VX SS revs surging when slowing down or revving

[goldvnaero]

Hi there,i have an auto VX SS which has had a mafless tune,new rebuilt trans with all the usual good bits and a 2800rpm stally,pacemaker tri y's with high flow cats and an OTR CAI. It made 247rwkw on the last dyno run which was 6mths ago,but since then i have had the trans and exhaust done to what is mentioned above,previous trans was slipping and had an old crappy HSV exhaust on it which had a crappy droney note,have also had a touch up tune to match but havent had a recent dyno. Anyway,that isnt the problem lol. The last few weeks it has been playin up a bit,when revving it in park or neutral the revs go so low that it almost stalls and it also does this when slowing right down. I have recently changed the TPS and ISC sensors thinking that this might resolve the problem but it hasnt,so today i did the plugs and leads and gave the TB a good clean out and checked for any vacuum leaks,also cleaned the battery and the terminals and also reset the PCM several times but to no avail. Also has a brand new Battery as well,the surging issue started before the new battery,it actually started after i got the car back from getting the new trans,The mechanic there told me it was normal and that the ECU would reset itself after a little while,and it hasnt,So i asked the guy that did the mafless tune to have a look at it for me and he said it all looks normal,but it isnt.any ideas guys???

Just wondering if you guys have any suggestions or if anyone has encountered this problem before,i have read alot of things on here about the same problem,but all the things i have read so far havent worked,wondered if there is something i have missed or something that im not thinking of.oh by the way its not showing and fault codes when scanned either.

 

[st3r3otyp3]

Get a second opinion from another tuner.

 

[goldvnaero]

Get a second opinion from another tuner.

Hey there,thanks for the suggestion,i trust my tuner thoroughly but yeh i am at my wits end with this and its doing my head in trying to figure out what it is that is causing this to happen. Only after i got it back from getting the trans rebuilt with the stall that it has done this,do you think the stally could be confusing the ECU or something like that??it has had a touch up tune after the trans got done but that didnt solve the problem tho,it made it better to drive but didnt fix the revs goin up and down when revving it or when driving and slowing down.

 

[mrls1SS]

drive it harder

Sent from my GT-I9305 using Tapatalk

 

[NO HOON]

Have ya checked your o2 sensors?

 

[st3r3otyp3]

to me sound like a timing issue, not enough timing.

 

[07GTS]

if the stall is lighter and because its higher it could have an effect on the idle also being mafless the tuner should be able to fix this, i have simular issues with my clutch/flywheel are so much lighter than stock there isnt much rotating force at idle and needs to be tuned to compensate, the idle can be the hardest part of the tune...

 

[goldvnaero]

Have ya checked your o2 sensors?

yes i have checked the o2 sensors,theyre fine and both working correctly

to me sound like a timing issue, not enough timing.

i think i will take it to another tuner and see if they can fix it,seems strange how its only done it since getting it back from the trans place after the new trans

if the stall is lighter and because its higher it could have an effect on the idle also being mafless the tuner should be able to fix this, i have simular issues with my clutch/flywheel are so much lighter than stock there isnt much rotating force at idle and needs to be tuned to compensate, the idle can be the hardest part of the tune...

I guess that is a good point,a mate suggested basically the same thing,as in its the stall causing it, because it only started doing it after i got it back from there,Thanks for input tho guys, Much Appreciated

 

[goldvnaero]

oh i forgot to add that its also doing something else since i got it back from the trans place,every now and then when i go to start it,only when its cold tho,i turn the key and nothing happens,nothing at all,doesnt crank over,nothing,have power and lights etc,everything lights up on the dash and have interior lights and everything else works,so i turn the ignition off and on a few times then try and start it again and it works..bit odd.theres a gremlin in it somewhere causing these issues.Maybe a loose wire from battery to Starter motor or something??havent looked yet but thats my guess.Have Checked all the battery connections and Earth points and they all seem fine.

 

[07GTS]

if it dosnt start in park try neutral or push up on the shifter, could just be the nutral safety switch not engaging properly since the gearbox work