I changed my thermostat from the stock thermo to a 160 degree thermostat without changing the chip yet. Ive read somewhere that if I do this my car won't run right until I put in a performance chip. Is this true? Because other than a tune up which my car needs, its not running too good right now. Any help or imput would be apreciated. Thanks in advance.

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SS 17x9.5 wheels,
HOTCHKIS 1"drop springs,
HOTCHKIS tower brace,
Bilstein struts and shocks,
K&N filters,
MSD 6A,
MSD 8.5mm Wires,
MSD Cap & Rotor,
Hypertech airfoil,
SLP intake runner (plennum not ported yet, soon)
High flow cats,
SPOHN panhard bar, lower control arms, and subframe connectors,
Baer front track system,
3" Flowmaster Exhaust System,
2100 Stall High Performance Torque Converter,
300 watt sound system,
and soon to come...ZZ4 crate motor...hopefully.

 

Which motor & year?

Tim

 

I have a 1991 Z28 5.7L

------------------
SS 17x9.5 wheels,
HOTCHKIS 1"drop springs,
HOTCHKIS tower brace,
Bilstein struts and shocks,
K&N filters,
MSD 6A,
MSD 8.5mm Wires,
MSD Cap & Rotor,
Hypertech airfoil,
SLP intake runner (plennum not ported yet, soon)
High flow cats,
SPOHN panhard bar, lower control arms, and subframe connectors,
Baer front track system,
3" Flowmaster Exhaust System,
2100 Stall High Performance Torque Converter,
300 watt sound system,
and soon to come...ZZ4 crate motor...hopefully.

 

The only thing that I can think of that may be affected is the ability of the motor to go closed loop, if the minimum temperature to go closed loop is set higher than the thermostat rating - but it is probably not, from looking at a few '92 PROMs, which should be very close to the same, if not the same as '91 PROM settings. The parameter that specifies the minimum temperature that closed loop may occur at in a '92 Z28 F (LB9) motor, with manual trans, it is 25 C (77 F). A '92 GTA 8 (L98) motor with auto trans, is 45 C (113 F). You may check if the motor has gone closed loop by checking to see when air is no longer being injected at the exhaust manifold ports @ idle, or when air is injected into the converters at idle.

You should also change the primary fan turn on point to 185 F (and turn off @ 167 F), or so, or changing the thermostat will not have much effect on engine temperature, while driving around town during the warm season.

Tim

 

Thanks Tim for the help, but I'm afraid I don't quite understand fully what you are trying to explain to me.

------------------
SS 17x9.5 wheels,
HOTCHKIS 1"drop springs,
HOTCHKIS tower brace,
Bilstein struts and shocks,
K&N filters,
MSD 6A,
MSD 8.5mm Wires,
MSD Cap & Rotor,
Hypertech airfoil,
SLP intake runner (plennum not ported yet, soon)
High flow cats,
SPOHN panhard bar, lower control arms, and subframe connectors,
Baer front track system,
3" Flowmaster Exhaust System,
2100 Stall High Performance Torque Converter,
300 watt sound system,
and soon to come...ZZ4 crate motor...hopefully.

 

There are two rubber hoses leading from the air valves (the air valves are mounted to a pipe that is connected to the air pump) on the passenger side that lead to the catalytic converter air injection pipe and the exhaust manifold air injection pipe. If you squeeze the rubber hoses at idle, the one that is pulsating has air being injected through it from the air pump. If the rubber hose leading from the air valves to the check valve that is mounted to the pipe that goes down to the cats is pulsating at idle, the computer is running in closed loop mode. If the rubber hose leading from the air valves to the air pipes going to the exhaust manifolds is pulsating at idle, the computer is operating in open loop mode.

Tim

 

Thanks a lot Tim. I will check on that. But in the mean time I just ordered a JET stage 2 chip from JEGS This should help. Thanks again.

------------------
SS 17x9.5 wheels,
HOTCHKIS 1"drop springs,
HOTCHKIS tower brace,
Bilstein struts and shocks,
K&N filters,
MSD 6A,
MSD 8.5mm Wires,
MSD Cap & Rotor,
Hypertech airfoil,
SLP intake runner (plennum not ported yet, soon)
High flow cats,
SPOHN panhard bar, lower control arms, and subframe connectors,
Baer front track system,
3" Flowmaster Exhaust System,
2100 Stall High Performance Torque Converter,
300 watt sound system,
and soon to come...ZZ4 crate motor...hopefully.