Stephen3D

I just bought a 95- this is my first Vette and I love it! Might be a lifelong car choice now. Anyway, while driving a few days ago I noticed the engine temp suddenly spiked! Before that she ran very cool (between 190-210 in 104 degree weather in stop and go traffic).
I went through the system and found some debris in one my fans- came out easy enough. I also replaced the thermostat with a 180 degree and drained the coolant. After that I found that fans wouldn't come on so I figured it was the fan switch. I picked up an upgrade kit from the local specialty shop- it went in easy enough.

Here's the problem:
The instructions said the switch should be between the 1&3 plugs on the cylinder head on my 95. It was nowhere to be found. We traced the wires on the fans to the front of the engine below the thermostat. We found the bad fan switch (it was clearly broken). We swapped it out and sure enough the fans come on perfectly.
Any thoughts about why the switch would be down there?

The car runs great now (aside from starting hard- it takes a few extra seconds to turn over). However, the "service engine soon" light is on. I heard that this happens if you use the kit on a 96 but mine is definitely a 95 (at least that's what the VIN says).
Any ideas?

Thanks for any help.

-Stephen

STL94LT1

The temp sensor on the water pump controls the fans on/off and the digital temp gauge. The one in the head just signals the analog temp gauge.

Also, I would pull the "upgraded temp sensor" and install the right coolant temp sensor (CTS). Then your SES light will go away.

Blue89C4

Nice to see another local C4! Welcome to the Forums.

rodj

Some '95 owners have reported their cars were OBDII ( the computer system used '96+ )
With OBDII there is feedback to the computer if the fans operate without the computer commanding them to.
With earlier OBDI there is no feedback

STL94LT1

There were no 1995 OBDII Corvettes!!!

rodj

Losing your memory

http://forums.corvetteforum.com/1562699991-post11.html

STL94LT1

94/95 LT1 Corvettes used an OBDII style ALDL, which is just a connection point to communicate with their OBDI PCM's.

rodj

But as noted in that post you participated in '07;
'95's had some OBD2 stuff so seeing he is now getting the light up it is possible the fan run is one of them ?

STL94LT1

Most of the "OBDII stuff" is just emissions related.

I have a friend that installed a manual fan switch on his 94 and constinently throws a code, don't think it is anything special with the 95. If the fan is on and the PCM hasn't sent out that command, pretty sure it will throw a code.

Also, the PCM uses a signal from the coolant temp sensor to help control the engine. Who knows what this aftermarket sensor is doing to his engine's operation. Maybe that's why it doesn't want to start like it should.

Stephen3D

Thanks! I got a great deal from a Toyota dealer of all places! They had no idea what was on their lot.

Stephen3D

Thanks for all the tips.

The guys at Corvette Specialty are the ones who sold me the new cooling fan switch so I'm taking my vette down to them today.

Once she starts, she's better than ever. Just need to get passed that hard start. I figured the SES was nothing to be overly concerned about, but I'll have them look into that too.

Thanks again! I'll be sure to post their findings!

larry00

These computer cars are great until they are a pain !
You replace the Boise System you throw a code and get service engine light .

The 95's are all OBD1 and getting a jumper to read the codes is horse of another color.

Since your cars engine management system is designed around sensors like proper temp thermostat , knock sensor and Oxygen sensors you are defeating the computer which assumes it is cold/hot and adjusts fuel/ air to compensate and a cold water temp which should be high to increase fuel burn also fools computer into putting in more fuel and decreasing fuel mileage possibly washing cylinder linings .

Best keep it close to stock with stock replacement parts unless you want to mod it and go wild and crazy !

Lrod

I'm in Montclair by the 10 fwy, we should meet up & shoot the