TPS
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
TPS
My idle is not dropping down to normal on occasion. It set a code 22 and according to my Haynes manual it is the TPS. You guys think it could be anything else or should I just replace it?
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: TPS (cshuman)
If you set a code, and idle is too high, then it sounds like the TPS is set above 0.68v at idle speed. Drop her down to anywhere from 0.54v-0.68v, but NO MORE than 0.68v at idle. 
Race Director
Joined: May 1999
Posts: 14,267
Likes: 1
From: Plymouth MI Formerly Milford, MA MI
W. Detroit Events Coordinator
Cruise-In VI Veteran
Cruise-In VII Veteran
Cruise-In VII Autocross Champ
Re: TPS (scorp508)
Adjust it unless it's no adjustable depends on the year
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: TPS (cshuman)
If you have a TPI (L-98) the code 22 is saying that the ecm is seeing a very, very low voltage from the TPS. If you don't know how to check TPS voltage there is a good tech tip on the forum for this adjustment. However, make sure that you have a full range from just above 0.4V at idle to 4.5 volts or so (I believe 4.0 works) at Wide Open Throttle (engine off of course). Also confirm the 5V reference voltage is available at the TPS to begin with.
Edit, thought of another thing to check. TPS is like a volume control on a radio - it can get "scratchy". If this happens it really mess things up. When you are checking TPS voltage, run the throttle very slowly from idle to WOT and make sure the voltage increase is very smooth - it should not jump around at all (like a bad volume control). This test ("scratchy" TPS) is much easier to do with an old analog meter (the ones with the needle), but the adjustment is much easier and more accurate with a digital meter.
Good Luck,
Pete
[Modified by PeteL, 9:22 PM 8/21/2001]
Edit, thought of another thing to check. TPS is like a volume control on a radio - it can get "scratchy". If this happens it really mess things up. When you are checking TPS voltage, run the throttle very slowly from idle to WOT and make sure the voltage increase is very smooth - it should not jump around at all (like a bad volume control). This test ("scratchy" TPS) is much easier to do with an old analog meter (the ones with the needle), but the adjustment is much easier and more accurate with a digital meter.
Good Luck,
Pete
[Modified by PeteL, 9:22 PM 8/21/2001]
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Re: TPS (PeteL)
I checked the TPS voltage and it is set at 6.0 volts. I know that this is at the limit. I set it there because I read somewhere that it would help throttle response. I have not checked however it is smooth. All it is is a variable resistor. I can check the smoothness of it with a VOM to verify if it is out of whack. It has only happened twice in the last weeks. If it is the TPS it will only get worse. Great idea to check the smoothness! Could the OXY sensor have something to do with it?
