GenIV Electrical issue

[stiffy]

Hi,

My car has been playing up lately, defaulting to limp home mode (not a good thing if you nick name is STIFFY ).

It happens while taking off from a start, once every 10 times more or less.

I simply turn off the main power switch (its in the cabin) for 10 seconds it resets the computer and all good.

I drove the car yesterday to work and it only happened once, I did notice that the volt meter was just above 12v (it is normaally just above 13v).

The details, GenIV 6 litre, heads, cam, exhaust, standard GM computer,
25% reduced crank (hence the low voltage) it has gone into limp mode a few times on the track if I buss the rev limiter too much or spin off.

Assistance required.

STIFFY

[sideshow]

Buy a cheap obd2 scanner and see what codes u get
How long has it been running
Do u loose abit of power or do u loose the pedal completely

[sideshow]

Buy a cheap obd2 scanner and see what codes u get
How long has it been running
Do u loose abit of power or do u loose the pedal completely

[sideshow]

Has its started since u got a tune
Probably torque reduction coming in
Maybe ecu has an auto tune

Double check alternator charge with good multimeter at the battery terminals and if its 12
Then u have alt problem which could be related to tune or wiring
Should be around 13.5 v
Did your tuner flash a holden tune over the top of the ecu which was from USA?
Is it a loom ecu kit from USA

[stiffy]

Sideshow,

The car was wired by John C a few years back, he sent the harness to you as it was the first GenIV he had done.

It was tuned a couple of years ago by Trevor S in Shep, no issue until a few weeks ago when it started to cut out. The car will idle, the pedal moves (fly by wire) but it does not rev.

The alternator was replaced a couple of years ago (got wet) the volts run above 12 just since the 25% reduction pulleys were installed, kept blowing up the power steering pump on the track.

STIFFY

[Gav]

If your pedal or throttle body is knackered that would probably do it.
Maybe it is time for a FAST manifold and throttle body upgrade?

[Gaz64]

A Tech2 or Tech2Win like I use at work would help. You either have a pedal issue (APP1 or 2) or throttle body issue.
ECM data, and actuator tests will reveal which one. Could be a wiring or component fault.

[sideshow]

Cool. Least u got afew years out of my loom heheheh
Give me yr number or call me when u goto work on it and ill try to help u
As some stuff I can't say on here and would take ages
Or if u want a good code reader I bring some in from china thru my supplier
Or goto repco and get one
Do your brake lights work ok

[sideshow]

Maybe check if brake lights work just when it goes to limp mode

[kyleb]

Stiffy,
The DBW throttle bodies can give this problem. When I was setting mine up I used an old LS2 DBW TB and it kept going into limp. Replaced it, then all good.
If you are going to club meeting on wednesday I have a OBD scanner which will show what codes your throwing or talk to Steve at MKAL in croydon. He sorted mine.
Cheers

[sideshow]

most of the dbw throttle bodies have issues due to people fitting the wrong ones
to suit the ecu and the tune
there is a lot of little things people and even tuners don't know about ecus and year changes and what goes with what

it can still be bad throttlebody but ive never seen one fail so far
ive just seen wrong one used

[stiffy]

Sideshow,

I will check the brake lights when it dies again.


kyleb,

I will be there on Wednesday.

I am assuming that DBW is the standard throttle body?

I purchased the motor as a crate motor, so it should be standard.

STIFFY

[sideshow]

ok cool
see what codes u get and let me know
some code will show that are nothing really
one might be air flow meter don't worry bout that
see if u find one that's to do with pedal or throttlebody or torque reduction

[sambo]

Stiffy I have a couple of ODB2 dongles (bluetooth and wired) that you can borrow to check error codes. There's a free Android app called Torque or numerous others no doubt also available on iPhone/Pad if you have one of those toys.