89 GTA dual fans not working
 

So my GTA usually runs at about 160-180* and I realized the car was hovering around 220*, low and behold I checked to see if the fans were running, of course they weren't. What fuses can I check to see if they're blown? Also, what other areas might I check to see Why my fans aren't powering on.

Re: 89 GTA dual fans not working
 

ALSO, I'm running my car with the MAF unplugged until I get my new relays in. Would this affect anything?

Re: 89 GTA dual fans not working
 

the fan relay is close by the booster... on the left firewall. Check it and make sure the link is good.

Re: 89 GTA dual fans not working
 

if it is... I suggest you test the sytem and make sure it has current with a voltimeter

Re: 89 GTA dual fans not working
 

And having the MAF disconnected I believe will give you either too lean or to rich mixture. Most likely you'll be waisting gas I think

Re: 89 GTA dual fans not working
 

Dual fans run from 2 aspects:

1) Primary fan runs from the ECM - it senses temps from the CTS located by the thermostat housing - if the CTS is bad, fan may not run.

2) Secondary fan is run from the fan switch located in pass side head between #6 and #8 spark plug - has a single wire to it and a mushroom-looking connector. NOT in the block (that is knock sensor with same looking connector), but in the head. ALSO, A/C pressure switch in the A/C lines will turn on secondary fan when pressure is recognized (A/C should make secondary fan run as long as A/C is on and working).

Both fans run off relays - so could have one or both relays bad.

Hope that helps.

Re: 89 GTA dual fans not working
 

Thank you very much for all the input! I'll be sure to check all those leads. Any chance my T-stat went bad?

Re: 89 GTA dual fans not working
 

Yeah the T-stat could be bad but that has nuthing to do with the fans not kicking on when she warms up.. are you gettting power to relays and or fans when warm? kick on your AC and see if the pass side fan kicks on.

Re: 89 GTA dual fans not working
 

So I've learned my drivers side fan is working when the car reaches about 230, and the pass side fan will not turn on even with the AC on

Re: 89 GTA dual fans not working
 

unplug it and put jumper wires power and ground and see if the fan motor is good.

Re: 89 GTA dual fans not working
 

Any idea what temp a 350 TPI should be normally running at?

Re: 89 GTA dual fans not working
 

with a factory 195 t-stat itll run 220-240ish

Re: 89 GTA dual fans not working
 

That's what puzzled me. My car always ran really cool, around 160-170*

Re: 89 GTA dual fans not working
 

My 1989 GTA L98 is doing the exact same thing. Before I go and start diagnosing everything, did you find the solution on yours? Fan relays, etc. I am running a 160 tstat on mine and i run 160-170 driving but 220-240 in traffic and I feel that is too warm in my opinion.

Re: 89 GTA dual fans not working
 

If you run the car in limp home mode the fueling will be high and the timing will be retarded which will cause it to run much hotter than usual.

If you run a non-stock thermostat you need to have a chip burned. The computer has many parameters (including the primary fan) that will not operate correctly at a lower temperature.

Re: 89 GTA dual fans not working
 

Thanks, I will pull the thermostat out as soon as I get back to Texas and replace it with a stock 195. Funny thing is, when I bought the car 3 weeks ago and drove 1200 miles from Nebraska back to Houston, the temperatures were exactly the same. 160-170 on the freeway and about 220-240 while sitting in traffic. Thanks for the info.

Re: 89 GTA dual fans not working
 

At freeway speed the fan is off. The thermostat allowed coolant to flow through the radiator and maintained temp. In traffic the fans will not come on till 215* and 235* IIRC, so hot coolant passed through the stagnant air in the radiator until it got hot enough to kick the fans.

Re: 89 GTA dual fans not working
 

sounds like the primary fan(dr side) is bad or has a power supply issue.
buy this hypercraptastic fan switch instead of a warmer t-stat.
http://www.jegs.com/i/Hypertech/533/4026/10002/-1
also fix your maf problem

Re: 89 GTA dual fans not working
 

The temp affects more than the fan on/off in the chip. The car will not run right without either the correct thermostat or the correct tune.

Re: 89 GTA dual fans not working
 

IF that were true (thermostat) it would have a running problem until warmed up to thermostat temperature. A cooler thermo (180°, pretty acceptable) is warm enough to get beyond cold fueling (mainly affects mpg).
On a unmodified motor/tune, there is no benefit to running the engine cooler. It will mainly drop mileage, slightly, with no real gain in power.
A lean motor and/or, to much timing (to much base time), will make a gas motor run hot.
The ECM runs rich and pulls timing for limp home because it decreases a chance for detonation and a rich motor runs cooler (black smokes). Lean a/f ratio runs hotter and increases chance of detonation. JMO, though.

ECM fan on at 220°F and fan switch is 238°F, for whatever it's worth. .

Re: 89 GTA dual fans not working
 

Cars do have a running problem till they get up to temp. :rolleyes: Idle speed is affected, AE is affected, PE is affected. The stock chip is working off a set of parameters it thinks are correct, if you start f***ing that up the stock chip will not work correctly.

Re: 89 GTA dual fans not working
 

Maybe, if you're running a megasquirt...

Re: 89 GTA dual fans not working
 

So you're argument is that all parameters in GM's ECM react the same way at 155* as they do at 210*?

Re: 89 GTA dual fans not working
 

Obviously not.

Your argument for saying an engine can only run 'proper' though, is like saying the engine can only run correct at sea level though.

The ECM can calculate proper fueling/timing for nearly any given condition so the engine runs proper.

Is that saying it is running at peak efficiency or emission output if it were running 195°, no. It is running properly for 'X' temperature/condition, though.

What 'problem', exactly, does the engine have running cooler ?

Educate me, please. I'm always willing to be wrong and learn.

Re: 89 GTA dual fans not working
 

GM designed the system to run through the warmup cycle until it hit a certain temp.

If you intall a 165* thermostat and jump the fan on (as I would wager a fair number of less-informed members on here are doing right now) your car will never warm up as much as the factory chip is expecting.

So when I see someone suggesting that the OP do this I inform him that he is mistaken. Now you come in here and troll the topic trying to start an argument with me.

You're not a stupid person, you know that these antiquated GM systems are dumb animals. They need to be spoonfed all the information they can't see. If you start changing the nature of the engine without changing the information they see they're just going to sit there doing the same thing and the car will run like s***.

But now you're all riled up and want to argue over the internet because I dumped on your beloved engine management system from the 80's. You need to make this ancient junk work for you, or move on. Stop arguing that it's running at peak efficiency at all times for all conditions on the stock chip, that's just silly.

Best of luck with your 305's. ;)

Re: 89 GTA dual fans not working
 

I would imagine this would be the same senario for an 88' 350 IROC? Thanks

Re: 89 GTA dual fans not working
 

I noticed I believe 3 relays on the firewall near the master cylinder. Is one of these a fan relay that might control the secondary fan? If so, which one? Thanks,

Re: 89 GTA dual fans not working
 

Please re-read what I said and understand it, too.

Re: 89 GTA dual fans not working
 

i wasnt aware the the computer "expected" the car to be at any temp...

it takes the information given and adjusts properly and the car crazy enough runs fine.

its not thinking oh my god if i was 5* warmer i could run so much better :crazy:

the worst thing i see happening when a car doesnt warm up is no heat.

Re: 89 GTA dual fans not working
 

Sorry for taking so long to post, after tons of diagnosing it, it ended up being bad wiring leading off of one of the relays. Replaced some wires and was good to go.