I'm trying to figure out what controls the single fan on an 86 iroc (5.0 tpi) and diagnos a code 54/ long crank situation... the fan setup on this thing is different than my 87 iroc (it has dual fans)... if anyone has these diagrams or can tell me somewhere I can get them online (I need them pretty quick) I would greatly appriciate it...

zroc

ps is you have the fan diagrag for the dual fan setup it might help me understand why they are different...

 

best thing to do is visit the dealer and
purchase the service manual for that year, make
and model of vehicle. well worth the cost.
saves in wrong part diagnosis.
the computer controls the fan. with a cylinder
head sensor for an over ride. both the temp
and a/c request use of fan. through a relay the
fan is switched on.
the dual fan unit operates the same way, but
one is engine switched and the secondary is a/c
when a/c request both usually switch on.
max airflow at idle across the radiator and
condenser.
airdeano

 

this thing does not have A/C... the dealer says it will take six weeks or more to get an 86 service manual and I need the info in a couple days so I was hoping someone might have the diagrams and would be will to help me out... I'm still hoping... thanks for the info it did explain a little of what I'm missing... I still need the color codes and the control locations though...

zroc

 

Service Manual? Why? That's what we are here for.

Anyway, Your single fan is controlled only by the ECM. There is no relation to the temp sensor in the head as that is only for the temp gauge. The coolant sensor in the front of your intake is where the ECM gets it's info, and doesnt turn on the single fan unless AC is requested, or the temp reaches 230* (or thereabouts) which is way too late in my opinion.

Before I converted to a dual fan setup, I ran a manual fan switch from the light green wire on the fan relay. This is also the ECM ground wire. Grounding the wire activates the relay...so wiring a switch is easy.

Another way to change your fan activation is to modify the programming on your chip, which has become a much more popular method as more and more people have the ability to burn chips.

Hard cranking when? Warm? Cold?

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Mike Metzler (Desert86Roc)[*] Check Out:SpeedWorldMotorplex.com[*] Check Out:Chevrolet F-Body Online Part & Illustration Manual[*] www.MetzlerRacing.com

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[This message has been edited by Desert86Roc (edited November 07, 2001).]

 

this car is for my fiance so I'm trying to get it where everything works like it was intended (I don't want to worry aboutwhen to turn the fan on and all that... basically at this point I'm dealing with a wiring nightmare (the previous owner got a little creative with his idea of repairing problems... I did find the relay but it just dangling with no wiring connected to it (he cut them all off)... it was set up with a switch but it was all fubar so I took that all out... what I need to do is get the wire to the right places on the relay so it will work correctly...

the long crank prob is this... it won't give power to the fuel pump untill the oil pressure switch activates it... and at the cold temps around here it is a real bitch to start when its cold...

I need this thing to be reliable for her so I want it in its original configuration...

also this car does not have A/C...

thanx for the info... its another step further in the right direction... the manual is on backorder so I still need the diagrams...

zroc

 

Sorry, but that it not right.
There are three sensors:
One for the temp guage,
One for the ECM (CTS),
One for the fan (in the right side head below the exhaust manifold) that is what turns on the single fan system.(green wire to the relay)
The dual fan system is somewhat controled by the ECM.



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The sensor on the right side head below the exhaust manifold is the knock sensor on an '86.

 

the place where the fan temp sensor would be (my 87 has this) has a plug in it (looks factory installed, really tripped me out) I'm considering the option of installing my own fan system now (when I get the diagram I can use the aftermarket setup on another car I will be building)...

the long crank is really my biggest concern now... all the relays seem to have a lot of wire colors common between them (its driving me nutz)... I tried slaping a fuel pump relay in on all of the locations to see if the pump would come on when the ignition was turned to the on position but I did not get any positive results (did not hear it kick on)... I was thinking that if fuel pressure was already present in the system that it might not activate (any ideas or thoughts on this?)... my next step will be to try the relay again but this time bleed off the fuel pressure between trys...

zroc