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I have been plaged with TPI problems and have changed about all the sensors including a rebuilt ECU and 02 sensor. but the engine will not idle smothly unless I disconect the 02 sensor.
Also what is this board called that the prom connects to in the ECU?The engine has been running good for 5 years and all of a sodden it rough idles and stalls out.
That is an adapter that allows an aftermarket chip to be used with the factory memcal/eprom (the tan bit connected to the adapter). Since it idles better with the O2 sensor disconnected it makes me think the computer is not liking something while in closed loop. You really need to datalog and see what the computer is seeing. Datalogging on 90-91 is a bit more troublesome with the CCM. I’ve found Datamasters (no longer supported by the developer) and Datacat work well on my 91.
That is a piggyback adapter for an aftermarket chip to connect.
The issue could be that, but is more likely something showing in closed loop operation. There are no codes set? It could be a number of things that you do need to datalog to see, either with a laptop and DataMaster or a OBD1 Scantool.
Okay sweet so tuning with tunerpro but logging with Datamaster and Datacat! Got it!
Can one disable the EGR codes oneself in tunerpro for 91?
If you want to disable the EGR there will be a scalar for setting the temperature when the EGR will enable. Max it out and it will effectively disable it. You can then increase the EGR diagnostic minimum speed to its maximum value and the computer will never check if it’s functioning. Hope that helps.
1990 TPI prom?
