This VW Scirocco came into us with an intermittent running fault, it would randomly put the engine management light on and go into limp mode.
Firstly we carried out a diagnostic code read to see if there were any stored codes and what they related to?
Several codes were stored relating to faults in different systems! Oxygen sensor, Boost pressure and EGR system.
We decided to carry out a smoke test on the intake system as all of these faults can be affected by an air or boost leak.
(A Smoke Tester fills a system with lightly pressurized smoke allowing the user to see any small leaks that may not be obvious to the naked eye.)
We found a leak from around the inter-cooler area but the car needed stripping further to be able to access this area, once the bumper had been removed we could see clearly that there was a split in the inter-cooler housing which was small enough to allow the car to still run reasonably well but bad enough to throw out several sensor readings.
Big Strip Down To Remove The Inter Cooler.Split Inter Cooler.
After we replaced the inter-cooler and cleared all related fault codes we carried out a road test and checked live data, all sensors were reading as they should and the car drove perfectly without putting the engine management light on and no more limp mode.
During the strange and worrying time of the Corona Virus it is not only ourselves and our loved ones that we need to consider but also our cars and vans.
Leaving vehicles standing for long periods of time is not good for them, doing just a couple of simple things once or twice a week will help keep your car or van fit and healthy so that when you do need to use it it will be ready and not let you down.
Firstly, start the car or van and allow the engine to run until it starts blowing warm air from the heaters inside the car (make sure to turn the temp to hot so you know when this happens) this will allow the alternator to put charge into the battery and help keep it healthy. This will take around five to ten minutes.
Secondly, when your car or van has warmed up sufficiently, release the hand brake and roll the vehicle backwards and forwards gently applying the brakes to slow you in each direction. This will stop your brakes from seizing on and also move the weight around the wheels reducing the chance of deforming the tyre carcass whilst it is being left standing.
Also it would be beneficial to visually check the tyre pressures by making sure they all look similar, if one looks flatter at the bottom than the others you may need to physically check the pressures with a gauge.
If you are feeling really brave you could check your under bonnet levels such as Oil, Coolant and Screen Wash, but only do this if you feel confident.
For any more information or if you find a problem feel free to contact us on 01332 205070 or by email on info@aaronsautos.co.uk or through our Facebook page.
We had a Mini cooper S come into us with several fault codes in its ECU (engine control module) relating to different faults and had no boost pressure until high revs when being driven.
Once we had cleared the codes and ran the car up to read some live data it was quite puzzling! we were still getting codes relating to boost pressure control, yet everything we checked seemed to be working as it should.
We checked boost pressure sensors, MAP sensors, MAF sensors, turbo actuator, boost pipes but we couldn’t find a fault with anything. After spending couple of hours checking all these items we decided we needed to check the timing of the engine which meant removing the rocker cover to allow access to the camshafts.
Once we removed the rocker cover we noticed something strange, the top timing chain guide was missing! the mounting bracket was still in place but the guide itself was missing.
Chain Guide Broken Away From Bracket.
On further inspection we noticed that the missing guide had broken off and dropped down in-between the timing chain cover and engine. we removed the broken guide and carried on with checking the engine timing.
When we fitted the engine timing tools we could see that the inlet camshaft was at least one tooth out of alignment. As we started to strip the engine to remove the timing chain and guides we noticed that as the top guide had been rattling around inside the timing chain cover it had caused damage to the other guides!
We removed the sump to check for any other debris from the damaged guides and found quite a few bits, one in particular had managed to wedge itself inside the oil pick up, luckily the gauze filter had stopped it being picked up and thrown around the internals of the engine.
Debis In The Oil Pick Up.
After removing all the debris we fitted a new timing chain kit including new guides and a new tensioner, rebuilt the engine using new gaskets and seals where required and making sure that the engine timing was now correct.
Now that the engine was ready for testing we made sure all codes were cleared from the ECU and started the engine, so far so good, no codes had returned and the engine sounded a lot smoother.
Time for a road test to see if we had cured the boosting problem, the car drove faultlessly and had full boost from the off.
This just goes to show that you can’t rely on fault codes alone, the codes in this car had us chasing our tale for while until we decided to go back to the start and check basics.
What we presume had happened in this case is that the chain guide had broken dropping on top of the crank gear and jamming it enough to allow the chain to jump a tooth which in turn meant the engine timing was out causing our running fault.
