6 bolt swap- 1g cas causes cooling fan to spin? *VIDEO*

[turbo98eclipse]

Finally got around to testing my 1g black top CAS and get ready to start the car. When I would turn the CAS by hand, nothing would happen, so I went to inspect the wiring. Im using the RRE 1g cas into the 2g harness adapter. When I touched the connector, the fuel pressure would go up and things would seem to work as designed when Id spin the CAS by hand... BUT If I spun it fast enough or just fiddled with it enough, the engine cooling fan would come on. If I tried to crank the engine, the fan would also come on. Any clue what this could be from?

1g cas dsm issue - YouTube

####### Just a quick update:

I checked resistance in the adapter harness & checked voltage at the end of the harness for 5v in the two wires: both checked out good.

Im just concerned why the fan turns on when the cas spins/gets a signal. Are they somehow connected or am I looking at a weird short someplace?

 

[luv2rallye]

The fan issue is one of the strangest things I've ever seen. It's almost like a bad ground on the ECU and the CAS is now providing it. Is this on the 96 and is the rest of the wiring all factory? Is the ECU for the 96? Are the fans aftermarket and using stock wiring? Does the fan relay click when they come on?

The connector is obviously making intermittent connection - either a wire has a break in it near the connector or connector pins are not seating properly. Does bending the wires next to the plugged in connector change anything?

 

[turbo98eclipse]

Thanks for the reply rally! I thought I was going to have to tackle this issue solo!

This is on the 96, its a 6 bolt 2.3 stroker swap with a 95 ecu running link v3l. Fan is stock, and Im not sure about the relay, Ill double check for that tomorrow.

I thought it had to do with the connection at the pins as well, so I had bent them back a tad to ensure a good connection, but it didnt help with the issue. Im thinking about hard-wiring everything to see if it makes a difference. Bending the wire doesnt have an IMMEDIATE effect on this, I think its moreso just playing around with it than moving one wire specifically. I did a resistance test in all of the wires of the harness and couldnt find a break.

Any other ideas i should consider?

 

[luv2rallye]

Do a resistance check or better yet a continuity check with the buzzer function on your multimeter of every wire going through the connectors on that harness. Bend the wires and play with the connector while testing to see if the connection is lost or intermittent.

But no matter what that connection is I don't see how it would turn on the fan unless someone seriously rewired the fan circuit or the ECU is bad (since on a 2g it controls the fan).

 

[Infamous33]

Just a thought about this. The ECU would turn the fans on if it sees an overheating issue.
Is the ECT plugged in? When you spin the CAS, the ecu will react as if the engine is running or at least trying to run, and if the coolant temp. is registering high enough, it could turn the fans on to cool it down.
The other idea would be the CAS pulling ground on the wrong line, shorting the ecu into a 'fail safe' mode.
Sort of a stab in the dark here, but it almost seems like the ECU is cycling the fan rather than a gremlin...
Did you do the wire re-pin?

 

[turbo98eclipse]

Im going to go check the ecu as we speak to see if I see anything fried. I dont think it should be, as the cel still comes on for 5 sec and turns off. I thought I didnt have to do the ecu re-pin if I had link and selected "non 95-96 cas"?

 

[Infamous33]

Only asked about the re pin to make sure a wire or 2 didn't get put in the wrong place.

 

[turbo98eclipse]

I check continuity and it was all good. I went to hook up link to RE-verify my ECT sensor was working like it was last monday, and it was reading -74*. I went to check the connector and:

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Lets see if I have another pigtail

#############update:::: the coolant temp sensor was the problem! I have no clue how it was connected one day then broken the next. Luckily I had an extra pigtail on the half cut harness that came with my JDM motor I purchased 2 years ago. I appreciate the help guys!

 

[Infamous33]

Good find man !
Thankfully you didn't start tearing all the harness apart..
Time & electrical tape saved-priceless