patman

iTrader: (3)

no, you cannot read the ECU with a OBD data reader or anything of the sort. only way to do it is manually with a voltmeter. you can try checking the ecu codes, there is a writeup on that floating around somewhere...i think maybe on fc3spro.

pat

Mason Rx7

Update:

I replaced the coolent temp sensor. The last people who rebuilt the engine broke the connector and han't bothered replacing it of fixing it. The conncector was basicly just hanging there. I'm not even sure if it was plugged in or not. I replaced the sensor anyways and then fixed the connector as much as possible. I started her up and smelt gas pretty badly but that went away pretty quickly. When I first backed outta the driveway I had some driveability problems but those went away fairly quickly. I'm guessing it was just the ECU getting used to the new sensor. I drove around for a bit, watching the temp gauge and glancing at the road and it is not over heating or the like.

I'm hoping this fixes the gas mileage. I will let you all know exactly what my gas mileage is soon.

Thanks.

Falcoms

Okay, now I have changed the coolant temp sensor, and low and behold that wasn't the problem. Well, pulling all my thoughts together (like, all 3 since new years 2004) I came up with a theory that it was rather the IAT (intake air temp.) sensor reading that the air coming in is ~-30*C, forcing the ECU to flood the engine with gas. Well, my question is, does anyone know what the ohmage coming out of the IAT is supposed to be and at what temp so I can figure out if that is the problem? Also, if one of the wires to the IAT or CTS were broken, would the ensuing infinate resistance cause the engine to think that the temp of either one was way low, or is the computer smarter than the average bear?


Cliffs notes:
Something is telling the ECU that the engine is cold or air coming in is cold. New CTS makes no difference in gas milage, now thinking that it is the IAT sensor, or maybe a broken wire from the IAT or CTS causing situation.

WAYNE88N/A

Read it out from the ECU (voltage checks per the FSM), or, look up the resistance specs for a particular temp and read it out on the engine that way...

Basically what you do to cover the entire sensor spectrum is to gain access to the ECU, and start reading every pin out while comparing the numbers to the FSM specs. Heck, I've been doing this for so long I have PAGES of voltage readings for the different sensors taken at different times in the car's life. I have readings at idle cold, idle hot, cruising speeds (55 and 70 mph), WOT, you name it...

Falcoms

^ ya know, I feel like an idiot, but I STILL can't find the page(s) in the FSM that cover how to do said test. Could you please explain in depth? Links are acceptable...

WAYNE88N/A

For the S4 NA's (don't know about the S5 manual), it's on page 4A-30 and -31. In the Fuel/ECU section