Kyle86

iTrader: (1)

Hello, I am having problems with my 93 Chevy 1500 with the 4.3 v6 and TBI and the 4l60e. It keeps throwing a code 22 intermittently effecting driving behavior. It runs fine for a while maybe 15 minutes, then the check engine light will come on and it will start idleing high and the shifts are late and hard.*

If i pull over and read the codes with the jumper clip, it is throwing a 22 which is tps and 32 which is egr. Originally it was just throwing a code 22 only but both seem to be related and come on at the same time together. I pull out the paper clip and start back up and trouble light is off and driving/shifting is normal for a while maybe another 15 or 30 minutes.

I have checked voltage per haynes manual and it is 5 volts consistently. I drilled the mounting holes. And andjusted idle voltage to .61 per haynes manual. Acceleration appears to show a smooth and gradual increase up to about 4.55 which is within spec.

Other than a faulty tps which is $35, any suggestions as to what is causing the ecm to intermittently throw the code 22 and cause the high idle and hard shifts? Thanks in advance!!!

RFmaster

@Kyle86

Code 22 indicates that TPS voltage was under 0.2 volts for 2 seconds when the engine was running. Given your diagnostics I would look for broken wire in +5 volt reference voltage circuit (ECM Pin C14, gray wire) at or near TPS. The +5 volt reference is used by MAP and TPS. So if there was an intermittent in this circuit at the ECM I/O connector both Code 22 & 34 would have been set. Most of the time a shot gun approach is used - replacing TPS. However, I would look closely at the TPS plug and harness for a broken wire. Once you take care of tps Code 32 may go away on its own....

//RF

Kyle86

iTrader: (1)

Thanks! What gets me is that mine consistently measures 5 volts on the gray wire and the plug looks fine. Could a bad ground cause this issue perhaps? This is very frustrating. When you mean below .2 is that only on the gray wire or could that also be on the blue wire which vaires voltage?

one92rs

iTrader: (5)

i would be checking the grounds on the back of the heads.

RFmaster

@Kyle26 A bad harness ground would cause Code 21 (voltage too high )

Kyle86

iTrader: (1)

Edit: cleaning grounds did not help the problem. Going to pull te ecm and check the wires like RF advised.

Thanks for the help!

Kyle86

iTrader: (1)

Ok I spoke too soon, it didn't work. I'm thinking about replacing the sensor.

Its strange, while driving it will be fine for 15 minutes or longer, then while going down the road the check engine light will just come on and start shiftig hard and idling high. When I pull over and turn the vehicle off, then turn it back on it drives fine again and check engine light is off.

Kyle86

iTrader: (1)

OK update, I checked continuity of the wires from the plug at the ecm all the way to the plug end at the TPS. The wires are good. I'm guessing this leaves either the TPS itself or the computer ECM. I guess the tps is the cheaper of the 2 so I will try replacing it first.

RFmaster

It is not uncommon for TPS sensor to go flaky once engine is up to operating temperature. When TPS is cold a good contact is maintained between two elements, once temperature increases the gap between two elements may grow to where an intermittent or high resistance junction is formed. That may explain what you see after 15 min of driving. Since you are dealing with 20 year old TPS - well, perhaps it not a bad idea to 86' it and get a new unit. Surprisingly, OE units last a long time, although I can not say the same for aftermarket.

//RF

Kyle86

iTrader: (1)

Fixed! Replaced the old "made in usa" TPS with a new foreign replacement and it now runs like a champ! Wanted to wait a few days just to be shure. Now only throwing Code 32 occasionally but no longer has high idle and hard shifts! I believe the 32 may be related to some cracked vacuum lines but not really worried about it.

Thanks all for the help, and special thanks to you RF, for helping me get this issue straightened out.

Kyle86

iTrader: (1)

Last update in case someone finds this thread useful. Replacing the tps completely fixed the high idle and shifting problems. Also, my mistake I replaced it with a BWD tps from advance which is a USA made part. It measured .74 volts and it works just fine like that. Throttle response is better than ever. About 300 miles now and all is well!