george-ascona Posted January 3, 2013 Share Posted January 3, 2013 Hi guys, I have an Opel ascona b with the 2.4 cih engine from omega/carlton and I would like to give me some information for my problem. Every morning when I start the car..it cranks about 30 seconds before the engine starts up and then about 30 seconds the engine works like two cylinder and misfires on idle, but after a minute the engine works perfect on idle and during the drive. During the day when I start the engine it cranks and starts perfect but the next morning the same. I have change sparks plugs,leads, distributor, temperature sensor, I have checked the idle air control valve and the plugs and all works. I have a thought that it is the fuel pressure regulator or i should install an aftermarket, because in the morning I think when I crank the engine the fuel supply in manifold vaporized due to cold. Is this thought right. I am waiting your opinions for my problem!! Thanks in advance!! Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 4, 2013 Share Posted January 4, 2013 I have change sparks plugs,leads, distributor, temperature sensor, I have checked the idle air control valve and the plugs and all works. I have a thought that it is the fuel pressure regulator or i should install an aftermarket, because in the morning I think when I crank the engine the fuel supply in manifold vaporized due to cold. Is this thought right. If the car runs fine when hot then you should not be looking at the fuel pressure regulator as that works exactly the same when hot or cold. Fuel cannot vapourise as the injectors are closed when turned off and under pressure when running. The difference between hot and cold is............ the cold start system so you need to look at how that operates. What RPM does it idle at when cold? What RPM does it idle at when hot? Quote Link to comment Share on other sites More sharing options...
george-ascona Posted January 4, 2013 Author Share Posted January 4, 2013 If the car runs fine when hot then you should not be looking at the fuel pressure regulator as that works exactly the same when hot or cold. Fuel cannot vapourise as the injectors are closed when turned off and under pressure when running. The difference between hot and cold is............ the cold start system so you need to look at how that operates. What RPM does it idle at when cold? What RPM does it idle at when hot? Thanks about the reply mantadoc!! The car's RPM at idle when hot are about 900.. when cold about 400 to 500, car misfires and if i press the pedal it dies..so I leave it without pressing the pedal until it works fine( i am waiting for 1 minute). Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 4, 2013 Share Posted January 4, 2013 Are you sure the auxiliary air valve works properly? It's idling a bit low and when you press the throttle it'll have no vacuum and air speed through manifold and might well stall. If when totally cold the aux air valve pipe is squeezed flat within the first 30 seconds of running I would expect revs to drop further. If they don't it implies it isn't open when cold. Quote Link to comment Share on other sites More sharing options...
george-ascona Posted January 4, 2013 Author Share Posted January 4, 2013 (edited) Are you sure the auxiliary air valve works properly? It's idling a bit low and when you press the throttle it'll have no vacuum and air speed through manifold and might well stall. If when totally cold the aux air valve pipe is squeezed flat within the first 30 seconds of running I would expect revs to drop further. If they don't it implies it isn't open when cold. Ok I understand your point..as concern the idle air control valve a friend of mine checked it with a on-off switch and a battery, and when we had the switch on, the valve was open and when we had the switch off the valve was close. Now about the revs you said if I understand right..after the 30 seconds misfiring and low revs,then the revs increased about 1200 rpm and then dropped to 900 rpm where the car works fine. Edited January 4, 2013 by george-ascona Quote Link to comment Share on other sites More sharing options...
MANTAMAN Posted January 4, 2013 Share Posted January 4, 2013 Make sure the fifth injector at the back of the plenum is working when cold, which could be a faulty injector, no signal getting to the injector or the injection system temperature sensor not working Quote Link to comment Share on other sites More sharing options...
george-ascona Posted January 4, 2013 Author Share Posted January 4, 2013 Make sure the fifth injector at the back of the plenum is working when cold, which could be a faulty injector, no signal getting to the injector or the injection system temperature sensor not working Hi mantaman and thanks for the answer ..my engine's plenum has not a fifth injector,so I am going to see if the idle air control valve operates properly and also I will check the maf.. Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 4, 2013 Share Posted January 4, 2013 Hi mantaman and thanks for the answer ..my engine's plenum has not a fifth injector Yep that's the carlton stuff ,so I am going to see if the idle air control valve operates properly and also I will check the maf.. You don't have a MAF you have an AFM. Greatly different. Ok I understand your point..as concern the idle air control valve a friend of mine checked it with a on-off switch and a battery, and when we had the switch on, the valve was open and when we had the switch off the valve was close. Now about the revs you said if I understand right..after the 30 seconds misfiring and low revs,then the revs increased about 1200 rpm and then dropped to 900 rpm where the car works fine.No, you misunderstood me I said squeeze the pipe flat within the first 30 seconds and if the revs don't drop the aux was not open hence the painfully low idle. If it is open revs should drop further. Quote Link to comment Share on other sites More sharing options...
george-ascona Posted January 4, 2013 Author Share Posted January 4, 2013 (edited) Yep that's the carlton stuff You don't have a MAF you have an AFM. Greatly different.No, you misunderstood me I said squeeze the pipe flat within the first 30 seconds and if the revs don't drop the aux was not open hence the painfully low idle. If it is open revs should drop further. Hi mantadoc..today morning I started the car but with AFM unplugged..the car started immediately without any hesitation but I had to play with the pedal in order not to die..I plugged then the AFM again,but because the car was warm it started ok. Also I tried then what did you said me and when I squeezed the pipe the revs dropped..Moreover I found later an idle air control valve from a working carlton, I changed it and I am waiting to see what is going to happen tomorrow morning..but I am confused why the car started immediately when I unplugged the AFM Edited January 4, 2013 by george-ascona Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 5, 2013 Share Posted January 5, 2013 This is unusual, a car with AFM wiring disconnected should stall when you open the throttle even a little bit because it will not see the extra air to know to add fuel and will go lean and stall. so either aux air valve isn't working, or mixture is very wrong or you have air leaks, for eample in the bellow from AFM to plenum or in the auxiliary valve pipes. Also lean o inlet manifold and rock it up and down to make sure RPM does not vary when you do so. Also check timing. Also try throttle switch disconnected, car should run gfine without it but will not know when to go max rich or max lean Quote Link to comment Share on other sites More sharing options...
george-ascona Posted January 11, 2013 Author Share Posted January 11, 2013 This is unusual, a car with AFM wiring disconnected should stall when you open the throttle even a little bit because it will not see the extra air to know to add fuel and will go lean and stall. so either aux air valve isn't working, or mixture is very wrong or you have air leaks, for eample in the bellow from AFM to plenum or in the auxiliary valve pipes. Also lean o inlet manifold and rock it up and down to make sure RPM does not vary when you do so. Also check timing. Also try throttle switch disconnected, car should run gfine without it but will not know when to go max rich or max lean Hi mantadoc..sorry I haven't reply earlier..but I was busy with the ascona!! Finally I fixed the problem as two cold mornings now..engine fires up immediately..i stripped the ecu harness..and I found that the coolant temperature sensor wire had cut..also i change the relay combination (for wiring harness and fuel injection system) as the previous relay had a fail circuit..because it was burned due to the fixings that support the relay into the relay cover were bad and broken..and the circuit touch the cover and create short circuit!! so until now the cars starts nice even with cold !! mantadoc thank you for your help!! I appreciate that!! George Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.