Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Greetings all, i am looking for a bit of help with an Astra. Basically the car struggles to start, it cranks fine but struggles to fire up. It does eventually run after about 5-6 seconds of cranking. Idle is horrible with 1 if not 2 cylinders missing. If you give it gas then higher up the rev range the better it runs.
Someone has been here before and me has replaced the egr valve, 2 coil packs and the spark plugs.
A garage came to look at the car when the owner broke down with the EML light on and they said they thought it was the throttle pedal or the throttle body.
The owner said that the cat was also glowing red whilst on tick over but seemed to cool down when the engine was reved.
So i read the fault codes and my god was there codes. Must have been 20 for EGR signal, coils, injectors, throttle body, misfires etc etc.
I basically cleared out the full memeory and was left with an egr code (which im sorry escapes me at the moment)
With just this one code now in the memory the car ran exactly the same. So i set about verifying systems.
I have
good fuel pressure
Injector pulse
Coil control
Good even compression
No back pressure in exhaust
I have tried to verify spark with an adjustable spark tester but was having difficulty with the COP design. I have some leads which i am going to fit to allow me test spark 100%.
I have done amperage tests on each coil and 3 out of 4 are between 12-16 A with 1 coil showing 4 A. I got another coil to test and that gave me 12 A but did nothing for the runnig issue.
If i unplug the camshaft sensor the vehicle wont start, so i was thinking may be the
Crank sensor is dead and is using just the camshaft for engine position? But scoping both sensors i am getting an AC signal for each. Scan tool data doesnt show me cam or crank signals, there is no fuel trim data.
Maybe someone could provide me the block numbers for fuel trim?
Basically once i 100% verify spark (as i was getting spark with my tester but not consistently) is there anything else i should/could be looking at apart from mechanical timing?
No i have not yet checked the mechanical timing. At the end of my OP i asked if there was anything else to check apart from that. This engine is a MAP engine not a MAF but no, there are no codes for it
Hi
if you follow a procedure linking the symptoms to a a kind of logical tests then; One other test you can do is to volt or scope the MAP; power, ground and focusing on the signal. I'm not saying that the fault can found there, but based on the observation of glowing hot Cat which could be due to over rich mixture mostly at idle and less at higher rev, as an air leak in a MAP speed density engine can increase the pressure (less Vacuum) in the inlet manifold. Then the ECu might interpret/ or understand this condition as more load and increase the ON Injectors Commend.
Very Good luck
Bashar
Thanks Bashar, i did infact scope the MAP and looked at the signal however i have very limited experience of what i should be seeing. I did message Paul and asked him for a link to his MAP sensor section with a hope to gaining more knowledge on the system.
it will help if you have put the year and the engine code if you have it. I understand that you are in the UK. Here we use Autodata (Which I don't currently have access to). If you know any of your friend running a garage and use Autodata and being further lucky that Autodata cover this engine code and show pindata information, then you might know the normal MAP signal at idle and also at higher rev
Bashar
This is values for Z14XE, idling 1,3volts and accelerante briefly 4,9volts. If you have a intake leak will not be a accurate test. you should use a vacum pistol tester!
If you have a intake manifold leak is nice to use water spray with engine running/idling.
But as Bashar saying the best is let us know engine is!?
