Hey guys so i was cruisingin the z on the highway, I was doing 80ks at 4th gear, as soon as the 100km/h appeared dropped to 3rd till 4000-4500 then boom! it was loud as literally made my car shake, after that tried to keep it to 100km, engine hesitated, now at traffic light my car has tendency to hold idle/rough idle, or die. Filled her up with 98octane bp before i went. I checked for potential vaccum leak, but my avcr still shows the same amount of vaccum when my car decides to idle. So here i went stop start through every traffic light till i got home. It accelerates fine but go past 3500 rpm it does backfire again. To me it feels like that backfire through inlet must have damage my MAF. I have twin sellin intake with translator so there are 2 MaF for each pod. I have driven my z hard at some point and this is the first time it happened. What do you guys reckon? Conclusion it drives after the bang, drive slightly harder and backfire occur, sometimes at traffic light it can hold idle but very rough, or just die once you put it in neutral, got home restarted it it was idling fine, and then gave it a little gas it stalled. Felt like.my MAF sensors got destroyed.....
Would be unlikely for you to damage a AFM with a backfire. I'd be checking for vac leaks first. And error codes. And possibly cam belt alignment.
Check for codes. If its not holding idle its probably TPS, also causes backfiring as it controls injector timing. Check codes, if no code, re-check TPS settign and if idle switch is activating.
hey guys got code 55 from that diagnostic, nothing else after that. Pulled all spark plugs (NGK Bkr6IX) all fouled so bad from burning oil from that inlet having decent amount of all. Out of 6 plugs number 3 cylinder is missing the sharp point before ground electrode. Going to pull the plenum for cleaning (might as well paint it with high temp engine enamel like black or so. Replacijg the plugs should i use the same or go for oem? i was boosting 12psi stock turbo. Also going to get me 750cc for my twin disco potato build. Cheers
also these pcv are they just pressfit or screwed in? Im going to get me new or still deciding to relocate it as I will be tracking this badgirl
If only this had been posted in English, perhaps the problems could have been solved by now? I've read it several times and still can't decipher any useful information that might give a hint as to what is happening.:br:
I wouldn't do a plenum pull just yet. You need to find the cause of the misfire/backfire. First thing I would do is change those plugs. As you have mentioned one plug is missing an important part of the electrode that puts out maximum consistent spark. Once that has been compromised it will not work properly causing rough idle & will stop working at all at certain rpms & backfire which in your case is around 3500rpms. If you normally have a little amount of oil in the combustion chambers it might be a good idea to have a compression check to see if it has an oil ring issue or buy plugs to burn off the oil but only if it is a small amount. So lets hope it's only a spark plug issue. Cheers Grahame
Check CAS first as suggested. Had a friend with a similar problem when the CAS plug slightly slipped off. If that seems fine after checking everything else also, I'd be looking at timing belt. Symptons also sound like when my Z was one tooth off after a late night timing belt install
I don't know how relevant it is, but the only time my car had a huge backfire was when one of the cats cracked (bottomed out on a driveway) and started to block up. The backfire sorted that out by shooting a big chunk of it out the exhaust.
Compression test done result awesome.... not 1) 140 PSI 2) 65 PSI 3) 135 PSI 4) 135 PSI 5) 100 PSI 6) 150 PSI I have a feeling my timing belt may have jumped or so since I do have slight leak around VTC area, could have possibly dripped on the belt and during hard acceleration may have slipped. Now my head got a decent amount of bent valve.... I used a compression test with rubber seal end not screw type. Even then it still shows variation with my cylinders.. I guess motor rebuild time P.s I had the plenum off when I did this, all turbo intake wide open, will check timing marks this weekend.
Although I find it quite weird, after that backfire when motor decided to hold idle its shows 525 hg cm2 vaccum pressure in my avc-r I normally get variation reading from 495-530, something shyt aint right
If you had a bent valve from contacting the piston it would not seal & you'd have no pressure on your compression gauge. The loss of pressure could be related to a valve sealing issue from wear. Did you retest with oil in the cylinder? In any case #5 cylinder pressure is way too low as well. Your guess concerning motor rebuild time is an accurate appraisal.
Putting a bit of oil in the cylinder during s compression test will help the rings seal and give a suggestion as what the problem is. If oil helps, probably rigs. If it doesn't then probably valve or gasket issue.
