I need some help with my driveability issues and codes!!!

Camman

Founding Member
Jan 5, 2000
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Las Vegas, NV
I have been hunting down a surging idle and miss at around 2000 rpms for some time now. I ran codes when the problem first presented itself last week. I had 11 koeo, 11 koer, and 63 continous. I replaced the tps sensor, set it to .99 volts using an engine ground. I drove it and within 1 mile the c/e light was flashing at me. I then did a search and red the engine had to be warm and to use the sensor ground. I just did that and then reset the computer. The tps is at .90 volts now and it was idling pretty nicely. I went for a test drive and it flashed the c/e light again. I just ran codes and I have 11 koeo, 63 and 98 keor. I have no idea what the 98 means "Hard fault is present in-FMEM mode". So what would be causing the freaking 63? It seems to set the code when I am cruising at about 2000 rpm with my foot just barely depressing the gas pedal. I checked the tps at this position and it is reading voltage, I dont have an analog meter, but with the best I can tell there are no opens. Does anyone have any ideas? Thanks alot!
 
Code 63 - Throttle Position Sensor (TPS) signal too low TPS. Vref missing (5 volt reference voltage supplied by the computer), bad connections or damaged wiring, TPS sensor failed, TPS sensor way out of adjustment. Use a DVM to check for 5 volts on the Orange wire. If it is missing, look for +5 volts at the Orange wire on the EGR or MAP sensor located on the firewall near the center of the car.

Here’s a TPS tip I got from NoGo50…

When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a little in very small increments. I wouldn’t try to adjust it using marks. Set it at .97v-.99v, the closer to .99v the better. Just don’t go over .99, or you upset the fuel calibration and idle quality will suffer.

(copied from MustangMax, Glendale AZ)

1. Always adjust the TPS and Idle with the engine at operating temp. Dive it around for a bit if you can and get it nice and warm.

2. When you probe the leads of the TPS, do not use an engine ground, put the ground probe into the lead of the TPS. You should be connecting both meter probes to the TPS and not one to the TPS and the other to ground.

3. Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery lead for 10 minutes.

4. Check the procedure for your year, on my 90 I have to turn the idle screw until it just touches the tab, then insert a .010 feeler gauge and give it about one more turn. Then you adjust the TPS voltage to .98v, reset the computer. Start it up, if the idle is to low then turn the screw in until it is just right, then readjust the TPS voltage to .98v and reset the computer and start it up. The key is to adjust the TPS voltage and reset the computer whenever the idle screw is changed.
 
98 (r): Hard fault present. The ECA is running in FMEM (Failure
Effects Management Mode), so something is royally screwed up that the
KOEO test should have told you about. Rerun KOEO and fix whatever you
find there.
 
okay, so I have vref and everything at the tps. I still have a code 63, where should I go from here? I did run the koeo test again and am still getting 11. With a 63 in continous. I assume the computer can see the tps voltage since its flashing 11 during the koeo test.