Engine revving by itself

[Dozza]

It really doesn't seem right to me. There's like a jolt/jab before the gear change which I don't like. Is there anyway to solve this?

 

[J_D 2.0]

It really doesn't seem right to me. There's like a jolt/jab before the gear change which I don't like. Is there anyway to solve this?

Mine didn’t jolt on the change down but that might be an issue with your gearbox then if it’s old. Like i said, when mine would kick down during a downhill run I’d put it into manual mode and select gears which was the only way around it without messing around with transmission shift points and such (if you can even do that).

 

[BrisTim84]

It really doesn't seem right to me. There's like a jolt/jab before the gear change which I don't like. Is there anyway to solve this?

Hey Dazz, I am having the same problem with my VE SS. Just signed up to chat to you and see if you resolved the issue? I also have installed a VCM OTR, pacemaker and exhaust. I’ve had the above mods (basically only mods I’ve done) installed for over a year and everything went great but now my car is doing the same thing as yours. Not all the time, it’s temperamental. I can sit outside my car and watch it rev itself like it’s alive haha. Like a kids car movie. Well it’s nothing funny anymore and I want the issue gone.

One thing my car did that yours seemingly didn’t was, when I was driving it the other day, the temperature guage starting moving like it was revving too. I’d love to hear where you’re up to and hopefully we can get to the bottom of this.

To note: I never had the car tuned after I installed the otr, extractors and exhaust. It comes up with a check engine light several times each drive but I’ve just been ignoring and clearing it by pressing trip.

looking forward to hearing from you bud!

 

[timd29]

Pretty sure with these cars it needs a tune with otr, definitely if you put that on with full engine back exhuast

 

[lmoengnr]

With your mods, it will need a tune, but make sure the ECU is mounted correctly and the bolts are tight.

 

[BrisTim84]

Yes, you’re right. It does need a proper tune. I was trying to avoid paying for it because they’re so exy. And now my car is broken lol. Like they say, a poor man pays twice . I tried to upload an image of the ‘contact dealer X ’ warning sign that flashed up on my dash this morning but the file is too large. I’ve never touched the ECU but I’ll see if it needs to be tightened. I’m beginning to think I’ve cooked it

 

[Skylarking]

... It comes up with a check engine light several times each drive but I’ve just been ignoring and clearing it by pressing trip.

Not all DTC’s will set the check engine lamp. For the check engine lamp to be set, several times each drive, it must mean you have an issue that has logged DTC’s.

So have you actually checked for diagnostic codes? Did you understand the DTC’s you are getting? Simply clearing DTC’s without understanding why they were raised and correcting the problem can be rather detrimental to your engine/driveline.

In @Dozza ‘s case, he had a tune, he didn’t have any DTC’s, he also replaced his throttle body and accelerator pedal to no avail as he still has the problem

Since in Dozza’s has 0% APP reading and a 17-30% spiking TPS, it seems the ECU is doing the up throttle on its own volition. Other than cruise control, I didn’t think the ECU would ever command more throttle except to increasing idle for cold starts and/or when aircon is on and loading up the engine.

So clutching at straws, maybe you’d need to check/log the various temp sensors used for cold start idle up and check the HVAC (ecu) control logic to see if either is intermittently commanding the ECU to kick up the idle... Also not sure how auto down change works and whether TCU can in some instances command the ECU to up throttle before it does a downshift.... (And if it’s manual, which it’s not), no idea how launch control works and whether something on that side could also play up...)

Resolving this will require much more information on how the system actually functions than what is stated within the workshop manual It’s probably going to need specialist knowledge lots of hours and lots of data logging to get to the bottom of it

 

[Fu Manchu]

This might be a job for a tuner perhaps? They can poke around and see all the data while the car is running and find some strong clues?

 

[Skylarking]

This might be a job for a tuner perhaps? They can poke around and see all the data while the car is running and find some strong clues?

I'd suspect there are tuners and there are tuners... not all will have the same skill as in all professions. And whether all functions and logic within the ECU been fully decoded by the aftermarket isn't even clear to me (as it's not my thing)...

In this case it's likely some issue with the idle up logic that the factory has coded within the vehicle. Since Dozza had the issue before and after the tune, he's changed hardware and had his tuner look into it without success, I'd say it's going to be a pain to localise and then may end up being a temperature related intermittent dodgy sensor somewhere (which is why @07GTS post a page back was interesting but seemed ignored)...

Really, this is something that needs support from Holden to the dealer chasing this down (under warranty) but Holden has left the building and every deealer clown will want a blank check to be signed as a precondition to fault finding... And who knows how long it will take... There could be a hint in some service bulletin but we lowly owners can't get a see but there's always the Chevy SS and the service bulletins and other docs available via the NHTSA. I'd look through that information resource

(I had an issue with another brand of vehicle's aircon intermittently cutting out and the local mob were clueless. The dealer, auto elec and others had no clue, called themselves experts yet figuratively wanted a blank cheque signed off to fault find. I bypassed the issue and continued with occasional investigations... then found out the issue was part of a recall in the USA that the bods down under weren't interested in doing... turns out there was an intermittently faulty ps pressure switch which when I replaced resolved the fault ... Seems down under we had a fcukin clown of a distributor and the dealer service mechanics weren't far behind... And this brand's electrical architecture was neanderthalic in comparison to the VF electrical architecture... the neaderthals had no chance )

 

[BrisTim84]

Not all DTC’s will set the check engine lamp. For the check engine lamp to be set, several times each drive, it must mean you have an issue that has logged DTC’s.

So have you actually checked for diagnostic codes? Did you understand the DTC’s you are getting? Simply clearing DTC’s without understanding why they were raised and correcting the problem can be rather detrimental to your engine/driveline.

In @Dozza ‘s case, he had a tune, he didn’t have any DTC’s, he also replaced his throttle body and accelerator pedal to no avail as he still has the problem

Since in Dozza’s has 0% APP reading and a 17-30% spiking TPS, it seems the ECU is doing the up throttle on its own volition. Other than cruise control, I didn’t think the ECU would ever command more throttle except to increasing idle for cold starts and/or when aircon is on and loading up the engine.

So clutching at straws, maybe you’d need to check/log the various temp sensors used for cold start idle up and check the HVAC (ecu) control logic to see if either is intermittently commanding the ECU to kick up the idle... Also not sure how auto down change works and whether TCU can in some instances command the ECU to up throttle before it does a downshift.... (And if it’s manual, which it’s not), no idea how launch control works and whether something on that side could also play up...)

Resolving this will require much more information on how the system actually functions than what is stated within the workshop manual It’s probably going to need specialist knowledge lots of hours and lots of data logging to get to the bottom of it

I’m not a mechanic my cousin is though and I trust him. All I’ve ever done over the years is drive my cars into his shop. This fault is way outta my league and I’m starting to think it might be out of his league too because he doesn’t specialise in this type of modification like a high performance shop would.

Thanks for your feedback. When it first happened I took it straight into him and he said that he couldn’t find anything and to bring it back if it happened again. I thought I’d do some investigation for him to speedup the process and reduce the costs.

I understand what you mean about checking the sensors. I think they’re cooked or the ECU is cooked. I don’t think anyone that’s tuned their engines at the same time of installing the mods (OTR CAI and full exhaust) has had the same problem. I wonder if it would be wise for him to replace all the sensors and then replace the ECU (with a second hand one to minimise costs) and then get it tuned. Because it only become a problem about 6 months after the mods. I just need to get it back to that state and tune it. That’s my simplistic thinking methodology. Not sure if it’d work though.