Brant84

I have a 95 z28 i pulled the engine to replace the head gaskets. Engine is back in and runs great but wont come up to temp. The cooling fans come on along with the ses. Ive talked to a few people and i have checked the fuse for the air pump, unpluged it replaced the thermostat and both coolant temp sensors. Finally got a scanner to read got the 29 eas electrical system failure. Dont know what to do or what to check next. Any info would be great.

shbox

A good fuse and relay in the AIR pump circuit should keep the code 29 away. You don't indicate where you live, so it makes it hard to know what ambient temps you are having. If it is a cold climate, the constant fans may keep the engine cooler than normal. A scanner would be helpful to compare gauge and PCM indicated temps. You also should make sure the system is properly bled of air.

Brant84

I live in anderson indiana. Ive bled the cooling system after i flused it again. It didnt do this before i pulled it so i didnt know if it was possibly a vac problem or what im not that great at electrical so.

Brant84

As of right now the air pump and the air shut off solenoid are both unplugged and didnt make a bit of difference.

Brant84

I changed that relay and so far so good! Thanks!!!

Brant84

okay on my way to work and it did it again swapped out the relay again just to be sure and its still doing it please help me

nofun

Your thermostat sets the running temp of your engine(if running cold). If the thermostat
is closed no water is moving throught the system letting the engine to warm up to operating temp. Your fans can run all the time, if there is no
water moving through the system ( thermostst closed) the engine should
warm up. I would say thermostat is bad or you have coolant bypass
the thermostst sum how. ( maybe head gasket ?)

Brant84

ive already replaced the thermostat I unplugged the fans and the car got up to normal temp set there for a min and then the thermostat opened and dropped it to just above the first mark so im assuming the thermostat is working properly. when the fans aren't on everything works like normal but when they are plugged in they come on a little over 160 deg and then the temp wont go above it.

I have just replaced the head gaskets. hooked up a pressure tester and am not loosing any pressure. yesterday I changed the relay and it was doing like it was suppose to getting up to a little over half before the fans would kick on had good heat and everything was fine started it up this morning and the problem was back.

shbox

Has there been any custom programming done? Maybe the fan temps were altered. You should still use a scanner to compare the PCM observed temp vs. the gauge.

ahritchie

iTrader: (1)

^What he said, my temp gauge stopped working even with a new coolant temp for sensor for the gauge; now I have a gauge pod with a aftermarket coolant temp gauge (it's more precise anyway even if slightly ghetto)

Besides, cool is good for the LT1 making power! Just wait till a 95 degree day in summer and your stuck idling in traffic, you won't have any "too cold" issues

Brant84

no it hasn't had any programing. it blew a head gasket last fall right before I got ready to put it up and everything was fine before that happened. ill keep tryin to find a scanner to read it but I cant see the gauge being off by much because the heater is only putting out luk warm heat but yesterday when it actually came up it was blowing out good hot air.

RogueLT1

iTrader: (2)

sounds lile your computer is thinking that the engine is running hotter than it actually is. check your sensors again and make sure they are reading accurately. if they are corroded or have broken or kinked connections, it could be messing with the resistance and throwing your readings off. you can use a dvom to check the resistance in the sensors and compare it to spec.

nofun

Maybe the thermostat is bad, it would not be the first one bad out of the box. The thermostat is the only thing that would let the engine run to cool.
Also if the fans are coming on there nothing wrong with the relays.

Brant84

ill do some more checking this weekend and see what happens I appreciate the advice guys thanks a lot!!!

jsflyrv

What is the temp of the thermostat you installed? LT1 like a 190° thermostat.

shbox

180° is the stock thermostat rating for LT1s. They definitely don't like anything hotter.

Brant84

I finally found it. A rookie mistake should have caught it earlier. The ground strap for the engine to the frame wasnt grounded right. Cleaned them up and cleaned up where it hooked to the frame and evetlrything is back to normal. Thanks alot for the ideas and the advice guys i really appreciate it!

RogueLT1

iTrader: (2)

after i did my floorpans, i rubberized undercoated all of them to reduce noise and protect them a little bit better. went to start it and wasn't getting fuel. couldn't figure out why. turns out we had a similar problem. ground some of the undercoat off of the grounding point on the floor and resecured the strap and it fired right up. should have thought to suggest that to you sooner. sorry!