carlfino

Thanks for the very helpful info. I have not directly measured the voltage at the ECU for the IDL and E2 conductors. Rather, I pulled the connector at the TPS and measured the voltage on the connector. The 12V was measured IDL to E2 and IDL to ground (- at battery). I'll make the measurement with the connector engaged to the TPS and see what I get. If I get more than "about 0V" at idle (which I may since I have 12V being fed to it, rather than 5V), then this may be the cause of the code 51 problem, as the ECU would think the engine was not at idle. I did have to adjust the TPS to get the proper clearance between the throttle stop screw and the throttle plate tab, so this is correct. You indicated that the voltage should be about 0V at idle and about 5V at WOT. My read is that the 5V also should be measured anytime the throttle plate is not in the idle position. Does this sound correct? I have never looked at the ECU. I imagine that is has a 5V voltage regulator on its circuit board, which I know I could change out. The question is how accessable is the circuit board? What is the easiest way to gain access to the ECU? My manual states that it's somewhere behind the dash. Can you be more specific as to its location and how to access it? Thanks Toys, Carl...

I have 2 technical questions... 1. I am getting a fault code 51 ("Switch Condition") consistently after clearing the codes. The idle increases when I engage the AC, so that works. The starter will not engage when in a gear other than P or N, so I conclude that works as well. In checking the TPS the manual calls for a 5V signal being sent to the TPS via the IDL and E2 conductors. I am getting 12V, not 5V. Testing of the TPS shows that it does provide a resistance called for when at idle (2.3k ohms or less) and the resistance opens up just as the throttle opens beyond idle. Should the voltage that the ECU is sending the TPS be 12V or 5V? Do I have a bad ECU? And does error code 51 evaluate any other switches other than Neutral start, A/C and TPS switches? 2. I am attempting to set the ignition timing by placing a jumper wire between terminals E1 and TE1. It shows about 10 BTDC for base timing, which is what the manual calls for - no problem there. However, the manual also indicates that the "Advance Timing" should be 13 - 27 BTDC, which occurs when the jumper wire is removed. When I remove the jumper wire there is absolutely no difference in the timing or the sound/rpm of the engine. Timing stays at 10 BTDC. When I put the jumper wire in the engine idle increases to about 1500 rpm for about 2 seconds then goes back to base idle (700 rpm). Is something wrong? Shouldn't the timing advance when I remove the jumper wire? Also, could this be related to question #1 above? Thanks to all the technogeeks that respond. Carl...

I have a 91 ES250 (V6) with about 95k miles. It gets about 17 mpg in city (not tested on highway). I have gone through all the EFI sensors/tests and it has new plugs, wires, rotor and distributor. Is this all I can expect from this vehicle? Given its weight, I would expect it to get over 22mpg in the city. Looking for other owners' mpg values, and any suggestions on common problems this vehicle has that leads to low gas mileage. Thanks in advance Carl (newby)...