EEC IV technician (high idle)

[Guy Groves]

Just a thought...
Could explain the 73 and 23 error codes.

When you tested the TPS sensor was it attached to the TB?

While working on a friends car I noticed that some of the nylon bushing for the TPS sensor where it fits to the throttle butterfly valve stem was damaged. There was also a bushing that had become deformed and broken.

You might re-inspect the TPS mounting to the TB to make sure it is mounted so that the sensor moves as the throttle is opened. I have noticed on my TPS for a 5.0 engine that the TPS could be mounted so that the butterfly valve shaft would not mate properly with the TPS sensor (In other word, the throttle would turn the the butterfly valve, but the shaft of the TB would not turn the TPS).

If you just tested the sensor, not mounted to the TB, it may be that the mounting tabs did not align properly when installed?

 

[lonestar]

Yep, I tested the TPS on the TB. I backprobed the wiring harness and opened throttle. However, I did notice the idle position reference voltage was low, 0.5v. According to a thread here on high to adjust these nonadjustable TPS sensors by slotting the holes, it shouyld be 0.96v.

The reason I believe it is either electrical or ECU related is because when it sticks at high idle, I can simply turn the ignition off/on quickly to reset the computer and it idles fine.

I guess I will be looking at getting a ECU from a junkyard. $50, maybe they will let me plug it up first to make sure it works (and solve my prob) before I buy it.

 

[lonestar]

Back again....

Ok, I got a ECU from EBAY for $25. Plugged it up, and it did the same thing, so it's no the ECU.

My X broke down, so I drove it last week, I drove great, no probs all week until the last day, it started racing at the stop light. Flicked ignition off/on and it ran just fine.

I don't understande why I'm still getting the TPS code. It is new and tests fine. Output voltage varies from 0.5 - 4.5 v without any jumps. Input voltage is 5v.

Now I am getting a TPS code on my X, but no CEL. This TPS also checks out good. Varies voltage from 0.9 - 4.2 V.

I'm thinking of setting up a data aquisistion system to a laptop to monitor everything in real time.

 

[dogfriend]

Check the wiring from the TPS to the computer very carefully. Make sure that you don't have a wire that is partially broken.

Another possibility is corrosion in the wiring or especially in one of the connectors. Corrosion causes additional resistance which may throw the voltage out of range.

 

[lonestar]

FINALLY, I think I have found my problem. When I checked my TPS signal voltage it was low, around 0.5 instead of 0.96. When I adjusted the TPS by hand it worked fine. The problem was due to excessive play between the TPS and the shaft due to deteriation of the thottle body shaft. SO i just shimmed it up with peices of aluminum, from a SAMS coke can.

 

[tamaqua18252]

FINALLY, I think I have found my problem. When I checked my TPS signal voltage it was low, around 0.5 instead of 0.96. When I adjusted the TPS by hand it worked fine. The problem was due to excessive play between the TPS and the shaft due to deteriation of the thottle body shaft. SO i just shimmed it up with peices of aluminum, from a SAMS coke can.

Did the problem ever come back, i have had this problem for a few years and with a new baby on the way, i cant afford a new car, and i need a dependable one to go to the appointments with, i have tried everything and replaced everything twice with yard parts, please help, thank you

 

[lonestar]

yeah, I think so, its been awhile. never really figured it out.. I'm pretty sure it was somehow related to TPS or wiring as dogfriend suggested. Know the feeling, nothing more frustrating then spending lots of time trying to diagnose, replace and repair with no success. Best of luck.

 

[tamaqua18252]

oh boy, this sux.

 

[tamaqua18252]

did you get rid of your car?

 

[tamaqua18252]

fixed it, it was a bad throttle body, the rod that goes thru the throttle body was rusted badly, i got a new throttle body and she is back to normal, thank you all for your help.