I have an 89 Trans Am GTA that I've been working on for about a year and a half now. I just want this project to be over and done with, I want to drive my car again. Somebody please help me. The problems I'm running into are as follows:
- Oil Pressure Sender leaking (spewing)
- Can't connect aldl to ecm (ECM works fine, I can pull trouble codes, including 12)
- Car is overheating

I can't figure out why I can't connect to the ecm. I'm using windows 2000, latest version of Tunerpro RT, mastach aldl cable, and 730 ads file. The ecm seems to be working fine, because I can pull trouble codes with the paper clip. By the way, I've converted to a 727 ecm (speed density) from the 165. The aldl is on pin B5 by the way(727 ecm).

This is frustrating. The car is overheating. My temp gauge climbs to 240-250 before I kill the car. I know it's getting that hot because my secondary fan turns on to cool the car, but still won't cool it. The primary fan won't turn on, but I know the fan works because it kicks on with the paper clip. The temp sensor for the computer is in a remote thermostat housing because I have converted to an lt1 intake. Could it be possible that I'm not getting enough heat transfer through my cooling lines to affect the temp sensor downstream or the thermostat opening? This is bugging me. Should I drill holes in the thermostat to improve coolant flow and maybe help heat transfer?

A little info on the car.
It has a .040 over 350 2-bolt(balanced).
Holley aluminum heads.
Converted lt1 intake.
230/236 cam 114lsa.
Hedman shorty headers.
Dual 2.5" exhaust
Converted to speed density 727ecm.

All of your help is appreciated. Thank you very much.

 

Does it overheat when it is sitting still or driving?

 

Try a regular scanner such a a Tech/Tech II or SnapOn MT2500 to see if it will communicate. There may ba an issue with the resistance at the B terminal not invoking the correct mode in your ALDL cable.

 

If it's the original readiator the passages may have narrowed due to deposits. I just replaced mine with a stock replacement and the difference was staggering. Also check there are no kinks in the hoses, especially the lower radiator hose to the waterpump. I have inserted a metal coil in mine to prevent it from collapsing.
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If the oil pressure sender itself is leaking and the oil is not comming from whewre it screws in, it sounds like a replacement of the sender would sort that.

 

It overheats whether I'm driving or sitting still. The cooling system builds pressure, but my upper hose from the thermostat housing to the radiator doesn't heat up. I have about 5 feet of cooling line from each head to the thermostat housing. Could this be causing it to overheat?

 

it sounds like you have an air bubble or a stuck shut thermostat. while car is running, tap on thermostat housing with a screwdriver handle. this may make t stat pop open.

 

You could also try just taking the thermistat out and c how it runs.

 

I would just make sure that the t-stat is in correctly. also is your fan switch still in the head for the fan? i know you said you put it in a remote unit but do you have one in the head? also are you running a serp setup? when i built my motor i used a old style v-belt waterpump put my serp setup on it and had a overheating prob.

 

Of course you had an overheating problem. The v-belt water pump is standard rotation (clockwise), and the serpentine pump is reverse rotation (counter clockwise), so the pump just cavitates if it's running the wrong direction. To the original poster, it definitely sounds like a stuck thermostat to me. Try replacing it or just taking it out to see if the overheating stops. This would also explain why your primary fan isn't kicking on. If your thermostat isn't opening, and your temp sensor is in the thermostat housing, it'll never get a temp reading to kick the fan on. The only other thing I can think of for the overheating problem if it's not the thermostat, would be a big air pocket in the cooling system. If this is the case, you need to loosen a hose or fitting located at one of the highest points in the cooling system while the car is running to get the air to bleed out while you're adding more water into the system.

 

I'll definitely give that a try Pat. Thank you very much. I'll keep you posted.

 

on the connection problem with the ECM, check to be certain the data wire is in the right place in the ALDL connector.