VS 5L won't start hot??

[oosty85]

Hey, as the titale says I'm having a problem with my vs 5L not starting when its been running for a while..the only way to make it start is to give it throttle and even then it stutters and wants to stall for the first 20 seconds.

could this be incorrect spark plug gapping?? mods to the engine (if this helps) are:

stage 2 cam & injector package, extractors.

it cranks over fine, but wont start. SUGGESTIONS PLEASE!!!

cheers, josh.

[lukey383]

did you have it tuned after the mods?

[Brett_jjj]

Try doing an error code check to see if that shows up anything.Heres a link to a post that show you how, if you dont already know how to do this ,Its easy to do,and only takes a minute.Also if no error codes show up, then check the hall effect sensor (HES) in the distributor,and the actual ignition module itself.Also,does it blow any black smoke when it finally starts up when this happens?
Checking error codes VR/VS (Revised)

[oosty85]

hey mate, i've been changing plugs and leads all afternoon and still no change after it warms up.. and yes it blows HEAPS of black smoke because the only way to start it hot is by pumping the hell out of throttle!!

what about spark plug gap?? my previous cars had the exact same problem (s15 silvia) and didn't start hot until i gapped them more.

i will go over your error code attachment now

[oosty85]

oh and i only bought the car recently and i dont know if it got tuned..but there must be a simple reason why it runs perfect apart from 'hot start'

[Brett_jjj]

Do the error code check in the link I posted above to see if theres anything up with any sensors etc.

[oosty85]

i did the error code check and i got a 2 or 3 flashes of "12" which is OK from what i've read. and then it would do another 2 or 3 flashes of "16" which is VOLTAGE UNSTABLE???

i also put my ignition module in the freezer for 10 mins to cool it down because it was untouchable after 5 mins of idle.. still didn't start even when that module was stone cold!! (would this freezer test even work??)

[BlackVXGTS]

DTC 16 is engine coolant temperature voltage unstable. Replace your coolant temperature sensor.

[Brett_jjj]

The coolant temp sensor is most likely the cause of the problem then, seeing its temperature related. With the temp sensor not working, the ECU doesnt know what temperature the engines at, so it doesnt know the right amount of fuel to inject into the engine etc so it can run properly.

[Vee-ard]

leaking injectors?

[oosty85]

ahh man you're a saviour if this whole problem is caused by a faulty coolant temp sensor!! so it is actually possible that this sensor can mess with the fuel at start up??? is it best to buy new from holden or a place like repco etc? prices? difficult to remove/install? thanks man!

and VEE-ARD, i can't be certain but there is a bit of greasy residue around all injectors..can't smell fuel when i touch it though...

[Brett_jjj]

Yeah,try to use genuine holden sensors.Some cheaper ones can be dodgy.

[oosty85]

yeah i will order it from holden first thing tomorrow and hope they have one in stock.

i found a great write up on this s temp ensor in case the next unlucky fella with same problem needs help!!
Change a Coolant temp sensor (V8)

[db_notso]

coolant temp sensor predicts how much fuel is needed at that operating temp
if is disconnected it goes to a safe setting (but car runs very poorly normally)
+1 put a new sender in
if this fails to fix and holding throttle flat to floor starts the car then this indicates flooding either leaking injectors or poor fuel maps
if injectors cheap easy if maps are wrong when hot you need someone to look at it for you

[oosty85]

holding it flat to the floor is pretty much not working after the first couple of times doing it. keeps stalling after about 2 seconds with craaaazy amounts of black smoke!! fingers crossed it's sweet as new after i replace the temp sensor.

spewin, i only bought this car yesty and i never thought to stop and start again whilst hot. it's got bigger injectors and cam. So it's running rich even without the extra fueling from sensor. definately not helping the cause!!!!

[db_notso]

bigger injectors and a cam.....
when its hot if you hold the accelerator down does it still run or stall anyway?
try disconnecting the sensor starting hot...

[oosty85]

ah ok so u can still start the car without sensor plugged in to interfere??

nah the car stalls away IF it starts with flat to floor

[db_notso]

should start with it unplugged but wont run very well.
but with that code in the computer it has a problem with it.
vs 5lite code 16 then computer sets default value of temperature to 92 degrees
thts some info i had on it... but from what im reading it wont make the car overfuel unless its reading incorrectly WITHIN its range so sensor is nearly dead

but if you unplug it thew computer should read coolant temp as 92 degrees and turn engine light on so would still run

[oosty85]

hell yes!!! you're a champ, i unplugged it and now she starts first go every time.. stopped and started it 5 times after it got hot. perfect! well it will be with another sensor.

it's been a lonnng day under that damn bonnet.

THANKS for everyones input, much appreciated

[db_notso]

too easy mate good luck too you