mike40sm2

Hi I have Camaro TPI Z28, Just fitted a 5.7 engine from 88 Trans am, I have deleted A/C and smog controls, Having problems with single cooling fan running as soon as i start engine and runs continuously. Not sure why this is,?
It was fine before engine change. Is it a problem with the deleted A/C do you think ? also I do not have the cars heater connect at the moment all wires are just disconnected from A/c and Heater at the moment. Has anybody else have any issues like this please.
Cheers

deadbird

When the a/c as removed, a blue wire on the fan pressure switch needed to be grounded. its was part of a harness plug on the hard a/c line....

Ozz1967

iTrader: (4)

Also make sure the green wire that went to the fan switch in the head is connected properly and not grounded. Some times they get cut or burned to the header and ground that way.

mike40sm2

Thanks Guys will check out the suggestions and come back to you all.
I know I have not grounded the A/C Wire so that could be it cheers.

keykey

Can you tell me more about this wire,why you should ground it and what it does?

I have my fans running when they shouldn't. They always run when they should, but they also run sometimes when they shouldn't. For example they run when I cold start. I have replaced CT sensor, fan switch, ECM, relays and none of it fixed the problem.

mike40sm2

UPDATE

OK These are my wires, My color is not as your so need to do some investigation work to find the correct one My colors are purple/black and brown and black ?

killer777

There are only a couple ways the fans come on. There is an ac switch if it's grounded(For if the condenser reaches a certain pressure I believe), a switch in the passenger side head between cylinder #6 and #8, and the ECU for some years controls the other fan with a green/ white wire on the passenger side harness. So, if one of these wires is constantly grounded when it shouldn't be, the fans will come on. Check out http://www.austinthirdgen.org/?pid=19 and there will be wiring diagrams for your year so you can find what wires you are looking at.

deadbird

85-87, the a/c fan switch, shown above, was a ground input to the ecm. When the a/c was turned on, the switch opened at 'X' psi and the ecm turned the fan on. When the a/c switch is removed (or on a non-a/c car), the blue wire needed to be grounded to prevent the fan from running (open ground=a/c on).

88+, the fan request was reversed. The circuit is normally open and fan request is made by grounding the grey (iirc) wire.

Those look more like the plugs that went to your (probably) no longer present air pump diverter valves.

The fan pressure switch does not use that style weatherpack connector. The fan pressure switch looks like this.. http://www.wiringproducts.com/gm-a-c...tail-1-pc.html

I may be wrong, and this is assuming the 86 ecm/harness is being used here, but, iirc, 86 tpi did not have a redundant fan switch (like the v6 cars) since they were single fan.

mike40sm2

Yes using 86 harness, The original engine was a 5.0, it was only running a single fan. Now has 88 5.7 out of Pontiac, which is basically a Chevy engine anyway.

I have re installed the Single fan,but the fan now runs as soon as I start up. if I just turn ignition on fan will not run, its only when have engine running.

Thanks I will re look at wiring again, at the moment I have one wire going to I assume is the fan switch just under manifold, On drives side.

I will not give up lol

mike40sm2

It's looking like it would be easier just to run a complete new fan control relay and sensor

deadbird

You could always find it at the ecm...