Apparent Throttle Response Latency
Apparent Throttle Response Latency I'm just now getting the Firebird on the road and am trying to shake all of the weirdness out of it. What I have noticed is that there appears to be a latency/delay in depressing the throttle pedal and the engine revving. Is this normal or should I be trying to hunt down an issue?
Engine/PCM from 2003 Silverado SS which I believe is an E38, but don't recall off the top of my head.
Engine/PCM from 2003 Silverado SS which I believe is an E38, but don't recall off the top of my head.
Throttle response should be crisp/clean -- all DBW's that I've driven, if you didn't know they were DBW, you couldn't tell in normal driving. So I'd say you have a problem you need to track down. Seems like most problems come from the pedal assembly being incompatible with the computer being used. Mine were matched - worked like OEM from first start.
I'm just now getting the Firebird on the road and am trying to shake all of the weirdness out of it. What I have noticed is that there appears to be a latency/delay in depressing the throttle pedal and the engine revving. Is this normal or should I be trying to hunt down an issue?
Engine/PCM from 2003 Silverado SS which I believe is an E38, but don't recall off the top of my head.
Engine/PCM from 2003 Silverado SS which I believe is an E38, but don't recall off the top of my head.
Check for a vacuum leak all around, then go from there...
T,
Throttle response should be crisp/clean -- all DBW's that I've driven, if you didn't know they were DBW, you couldn't tell in normal driving. So I'd say you have a problem you need to track down. Seems like most problems come from the pedal assembly being incompatible with the computer being used. Mine were matched - worked like OEM from first start.
Yes, DBW.
Have you set yours up with a check engine light? I think a vacuum leak will light the CEL -- at least it does on mine (08 Corvette ECU). Have you pulled codes? And just to be certain -- did you pull the motor/ecu/pedal yourself?
I didn't do the motor pull, the shop that did it, does these a lot and I as told that it was the same pedal and it looked to be. That being said, I cannot guarantee it.
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Given what sounds like just a hint of uncertainty about the presence of a functioning CEL (it should come on during ignition on and then go out once the engine starts) and a bit of uncertainty around pedal compatibility --- I'd pull the codes. I found it pretty easy on mine - a $9 wifi/blue tooth dongle and a free (or less than $20) app that not only gives you a ton of operating info but also usually lists codes and allows you to reset them.
On mine I discovered that the ecu compares what it's seeing via the mass air sensor to what it calculates using the Map/Bap sensor -- and if those two things don't mesh -- it sets a code/CEL. This enabled me to discover I had a slight air intake leak somewhere between the mass air sensor and the throttle body. Smoothed some inlet piping surfaces, greased elbows, tightened clamps, etc. -- and no more leak, no more CEL. A vacuum leak would, I think, set the same type of code. So -- seems to me that pulling codes is a reasonable next step to determining why the throttle response seems abnormal.
On mine I discovered that the ecu compares what it's seeing via the mass air sensor to what it calculates using the Map/Bap sensor -- and if those two things don't mesh -- it sets a code/CEL. This enabled me to discover I had a slight air intake leak somewhere between the mass air sensor and the throttle body. Smoothed some inlet piping surfaces, greased elbows, tightened clamps, etc. -- and no more leak, no more CEL. A vacuum leak would, I think, set the same type of code. So -- seems to me that pulling codes is a reasonable next step to determining why the throttle response seems abnormal.
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Verdad Gallardo I'll check it out. The CEL does illuminate when they key is in accessory position, but does not light up when running. I am pretty sure everything is toght on the intake side as I just reinstalled it (the issue was happening prior). I am not sure what the rules for the MAF are as far as location with respect to the air cleaner, distance from throttle body, etc. mine is probably 10" from the 90 to the tb and the air filter is hooked directly to it. I've seen differing info about location etc. I'll also have to double check on a vacuum leak in the system as well.
Thoughts on the tb servo not doing what it should to open the butterfly or is its operation pretty binary?
I'm actually looking at the Edge CTS2 for PID display. I had one in my F350 and really liked how customizable it was.
Thoughts on the tb servo not doing what it should to open the butterfly or is its operation pretty binary?
I'm actually looking at the Edge CTS2 for PID display. I had one in my F350 and really liked how customizable it was.