Guest bastaad525 Posted August 18, 2003 Share Posted August 18, 2003 okay, what exactly does a miss feel/sound like?? I THINK I know what it is but I'm not sure, and if it's what I think it is, my car is doing a LOT of it, at idle and low cruising. The exhaust sound is riddled with very erratic pop.... poppop... sound like a very quiet backfire, and makes the idle feel almost as lumpy as my N/A motor with the cam was as every time I hear the pop from the exhaust the car shakes a bit. It's very very erratic, sometimes doing it several times in a few seconds, sometimes only once within like 5-10 seconds but never much longer than this w/o it doing it, this is even with the revs up at like 2000. I have checked the plugs many times and they look good, though the exhaust smells rich, but I thought that was just because it's open and has no cat. What are some other causes of this popping? For anyone who hasn't been following along, I have already checked/adjusted/cleaned/fixed: Timing, vacuum leaks, plug gap, tps, all wiring harness connections at all sensors and ECU ports I wouldn't mind the popping so much but it can make the car kind of lurchy when cruising at low speeds, oh and I also notice that it does it less after the car warms up, but still does it noticeably. Quote Link to comment Share on other sites More sharing options...
john kosmatka Posted August 18, 2003 Share Posted August 18, 2003 Kind of hard to explain, its almost like an hesitation, or stumble when idleing. Quote Link to comment Share on other sites More sharing options...
Jwink25 Posted August 18, 2003 Share Posted August 18, 2003 "Think the motor might be missing" Just in case you haven't found it yet...have you looked under the hood? Jason Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 18, 2003 Share Posted August 18, 2003 Plug wires, cap, rotor??? Spray some water on the spark plug wires with it idling. You will see/hear the crossfire if that's the problem, or check resistance in the wires if you want to be really sure. Check for carbon tracks in the cap, and make sure you don't get a cap with aluminum electrodes if you replace it. They corrode fast. Could also be a bad spark plug. Clean/re-gap it as much as you want, if its bad you're not gonna fix it. A miss sounds just like you described. Jon Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 18, 2003 Share Posted August 18, 2003 I saw that one coming..... :malebitchslap: I'm not sure if this is so much a hesitation, I guess it could be considered that? It's mostly noticeable by the exhaust sound, the erratic popping. I guess it IS a bit of a stumble when I'm cruising around at low rpms.... so what are some other causes of this, other than the things I listed that I've taken care of already?? Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 18, 2003 Share Posted August 18, 2003 thanks for the tips jmortensen. If a spark plug were bad though would it still look like all the other plugs if you pulled them all? They all look light tan as they are supposed to. I'll check the cap and rotor today, and I'll swap out the plug wires, I still have my set of those expensive ass jacobs wires from my other car, dont know why the guy who did my swap just didn't put those on instead. I still haven't installed my msd 6a either, think that might help? Have to figure out a place to mount it... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 18, 2003 Share Posted August 18, 2003 I've got the MSD 6AL, and yes, that should help. You'll get 3 high voltage sparks until 3000 rpm, which really works well, sometimes too well. I had a hard time when I was trying to adjust my Mikunis because no matter what I did, the plugs looked the same. Finally hooked up an O2 to get the carbs situated, which I should have done in the first place. Everything I've heard about Jacobs wires has been positive, except price. Do that 1st. As far as plugs go, my 1st Z wouldn't rev past 5000 rpm. I changed EVERYTHING in the ignition except the plugs, because they looked great! I even took the car to a Nissan master tech, and we couldn't figure it out. Finally changed the plugs out (just out of desperation at that point) and the car ran much better, and revved to 7000. Plugs may look good but not be fully functional in my experience. Jon Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 18, 2003 Share Posted August 18, 2003 okay, pulled the cap, rotor and cap contacts looked pretty good, I sanded them down a little to clean them up. Replaced the plug wires with my jacobs set... yes they are good wires and very expensive at like $70 for the set Figured I have plenty of room where the washer fluid bottle used to be, to mount the MSD, as someone suggested. I'll have figure out just how to mount it though, the brake master cylinder and clutch cylinder will make it hard to get a drill at that area to tap the holes. So for now it's out... thinking of maybe just mounting it in the cabin, but I really dont want to unless I have to, or maybe I might have to pull the brake and clutch cylinders out... but that's gonna be a pain in the azz. I am more anxious to install it now though if it would really help with this miss. Then again maybe I shouldn't just for that same reason... it would just be a bandaid fix and not really solving the problem, right? For the plugs, I'll replace them this friday as I have no $$$ until then... you know you're broke when you can't even aford spark plugs eh? Though they do look good color wise, they also do like like they've been used for a while, maybe too long. But since nothing ever ends up being simple with me and my Z's, I dont expect this to solve the problem... I'll replace the cap and rotor this friday too just to be sure. I will say this, cleaning up the cap and rotor and replacing the plug wires DID seem to clean up the idle a bit, it was a lot less poppy afterwards. But, it still misses and stumbles really bad at low throttle cruise, anything under say 2500rpm, and especially on deceleration if the car is in gear. It seems fine at high or wide open throttle though, and will pull to 6k no problems now (before this wasnt the case). TPS was adjusted by a Z shop so I dont think that's it. Maybe the AFM is adjusted to 'loose' i.e. the flap is opening too much at low throttle? Other than ignition, what other problems can a miss be an indication of? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 27, 2003 Share Posted August 27, 2003 Hey there, My 280Z Turbo was running pretty smooth for the first few days after the swap. I had an exhaust system put on it last week. SS 2.5" including custom DP. They changed my O2 sensor in the process 'cause the original one broke. Now my Turbo motor exhibits these "pops" in the exhaust at idle. You can hear the "pops" at the tailpipe and feel them in the motor vibration. I am blaming the cheapo O2 sensor and I am trying to get an original one or a better one. good luck Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted August 27, 2003 Share Posted August 27, 2003 my car had an odd problem when idling, the RPM would flutter, the engine sounded like crap and sometimes the engine would stall. I had an old O2 sensor on it, it had to be bad after what it took to get it off during assembly prep. When I unplugged it, the idle smoothed out and I haven't had any stalling problems yet. It ran fine but after doing some other electrical stuff I had left the connector laying accross the top of the intake manifold. I started it and it ran like crapola. I popped the hood and almost immediately the idle went back to normal. I guess the contact was grounding against the hood and causing grief for the ECU. I moved the wire so it wasn't touching anything and the motor ran fine. Anyway... O2 sensors can cause some problems as I have found out. I need to get a new one. Unplugging it didn't do anything for the popping exhaust when I let off the gas. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 27, 2003 Share Posted August 27, 2003 same here when I unplugged it it really seemed to make no difference at all in the way the car ran. To me this indicates that it is probably a good idea to change it anyways but I'm 99% sure it is a bad distributor or CAS that was the cause of my problems. The spark timing was doing funny things, sparking really erratically on plug #1 and retarding instead of advancing when the throttle was opened. Quote Link to comment Share on other sites More sharing options...
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