Help with 1995 Trans Am

[Mulletbird]

I have a '95 T/A I got, and the fans aren't coming on soon enough (already cost me a brand new radiator :-x ) and I was wondering if anyone has a hypertech programmer I could use, just for a short while, to reprogram the fan on/off temperatures. I'm sure someone must have one of these things... also, if you know of a cheaper alternative that could reprogram the fan activation temps, lemme know.

THANKS!
- JR

[Anti_Rice_Guy]

I'm pretty sure the hypertech can only be used for one VIN at a time.

[BonzoHansen]

um, fans coming on at OE temps will not cost you a brand new radiator.

you could buy an aftemarket fan controller and take the ecm out of the equation.

[LTb1ow]

Install manual switch, win?
http://www.xious.com/camaro/install-fanswitch.html

[madness410]

why did u have to buy a new radiator. im with matt on this one, get a manual switch or something

[WildBillyT]

um, fans coming on at OE temps will not cost you a brand new radiator.

you could buy an aftemarket fan controller and take the ecm out of the equation.

Right. Don't fix the symptom, fix the problem. What's wrong with the cooling system?

[LTb1ow]

http://shbox.com/1/4th_gen_tech2.html#radflush

Stock fan temp is ~220 btw.

[Mulletbird]

Yeah, idk why they're not coming on with A/C and such. Thanks for the manual install instructions link, and I'll probably go that route. Guy at the shop said, with the diagnostic tools, he could turn them on by manually commanding them on/off, so idk why they're not coming on. One idea is the leaks (upper & lower rad. hoses + radiator cracked and leaking) is causing it to (for various reasons) not activate the fans? We shall see what happens after I get the new radiator and install it. Regardless of whether it works or not, I'll probably still wire it up to operate manually so I don't have to worry about getting stuck in a traffic jam on 76 again without working fans.

THANKS AGAIN, and see everyone (who is going) at the meet at Circus Drive-In!
- Jake / Mulletbird

[BonzoHansen]

So did the tech mention if the ecm was getting a good temp reading? If the fans and relays work, that leaves the ecm. either it doesn't know how hot it (CTS, harness issue? low coolant?) is or the ecm is bad. a manual override is fine. manual only is hack.

[LTb1ow]

So did the tech mention if the ecm was getting a good temp reading? If the fans and relays work, that leaves the ecm. either it doesn't know how hot it (CTS, harness issue? low coolant?) is or the ecm is bad. a manual override is fine. manual only is hack.

Yea, if that sensor is bad, have fun with your gas mileage sucking cause the engine prob is seeing some ungodly cold number if the fans never come on.

If you do decide to change it, make sure you get the correct sensor, the one on the head is different than the one in the water pump. Also, if the car was "tuned" before, someone may have forgot to turn the fans on. Just a thought. Happened to mine.

[Pampered-Z]

Hypertech use to make a fan controller. I've run on for years in my 93, but haven't seen much posted about them in a while? not sure they still make them???

It screws into the passenger side head, then connects into the wiring harness and will turn the fans on 185.

The stock sensor the ECM uses is mounted in the lower/front of the water pump and is independant of the sensor in the driver side head that controls the dash gauge.

[Mulletbird]

Yea, if that sensor is bad, have fun with your gas mileage sucking cause the engine prob is seeing some ungodly cold number if the fans never come on.

If you do decide to change it, make sure you get the correct sensor, the one on the head is different than the one in the water pump. Also, if the car was "tuned" before, someone may have forgot to turn the fans on. Just a thought. Happened to mine.

untuned. It was bone-stock until I dropped a K&N in the factory air box, more for cost-savings than performance. Stock tune I'm pretty sure, although it's not impossible the previous owner is lying and indeed did mod/tune it.

[Mulletbird]

Well, an update. Got 'er outta the shop last night (around 6:30-ish) and took her home, let her cool (and wait for the rain to stop) and around 7:15-7:30 I took 'er out for a quick spin, with light traffic, just to see how she was running and do a quick test-drive before the meet (so I wouldn't get any surprises out there) and ... she overheated. Cracked the brand spankin' new radiator, blew the hoses, and sent a nice geyser of gasseous coolant flying. Took 2 seconds to go from 180F to 260+F. No fans.

I did shut 'er off the instant she went, so we're thinking I got 'er off before I lost the HG, but not 100% on that yet. Still no fans, so Shaun over at NTB's running a diag on her to see if they can get those to work; they came on with A/C but nothing else. Another idea is (the shop in WV) fudged up that thermo when they put in the 180 to replace the 2xx? They ***'d up a lot of other work on this car, so I wouldn't be surprised. (I got written up twice for working on my car in the college lot, and the third time they tow the car ... so I figured I'd take 'er into a "professional" shop)

[WildBillyT]

Well, an update. Got 'er outta the shop last night (around 6:30-ish) and took her home, let her cool (and wait for the rain to stop) and around 7:15-7:30 I took 'er out for a quick spin, with light traffic, just to see how she was running and do a quick test-drive before the meet (so I wouldn't get any surprises out there) and ... she overheated. Cracked the brand spankin' new radiator, blew the hoses, and sent a nice geyser of gasseous coolant flying. Took 2 seconds to go from 180F to 260+F. No fans.

I did shut 'er off the instant she went, so we're thinking I got 'er off before I lost the HG, but not 100% on that yet. Still no fans, so Shaun over at NTB's running a diag on her to see if they can get those to work; they came on with A/C but nothing else. Another idea is (the shop in WV) fudged up that thermo when they put in the 180 to replace the 2xx? They ***'d up a lot of other work on this car, so I wouldn't be surprised. (I got written up twice for working on my car in the college lot, and the third time they tow the car ... so I figured I'd take 'er into a "professional" shop)

Wait. Don't LT1's take specific themostats? Did you use one of those? And aren't LT1 thermos 180* stock?


While on the subject of thermostats, the LT1 reverse flow system uses a special, long thermostat that works together with the passages in the water pump to provide proper coolant routing. If you use an old SBC style thermostat, you run the risk of the system not operating with proper efficiency and it may overheat. Escalating temps can be caused by poor air or coolant flow.


http://www.shbox.com/1/tstat.jpg

[Anti_Rice_Guy]

And aren't LT1 thermos 180* stock?

Yes.

[Mulletbird]

That well may be, but the thermostat that was in there was keeping 'er running at 205-210 on the highway, the new one in there keeps 'er at 180 until I get into the city, then it climbs up. Fans come on at 228 (single, low-speed) and it climbs up to 240-245 before the fans start cooling 'er down.

Water's been boiling over, although we can't find out what from. No smoke in the exhaust, no oil/water mixing, so that's another confusing problem. Hopefully (in another 20 minutes, once it cools) we'll try seeing if we can flush out any more air bubbles that might be left. After that, I saw something on camaroz28 forums:


Credit to 69gto96z on CamaroZ28 Forums for this...

"check the small hoses directly below the radiator cap. The top one should go to the overflow tank, and the bottom one should go to the return line. They are the same size and are easy to mix up. If you mix them up, the car will do exactly what you are describing. I did it on mine back when I first got it, and it took me a while to figure out what was wrong with it."


Gonna try checking that too, something simple and stupid, logical, and would explain all the symptoms, as well as the lack of others. As far as the question of the other sensor, it's reading (+/- 5 degrees) the same as the gauge, so we know that gauge is reasonably accurate for what its worth.

(hopefully) I'll see you all on Sunday. Gonna be a long night of cleaning, washing, and waxing this car after all the mess from the coolant boiling over. New radiator in 'er too...

EDIT> Problem solved. Air bubbles got in the heater core. Took 4 times of bleeding the system to get it all outta there, but it finally cleared up. No more problems after a quick 10-min drive. Fans are operational. Should she pass the 10 minute idle test (see if she overheats/smokes/blows) I'll be taking the T/A out to the meet tomorrow. See everyone there!

- Mullet

[Mulletbird]

More fixes:

new radiator cap (installed last night @ 9pm) to fix coolant seeping around the old cap.
replaced the contacts in the fuse box for the relays

fans are coming on fine now, although hotter'n I'd like (mostly b/c I want this HG to last another 2-3 years, minimum). Gonna follow the advice of others, and start with a manual switch ... 99% of the time, I know before it creeps past 210 that it's gonna be running hot, so should be able to manually keep it where I'd like it (180-210 op. temp).

Elbow (intake) is shot, and it looks like the throttle body could use a good ol' fashioned cleaning, so I'll take care of both of those early this week (as soon as I can get a new elbow... might as well do both at once). Should get some more HP that way too, and one of the cheapest HP mods I'll do yet, I hope, in terms of effort exerted vs power gained. Should be a 14-second car after this FOR SURE.