Vectra SRI 150 - rough idle

MikeS

MikeS

Former Staff
Senior Member
viewtopic.php?f=3&t=11465

the car should start fine when cold with the cts unplugged as the ecu uses a default value - something like minus 20c

the fan should kick in immediately and stay on
 
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M

MarkGolf

Member
Well, I've changed the sensor but the problem persists! As soon as I unplug, it runs smoothly but the fans did come on this time! I really don't get it now.... Why would having that sensor plugged it make it idle like crap?!
 
M

MarkGolf

Member
Yeah, unfortunetly not!

Im really stuck now, I just can't understand how the coolant sensor causes the issues.. I'm going to fix the exhaust blow and then reset the ECU and see what happens then. Doh
 
MikeS

MikeS

Former Staff
Senior Member
as soon as u unplug it is pumping more fuel in based on reference engine temperature

if u unplug the sensor then the fan kicks in which is good !

once u rule out mechanical such as incorrect timing, blocked cat, low compression then it can only be fueling or ignition

might be worth buying some obd2 software and retrieving the various sensor readings

i spent 4 months messing with my poor idle to find it was a blocked precat, does she rev easy and hit over 5k when warm or cold ?
 
Micro

Micro

Member
i have tried spraying carb cleaner arround the inlet manifold whilst the engine was running, i noticed nothing. if the egr cheater dont work i guess il have to try a new throttle body, its been off and cleaned a few times now but makes no difference.

if the timing chain was streched, could it cause this? engine has done 44k & ive no idea if its been changed, has no rattles though.
 
MikeS

MikeS

Former Staff
Senior Member
you would get the tell tale signs anyway, severe rattling on cold start and idle

like i said if it aint mechanical then it has to be fueling & ignition
 
Micro

Micro

Member
As if having a lumpy idle wasn't bad enough, today whilst driving home after work sitting in traffic my car started to missfire and was running on 3, i got a eml and traction light come on, it wouldn't rev past 2000rpm and was tring to idle there too. it appears to be an intermitant fault and after 5 mins or so it went back to normal running, only for it to start running on 3 again a few minutes later. still doing the same thing now its sitting at home on the driveway.

Just had a mate round to read my ecu codes on his mac tools scanner..
P0378 REF TIMING HIGH
RESOLUTION SIGNAL B
INTERMITANT ERRATIC PULSES
C3F83 UNIDENTIFIED
U3111 UNIDENTIFIED
P0778 PRESURE CONTROL
SOLINOID B ELECTRICAL
B0387 UNIDENTIFIED
U1000 UNIDENTIFIED

These mean F A to me, anyone got idea what these refer to, or how to fix my car. :(
 
MikeS

MikeS

Former Staff
Senior Member
p0378 would relate to your crank sensor

p0778 is for automatic gearboxes :)


and your m8's scanner hasnt picked up the correct vxhall codes m8

last time i saw those codes is when an rac man plugged in his tiny little odb2 reader [size of a mobile fone], i plugged in my vauxcheck interface and didnt show those codes except for a random p0300 misfire

u need to either get hold of a proper reader that is elm327 compatible and supports vxhall dtc codes or a trip to vxhall to plug in their tech2

so those codes i wouldn't take a pinch of salt with

where do u live ?
 
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