GM TBI question.

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GM TBI question.

none
Do any of you happen to know what the coolant temp must reach to go into closed loop on a 1990 5.7L Throttle-body injected Chevy P/U? Would it go into closed loop with a 160 thermostat?

I have a 1969 Toyota Land Cruiser that I have a GM TBI injected 350 in. I have been running a 195 thermostat but I want it to run cooler. I was going to run a 180 but then I saw that A/C Delco has a 160 thermostat for this thing.
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!
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Re: GM TBI question.

Iconcur
just looking at shopkey it says it needs to be higher than 130-150F to enable the TCC. nothing about closed loop
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Re: GM TBI question.

none
Thanks. I couldn't even find that when i searched ALLDATA. I'm going to plug in my scan tool tonight and see if I can figure it out looking at the data.

I was going for a long shot that someone might have known from doing some diag on one of these trucks.
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!
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Re: GM TBI question.

barrym95838
Administrator
I know from personal experience that it's 80 °C (176 °F) and not a single degree less for many of the old OBD1 Caddies, but I'm nearly certain that it's lower than that for most other GM products.  Your idea about using a scanner to see exactly when it happens is precisely what I would do under the circumstances.

barrym95838
EO/EI/LA/BA144107
“Never attribute to malice that which can be adequately explained by stupidity.”
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Re: GM TBI question.

none
I was shocked that it went into closed loop at 105 F.

I got the live data up and started it from cold 75 F and ran it at 2500 RPMs so the O2 sensor would heat up fast enough and it went into closed loop much faster than I thought it would.

I'm going to try a Delco 160 deg thermostat. My only draw back may be that it could take longer to cook my foil rapped burritos on the motor. 
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!
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Re: GM TBI question.

barrym95838
Administrator
In reply to this post by none
none wrote
I have a 1969 Toyota Land Cruiser that I have a GM TBI injected 350 in.
I helped my friend put a 350I 4-bbl in a Land Cruiser about 30 years ago, but we couldn't take it off-road because the harmonic balancer was too close to the front diff.  He sold it and got a Sunbeam Alpine, and I helped him put a Mitsubishi 2.0L and 5-speed in that.  He didn't really need me for either job until it came time to adapt the wiring to get as many electrical things working as possible.  Around that time I was upgrading the suspension and tires on my 1978 Fiesta and pumping up the engine to almost 100 HP (oooh ... wowwww).  I was able to almost red-line it in fourth gear at about 105 MPH on Clay Station Road in Wilton, and it never had a fifth gear, so I guess I could call that a success.
 I have been running a 195 thermostat but I want it to run cooler. I was going to run a 180 but then I saw that A/C Delco has a 160 thermostat for this thing.
Any particular reason why 195° is unacceptable?

barrym95838
EO/EI/LA/BA144107
“Never attribute to malice that which can be adequately explained by stupidity.”
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Re: GM TBI question.

none
barrym95838 wrote
Any particular reason why 195° is unacceptable?

barrym95838
EO/EI/LA/BA144107
I'm thinking 160 for two reasons. One is all the engine compartment heat goes right to the passengers through the metal firewall and floor boards, and the main thing is this thing runs HOT. I know a 195 T-stat and a 160 are both wide open at 230 deg but I'm hoping it will take longer to get there when it is under load.


The thermostat I have in now is acting erratic and going hot with no reason. I'm probably thinking about this too much but its my hobby car so waisting time on this keeps me from other pointless discussions.
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!
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Re: GM TBI question.

Midnightdrummer
none wrote
One is all the engine compartment heat goes right to the passengers through the metal firewall and floor boards, and the main thing is this thing runs HOT.


I feel you on that. I have the same problem with my Nova. Driving that thing on a summer day is miserable. Mine use to climb to 230-235 as well with a 160 thermostat when I had an electric water pump. I switched it out to a $20 Autozone pump and it rarely gets past 180, but its still like running the heater inside.
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Re: GM TBI question.

Iconcur
the guys next door to me install sound insulation and helps with heat a lot. he is a certified vintage air installer. nobody ever had any complaints about heat.
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Re: GM TBI question.

none
If you have carpeted interior then Dynamat and those type work well. It won't work for my FJ40 but may work for Drummer's Nova. I was going to add some to the back of the cab of my Dodge diesel to quiet it down some inside.
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!
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Re: GM TBI question.

Midnightdrummer
Ive already laid down carpet, juke padding, and that other stuff that looks kinda like aluminum foil with tar underneath. Its helped a lot for sound and heat, but it still makes its way through.
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Re: GM TBI question.

none
In reply to this post by none
I got my AC DELCO thermostat today and pulled it out of the Delco box and it says MOTORAD right on it.
I've hit rock bottom but I brought a pick and a shovel and I'm ready to dig!