hi my daughter has a 1997 Holden Astra F series 1.4 litre manual. when you drive around in it and pull up to a stop -lights , intersectionetc. the car stalls.
The engine management light seems to come on when engine is on overrun=down hills slowing down etcand car will stall at next stop.
Will restart easily and continue on sometimes engine management light will go outsometimes not. Have attached scanner and came up speed sensor fault.
Is this the sensor onfront of gearbox! any help appreciated thanks
incar.,
Jan 11, 6:23am
Get a diagnostic scan, dont guess. also clean throttle body, they have a pin hole that blocks and can cause engine stalling.
mechnificent,
Jan 11, 9:44pm
I'm betting it will be the speed sensor myself!
Some cars use the speed sensor to tell the difference between a shut throttle when stationary and a shut throttle when coasting down a hill. When you are coasting down a hill with the throttle right off they cut the fuel to give good engine braking. If they cut the fuel right off like that when you were stopped and throttled right off. the engine would die. So, they detect no speed and the ecu decides that it shouldn't cut the fuel right off but that it should inject enough to keep the motor going. They don't actually wait for the speed to reach zero, it usualy resumes injecting fuel at about five or so kilometersan hour.
scuba,
Jan 12, 12:49am
i did get a scan hence speed sensor. i sprayed throttle body with carb cleaner -may have to take closer look there, thanks
scuba,
Jan 12, 12:51am
I'll try the cheap option first-clean throttle body but willreplace speed sensor if need be - thanks for that will post result
bigfatmat1,
Jan 12, 12:57am
cam sensors are a common failure causing these symptoms on this particular vehicle either way save the guess work get it scanned
scuba,
Jan 13, 2:19am
ok thanks for that
mechnificent,
Jan 13, 2:54am
Hey Scuba, the speed sensor may not be faulty. It may be the signal that is faulty. When the car is moving a signal gets sent to the ecu which causes the fuel to be completely cut when you throttle completely off. What you have happening is that the fuel is not getiing turned back on again when the motion and supposedly the signal stops. There could be interference getting into the speed sensors signal/wire, making the ecu think the car is still moving. The other thing that could be happening is that the signal wire is actually broken and there is no signal so the ecu is disregarding the speed sensor and using a fixed speed. That could also give the symptoms you are getting. If you don't want to waste money replacing things that may not be defective the best thingto do is couple up a scanner, or an electrical gauge right at the ecu, and go for a drive and see what the speed sensor signal is actually doing. If the car is OBDii, there is also data saved in the ecu that can be read called "freeze frame", it is logged at the moment a fault is detected and a trouble code is set. If you read the freeze frame data it should be obvious whether the speed signal is getting through or not.
mechnificent,
Jan 13, 2:56am
What Mat says is correct too. they do have a history of faulty cam and crank angle sensors, but in this case since you have a speed code set it is almost certain to be the speed signal.
scuba,
Jan 13, 3:16am
was put on a snap on scanner came up speed sensor faulty .
apparentley sensor read 146kmh while parked .
tech not familiar with astras but familiar with scanner- was reset and i took car for drive -fault re occurred immediately,
i think he did the freeze frame thing.
mechnificent,
Jan 13, 3:25am
Interferance in the line or a dud ecu I'd say.
Electrical gauge fitted to the speed signal wire right at the ecu will find interference. Inspection of the ecu's inside may find a faulty component, otherwise the recommended practice is to fit a KNOWN GOOD UNIT. a ecu that you know is operating properly.
mechnificent,
Jan 13, 3:27am
If the speed sensor was showing a reading with the motor off. it's probably a dud ecu. the interference would only be while the motor was running I'd think.
scuba,
Jan 13, 5:48am
ok thanks again
scuba,
Jan 24, 3:06am
talked to franchise foreman advised possible sticky egr valve -removed and cleaned egr valve with carb cleaner- no more problems also advised to run on 95 octane as car runs better and 91 contributes to fouling egr valve. long road test car seems fine. thanks for advice people
mechnificent,
Jan 24, 3:11am
Ha, so much for computer technology aye!
scuba,
Feb 1, 3:17am
problem returned intermittently- have removed throttle body and cleaned properly this time -there is a small inlet in the throttle body to allow measured amount of gases from engine that gets carboned up and causes fault- again long roadtest looking good
incar.,
Feb 1, 5:44am
Get a diagnostic scan, dont guess. also clean throttle body, they have a pin hole that blocks and can cause engine stalling.
Edited by incar. at 1:25 am, Wed 12 Jan
Quoteincar. (8 )1:23 am, Wed 12 Jan #2
most dealers aren't aware of this pinhole, if they cant plug a vehicle into anything than chances are they cant fix it!
guest,
Sep 12, 9:42am
Hi All,
I have a Holden Astra 1997, did only 90,000kms. The problems I am facing is when the car is cold and starts the engine diagnostic light comes on, once warmed up I stop and restart the engine and the engine light disappears, and the car runs like a dream. I have changed the starter motor, the alternator, the crank angle sensor, throttle body, cleaned out the air intake sensors, replaced exhaust and removed the immobilizer. Please advise urgently as to what else to do.
Thanks
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