My DBW throttle does not work, sometimes...?
Thread Starter
On The Tree
Joined: Jan 2006
Posts: 180
Likes: 16
My DBW throttle does not work, sometimes...? The engine is an Magnacharger-blown LQ9 6.0 liters in a '70 Impala; all worked well for 5 or 6 years since the swap, until this started.
Sometimes, with a cold engine (not run for a few days), when I start the engine, the idle is a bit too high (around 1500-2000 RPM) and the DBW throttle does not work (i.e. I depress the pedal but nothing happens). After a few minutes idling, the idle comes down by itself and the throttle pedal works fine again. Sometimes, I will turn off and re-start the engine a few times and after a few tries, all goes back to normal. The Check-Engine-Light stays on when this happens and stays on after back to normal. The code reader gives a code P1516.
A couple of weeks ago, after experimenting that, I have changed the TPS, but nothing changed.
The strange thing is that this does not happens each time I start the car, just every 3 or 4 other times... I have never experienced loss of throttle while driving.
Could someone tell me what is going on and what to do?
Sometimes, with a cold engine (not run for a few days), when I start the engine, the idle is a bit too high (around 1500-2000 RPM) and the DBW throttle does not work (i.e. I depress the pedal but nothing happens). After a few minutes idling, the idle comes down by itself and the throttle pedal works fine again. Sometimes, I will turn off and re-start the engine a few times and after a few tries, all goes back to normal. The Check-Engine-Light stays on when this happens and stays on after back to normal. The code reader gives a code P1516.
A couple of weeks ago, after experimenting that, I have changed the TPS, but nothing changed.
The strange thing is that this does not happens each time I start the car, just every 3 or 4 other times... I have never experienced loss of throttle while driving.
Could someone tell me what is going on and what to do?
Thread Starter
On The Tree
Joined: Jan 2006
Posts: 180
Likes: 16
I have changed the black plastic "cover" on the plug side of the throttle body. From the factory, it is attached with rivets, you drill them out and you can buy an aftermarket (Dorman, on Rockauto) part that bolts in place. This Dorman TPS also comes with the plug and pigtail, that I have not changed yet: maybe I will have to do that?...
I had seen this repair as a common thing to do on these engines, it seems the TPS fails often.
I had seen this repair as a common thing to do on these engines, it seems the TPS fails often.
If I was you I would change the TB for another one, even in stock form they are special. What I have learned over the years of doing swaps is that DBW systems are better left unmodified and avoid mixing different model/years.
DBW system is heavily monitored by the TAC and PCM, if something is not within factory tolerance it will not work. Dorman is not exactly top notch.
JMO
DBW system is heavily monitored by the TAC and PCM, if something is not within factory tolerance it will not work. Dorman is not exactly top notch.
JMO
Thread Starter
On The Tree
Joined: Jan 2006
Posts: 180
Likes: 16
It all worked well for several years...
I think I have an extra throttle body, originla to the engine, somewhere... If I can find it, I will try it.
The thing that I find strange/funny is that this problem only happens sometimes and that it "fixes itself" after a few minutes idling... I cannot make sense of that!
I think I have an extra throttle body, originla to the engine, somewhere... If I can find it, I will try it.
The thing that I find strange/funny is that this problem only happens sometimes and that it "fixes itself" after a few minutes idling... I cannot make sense of that!
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