Did the caprices or trucks that were TBI ever have electric fans from the factory? I'm considering a cop car chip, or a thermomaster for a caprice, but I figure it will only work if they had an electric fan too like my car right?

 

I doubt a truck would (reliablity issues). the B-body might.

 

I know the trucks had a clutch fan. I'm pretty sure the Caprice did too. The cop cars may have had an electric assist fan.

 

The only b-bodies to get electric fans were the 94-96 models with the LT1s. No TBI b-body or truck came from the factory with an electric fan.

 

Confirming above. Been thinking of converting to electric to gain a few hp.

 

We had an 89 and 90 cop caprice with the LO5 and it was not electric

 

My '93 Silverado has a clutch fan.
SC

 

so how the heck do you use the caprice cop car chip with a late model TBI car?

 

The 8746 ecm (b-body and f-body) is just like the 7747 (trucks) with TBI, both don't have any control over the fan on temps. The engine driven fans are electronic clutch just like on the a/c compressors. They have their own switch in the passengers side head just like the f-body.
So yeah, the eprom will work with no problems since it has no control over the fan operation.

 

Hmmm, this is an interesting thread...

I just finished up my 350 TBI swap this weekend, LO5 with LT1 cam, TBI, and I am using a slightly modified caprice chip. Now, according to Jon, the chip has no control over the fan, however, the only thing not functioning after the swap is the fan. I had installed a lower temp fan switch 200 on / 185 off when I had the 305, and I just swapped it to the 350. Nothing looks bad with the wiring harness or switch, but the fan will not come on at the specified 200 mark. Everything always worked fine with the 305. It will come on when the AC is on, so the fan itself and related wiring / relays seem fine. I have been using this temporarily as a fix, but I would like to figure out the problem. Without the AC on, the engine goes right past 200, but the fan does come on at about 250 or so. (possibly a safety in the chip to prevent overheating?) Any ideas? I also installed a new CTS, and scanned the car with winaldl, so I know the computer is seeing the correct temperature.

 

When the A/c is on even then the computer doesn't turn the fan on, that's a completely seperate switch. The climate (hvac) controls the fan on/off temp, TBI vehicles and most other older 160 baud ALDL and 4K eproms (2732a) seem to have have any control over the fan operation. When I get into assembly code programming I hope to be able to replace the EGR on/off control of the ecm with a fan on/off control. It wouldn't be hard, just need to hack apart the ecm code and I just don't have the time to do as much reading about is as I would like.
Trust me, ecm doesn't control the fan operation, if it did we wouldn't need that fan switch in the passenger side head! The ecm already has it's own coolant temp sensor in the intake manifold!!! The Guage has its temp sender in the drivers side head and the fan is in the passengers, a/c just turns the fan on with a bypass from the hvac controls.

 

Ok, so any suggestions on where to start diagnosing my problem? How does the fan switch work, exactly? If i disconnect the switch and ground out the circuit, will / should the fan come on? Is there anyway to test the fan switch itself? Any other alternatives? New fan switch, etc?

Btw, Jon.. finally got the chip in a running car, and so far, so good!