View Full Version : Intermittant fault Z20 LET
bloofire
26-03-2006, 19:13
Hello there. I haven't made many posts on this forum but I have been reading it for quite some time - so thank you for all the useful information.
I have started to notice an intermittant fault on my 2002 Coupe Turbo. Occasionally when the turbo is making positive boost (ie accelerating) the car basically coughs and kangaroos slightly. It doesn't do it every time, I have no warning lights, and I haven't spotted a pattern. The other thing I have noticed is a slight misfire on the slow idle.
So my theory is that this is an air flow meter problem - it sending an incorrect voltage to the ecu causing fueling and ignition problems. Although I'm not sure if it is actually the AFM that controls fueling and ignition timing on this engine or whether that is the MAP sensor.
I don't think the misfire is related - probably plug or coil pack related.
A lot of posts on here refer to the Air Mass Meters on this engine being notoriously bad, so I'm guessing that's what it is.
Confirmation anyone?
Cheers,
Jon
bloofire
27-03-2006, 11:55
Really would appreciate your input on this.
AFM doesnt all ways show an engine management light.
Only real way if seeing if its the AFM is to try another one
where are you located bloo
MikeWarner
27-03-2006, 12:39
What spark plus are you running and what gap? Is your engine standard? If not, what peak boost are you running?
It doesn't sound much like a typical AFM issue.
Scottyboy
27-03-2006, 12:44
What spark plus are you running and what gap? Is your engine standard? If not, what peak boost are you running?
It doesn't sound much like a typical AFM issue.
Certainly doesn't, if it was and it caused the car to judder or kangaroo, it would almost certainly bring up a fault code.
Sounds more like an ignition issue to me. Spark plugs are the starting point, then coil pack after that I would have thought.
just before my remap the spark was being blown out causiing a judder
MikeWarner
27-03-2006, 12:53
I fitted some NKG BKR6EIX plugs at the weekend. I left them at the standard gap (0.8mm), and they are not igniting at all at 20psi! I have to drop them to about 0.7mm when I get a chance. This gives a very distinct judder at max boost - very much like what you describe.
This sounds a similar problem to what i have described in my thread about when my dad test drove a 888 astra on friday, and i have almost come to the conclusion that it is the DV that the previous owner fitted being fitted in the wrong place, but now im not so sure, maybe it is a colipack issue or something instead. Bloo - does your car have a bailey dump valve on it?
bloofire
27-03-2006, 16:11
Thanks for your replies guys.
I have just purchased a set of BKR6EIX plugs and am going to fit them at the weekend, do you recommend gapping them or not?
That's what is confusing me - no engine management lights coming on. This leads me to believe that it is unlikely to be the air flow meter. Therefore it must be related to the other misfire (on slow idle) or perhaps a sh1t tank of fuel with bits in it? As I said it only happens on high boost - strange...... I called the guy at Courtenay and he was doubtful that it is AFM related. I don't think it's worth taking to Vauxhall to find any fault codes as there have been no warning lights.
As far as I'm aware the car is running the standard map but it does feel quite quick. I will have to do a power run soon to find out what she's making.
888rich - I live near Ipswich.
I don't have an aftermarket Dump Valve/Blow off Valve/Diverter Valve so this is unlikely to be the cause.
If the plugs don't cure the misfire I will swop out the coil packs one at a time and see if that cures it!
PS. My lovely Brembo large caliper conversion is finally arriving (only 4 weeks late......) from Regal this week :cheesy:
pt_coupe
02-08-2006, 00:58
Bloofire,
Did you manage to solver the misfire?!
If you did, what was causing it?
Regards,
Claudio.