Momar

I have an 85 T/A with an lg4 and am changing motors but sticking with the ccc. I was wondering what are all of the sensors because I want to replace them all. I have heard that I should use a different knock sensor for a 350. Can I use the one from the tpi's? Thanks for your help and if possible I need this soon.

Ben

Tim Burgess

Here are the wiring diagrams for an '85 LG4, on line:

http://www.geocities.com/vtcamaro/Wire-Diagrams.html

The basic ECM sensors are: CTS, TPS, baro sensro, vacuum sensro, oxygen sensor, and knock sensor. I'd stick with the '85 knock sensor meant for that ECM - unless the 5.7L Vette used that same ECM part number with a different knock sensor.

Momar

What is the baro sensor, and where is it?

Thanks for your help

Ben

Momar

Oh, and where is the tps on a lg4 being as it is carburated. Is it built in to the carb. I know that there are wires that run to the carb.

Thanks again

Momar

Ok, I figured out where the tps is, but have another question. I thought that since the 305 and 350 resonate different I would have to use one from a 350 or will get a lot of knock retard. Is this true. Does anyone else know which knock sensor I should use and out of what kind of car and what year.

Thanks

Ben

Tim Burgess

The barometric pressure sensor is a small (approx 3" x 1.5" x 0.5") black rectangular sensor with a 3 wire plug connecting to it. It is usually mounted near the cowl area under the hood - above and to the passenger side of the distributor. Go to your local GM dealer & see if an '83, '84, or '85 Vette uses the same part number ECM as your '85. If it does, buy the knock sensor for it. Also verify that the ESC (electronic spark control) module, which the knock sensor connects to, is the same part number between the Vette & your '85. If it is not, then you will need one of those, as well. Finally, you may want to get an aftermarket PROM from Hypertech, for example, for the Vette to optimize the spark curve.

Momar

I thought that was the map sensor. I was told that it has both and the parts store showed both for my car. I have only found one. They both looked like what you have described a parts store. The only visual difference was the color of the plug. Do I need both of these or just one? I know where the one on the mounted hanging off of the overhang from the firewall is(green plug) but is there the another anywhere(blue plug) or was it for a different car. Thanks for your help.

Ben

Momar

Oh, and I called autozone, and the lg4 and 305 tpi take the same knock sensor so I figure that I can use the knock sensor and esc module or whatever from a l98. Thanks for your help.

Ben

Tim Burgess

The way to differentiate between the MAP (vacuum) sensor and the baro sensor is to look for a hose connecting to manifold vacuum on the MAP sensor. The baro sensor has no hose connecting to it, since it is reading atmospheric pressure relative to to a closed cell within the sensor. The MAP sensor may be located on the driver's side, under the hood, near the brake booster.

Momar

Well that clears it up some, but I already knew where the map sensor was, I just need to know where the baro sensor is.

Thanks for your help

Ben