What should IAC and TPS levels be?
Thread Starter
Teching In
Joined: Oct 2015
Posts: 13
Likes: 0
What should IAC and TPS levels be? I'm having a warm start issue with my stock 06 Silverado with the 6.0 lq4.
Long story short, its dumping way too much fuel at startup and I can only get it to start if I hit the gas so the TB opens up and gets some air in.
I'm monitoring with the torque app.
My IAC says 1.0 all the time.
My TPS at idle floats around 7-9% and is more like 15% with key on, engine off.
What should the numbers actually be?
Are these drive by wire TBs adjustable?
Thanks!
Long story short, its dumping way too much fuel at startup and I can only get it to start if I hit the gas so the TB opens up and gets some air in.
I'm monitoring with the torque app.
My IAC says 1.0 all the time.
My TPS at idle floats around 7-9% and is more like 15% with key on, engine off.
What should the numbers actually be?
Are these drive by wire TBs adjustable?
Thanks!
Last edited by Sam Loffler; Jul 8, 2016 at 11:50 PM.
No, those TB are not mechanically adjustable. You need PCm tuning to change the way they operate.
Your TPS readings are within normal range. However IAT should go from ambient temp to higher values, in degrees. If you think you are having IAT heat soak problems, unplug the MAF when the engine is hot and crank the engine to see if it starts quicker.
Your TPS readings are within normal range. However IAT should go from ambient temp to higher values, in degrees. If you think you are having IAT heat soak problems, unplug the MAF when the engine is hot and crank the engine to see if it starts quicker.
Thread Starter
Teching In
Joined: Oct 2015
Posts: 13
Likes: 0
Ugh. Too many acronyms.
I meant the idle air control valve, not intake air temp.
The MAF was replaced about a month ago. To my understanding, the IAT sensor is integrated with the MAF. Right?
I'll see if I can edit the title...
I meant the idle air control valve, not intake air temp.
The MAF was replaced about a month ago. To my understanding, the IAT sensor is integrated with the MAF. Right?
I'll see if I can edit the title...
Well, there is no IAC in the drive by wire throttle body (DBW TB). It controls the idle speed opening/closing the main blade.
To check exactly what you need to change you need tuning software to datalog a few air parameters. There are no IAC steps you can scan like older engines with DBC (drive by cable)
Normally your problem can be solved by a simple tune, I have fixed a lot with this problem.
To check exactly what you need to change you need tuning software to datalog a few air parameters. There are no IAC steps you can scan like older engines with DBC (drive by cable)
Normally your problem can be solved by a simple tune, I have fixed a lot with this problem.
Thread Starter
Teching In
Joined: Oct 2015
Posts: 13
Likes: 0
Alright. I thought I had read that before, but couldn't find anything lately to confirm.
I would think that the 15% or so that the blade is open before starting would make it start easier then it wouldn't run right at the 6-7% it idles at.
Are there any other mechanical things I haven't thought of that I can eliminate as a possible cause before I get a tune?
I've done the following.
MAF and IAT
Fixed any vacuum leaks and checked for more
Also cleaned the TB yesterday and a couple times before.
I've also replaced the fuel pump recently.
MAP shows about 6.5 psi
STFT is bouncing around -6 plus or minus 2.
All the other stuff makes sense based on current temps, ect.
All of those are at idle.
Sorry for the info overload. I've been chasing this issue for about 6 months now and I'm ready to drive the truck into a lake.
I would think that the 15% or so that the blade is open before starting would make it start easier then it wouldn't run right at the 6-7% it idles at.
Are there any other mechanical things I haven't thought of that I can eliminate as a possible cause before I get a tune?
I've done the following.
MAF and IAT
Fixed any vacuum leaks and checked for more
Also cleaned the TB yesterday and a couple times before.
I've also replaced the fuel pump recently.
MAP shows about 6.5 psi
STFT is bouncing around -6 plus or minus 2.
All the other stuff makes sense based on current temps, ect.
All of those are at idle.
Sorry for the info overload. I've been chasing this issue for about 6 months now and I'm ready to drive the truck into a lake.
