug the stock one and put in a modified one and does anything have to be recalibrated or does it do it by itself. Like cooling fans kicking on earlier and so forth.
Thanks Rich

 

[Edmond]

Rich,

The computer chip is located behind the bread box. Where the passengers feet would sit, above that is a panel that you have to remove. Remove that panel and you'll see a rectangular box held in by two small bolts. Remove the two bolts and a metallic box will slide down.

Do no pull too hard on the metallic box because on the top end of it are the connections from the chip housing unit to the rest of the car. Remove unplug the connections from the top of the chip housing unit. Remove the two screws that hold the metal panel on and you'll see the chip. Putting the chip back is is just the reverse of what you've just done. The metallic housing unit can only go in one way so you can't mess that up.

But before you do any of that, make sure that you unplug the negative terminal from the battery!

In all, it can be done in less than 15 minutes if you take your time.

 

[diesel1456]

thanks so much
Rich

 

[Edmond]

Rich,

Did you manage to get to the ECM?

 

[diesel1456]

yep job complete but the only thing is my fans still came on at 200 i thought they would of come on at 180. i am going to put the 160 stat in anyway in a few weeks maybe that will keep the temp down a little more.
thanks for your help
Rich

 

[John Robinson]

Whats your objective

Are you doing this because you believe the temp is to high? On my 93 the water gets to 220 before the fans kick in and the oil gets to as high as 235 at times in the summer. On the early models of the C4 I believe all the L98 (someone correct me if I am wrong please) the car had an oil cooler with the advent of the LT1 Gm removed the oil cooler. They found out that the oil temp would run in the same temp range as before with the use of Mobil one. Therefor they were able to reduce the cost of the oil cooler and the cost to install it at the assy plant. I personnely would not change anything to alter the operating temps. If they had only given the C4 owners idiot lights we would be driving along without overloading our fear sensors. Thats my take on it anyway.:W

 

[Edmond]

The reason why it runs so hot is for emissions.

If you use a bottle of Water Wetter, it will drop the temperature down quicker after you get moving. It will not keep the temperature low when you are standing.

 

[diesel1456]

i plan on putting a bottle of that in when i do my stat.
thanks again
Rich

 

[gmjunkie]

Are you doing this because you believe the temp is to high? On my 93 the water gets to 220 before the fans kick in and the oil gets to as high as 235 at times in the summer. On the early models of the C4 I believe all the L98 (someone correct me if I am wrong please) the car had an oil cooler with the advent of the LT1 Gm removed the oil cooler. They found out that the oil temp would run in the same temp range as before with the use of Mobil one. Therefor they were able to reduce the cost of the oil cooler and the cost to install it at the assy plant. I personnely would not change anything to alter the operating temps. If they had only given the C4 owners idiot lights we would be driving along without overloading our fear sensors. Thats my take on it anyway.:W

That's a BIG 10-4!!