1990 5.7 Tbi

[rjh1936]

I have a couple of questions on my 1990 G30 motor home with a 350 TBI that I would like your opinions on.

 

 

The first is that I am considering trying to boost the power when going over our local mountain passes when I am cruising at about 60 MPH. Sometimes I start losing speed near the top and I don’t like to impede the other drivers so I have been thinking of installing a double pole, double throw toggle switch on the temperature sender. On normal running it would hook up the sender to the EMC. When I need a boost it would put a 640 ohm resister in its place that would make the EMC think it is still cold and then increase the fuel as in cold engine running. When I get to the top, I would put it back to normal. I do not know if this would make a fault appear or not, and if it would truly make much difference,.

 

 

The second is that I have considered installing a three wire oxygen sensor in place of the one wire sensor as they are suppose to be more accurate most of the time.

 

 

What is the opinions you guys have on these changes. Thanks.

[redvett]

#1 the MAP sensor reads barometric pressure and the ECM compensates for the altitude.

#2 A heated O2 isn't any better than a unheated it just allows the ECM to go closed loop earlier.

[rjh1936]

The problem I have at the top of the hill is not altitude related. It is the hill increases in grade near the top. I believe that by making the enging appear to be cold that the fuel will be increased slightly. They use a resister like this when racing sometimes for that reason. The 640 ohms simulates a water temperature of about 140 degrees. I understand that this can enrich the fuel some, but the oxygen sensor will monitor it also.