Throttle after releasing pedal.

[MZahn]

The '05 seems to have a delayed response when lifting off of the throttle. It seems to keep accelerating after pedal lift.

Suggestions for what to look for? No codes.

 

[Killer223]

miles? i think that most i've read doing this ended up being an APPS, or injectors.

 

[MZahn]

310,000 miles. Injectors at 275K.

 

[MZahn]

I guess I will check into a drive by wire module.

 

[DonFitzwater]

Any mods? My 06 only did it when running the programmer on it.

 

[MZahn]

Any mods? My 06 only did it when running the programmer on it.

The injectors are +75HP. It has an Edge tuner but did this before both were added.

 

[cerberusiam]

If you slap the throttle hard and lift quickly it won't back down right away, that is normal even with stock parts. If you are cruising at steady speed and lift off the throttle it should drop evenly, If it doesn't then it is time to investigate. One of the test for injector wear and balance is free rev the engine to 3000 rpms and hold for 10-15 seconds then lift all the way off the throttle. The rpm drop should start almost immediately and should be smooth down to idle. Any hangs or notchy drop means there is an issue somewhere.

 

[sag2]

Most likely an injector sticking open. When you lift from the throttle the ECM holds the rail pressure up for a few seconds anticipating you may want to get back on it. If the injector is mechanically stuck it continues to fuel. A quick peek at a scanner that reads the APP will rule out everything else. You need to fix it quickly or risk a melted piston.

 

[MZahn]

Thanks, the advice is appreciated.

 

[MZahn]

My pal that has the truck in his shop can do an injector kill test with his scanner. Would that shed any light on the issue?

 

[KRSmitty]

If you slap the throttle hard and lift quickly it won't back down right away, that is normal even with stock parts. If you are cruising at steady speed and lift off the throttle it should drop evenly, If it doesn't then it is time to investigate. One of the test for injector wear and balance is free rev the engine to 3000 rpms and hold for 10-15 seconds then lift all the way off the throttle. The rpm drop should start almost immediately and should be smooth down to idle. Any hangs or notchy drop means there is an issue somewhere.

X2 on my 2007.

 

[cerberusiam]

My pal that has the truck in his shop can do an injector kill test with his scanner. Would that shed any light on the issue?

It is not really an issue, just the way the system is designed. There is a lag between electronics changing state and the mechanical process of ramping rail pressure up and down, the electronics change much faster than the mechanical part can change pressure ramps. Injector kill test will just tell if the injector is functioning at an idle, same with the contribution percentages. They are all steady state tests, but, what yoo are describing is operational and there is really no test other than what I indicated to check if there is a potential problem.

 

[Bob4x4]

75 hp injectors?doesn't really say much about the injectors. Were they built of new injectors,reman.your old injectors?

 

[MZahn]

75 hp injectors?doesn't really say much about the injectors. Were they built of new injectors,reman.your old injectors?

Bob, they
are +75HP from Injectors Direct several years ago. IIRC they were Bosch remans. I understand about the engine run on after lift but this is a bit longer and scary at times.

 

[Bob4x4]

They don't show any performance injectors on their website ?

 

[MZahn]

I noticed that today when I went back looking them up. They used to, I bought a +75HP set of 6 and new tubes.

 

[MZahn]

Bob, I stand here to correct myself. The invoice from 8-14-2013 says:



04.5+ INJECTOR SET BOSCH NEW +50HP - SPECIAL ORDER
$2,400, REFUNDABLE CORE CHARGE 6 @ $100 - $600. BOSCH HIGH FLOW CONNECTOR TUBES. 6 @ $45.00. TOTAL $3,270.

 

[cerberusiam]

I understand about the engine run on after lift but this is a bit longer and scary at times.

You stated it did before the injectors and tuner, is it better or worse now?
A tuner and larger injectors are just going to make it worse. I can tell you from experience, just STOCK, if you slap the throttle hard enough in a parking lot the pucker factor is high, you WILL get some dirty looks from by-standers.
The time of the engine run on is proportional to how far and how long you shoved the throttle, it will vary. Short answer, don't do that.

 

[MZahn]

You stated it did before the injectors and tuner, is it better or worse now?
A tuner and larger injectors are just going to make it worse. I can tell you from experience, just STOCK, if you slap the throttle hard enough in a parking lot the pucker factor is high, you WILL get some dirty looks from by-standers.
The time of the engine run on is proportional to how far and how long you shoved the throttle, it will vary. Short answer, don't do that.

OK. Pal driving it suggested that I bring the topic up here to see what you all thought. It happens to me when going from 55 MPH to 70MPH. Hard to woah up.

 

[Bob4x4]

Not enough info to know exactly what you got.If they are bosch motorsports I believe the spray angle may be incorrect and it seems they don't have the best reputation.If they are real Bosch new you have no idea if they are honed stock nozzles or even some off shore nozzles.Might be time to contact the supplier and find out if they can give more info/test your injectors.