octaneforce

So over the summer my 89 was running hot like most l98s. I ended up removing my stat completely to mask the fact that i needed a water pump. I did the pump a few months back and with no stat the temps were pretty low (160-180). Now its getting cold here on long island the engine temps are really really low (100-130) and my car is stumbling at low rpms. It bucks and just runs rough when getting off the clutch. High rpms seem ok. Could these low temps be messing with the computer? I also suddenly have a check engine light which no mechanic seems to have the scanner to read the codes.

QCVette

You can pull the codes with a paper clip to connect two pins in the ALDL connector. See:
http://www.corvettephotographs.com/c4vettes/ecm.htm
Or
http://www.corvetteforum.guru/module...topic_id=20212

The low temperature may not be enough to cause the computer to go into open loop and read the sensors. I think that happens at about 140°.

Good luck.

don hall

Eng temps of 100-130 do not exist, even with ice cubes in the radiator, except during warm-up.
No tstat just means it takes longer for the coolant to reach operating temp.
Winter temps could keep coolant temps around 180
after warm-up. Might be time for a new temp gage.

WW7

I think you mean it's not going into closed loop.....

The OP needs to put a thermostat in his car as soon as possible because at those low temps, he's getting excessive wear on his motor, also his oil isn't getting hot enough to burn off the condensation which can cause sludge and early bearing failure......The stumbling is probably because the car isn't going into closed loop like mentioned above, not having a thermostat installed can cause many problems..WW

ex-x-fire

I just want to know how low his average mpg reads. Low coolant temp=bad mpg.

octaneforce

Ran the codes and got a 15 and a 32. 15 is a low temp coolant code (what a surprise) and 32 is an egr code.

octaneforce

Also just found a broken wire at what u would think is the egr tube. Looks like somebody tried to solder this once before.

bjankuski

Check the code and put a T-stat back in, if you do not want to put the 195 stat back in put a 180 back in. The car goes into closed loop around 122 degrees, and if you are running below that temp it could cause some running issues. You also need to see what the code is and eliminate that issue. Also as noted you really do not want to run the engine that cold for extended periods of time, due to accelerated engine wear and oil temps that do not get hot enough to burn off condensation.

bjankuski

FYI, he could see temps that cold without a T-stat, my car will run engine temps between 80 to 100 degrees below ambient, if it is 30 degrees outside I could believe 100 to 130 engine temps without a T-stat.

WW7

When I had the 160 racing stat with the 3 large holes in my 383, I had temps down to slightly below the thermostat setting in cool weather..As soon as I saw this I changed it out for a higher degree "normal" thermostat..WW

Tom400CFI

That is not only possibly, it's likely. It's why we have a t stat to set the minimum operating temp.

octaneforce

I threw in a 180 degree stat and soldered the wire back onto the egr tube. I disconnected the negative battery terminal for about a minute but i keep getting the same codes. 15 and 32. I dont understand why its still throwing a low coolant temp code. Unless im just not clearing them.

Tom400CFI

Are you getting up to operating temp now?

If so, I'd check the coolant temp sensor circuit.

octaneforce

Yeah its finally getting warm now. Top rad hose is cold until the dash reads 180 degrees and then the top hose gets hot. So the stats opening correctly and i could only assume that the dash reading is pretty close.

Tom400CFI

Sounds like its working right now.
So I would check the coolant temp sensor and circuit.

octaneforce

The sensor in the rad is the "low coolant level" sensor right? Would I have to check the coolant sensor in the side of the block somewhere?

DinoBob

Correct.

The poster here was right. Don't run your car without a thermostat. Especially in winter. His reasons were spot on.

Tom400CFI

The coolant temp sensor is at the front of thee intake manifold -near the thermostat housing. Test using this chart:

octaneforce

I took a look near the front of the intake and noticed the plug was broken off the sensor. Rigged it on with a little electrical tape and my check engine light is off now! Car seems to be running alot better too. Thanks for the help!

Also my fans never turned off until i fixed that plug. I just never gave a $hit. Fans are operating properly now.

Tom400CFI