Perplexing Problem...Can Anyone Help Me Out - Please?

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Jul 3, 2002 | 11:23 PM

rubyred93

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From: NY

Perplexing Problem...Can Anyone Help Me Out - Please?

Hi -

Well, I'm not sure what to make of this situation. Here is what happened: I decided to take the car out for a little ride this evening. Put the key in the ignition, started just fine. About 10 seconds after it started, the FANS CAME ON!

I could not believe it, the motor was ice cold - why in the world would the fans come on? About 5 seconds after the fans kicked on, the "Service Engine Soon " light came on. :crazy:

I then shut the car down, waited a bit, and started it back up. No fans this time and no "Service Engine Soon" light. Decided to take the car out for the drive and did not have any problems.

Can anyone offer a direction that I should go with this? I realize that I should invest in a scanner for this stuff so that I can read the code, but until then - any ideas? I'm at a loss with this. Thanks. :)

Jul 4, 2002 | 12:51 AM

65Z01

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From: SE NY

Cruise-In II Veteran

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (rubyred93)

My bet is you had the A/C on with this heat wave.

When the pressure in the A/C line becomes high it signals the ECM to turn on the fans.

Jul 4, 2002 | 12:51 AM

old salt

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Joined: Apr 2002

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From: port saint lucie florida

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (rubyred93)

did you have the a/c on, if so was it on "auto"? i just tried my '94 . with the a/c on and in the "automatic" mode right after it started the fans and the a/c kicked on about 10 to 15 seconds later it kicked off(due to the setting on the a/c ) . if i start it without a/c on the fans do not come on. hope it helps.

Jul 4, 2002 | 12:59 AM

jfb

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From: Cincinnati, Oh USA

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (rubyred93)

If you could have read the error code then you would have an idea of why the fans came on. When the starter kicks out there is a very large voltage pulse developed. While there is protective circuitry to prevent this kind of electrical "noise" from getting into the ECM, it isn't perfect and every once in a while one of the logic circuits in the ECM gets set and does something goofy. It happens once or twice a year in my 87 and as long as the SES light doesn't stay on, the error code will be erased and your car will run normally. I wouldn't worry much about an occassional burp.

Jul 4, 2002 | 02:28 AM

Bob Mosaic

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Joined: Feb 2001

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From: Denver CO

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (jfb)

the SES light will come on if a sensor is found to be faulty, but if the problem goes away within 10 seconds the ECM ignores the code. Thus, you probably have a sensor on its way out, but no worries.
Cheers,
Robert

Jul 4, 2002 | 03:13 AM

Mike_88Z51

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From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (rubyred93)

A scanner would help, but you may not need one in this case. It probably was due to the a/c like 65zo1 and old salt said. In any case you can short the A&B terminals of the ALDL with a paper clip and see what the PCM/ECM thinks caused the SES light. If it was a transient code you will either have no code set or the PCM/ECM will display the code that was set but is now ignored as transient.

Some codes are forgotten across engine restarts. Some are remembered as transient and ignored on restart. If it was forgotten, you shouldn't worry. If it is retained as transient and ignored on restart it should be looked into, but probably isn't a big deal.

Jul 4, 2002 | 09:13 AM

LD85

Race Director

Joined: Feb 1999

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From: Indianapolis IN

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (Mike_88Z51)

Once, my secondary fan wire on the passenger side had melted & grounded out on the exhaust manifold and my front fan stayed on all the time. Maybe?

BTW, it cracks me up when I see questions about a manual fan switch, just pull back the wire insulation next to the sender switch and wrap it around a screw or bolt or touch to to the block.

Jul 4, 2002 | 10:27 AM

rubyred93

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From: NY

Re: Perplexing Problem...Can Anyone Help Me Out - Please? (ld85)

Thanks for all of the ideas, guys. :yesnod: It's very nice to be able to communicate with other owners that have more experience than myself.

I wish it was as simple as the A/C being on - but it wasn't on. :nonod:

Having a code thrown always makes me nervous; I feel like the car is trying to tell me something, I just have to figure out what it is. :confused:

After restart last night I waited for the SES light to come on again, but it did not. Like others have mentioned, I'm wondering if it was stored or not. A faulty sensor was also something that I was wondering about, so it was interesting to see it mentioned as a possible culprit.

Hmmm....to be on the safe side, I think that I'll take it in to be read/looked over by the guy that works on the car. In the meantime, I should also look for a scanner for such situations. I'm going to start it up later today and see how it behaves.

Thanks for all of your help - always appreciated.

:D