Engin Probz Help LOL

sean1979

hey guys i have a 53plate astra mk 4 2.2 sri and i am having some problems that i cant figure out.

when i start the car from cold the engine starts racing it revs at 2500 and stays there for about a minute or so then drops and starts fluctuating between 400 and 800 revs.
it seems to try and cut out then revs itself up then goes to cut out then revs itself up again and continues to do this untill i switch the engine off and remove the keys.
the emissions light and traction light are lit up too.

i have cleaned the throttle body and egr and had the plugs changed and the coil pack checked and all seems to be fine.

any help would be much apreciated coz i am really stuck.

thanx guys 🙁

dragon-sri

Maybe idle control valve? One of the other guys will probably know. I'd be inclined to hook it up to a code reader mate. So many damm sensors on these new cars notsure.gif

sean1979

i had vauxhall take a look and they found nothing.

i will say though once the engine is slightly warm the car runs perfectly and no lights or engine troubles, its only when left overnight.

i have also checked the plug holes and they are perfect no cracks or leaks.

there is no vacume problems either.

i am just baffled and lost lol.

BURT150

That is a bit odd.

Could be a coolant temperature sensor fault.

The sensor gives a resistance as to how hot or cold the car is so it might be worth looking at or just take a punt for £12.

And welcome to the site :thumbup:

sean1979

i will try the cts and see if that works.

s999dave2_2sri

i had a similar fault about 3-4 weeks ago and it was the coolant temp sensor, £14 from dealer :thumbup: worth a shot

BURT150

Let us know how you get on :thumbup:

sean1979

no probs will go to vaux 2moz and get a cts.

i will update at every turn.

thanx again guys.

si_c1978

no idle air control valve, ecu electronicly positions the throttle plate to compensate :thumbup:

sean1979

rite guys i bought a cheap code reader today but i will say that for £70 its pretty damn good.

i scanned the car and it found the following errors:

P0107- MAP/BARRO Circuit Low Input

P0405- EGR Flow Sensor A Circuit Low Input

P0606- PCM Processor Fault

it also came up with U2900 and P0606 P wateva they mean lol.

i also cleared the faults just to see if there is any difference.

i am taking the car for a spin tonight then i am going to scan it again before retiring, then i am going to rescan first thing in the morning so i can get a better picture of what is going on.

does anyone have any ideas on prices.

BURT150

That is a bit odd :think:

It might pay you to check for an air leak and check the map sensor isnt blocked up.

When the engine is running spray some wd40 at the inlet manifold and throttle body and see if the engine note changes or try's to die.

Dont go mad with the wd40 tho. Also have a look at the fuel evap pipe vacume next to the throttle body, the egr pipework and all other vacume pipes :thumbup:

sean1979

UPDATE

i took the car for a run and when i got home i re-scanned the car and the only error i got was the P0606.

i am told that its the ecu so i need some advice guys.

would re-flashing the ecu be a fix or would i be looking at an £800 repair bill.

MikeS

TIS says that if any of these fault codes are also present

P0601

Internal Control Module Memory Checksum Error

P0604

Internal Control Module Random Access Memory (RAM) Error

P1621

EEPROM Failure

then reset ecu with tech2

Reset concerned control unit (engine or immobiliser control unit) with diagnostic tester before replacing. Select immobiliser in the diagnostic tester and call up the corresponding test in the menu ADDITIONAL FUNCTIONS. Ensure that both control units are never reset and replaced at the same time.

if non of those codes are present then the ecu will need reprogramming

as these ecu's are pretty common now u can pick up ecu, chip & transponder for £100

MikeS

http://shop.ebay.co.uk/i.html?kw=astra&kw=2.2&_kw=ecu

pretty much plug and play m8 and takes minutes to replace

sean1979

thanx for the help guys i am going to book it into vaux tommorow and get them to flash the ecu with the new software and see if that works.

will post if all goes well.

sean1979

rite i went to vaux today and they charged me over £100 to look at the car and then told me that i would need a new ecu. :thumbdown:

i thought bugger that and went home.
my m8 then suggested i try an egr blanking plate, which i did and then took the car for a spin an to my surprise the car was idling as it should and the throttle was back to normal but the engine was hot, also the rich fuel smell went away.

we then figured out that the ecu was throwing up these faults coz the egr wasnt working properly and that was causing the map sensor to give false readings which then tripped the emissions light and the ecu.

i have to wait untill the engine is cold before firing her up again to see if the plate has helped. will post if that has fixed my problem. 😃

sean1979

well guys i have fired up the car and guess what the blanking plate hast made any difference so it looks like its back to square one. 🙁

vocky

could be an air leak or throttle body problem

MikeS

i would get some obd2 software and get live readings of your sensors m8 - DTC codes wont tell you the full story, they simply tell you if there is a fault concerning the sensor or circuit

i know vauxhall are right gits now where they just plug in a tech2 and clear down the codes and if the code re appears they advise to replace sensor - they will not do any further diagnosis unless you agree to pay extra

you need to do actuator tests on the EGR valve, live sensor readings of the map sensor, cts, lambda, tps before you can think about replacing ecu & loom

if you got a laptop we can advise on the software to get

sean1979

i bit the bullet today and paid vaux to check the car, it turns out that i need a new ecu and loom.

i refuse to pay over £1000 to get the car sorted when its their fault for putting the ecu in such a stupid place.

i cant believe that a new ecu is £737.56 including vat.

a software update and reprogramming of the keys is £150

and a new loom is £200 plus vat

total £1087.56 and wateva else they decide it might need.

its an absolute joke :x