Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

LS1 Revs high and runaway when moving

_R_J_K_

Well-Known Member
Joined
Dec 20, 2008
Messages
5,937
Reaction score
1,205
Points
113
Members Ride
Zenki S14
Sounds like valve timing, and with all the other parts checked if it is valve timing it would have to be cam degree.
What kind of timing chain kit does it have? Unless it's one that specifically allows it to be degreed, it will just be set with timing marks - which you could also mess up but you'd have to be suuuper careless as it's really obvious. Have you had a timing light on it yet? I'd almost wonder if your cam angle sensor and crank angle sensors have been bent out of the way slightly or aren't close enough to their teeth.
 
Last edited:

s_ikari2015

Fun IS easier with an 8
Joined
Nov 16, 2007
Messages
697
Reaction score
28
Points
28
Location
Australia
Members Ride
'02 Monaro V2 CV8, '90 Toyota Sera
It's a Howards double row kit to go with the custom grind cam. I believe it is fully adjustable as it even cam with a handy-dandy degree-ing chart.

I found on a forum post about a guy with an LS1 powered Cobra kit car that has EXACTLY the same rev runaway problem. It is totally 100% the Throttle Cracker/Throttle Follower base maps. They sometimes need to be retuned to suit bigger camshafts, reducing the stepping/opening of the idle air control valve. That's great to know, finally.

Tried a set of cheap ebay injectors to address the stutter/surge/bogging. Sadly they weren't even a full set of the same injectors, they were 4x 12Ohm and 4x 14Ohm... How do you screw that up when picking the parts? OMFG this car truly IS cursed! It idled like crap, but acceleration was better and it didn't seem to sputter or surge.... until it got to 3500rpm and it just died completely due to the mismatched injectors.

Hopefully I can get the correct replacement set from the ebay seller before the car gets sold... oh yeah.. I'm selling it. Listed on Carsales, Gumtree and this forum. There's a discount for forum members if you're interested.
 

s_ikari2015

Fun IS easier with an 8
Joined
Nov 16, 2007
Messages
697
Reaction score
28
Points
28
Location
Australia
Members Ride
'02 Monaro V2 CV8, '90 Toyota Sera
Installed a full different set of new injectors, it still stutters. Battery isn't happy being drained all the time so will have to replace that tomorrow. I know low voltages can cause some problems. The car is drivable so will drive it to my local parts/battery store and get the new battery. Then I'll take it to a tuner and ask them what they think should be done next (probably 8x coils and both O2 sensors again), and also book it in for a dyno tune so they can fix the throttle cracker/follower tunes as well.
 
  • Like
Reactions: Lex

Chuckmeister

Well-Known Member
Joined
Oct 18, 2018
Messages
213
Reaction score
307
Points
63
Location
Perth
Members Ride
VX SS 383 Harrop enhanced
I had major problems when I had my car cammed some time back. Cost me thousands replacing everything. Mechanic couldn't figure it out nor the Sparkey. I know yours isn't throwing codes by the look...mine was jumping into limp mode but wasn't all the time. Ended up being a seal in the throttle body not sealing correctly. The problem is a little different to yours but might still be worth having a second look.
 
  • Like
Reactions: Lex

s_ikari2015

Fun IS easier with an 8
Joined
Nov 16, 2007
Messages
697
Reaction score
28
Points
28
Location
Australia
Members Ride
'02 Monaro V2 CV8, '90 Toyota Sera
new battery fitted, which is good because now it's not even starting without mashing the throttle. Perhaps the chinese 42lb injectors are putting too much fuel in on startup. It revs fine now, doesn't seem to be struggling or missing when accelerating, just idling like crap. With the IAC valve connected and the AC on, it will rev to 2200rpm whenever the car is moving, but even with the IAC valve disconnected it still revs to 1500rpm when moving, not dropping back to 900rpm until the car is completely stationary for a couple of seconds. This still needs tuning to fix.
Next thing is new cat converters hoping the existing ones are blocked and screwing up things. Then I'm taking it to a different workshop and just saying "fix it, but cheap because I'm selling it"
 

Chuckmeister

Well-Known Member
Joined
Oct 18, 2018
Messages
213
Reaction score
307
Points
63
Location
Perth
Members Ride
VX SS 383 Harrop enhanced
mate,, cats are not going to change this issue. Injectors are likely not your problem....my bet is still the throttle body.
I'm not a mechanic but I've been through a few of these issues.
IMO remove the TB, make sure its installed right...its a simple (inexpensive) step anyway.
 
Last edited:

mpower

Well-Known Member
Joined
Jan 22, 2007
Messages
4,859
Reaction score
1,397
Points
113
Location
Brisbane
Members Ride
V2 CV8 Monaro and VF SSV Redline
how after all this time have you not a) driven it into the ocean or b) taken it to someone that knows what they are doing!?

In Perf WA Performance come to mind immediately.
 

s_ikari2015

Fun IS easier with an 8
Joined
Nov 16, 2007
Messages
697
Reaction score
28
Points
28
Location
Australia
Members Ride
'02 Monaro V2 CV8, '90 Toyota Sera
Took it to a different tuner. They spent the day tuning the new injectors etc... then handed it back. Didn't fix the 2000rpm while coasting problem. Took it back and said "hey, what gives?"
they said "oh, yeah, I tried but nothing I did seemed to work".
"So you just handed it back not fixing what I brought it in for? Great. So, now... fix it"

Three days of troubleshooting, they replaced the ECM (engine computer) and reflashed the tune they made previously. Suddenly the changes to the Throttle Cracker settings were actually being applied. Something went screwy in the old ECM and it just wouldn't actually read the changes they made to that part of the tune.

It's working. The high revs when coasting is entirely the Throttle Cracker (Enable and Disable Speeds), but the secondary problem of a mystery ECM fault caused so much butt-ache. The original tuner that did the tune when the cam was installed used a second hand ECM to save money, and I can pinpoint when it went wrong... 1 month later.

The thing that made me really crazy was I swapped the ECM over and it still did the same thing. So, either the new tuner replaced something else as well, or something in my car maybe killed that part of two ECMs?

Either way.... it's working. Who wants to buy the car now?
 

s_ikari2015

Fun IS easier with an 8
Joined
Nov 16, 2007
Messages
697
Reaction score
28
Points
28
Location
Australia
Members Ride
'02 Monaro V2 CV8, '90 Toyota Sera
how after all this time have you not a) driven it into the ocean or b) taken it to someone that knows what they are doing!?

In Perf WA Performance come to mind immediately.
a) I have been tempted, including to drive it through the shop window of the engine builder, but it's not insured for what I could sell it for. And b) I started a new full time job and it hasn't been a priority to take it to someone else until recently.
 
Top