Bad Performance with no stat?
Thread Starter
Instructor
Joined: Jan 2013
Posts: 212
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Bad Performance with no stat?
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.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
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.
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.
Last edited by QCVette; Dec 11, 2014 at 09:42 PM.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
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.
Last edited by don hall; Dec 11, 2014 at 10:18 PM.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
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.
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.
..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
Last edited by WW7; Dec 11, 2014 at 10:35 PM.
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
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.
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Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
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.
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.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
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
Last edited by WW7; Dec 12, 2014 at 10:09 AM.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
That is not only possibly, it's likely. It's why we have a t stat to set the minimum operating temp.
Thread Starter
Instructor
Joined: Jan 2013
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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.
Thread Starter
Instructor
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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.
Melting Slicks
Joined: Apr 2011
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From: New Jersey
Team Owner
Joined: Aug 2004
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From: Park City Utah
Thread Starter
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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.
Also my fans never turned off until i fixed that plug. I just never gave a $hit. Fans are operating properly now.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
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.
Also my fans never turned off until i fixed that plug. I just never gave a $hit. Fans are operating properly now.
