TVIROCZ

iTrader: (1)

A few weeks ago I bought a 87 IROC 305 TPI and having a few minor probelms with my iroc. First the fan goes on when I start the car right away and it will turn on if I just turn the key and dont start the engine. Second my temperture gauge is not working and sometimes oil gauge jumps up and down. I would like to brighting up the gauges so I would like to change them to LEDS or maybe just get a brighter bulb or get reverse glow gauges, what do you think would be easier to do? Also I was told that my car rpms are a little high when idling. I would like to know if anyone else experienced these probelms and what could be causing the issues and how to fix it.
Thanks.

el_muerte

The fan staying on like that either means that your car is in "limp mode" or someone jury-rigged it to run all the time. If you don't have an SES light it's probably been rigged... isn't it a dual fan setup? If so, you should figure out which fan is coming on... one is controlled by the ECM and the other by a fan switch in the passenger cylinder head. The temperature sensor for the gauge is in the driver's side of the engine; can't recall if it's in the head or the block itself; regardless, it has only one wire running to it. Make sure the wire is in good condition; mine was chafed through and grounding out. If you disconnect the wire you should read a voltage to ground, if you do the sensor itself is likely bad. The oil gauge jumping around is normal (or at least a common occurrence), I don't know if there's a fix. Brightening up the gauges will be a trick; whatever route you go you'll need to pull the gauge cluster out. Your idle speed is controlled by the ECM driving the idle air controller, the procedure to adjust it is found here.

rgarcia63

Check engine light on?
I've worked on a few thirdgens that the fans turned on like that:
1.) ECM was bad
2.) stuck relay
3.) shorted wire
4.) fans were rewired to run all the time.
High Idle, a little difficult, take your pick.:
vacuum leaks
IAC, and or dirty Throttle body
coolant sensor
TPS
MAF sensor

TVIROCZ

iTrader: (1)

I dont think its a dual fan assuming that I only see one fan. Also the engine light comes on once in awhile, it was code 32 or 33, I forget> Dont take the car out much due do a busy work schedule. I just want to brighting up my gauges, really dont want to change them bc I like original gauges and I dont want white gauges. If I can find some cool gauges then i will swap them but I have not found anything. Another question, is it easy to do a true dual on a 3rd gen camaro?

cdoyle

Sorry to bump an old thread, but reading this one brought up some questions about my car.

I have the dual fan setup, the fan on the passenger side turns on as soon as you turn the key. The one on the drivers side, I don't believe I've ever seen that one turn on.

My car will get an occasional code 32. could these 2 be related?

I've also noticed that while driving the temp gauge in the car, never goes past 195. Is that normal?

how are the fans supposed to work? Are they only supposed to come on under certain conditions?

Could any of these be linked to why I'm getting the SES light occasionally?

Thanks!
Chris

rgarcia63

One fan is controlled by the ECM and shouldn't turn on until the coolant reaches a preset temperature. if it's turning on right away it could be a short, faulty relay, and or ECM.
The other is a heavy duty high temp (230 degrees, or so) fan which is turn on by a temp switch in the passenger side head.
Code 32 is EGR.

cdoyle

Ah OK, so neither fan should do anything when the key first turns. Did not know that. I always thought the fan that wasn't going was just bad and was going look for a replacement. Instead that one might actually be working the way it supposed to work.


Where is the relay for the other fan located? How often do ECM's go bad?

el_muerte

The relays for both fans are located together, roughly between the battery and radiator. Either fan could have been wired by a previous owner to run all the time; if the secondary fan is the one that comes on then the primary one controlled by the ECM could be completely fine, and just never need to come on due to the temps staying low. If your ECM is bad, odds are your car will be running in "limp mode," where not only does the fan stay on, but timing is retarded, extra fuel added, and the torque converter will not lock up. It should be pretty obvious from the lack of power if it's in limp mode. Otherwise, I'd recommend just following the wires to the fan relays to see if something looks out of place.

cdoyle

Thanks for the info, I don't believe the car is in limp mode. It feels like it has pretty good power, and accelerates OK.

do you happen to know which fan is which? When should the drivers side one come on, and when shoudl the passenger side fan come on?

Could the coolant temp sensor be causing it to come on right away? What I mean is, could it be telling the car it's hotter than it really is?

cdoyle

so today, I was trying to find the coolant sensor (haven't found it yet) but looking down on the passenger side toward the back. When shine might light down, I noticed what looks like a yellow wire that is cut.

Looking at my book, from the ECM to the coolant sensor is a yellow wire.

If this circuit is open, would that cause the fan to come on all the time?

I need to get some jack stands so I can get under there, and see if I can fix it. but just curious i that condition would cause it to run all the time. Would that tell the car it's running hot?

I've attached a pic of what I can see from the top. Wish I had some jack stands here today.

el_muerte

I don't remember offhand which fan is which, and my car is under some snow right now so can't really check.

The fan switch turns on the fan by grounding the wire - if the wire is cut, that fan won't come on unless the relay is being grounded from somewhere else.

Here's a wiring diagram for the dual fan setup.