Help me solve my rev hang/jump *Reward offered*

[Jabbit]

Check this video out please - https://youtube.com/shorts/-mxbNuwlK6Q?feature=share

Accel pedal position reads zero when this happens. Throttle body? The rev hang/jump does not happen in first and second, sometimes in third, frequently in fourth and fifth. But based on the video even clutching in and out, no change.

Data logs are with the tuner to investigate. Mods since the car was down are (deep breath) - new trans, Quaife LSD, final drive gear swap, RTS clutch and flywheel, xdi hpfp, Bosch injectors, aem 5 bar map, Bosch 4 bar TMAP.


EDIT: This turned out to be a mistake by multiple reputable tuners. Gearing config was not updated from 3.8 to 4.3. That fixed everything.

 

[Erick_V]

Something similar happened to me when the line from my catch-can popped off the intake manifold. I didn’t push the fitting on enough so it popped off under boost. My rev hang was a little more exaggerated than that, would also bounce a little with the clutch in

 

[dhminer]

I had a similar experience to Erick when the car was sucking in air from a leak somewhere in the intake tract. Basically had cruise control without turning cruise control on, and in 1-3 it’d accelerate with no throttle input

 

[Erick_V]

Basically had cruise control without turning cruise control on, and in 1-3 it’d accelerate with no throttle input

Mine also did this. Might be worth spraying carb cleaner around the engine bay to track a potential leak

 

[Jabbit]

Couldn't find any leaks, swapped to a new throttle body and gasket, reflashed, swapped TMAP sensor back to stock (with different tune), nothing has worked. Argh!

 

[dhminer]

Couldn't find any leaks, swapped to a new throttle body and gasket, reflashed, swapped TMAP sensor back to stock (with different tune), nothing has worked. Argh!

What was feedback from tuner?

 

[Jabbit]

What was feedback from tuner?

I've been sending logs of various length, that's what lead to replacing TB and TMAP. Feedback still pending since then.

 

[Jabbit]

Problem still exists, getting feedback that it's a hardware issue. Anyone else have any thoughts?

 

[Erick_V]

Have you tried carb cleaner around various points in the engine bay for vacuum leaks? Maybe cleaning the MAF?

 

[TyphoonFiST]

Ever thought about buying or using an EVAP smoker and using it to test for leaks? Food for thought.....

 

[Jabbit]

Have you tried carb cleaner around various points in the engine bay for vacuum leaks? Maybe cleaning the MAF?

I double checked all vacuum lines but didn't use any spray. I'll try that.

 

[Jabbit]

Ever thought about buying or using an EVAP smoker and using it to test for leaks? Food for thought.....

I had no idea that was a thing! Just bought one.

 

[CarGuy]

I had no idea that was a thing! Just bought one.

Link?

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[Jabbit]

Link?

Sent from my SM-S908U using Tapatalk

Just search "smoke tester" on Amazon, there are a bunch.

 

[Jabbit]

Ran every test in ForScan, nothing weird. Got the usual codes I would expect with gutted interior, etc but none of that changed. Smoke tester here tomorrow and hopefully test it on Thursday. Any suggestions on what to test? Basically going to start with the evap harness and go from there. Also picked up some intake adapters.

 

[TyphoonFiST]

Which tester did you buy? Hopefully one that is in PSI and not KPA* So you dont always have to convert.

 

[Jabbit]

Which tester did you buy? Hopefully one that is in PSI and not KPA* So you dont always have to convert.

AUTOOL Automotive Leak Detector Tool Cars Leak Locator Tester Car Pipe Leakage Tester Support Evap for All Vehicles https://www.amazon.com/dp/B07P1FRBNW/ref=cm_sw_r_apan_i_XZQJP23PP1TTP1XJ5VQA

 

[TyphoonFiST]

AUTOOL Automotive Leak Detector Tool Cars Leak Locator Tester Car Pipe Leakage Tester Support Evap for All Vehicles https://www.amazon.com/dp/B07P1FRBNW/ref=cm_sw_r_apan_i_XZQJP23PP1TTP1XJ5VQA

This is the one I have does Psi up to 30psi

AUTOOL EVAP Vacuum Automotive Smoke Machine Leak Detector Diagnostic Tester https://www.amazon.com/dp/B08QV6RGVS/ref=cm_sw_r_apan_i_D52JE8JA8X8YXVDWJMCG?_encoding=UTF8&psc=1

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[Jabbit]

Smoke test did not reveal leaks, tested intake tract and the evap lines. Did I miss something? Evap harness looks fine I pulled it out to confirm. Replaced it about a year ago.

At this point I'm willing to offer a PayPal donation to anyone that helps me fix this.

 

[TyphoonFiST]

Smoke test did not reveal leaks, tested intake tract and the evap lines. Did I miss something? Evap harness looks fine I pulled it out to confirm. Replaced it about a year ago.

At this point I'm willing to offer a PayPal donation to anyone that helps me fix this.

Did you pressurize the system? Or just fill it with smoke?

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