Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 First off, as I am apt to do, this is going to be a long post You have been warned! Okay, I'm hoping someone here can give me some oppinions what you guys think this might be. I've heard ping before, for sure (though not with the turbo motor so far as I know), and I've had misfire at idle/low load (turbo motor DOES misfire a little here or there at idle), so I kinda know how those things sound. But my car occasionally does something when I romp on the throttle and I'm trying to figure out if it's misfire or ping. Okay, this usually happens when I'm cruising on the freeway and suddenly go to take off. Say I'm cruising at 75mph/3000rpm, then I'll downshift to 4th gear (4000rpm) and nail it. Boost will jump up very fast, and will spike 1-2psi to 15psi. Sometimes, right when it spikes, I'll hear a loud TICK from the exhaust (at least, it sounds to me like it's coming from the exhuast), and I'll see a puff of smoke come from the tailpipe (not sure what color smoke as I usually drive at night, but I dont' think it's black). Sometimes, the car will stumble for that split second as well, though usually it does not do anything 'feelable', just the loud tick and smoke. It usually just ticks once. As I said, I've heard ping before, and this does sound somewhat similiar, but I'm inclined to believe it's NOT ping, for several reasons. Anyways, here are the details, reasons why I don't think it's ping, and some details on my setup: 1. the puff of smoke... wouldn't this be fuel that didn't get burned, indicating a misfire? 2. I'm running an RRFPR, and have dyno tuned it with a wideband O2. We saw that the RRFPR consistently would run pretty rich when boost first hit, like around 10:1 air/fuel ratio, and also runs generally rich overall. Now, I think I've heard from somewhere that running TOO rich can also cause ping, though this doesn't make sense to me (how rich is TOO rich?). I'm thinking, that initial richness, plus the sudden boost spike up to 15psi, maybe is 'blowing out the spark'? 3. I have my spark plug gap set kinda big, I think it's at .050" last I adjusted it? I have seen people say at higher boost levels (thinking of that 15psi spike) it's better to run like .035-.040. I though I could get away with the larger gap since I'm also running an MSD 6A and Blaster 2 coil. 4. I'm running a good I/C, stock heat range plugs, and 91 octane fuel. So what do you guys think? Sound more like misfire or ping? Could someone who has had their car misfire under high load like this describe to me what it sounds/feels like? Is it as I described? Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 21, 2005 Share Posted August 21, 2005 Well, that is really rich, which could cause a miss. Now your gap is insane! A lot of people have recommended running .030" gap on boosted applications. I think you might be running too rich, then coupled with the gap, it might not be possible for your system generate a good spark, causing the miss. Mario Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 yeah I think I'm gonna lower the gap right now. Thing is, I notice a difference in throttle response with the larger gap. Again... I only thought I could get away with that big of a gap because of the MSD and coil. Maybe I'll try like .035. EDIT: okay went out and pulled the plugs and regapped them from .050" to .035". I think .032 is supposed to be stock right? I wont get to test it out until morning to see if it cured the problem. I'm still really surprised that the MSD + blaster 2 wasn't able to support the larger gap... I know Thumper from these boards ran around .045 at 18psi of boost with similiar ignition components. Maybe this is a sign that my wires are already worn out... they are NGK also, the blue ones, I think I've had them for 2 years? Quote Link to comment Share on other sites More sharing options...
Forrest Posted August 21, 2005 Share Posted August 21, 2005 Are you running resistor NGK wires? You can't run those with MSD. That will definitely cause what you're describing. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 hmm I believe so? The guy I ordered is pretty Z-knowledgeable, and when I ordered them, I was under the impression that all Z plug wires would be the same. But he asked specifically if they were for the turbo motor, and I think I remember asking why and he said something about the turbo ones being resistor wires, so yeah I'm 99% sure they are. Quote Link to comment Share on other sites More sharing options...
Forrest Posted August 21, 2005 Share Posted August 21, 2005 Yes, it's fine to use resistor wires on a STOCK turbo motor, but not with MSD. Lucky for you, I can't imagine a simpler problem to fix than swapping out the wires. Get some Magnecores. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 hm, would I be able to tell just by looking at them if they are resistor or not? The only markings I see on the wires are like this: first, a symbol like the letter L written in cursive handwriting several times in a row, like a coil, then it says R-8 NGK SPARK PLUG WIRE. Does the coil symbol and/or R-8 mean resistor? Where are you guys getting your Magnecors from? I know a few guys on here think pretty highly of those wires. Also, what about the plugs? I'm using resistor plugs as well (the R in BPR6ES). Can anyone else confirm that MSD ignition boxes aren't compatible with resistor plug wires? I've never heard this one before. Forrest - so do you think that it is indeed misfire I'm having and NOT ping? Quote Link to comment Share on other sites More sharing options...
Clifton Posted August 21, 2005 Share Posted August 21, 2005 That's really rich plus the plug gap. I'm suprised it doesn't miss more than a little even with an MSD. The spark will go were there is least resistance. If that is ground somewere else it will do it. The power you are loosing running by running so rich. You are on the verge of misfire there too. You could drop the boost 2 psi and run 11.8 and make as much or more power and be. I have run resistor plugs (NGK) with an MSD 6a for over 10 years with no problems. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 yeah no offense to you Forrest but I highly question the whole thing about resistor wires and MSD. Considering how rarely this happens, and that the car does run fine generally, I have trouble thinking the resistor wires are 'incompatible' with the MSD, or wouldn't I be having much more severe problems? About the running real rich, it only runs rich like that when boost first hits, then leans out to about 12:1 as RPM's increase. This is caused by the RRFPR + the stock 280zxt EFI. The RRFPR can only move the entire fuel curve up or down, and the stock EFI likes to run real rich in the 3000-4000rpm range even by itself. When I dynoed with bone stock EFI/no intercooler/10psi of boost, the air/fuel ratio dipped into the high 9:1 at 3000rpm. Also, even the last time I dynoed at 14psi, and was adjusting the RRFPR between runs, I didn't see a very big difference from running it more lean, it picked up a little torque at about 3500rpm... only about 10ft lbs, peak power actually went down by like 5hp but I think both of those are within possible regular fluctuation limits from run to run anyways. The stock efi/RRFPR setup is a compromise, I know, and there's not really anything I can do about it... Programmable EFI is not an option for me now or any time soon. I do have an '88 300 ZX Turbo ECU and MAF just waiting to be installed. I'm saving up to have my wiring harness rewired soon so I can install that stuff, and hoping that will help with the super rich midrange. About leaning it out and running less boost, nah, I've dynoed almost every time I've made a change to my setup (boost/fuel changes)... when I upped boost and fuel power increased significantly. Anyways the air/fuel ratio is just about perfect where power peaks at like 5000rpm, it's only rich when boost first hits. So... still no one has even said yay or nay... does this sound like misfire or what? Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 21, 2005 Share Posted August 21, 2005 Hey bastaard just had a smiliar problem on my z last night. I just got her running and last night I turned the boost up too 17 spike and 15 hold. Right as the boost would spike it would stumble some of the times. I have the msd 6al w/ blaster 2 coil and magnecore wires. Only bad thing is I have some old bpr6es-11 spark plugs in there. I had them gaped at .050" then lowered them to .040 and the miss went away. I'm going to throw some new bp7es-11 in there today and put the gap at the the stock .043" It should be able to handle it. But I am fairly certain that you have a miss. About running rich have you played around with your afm spring. I am running the stock efi and a adjustable frp. The fpr is a 1:1. My a/f ratio is 12:1 when boost is building drops to 10.5:1 then goes to 11.4:1 I could lean it out alittle bit but I was just trying to get it close to what I wanted. I would try tightening the afm 3 teeth then upping fuel pressure 1 or 2 psi. This will make it more lean at idle, cruise, and boost build. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 okay small update. I regapped the plugs to .035, and leaned out the RRFPR slightly. I was pretty rough on it on the way home, doing several drops into 4th gear and nailing it, and I did not get any noticeable bogs, ticking sounds, or puffs of smoke from the exhaust. I'm not 100% convinced it's gone... as I mentioned this problem occured pretty rarely as it was. I am however, pretty convinced now that it was indeed misfire and not ping, based on what you guys have said so far, and the fact that leaning out the fuel definately did NOT make it worse. I just realized as well that my plugs are fairly old... they didn't look so hot when I pulled them out, so will make getting a new set of plugs a priority. I'll try to up the gap to .040 and see if it comes back. About messing with the AFM... actually I have already leaned it out a bit, to where the idle has stayed nice and smooth, if I lean it out any more it starts to roughen a bit and the light misfire that I get only at idle will start to worsen. I've tried richening it as well but honestly I can't go very far in EITHER direction w/o the idle worsening noticeably... I seem to have found the 'sweet spot'. I am starting to wonder just how much more I can lean out the RRFPR... I mean... when I tuned last on the W/B, it was very rich up to 5000rpm, in the 10-11:1 range, then leaned out slightly by redline to about 12:1. However, I've read time and again that detonation is most likely to occur when torque, and hence cylinder pressures, are at their peak, which for me, is between 3000-4000rpm. So I'm wondering just how lean I could safely let the top end go since torque has fallen off so much by redline (from 300ftlbs peak down to about 200ftlbs), as long as I keep the midrange in the 'safe zone' of around 11:1... would 12 or even 13:1 be safe for the upper rpm ranges where cylinder pressures are much lower? Again... I can only adjust the fuel curve as a whole with the RRFPR... I'm thinking I could gain back both midrange torque AND high end HP by leaning out the whole fuel curve a bit... but would it be safe? Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 21, 2005 Share Posted August 21, 2005 Only problem with the hige end leaning it out is when the demand for air is the highest. So the turbo is trying harder at 5500rpms then it would be 3500 but at the same boost. So the turbo is shooting even hotter air then normal. So although you have less power there and it is more likely to ping at lower rpms because of this you still have the problem with hot air being shoved into the combustion chamber. Worse case senario 13:1 could be done probably with no ping. I have even done a run at 14:1 with no ping (on accident) But on safety side I would try for 12.5:1 at your shift point so 5500-5700. I too have the problem with a slight miss at idle and when slowing down in gear. If I richen it up it goes away but then a/f ratio is way too low. I will live with the slight miss for now. Soon meqasquirt soon. Quote Link to comment Share on other sites More sharing options...
Forrest Posted August 22, 2005 Share Posted August 22, 2005 Read your MSD manual. Quote Link to comment Share on other sites More sharing options...
burnedbigas Posted August 22, 2005 Share Posted August 22, 2005 Where are you guys getting your Magnecors from? I know a few guys on here think pretty highly of those wires. Bryan, I just ordered magnecor wires from http://www.cyberauto.com. I paid about $85 shipped. Mark Quote Link to comment Share on other sites More sharing options...
akeizm Posted August 22, 2005 Share Posted August 22, 2005 When I got my car dyno'd last week it was misfiring when you got under it at around 4000rpm. This was because I was running too hotter plugs, and I had a too larger gap (.040") and that was causing the problem. The person doing the tune replaced the spark plugs and told me to run a gap of .026" (hes the turbo expert, pretty well known one so I trust his information). And said the higher the boost the colder the plug needs to be. Thats prolly be covered before but I thought I'd post it. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 22, 2005 Share Posted August 22, 2005 but hotter plugs shouldn't cause misfire, if anything they'd cause preignition. COLDER plugs are more apt to cause misfire since they don't burn off the carbon deposits fast enough. Kinda odd some of the conflicting info some of us get from people . Plug gap has been suggested again and again though... so I'm hoping that lowering the gap will be enough to cure the problem. Also I think it may just be that the plugs are fairly worn... I need to replace them soon. Those magnecor wires are expensive Does anyone know how the Jacobs wires stack up against the magnecors? I actually have a set of Jacobs wires that cost about that much, $60 or $80, one of the connector/crimps had broken off, I always meant to send them back since they are covered by lifetime warranty, but they made it sound like getting them replaced was goign to be a real hassle. Maybe I should follow up on that though and go back to the Jacobs? Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 22, 2005 Share Posted August 22, 2005 I have run both jacobs and magnecores. Not a big difference except I have found jacobs ignition systems suck on imports compared too msd so I stopped using there products. Long story short I got shafted of $250.00 when I was 17 so $250.00 was like $2500.00 now. So I with either run magnecore or Tuscan wires. The tuscans are very rare. I have run magnecore on my last three motors and noticed a difference everytime I installed them. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 22, 2005 Share Posted August 22, 2005 I WAS going to actually buy the whole Jacobs ignition system, but after talking to a few guys about it, hearing some not-so-great experiences, and then comparing that the MSD is SO much cheaper and even pro racers run MSD stuff... the choice seemed pretty obvious. The sales guy had already talked me into buying the wires though, and they worked great for me, and looked great... big fat wires and cool clips to keep them neat and organized. Anyways, as I said if they would work well I would prefer to use them as they would basically be free since they are covered by a lifetime warranty. Quote Link to comment Share on other sites More sharing options...
Guest Z Draci Posted August 22, 2005 Share Posted August 22, 2005 I have the same thing happen on occasion on my FULLY STOCK 280ZX turbo. I hear a pop then a slight hesitation before full boost. It happens when it's not up to temp as well. I always assumed that it was a misfire caused by a sudden spike in boost. I'm not entirely sure since I still have the stock boost gauge. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 23, 2005 Share Posted August 23, 2005 oh man yeah forget it if it's not warmed up... runs pretty rich when cold... generally I try to refrain from getting on boost until the motor warms up just to be nice to it, but there's been a couple times I wanted to take off in a hurry... man it will pop so loud that everyone in the vicinity will duck for cover. This isn't a pop like that though, what I was describing, just more of a loud, high pitched tick. Quote Link to comment Share on other sites More sharing options...
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