M20 not getting to temp

[kronus]

So, I'm trying to get my 89 ix running well enough to pass smog, but I can't get it to operating temperature and it's failing idle smog. Curious if I'm missing something dumb and obvious.

What I'm seeing:
- temp stays at 3/8 on the gauge when idle
- drops to 1/4 immediately when moving, even when driven hard
- high idle HC (219/120 allowed)
- feels a little low on power, but maybe I'm just used to M50 torque
- poked around with an IR thermometer after driving hard at high RPMs for 30m
- thermostat housing hot side is at 75C
- thermostat housing cold side is at 50C
- lower rad hose is cold enough to touch

I'm using an M30 179 ECU with a stock M20 chip in it, but the car was doing the same thing with a stock 153 ECU as well.

I've got a new CTS and thermostat to go on, but I'm not sure that they'll do much. If the thermostat is stuck closed but the motor was working normally, the car would heat way up. It smells a little rich when running, but not rich enough to stay this cool. So, what the heck? Any other bright ideas?

[kronus]

on the list to check:

- fuel rail pressure
- return line openness
- whether some asshole put 19# injectors on this motor and didn't tell me
- AFM fuckery
- plug reading


I guess it's also possible that my cat just sucks. but why the cold running?

[jeffnhiscars]

Has to be the tstat stuck open...or not there.

[e30davie]

Do you understand what a thermostat does....?

[kronus]

Do you understand what a thermostat does....?

me? yes.

[ForcedFirebird]

I'm also going to agree with Jeff. T-stat is stuck open, or missing.

[TobyB]

One more for 'uneeda thermostat'

t

[kronus]

thanks for the suggestion. will find out if the previous idiot left the t-stat out tomorrow night.

in my experience attempting to run an M30 without a thermostat, it got hot rather than cold, though.

[MrBurgundy]

Same thing was happening with my car when I first picked it up.

Was missing a tstat

but had plenty of silicone in there.

[ak-]

thanks for the suggestion. will find out if the previous idiot left the t-stat out tomorrow night.

in my experience attempting to run an M30 without a thermostat, it got hot rather than cold, though.

It's dependent on the engine/rad/hose design for this to happen, but if the coolant is running through the rad faster because of a non-existent thermostat, then it doesn't have enough time to dissipate heat therefore can over heat the engine.

[digger]

It's s myth that water moving too fast means it can't dissipate enough heat

[LJ851]

thermostat. Buy an OE/OEM one too, aftermarket are a crap shoot.