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Nathan B
Nathan B, Nvq3 motor mechanic
Category: Vauxhall
Satisfied Customers: 3
Experience:  Over 20 years experience including running my own garage working on a wide range of vehicles.
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I have a Astra mk4 year 2000. The exhaust is making a noise

Customer Question

I have a Astra mk4 year 2000. The exhaust is making a noise which i can best describe as a popping sound! The acceleration is hestiate and the car tends to shake when it is idling and i press the accelerator. All this only take place when the car is at its operating temperature. It doesnt happen on first start up when the car is cold.
Submitted: 3 years ago.
Category: Vauxhall
Expert:  Shantal-Mod replied 3 years ago.

I'm Shantal and I'm a moderator for this topic.

We have been working with the Experts to try to help you with your question. Sometimes it may take a bit of time to find the right fit.

I was checking to see if you had already found your answer or if you still need assistance from one of the Experts.

Please let me know if you wish to continue waiting or if you would like for us to close your question?

Thank you,

Customer: replied 3 years ago.

Not yet had a reply will continue to wait!

Expert:  Mike replied 3 years ago.
Hello and Welcome..

My name is MIKE - Im happy to help / advise you -

I need to ask a couple of things to clarify events -

What exactly has been done with the ECU?

WHEN was that done ?.. In that you say... "....Popping exhaust note started only days before ECU was removed...."... ??

Are you saying the popping noise was there before the Ecu had work done... and its still there now - or , its only there after replacement?

Does the engine fault lights come on at switch on- and go off when engine is running?

What is the mileage?

What is its service history like?

HAs anything else been done other than / added to what you have mentioned above - any tests / parts replaced etc?

Any current fault codes / diagnostic results etc?

Please also give me the cars FULL reg number...

--- The more you can tell me , the better I can help you - but at least the answers to the above please - Thank you.

When I receive your reply, I will get back to you asap thereafter -

Rgds, MIKE...................................

Customer: replied 3 years ago.

Hi Mike sorry for the delay in replying. The answers to your questions are as follow. The car started to go wrong in September of last year when i was about to go on Holiday. When i started the car up from cold all the usual lights came on but as they went out the Engine Managment Light stayed on. Once the car had warmed up the acceleration was hestiate and the Engine Management light was still firmly lit. I drove the car like this for the weeks holiday and then returned home. The popping sound from the exhaust had not yet appeared. I then put the car in for repair. The garage diagonised the problem as a faulty throttle body assembly. They fitted a new assembly but the problem was still there. In order to save costs the garage removed the new assembly and fitted the old one as they now thought it wasn't to blame! The Engine Management light was still on and hestiate acceleration. The garage then decided to call in a Auto Electrician. The conclusion he came to was that the ECU was damaged or the wiring to and from the ECU was damaged in some way. He also fitted a earth lead from the ECU to the battery, something i was rather puzzled about because the car had never had this earth lead as orginal. The garage then quoted a figure of £1300 to have a new ECU fitted. At the time it was impossible to meet this figure so i decided not to have the work done and continue running the car until the situation improved. The garage advised i could do this on a low mileage basis. As the weeks went by nothing changed and the car didn't get any worse. During the time i was running the car a friend was able to use his OPCOM diagnostics software on the car. The laptop displayed code PO505 Idle Control System Malfunction. Some weeks after this was when the popping sound from the exhaust started. I assumed at the time that things maybe were getting worse and the ECU should be looked at. Because of the cost i decided to have the ECU tested and rebuilt which was on the 18th March 2014. I dont have a written account of what work was done but i was told on the phone that a circuit had been replaced? I actually removed the ECU and re-fitted it. When the car was started again the Engine Manangement Light was hestiate to go out but did eventually go out and has remained so. No lights at all appear on the dashboard now. However the popping exhaust note and the hestiate acceleration still remain. The mileage on the car is 120,000 miles. Reg number is W266 UAN Servicing is complete and up to date during the last three years i have owned it. The following is a dateline of how things have transpired

1. Sept 2013 Management light and hestiate accleration appear

2. Sept 2013 Car used on holiday

3. Sept 2013 Car enters garage, exhaust note normal, engine

management light on, accleration hestiate

4. Sept 2013 Garage remove throttle body assembly fit new one but

no change. Old assembly re-fitted. Tests done and advice given on

ECU. Engine Management Light and exhaust note still present

5. Oct 2013 to Feb 2014 car is run. Diagnostic check done. Code

PO 505 Idle Control System Malfunction appears

6. Feb 2014 Popping exhaust note appears

7. March 2014 ECU removed. reconditioned and refitted. Engine

Management light goes out but popping exhaust note and hestiate

acceleration still remain


Hope all this helps!! Regards Anthony



Customer: replied 3 years ago.

Not yet had a reply and a solution to my problem!

Expert:  Mike replied 3 years ago.
Hi again -

This is MIKE who responded to you as above.

Im afraid I have to apologise to you as well...for the delay this end. Im afraid I have had to be off all least week due to system issues - I can only apologise -

So - I have noted what you have said above by way of a response to my info request - but as there has been the delay - please just clarify / let me know if indeed you do still need help with this - and then if so - we can carry on...

Kind Rgds- MIKE......................