Hey guys, Been lurking for a while but only joined as I got my Z today. On the drive back from Sydney it randomly dropped a cyl (I think, WRX sound, hesitation to rev/build boost, shakey EVERYTHING) and limped it home to Canberra (80km/hr for 4.5 hours ). I've read and am going to try some of the things re: coilpack wiring, MTU etc.. but was wondering if any of you guys are free (preferrably tomorrow as I need this having sold my other car) you could swing by while I take a look. I did find a loose coilpack plug on cyl 2/4 (middle left, don't know the orientation yet) but haven't had a chance to rectify and try with the car running. Can't get ECU fault codes as its running a Microtech. Give me a call on 0411488128 if you're free tomorrow and hopefully you can help me out. Cheers guys Sean
Would love to help you out mate, but my knowledge is zero. Good luck with it though! Always good to see more Z's in Canberra
coil pack and injector connector plugs and a common thing to break on nissans of this age you can purchase new ones from cazracing.com.au and just crimp them on. mines done this before aswell but i ended up rewiring most of my loom. Andrew
First thing I would do is change the oil and filter now, if you drove it for 4.5 hrs with one of the coil packs not firing, the injector for that cylinder would have still been firing and pumping unburnt fuel into the cylinder which would have finished up in the sump, thinning out the oil and contaminating it. Then check all of the connections on your coilpack and fuel injector plugs.
Yeah complete service is on the cards for today/tomorrow. Had a stick in and checked out all the coilpack/MTU connections - all were in good condition. Most of my coilpack plugs are broken though. Injectors are firing happily. I need to source a second MTU to test to see if its that, anyone wanna come around and do a switcheroo for a bit? Sean
PTU??? likely your misfire/nofire would have been coil pack 5 or 6 (2 rear) ones coming unsecured. Particularly No 6 as it has the shortest wire of them all.
what side of canberra are you? im pretty busy today, but if you are in my area ill drop by for a bit and give you ideas on what to look for and how to fix it.
Yeah as I said before, if you were running on 5 all the way back then that corresponding spark plug would have easily been fouled from pumping fuel in, as they are only copper plugs Have you tried starting it again since? If it's a grudual thing and it just drops out over time, then I'd have my money on the PTU, injector O-rings or the fuel line that we talked about. Cheers Greg.
Well a MASSIVE thanks to all who helped today, in particular Charles (don't know your screen name). To sum up - it turns out we were running on 4 cylinders instead of 6, both duds on the RHS bank. We tried a second PTU and it made no difference. We then (through many and varied interesting techniques haha) found out that cylinders 1 and 4 weren't sparking. We replaced spark plugs with platinums and also sourced two new coils which cleaned up the idle/missing issue a bit but its still present. It still backfires occasionally and stalls at lights intermittently, mostly when backing off and coming to a stop. That being said its making 10psi instead 5psi now and also revs somewhat cleanly through the ranges, only seeming to miss a few times. No smoke is blowing on gear changes, startup or general running, even under boost. I suspect it may either be injectors or (sad face) loss of compression (but it doesn't blow any smoke?). Interestingly the original coils were all under 1.3 ohms and the original sparkplugs weren't fouled at all... If anything they were perfect. Since I've got a Microtech we couldn't run consult on it so I'm taking it into Ultimate Tunes on Monday to get a diagnostic run. Will also get them to test the injectors, possibly clean them and then run a compression test etc.. My coilpack connectors are horribly, horribly molested so I'll see about sourcing some of them. Tomorrow I'll service again and fix up some of the wiring - stereo wiring was a dogs breakfast and the amps don't actually power on at all. So all in all my introduction to Zed's has been a swift (and frustrating) introduction into contortionism. I'm just glad to have something in my driveway to tinker with again and the long, long road to getting it how I want begins. A massive thanks again to everyone who seemed to jump to my aide - I really appreciate it and hope I can repay the favour - but only after I get my car running again If you have any more suggestions then just let me know Cheers Sean
Glad it's working better Sean - I'll keep in touch. When you drove off I thought that I still heard a slight miss. CharleZ
well done ACT zedders ... and especially to Charles who has been a little quite, lately ... in looking after a very new member ... top stuff ... !!! .. yet another wonderful affirmation of the depth and excellence of this site .. especially given the amount of recent rubbish floating around ...
Well today was productive. I took out pretty much everything except the dash and seats and rewired EVERYTHING. Whoever installed the previous stereo system mustn't have done so before as it was a dogs breakfast behind there. Amps now power on fine however a bit more tidying up to do, namely in the engine bay (loose power lines running directly over a searing turbo wouldn't help... and I also moved the turbo timer to the centre console. However when relocating it I couldn't find a source for the handbrake to connect to the turbo timer. I tried the handbrake switch itself but as its a normally open switch I could only get the turbo timer to activate with the handbrake off. Where abouts is the wire located under the dash which is linked to the handbrake light so I can wire it all up correctly? Thanks guys, looking forward in hesitant anticipation to the diagnostic tomorrow to hopefully get some good news about the engine problems. Cheers and goodnight Sean
Well it seems Ultimate Tunes has found rust forming on the sparkplugs. Mechanic (who hates but has worked on numerous Z's) seems to think this may suggest a headgasket leak/blow. I can't remember which but a cylinder is down on compression too, I will have to find out the actual figure. My question - Can a headgasket failure cause the above symptoms (rusty plug, dropped comp.)? Startup is fine, no smoke blowing at all. Oh and for the ACT Zedders who helped me out on Saturday - he said the coilpacks are just fine . Now depending on price to pull the head etc... and bearing in mind I still have to do the 200k km service I'm contemplating just dropping in a new (factory rebuild) engine in and replacing the loom/associated hoses at the same time. I guesstimate around $6,000 for this, hopefully less if I exchange my long motor - feasible? Thanks guys, let me know what you think Sean
There is more possibility that the plugs are showing signs of the car not having been used for the last couple of years(due to to serious illness of the former owner). I drove the car a few weeks ago and it ran smoothly and had huge acceleration on tap. It also performed very strongly a few months ago(on the Doug Lunch Cruise)where it easily kept up with the rest of us whilst we were 'hurrying' to reach the Pub at Lapstone. There was no indication of head gasket problems at those times(and most definitely no drop in power or performance). If there is such a problem now, it may have occurred during your drive back to Canberra(and therefore may not have caused too much damage)so a new engine could well be overkill. Ask IB(Ian) or Zcar91(John) for some input.:zlove:
Yeah - we swapped the plugs twice though - once with coppers and once more with platinums and the rust has come about in 2 days so not sure there. I'm stumped, I may be young but I've worked on and built a fair few cars but I've never seen these symptoms... Yeah it drove strong during the test drive etc... So we'll see. Hopefully the problem is minor, I just want it to run... Cheers guys - will keep you in the loop.
That's really strange man, I've still got the original plugs I pulled out of the zed, I'll go check them out when I get home. There wasn't any rust on any of them though, just a little blacker than usual from over wear (and cracked insulators). Unless there was rust underneath the layer of carbon?
Ok guys - here's the mechanic's report. Cylinders 1 and 4 have moisture on the plugs with some corrosion forming as well. Mechanic reckons its a head gasket issue and would probably require 4-5 hours engine removal, 1-2 hours labour to replace the gaskets and another 4-5 hours replacing the engine plus parts and ancillaries on top of that. Crunch time - what does everyone think? Does it sound likely that the gasket is the cause of all of this? I now have the car back in my possession and the symptoms are still there (hunting, missing etc..). I'm unsure as to repair this engine then service (200k km) or just get a new engine and be gone with any more potential issues engine wise. Advice please? Also, John (Zcar91) and Ian (IB) - can you please contact me ASAP if you can? My number is 0411488128. Cheers guys Sean
You can change head gaskets with the engine in the car, not much fun though. If you do pull the motor and pull the heads off you might as well rebuild it, won't cost that much more to do a standard rebuild. Only really gets pricey if the valve seats have receded. Least then the engine would be good for another 200K Imported/second hand engines are always a gamble.
I'm still not sure that the diagnosis is correct(but it is possible). What was the result of a compression test on those two cylinders? Hard to imagine that it blew the gaskets on BOTH heads, simultaneously(I also feel that 10 hours to remove and refit the engine is a bit overboard). BTW, that engine is far from "stock", so replacing it with a "stocker" would be a backward step IMHO.:zlove:
Mate take take the plugs out and take some pictures. If 2 days is enough for the plugs to look visibly corroded/rusted then you would be able to see now. I've got all 6 plugs I pulled out here and they are all burnt with a layer of carbon on them, I've scraped the carbon back on 4 of them and they all look fine. A little burnt, but definitely not corroded or rusted. These plugs have been in the car ALOT longer than the ones I, you or the mechanic have just put in, so these would be perfect for comparison. Cyls 1 and 4 are the from the front, so they are easy to get to (you don't have to remove the balance pipe to get them out). Did you get the exact compression figures back? Dumping that amount of money and time on the zed without being absolutely sure isn't the best idea IMHO. Cheers Greg.
