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Discussion Starter · #1 ·
Guys need help my 92 RMW is sick ,not feeling good.Its at the shop being probed and scanned finally.I've searched in the options and all I can find is obd2 info.Wagon is runing rich and change the single new o2 bosch with new delco o2 sensor . Does anyone know when open and closed loop ocur on the LO5(350v8 TBI) not the LT1.
 

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The nice thing about the Roadmaster is that you can get the codes without taking it to the shop. You can read them right out of the climate control. You can also check things like real time coolant temp. This will show you when the thermostat opens, which would roughly correspond to closed loop operation.
 

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Closed loop occurs when the engine coolant temp is around 160 degrees from what I noted. IF the coolant temp Under 150 degrees after being warm, its in open loop.
 

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Discussion Starter · #4 ·
The nice thing about the Roadmaster is that you can get the codes without taking it to the shop. You can read them right out of the climate control. You can also check things like real time coolant temp. This will show you when the thermostat opens, which would roughly correspond to closed loop operation.
I thought this climate control opition only works on obd2 LT1 94 to 96
 

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Discussion Starter · #6 ·
On TBI cars, if you put a jumper between pins A & B on the data link connector (12-pin connector under the dash), the service engine light will flash codes like so: http://www.troublecodes.net/GM/
Thanks,I have no codes present.My tech as a snap on scanner that reads it all ,I just want to put him in the right direction on what to look for on our cars.He mainly plays around with acura vigors and bmw.
 

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The climate control data works the same for the 91-93. You don't need to jumper the connector. BTW, 94 and 95 are still OBD1.

 

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The climate control data works the same for the 91-93. You don't need to jumper the connector. BTW, 94 and 95 are still OBD1.

YouTube- 1994 - 1996 Buick Roadmaster climate control diagnostics

I completely forgot about that video, thats my car there and my friend made it.

Did you try unplugging the battery after replacing the O2? I bought an autoxray 3000 scanner for my older cars. It interfaces with the older OBD systems and lets you view the sensors in real time. It was a worthwhile investment.
 

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Try pulling the stud out of the manifold at the thermostat, and cleaning it really, really, really good. Wait until the engine is cold so you do not have pressure in the cooling system. It is the ground for the ECM and the O2 sensor (G103). Mine was running max rich, and when I cleaned the stud, threaded hole, and lugs for the wires, it instantly started working correctly.
 

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And, while you are doing that, pull your thermostat. I had a sticking thermostat on my 92 RMW, and it would not heat up enough. Bad gas mileage, high emissions.
 

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Pull the plug on your CTS (coolant temp sensor) and if it clears up that might be dead and need replacing, that will cause a fueling issue.

EBL Flash is your freind. :) Get it.

BTW it will not show a CEL just drive you crazy.
 
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