ktace

I have 95 z28 bought a used 96 z28 motor due to overheating my last motor i put bit in everything runs good but ses and low oil lights come on went to local auto parts store and said they cant scan it cause they dont have the right one. Temp guage only goes up to the quarter mark when warm

ktace

Also can smell gas fumes once in while

ACE1252

I think this really belongs in the LT1 Tech section.

Are you having the low oil level light coming on? What is your oil pressure reading at idle? Are you still running the '95 PCM?

Injuneer

Your 95, assuming you kept the original 95 PCM, has an OBD-I PCM, and an OBD-II style 16-pin ALDL connector. You need an OBD-I scanner, with the correct 12-pin -> 16-pin adapter, or you need to jumper the pins as shown by Shoebox:

http://shbox.com/1/xraycable.jpg

The low oil light doesn't involve the PCM. The sensor sticks in the side of the oil pan. Have you checked to make sure the harness connector is plugged into the sensor, and the wires are not damaged?

http://shbox.com/1/low_oil_sensor.jpg

The coolant temp sensor for the gauge is in the passenger side head. It also has nothing to do with the PCM. With a scanner, you can compare the coolant temp reported to the PCM by the coolant temp sensor in the water pump housing. 1/4 of the gauge is approx 185*F which is possible with a 160* t'stat and reprogrammed PCM fan on/off temps. Is your PCM stock? Is the t'stat stock (180*F)?

ktace

Sorry ace im a newby i have no idea how to use the site also the low oil light will come on and stay on sometimes and it turns off sometimes. Im not surewhat tstat is inthere i had my dad take it one day ithink he took it to his buddy and he said the pcm was reading -4 degrees

Injuneer

The PCM can display numerous operating parameters and sensor readings. A reading of "-4 degrees" would sound more like a value for knock retard. Or did he possibly scan for the oil temperature reading? That will show up as about -40-degrees, since there is no oil temp sensor used on an F-Body LT1. Only the Corvette LT1 has an oil temp sensor.

In any case, if his buddy was able to connect a scanner, you might want to check back and see if he found any codes.

ktace

What is a value for knock? And yeah im not sure what he was talking about to be honest i dont thinkhe even knew or i just misunderstood what paps said but ill get it checked and see what codeit throws me also are you talking like a knock sensor its reading there is a false knock? Sorry im not a mechanic and may be diffucult lol

ACE1252

Ktace,

If you are not good mechanically/electrically then you need to get someone to help show you the ropes.

You didn't tell us if you are still using the '95 PCM. I would assume so....if so, did you transfer the knock sensor from the 95 engine to the 96 engine?

The 96-97 knock sensors are different from the '95 and down. If you are running a 96 engine, without switching that sensor, you very well could be running the incorrect type knock sensor.....that could be causing the knock reading.

If you do need to switch them, be sure to use a torque wrench to tighten it to the correct value(14 lb/ft...this is VERY important) and also, be ready for a coolant bath.....even when draining the coolant from the radiator. There will be plenty left in the block(coolant sensor goes into the water jacket).

On my low oil light question, I just wanted to make sure it was a low oil level light issue and not a low oil pressure issue. Assuming it's the low oil level light, as Injuneer mentioned, the low oil level sensor is simply a switch type sensor. It is either closed or open. If the oil level is fine(check with dip stick), then buy a new oil level sensor and carefully replace it(will need to drain the oil first).

You can verify the low oil level circuit operation by pulling the plug off the sensor...the light should come on. Take a piece of wire and short both terminals in the plug. The light should go off.

For the scanner issue, if he told the autoparts store that he had a '96 engine in the car, then they may have tried to scan the car with an OBD II scanner. Tell them that you have a '95 and to use an OBD I scanner(if you are still running the '95 PCM).

ktace

Thanks alot ace yeah im not completely dumb founded when it comes to this stuff theres just alot of little things to know like you said need someone to show me and yes i will get the low oil level sensor changed and check into the knock sensor also yes i am running the 95 pcm still

ktace

Alright i did misunderstand what my dad said he said it read -32 degrees on the coolant temp sensor and it is running rich? Due to that? ? Also it said the right o2 sensor was not working and it is plugged in so would that be bad obviously?also the knock sensor was changed over

ACE1252

If the PCM is reporting a low coolant temp check the PCM coolant temp sensor in the water pump for proper operation. An O2 sensor not working is a problem that does need to be fixed as well.

How did you find out that the PCM is reporting a low coolant temp of -32*? If you can see that in the PCM, you should be able to pull codes from it.

ktace

My dad said he had his buddy hook itup and thats what it read and he said he cant remember t
What code it read its more convienent when you just have it done in front of you instead of taking the info from.other people but thats what he said it read was -32 degrees.also ace its not hard to replace and o2 sensor is it?and the oil sensor thats causing the low oil light to come on will be easy replacements?

ACE1252

With the oil drained, the oil level sensor should be easy....just don't over tighten it when installing the new one. I always use a torque wrench whenever I can(16 lb-ft for the oil level sensor), but snug is what you want......don't put He-Man like force into it.

Here are other torque specs if needed...
1994 LT1 Torque Specs

Sometimes O2's can be tough to come out. I've got one in my stock y-pipe that has not come out, nor will come out, without heating it up with a torch. I would advise that you let someone with good mechanical experience do the O2....the last thing you want to do is round off or break off the sensor in the exhaust manifold.

Before going too far with the O2 replacement, make sure it's plugged up. They can be easy to forget sometimes.

ktace

Okay thanks alot ace i will get those taken care of and keep you updated and let you know if my lights came off