stokes Posted May 4, 2004 Report Share Posted May 4, 2004 Car is finally back in good health,turned out to be the ECM.Put the new one in everything seems to fine except the mpg/fuel data on the IPC is giving erratic info.Tha anolog fuel gauge is okay,shows just less than half tank.The IPC data shows 8.4 gals. But the digital "Range" info shows L even tho the instant mpg seems to be normal,the avg.mpg reading seems to be out of whack,at times showing 4 to 7mpg at idle.Anybody got any ideas?There are no error codes Link to comment Share on other sites More sharing options...
KevinW Posted May 5, 2004 Report Share Posted May 5, 2004 I guess there's a chance the hardware (in the new ECM) related to the vehicle speed output could be defective, but that would affect the speedometer display, Cruise Control, etc. too. The fuel gauge readout is dependent only on info from the fuel tank sending unit. BTW, which Memcal is installed in this ECM? ___________________________________________________ Link to comment Share on other sites More sharing options...
stokes Posted May 5, 2004 Author Report Share Posted May 5, 2004 The Memcal is from the original ECM. I had trouble with the car (see previous thread-Bad Gas?).When I got it back from the first mechanic the Range displayed LO-I assumed this was due to the way it was running(sputtering,surging etc.).Now with the new ecm everything else on the IPC is fine except the readout for the range,after filling up the tank it says I have only 50 miles worth of gas.The instant mpg seems to be okay,but the avg.mpg is erratic.I have the Caddy service manual,but cant find anything that points to an error in the Fuel Data Center. I have a feeling the mechanic might have messed with something he shouldnt have,since I already had to re set the TPS angle after he tried to change that.Said he put a new one in and then put the old one back since it didnt help and obviously did not know it had to be adjusted. Link to comment Share on other sites More sharing options...
stokes Posted May 6, 2004 Author Report Share Posted May 6, 2004 The mystery is solved.Apparently the IPC stored the bad gas mileage info from the five days the mechanic was trying to diagnose the poor running condition.With the stored mileage info,even a full tank showed that I only had 50 miles range in the tank.As I kept driving the range kept increasing,at first it looked like the FDC was going in reverse.When I left for work it showed 50 miles range.After 20miles the range increased to 85.When I checked the fuel level through the ECM data as opposed to the gas gauge I had only used 1 gal of fuel.20mpg in rush hour traffic on the Bklyn Queens distresway,not bad! Gotta figure the new ECM is working fine with numbers like that. Thanks to all who replied with advice. Link to comment Share on other sites More sharing options...
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