capt_furious Posted April 27, 2009 Share Posted April 27, 2009 This is a strangely intermittent issue I've been having ever since I swapped the motor & trans in my 260. Prior to the swap the car had been dead solid reliable with no issues to speak of. After the swap, it's been giving me no end of trouble and grief in various forms related to spark / running right. CAR SPECIFICS: Early 260 Z N42 L28 block & head. Round top SUs Unusual Chrysler 'orange box' ignition module conversion - more on this later. 5-speed trans w/out reverse safety switch. TROUBLE SPECIFICS: The car will run properly for extended periods, only occasionally giving me trouble, very randomly with no way to reproduce the problem until recently. Within the past two months, the issue has become pronounced, and has increased in severity to the point of my not being able to trust the car to travel even around town without issues. I have replaced most of the ignition system in an attempt to rid myself of the problem and have had limited success. When the problem occurs, the car will 'jerk' or cut out briefly, usually during acceleration. This was the first sign of trouble about a year ago. At the time, I attributed it to fuel delivery or just quirkiness. It has worsened to the point of killing the car while at idle or just off idle, stumbling at cruise, and stalling during acceleration from a stop. Just last week I discovered that the car will run in accessory mode. THE IGNITION SWITCH IS BRAND NEW, and is a stock-for-stock replacement made in Japan. I have no reason whatsoever to suspect it. While in accessory mode, the car exhibits all the hallmarks of my problem; stumbling power delivery, dies at low rpm, dies when power is applied. When the switch is turned back to 'run' and the problem isn't rearing its ugly head, the car will return to running fine. I'm aware that the car should immediately shut off no matter what the throttle position is when being switched to accessory mode. Currently, if the ignition switch is turned from run to accessory while throttle is applied, it continues to run until rpm drops off, then it dies. This is while the issue is NOT occuring. When the issue does occur(at complete random), all of the above happens while the ignition is in the 'run' mode. I have replaced: Ballast resistor Ignition module All related wiring connectors and numerous wires which were in questionable condition Coil Cap Rotor Plugs Ignition switch SUSPECTED CAUSE OF THE PROBLEM: I have no real knowledge of what exactly is causing this issue. It is extremely odd in that it is very random and intermittent. I just drove it 80 miles this morning and only had issue in the last few miles of my drive, which were limited to a stumble on acceleration. The car then started exhibiting the issue full-blown after a rest and restart. When the motor & trans were swapped, the new(to me) transmission did not have a screw-in bung for the reverse safety switch. It was previously in a 240. I removed the switch from its wires and taped off the ends. I'm not sure of the relevance of this issue, but I have included it. The car came wired when I bought it with a Chrysler 5-pin 'orange box' ignition module (click for link) with 4-terminal ballast resistor which eliminated the points system. The distributor has an air gap reluctor setup that I don't recognize(it's possibly a Slant 6 piece) but I don't have reason to suspect. Prior to the swap, I never had any issues related to this setup at all. The car ran like a top. When we(auxilary and I) tried to start the car after completing the swap, it would not start. We were getting no spark. A friend of his helped us troubleshoot it. He connected a wire to one of the ignition switch leads(blue wire with red stripe) and ran it as the Chrysler diagram shows the 'run' wire, to pin #1 and the ballast resistor. The car started and ran as it should with no issues at the time. I've been driving it like this since. I feel the above is a critical piece of information to solving the problem. Prior to this 'fix', the ignition module did not have a 'run' wire connected to pin *1 or the ballast resistor. However, as it currently sits, it is wired correctly for the electronic ignition system. I'm not sure how to fix this mess. I need a reliable car! If I can't fix this myself, my last-ditch fit of frustration solution is to take it to an automotive electrician, where I'm fairly certain a fix is going to cost me thousands of dollars of labor. At that point, I might as well buy another car, which I don't have the money for anyway! I'm in the Santa Rosa, CA area and could really use some help from someone. This car is my lifeblood - my only car - and it's killing me slowly. It used to be a reliable friend and it's become a source of constant grief and extreme frustration and doubt. I will try to get photos of the setup and related components. Help! Quote Link to comment Share on other sites More sharing options...
woldson Posted April 28, 2009 Share Posted April 28, 2009 The absolute cut in power sounds ignition/electrically related. If I got read correctlly, my gut tells me ignition. Why not just upgrade ignition compodants, lets say MSD.? Sound like somthing is heating up and causeing failure. Dose it ever do it when frist started? (dead cold) Do you have an low oil cut off switch running on the car? I may be on the wrong track here, since reading what you wrote was a little difficult to get. Its not you, its me, but,,, I still want to be "friends"! Quote Link to comment Share on other sites More sharing options...
srgunz Posted April 29, 2009 Share Posted April 29, 2009 Check voltage. You do need a full 12v to the box. Next the box has to have a very good ground where it is mounted to the body. A supplemental ground is good too. Did you get the plug in harness for that box also? Good idea. Quote Link to comment Share on other sites More sharing options...
capt_furious Posted April 30, 2009 Author Share Posted April 30, 2009 I should have made my post simpler - the key to the issue is that the car runs in accessory mode. If the RPM is high enough, the ignition still receives run signal, although it's spotty and cuts out at low RPM or under heavy load / acceleration. The major issue is that the car will switch itself to accessory mode while running without the ignition switch changing position. This will inevitably kill the car once RPM drops low enough, and prevent it from starting again until the condition magically fixes itself, which has varied from an instant restart to lasting several days. I've actually had no problems in the past few days. She's behaved herself. I can still manually position the ignition switch to accessory mode and keep the car running /stumbling if the RPMs are high enough, but the involuntary switch while running hasn't occurred since Monday. To answer Woldson's questions, it doesn't really do it when cold, if it does, it won't start at all. That possibly does point to heat issues. There's no low oil pressure cutout that I'm aware of. I'm pretty much stuck with my current ignition system due to funds and other matters. srgunz - I haven't checked the voltage yet, that sounds like a very good idea. I also need to improve the mount and double check the grounds. I did pick up an inexpensive small heat sink at a local electronic parts supply and stick it onto the transistor housing. I considered the plug in harness for the unit, and I might still do it - it would clean up a lot of the wiring more than I've already done. Quote Link to comment Share on other sites More sharing options...
woldson Posted May 1, 2009 Share Posted May 1, 2009 Ok ok, dose not the car seem (appear) to be in acc mode once the engine dies?? Me go check my ZX this morning. I'll get back:) Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted May 1, 2009 Share Posted May 1, 2009 Does sound like an intermittent ground problem as srgrunz suggests. Just to rule it out, I would clean the battery terminals and double check the battery negative gounds to the chassis and starter. I recently killed an electrical gremlin on my own Z that turned out to be a simple battery ground problem. Quote Link to comment Share on other sites More sharing options...
capt_furious Posted May 9, 2009 Author Share Posted May 9, 2009 The car behaved itself for about two weeks, and then gave me hell yesterday and this morning. I'm changing out the alternator tomorrow. Next act of desperation is the voltage regulator. Quote Link to comment Share on other sites More sharing options...
capt_furious Posted May 11, 2009 Author Share Posted May 11, 2009 Battery posts and chassis ground have been cleaned. There's one negative ground next to the battery (I assume this is the secondary in case the primary cable fails), I unscrewed it and cleaned the bolt and the connectors going to it. Any other negative chassis grounds that I should be aware of and check? Checking with a volt meter this morning, the coil is only getting 11 volts. I assume this is bad. Shouldn't it be getting 14 or so? Run signal to the ignition module is also 11 volts. Could this be a bad voltage regulator? I haven't changed the alternator, I checked voltage while off and it was just over 12v, with the car running I'd get a fairly steady 14v at idle and up to 15v off-idle / rev. edit: also, the guts of my distributor look pretty salty. Is there a quick clean-up I can do without disassembling it, such as spraying in some contact cleaner and a little silicon lube? I'd REALLY appreciate some assistance from somebody local. I'm near Santa Rosa. Quote Link to comment Share on other sites More sharing options...
capt_furious Posted May 18, 2009 Author Share Posted May 18, 2009 Still battling this. I've got it reduced down to stalling when bringing the throttle off of idle. Stab it too fast and it cuts out. Bring the revs up slowly and it'll sputter on acceleration but won't stall. Am I totally off, could this be a fuel problem? It's still completely random, it gave me hell last night and ran fine today. Quote Link to comment Share on other sites More sharing options...
auxilary Posted May 22, 2009 Share Posted May 22, 2009 remember what I told you at Wingstop? That your electric is auxilliary and not meant to be primary, and may not be putting enough pressure to the carbs? But your float bowls should be large enough to hold enough fuel, so that when you stab the gas, it should simply empty out the bowls, not immediately stall out. How long of a time frame do you have between jabbing the throttle and when it stalls out? Is it instant or does it take about 2-4 seconds? If latter, then you're not getting enough fuel delivered, would be my guess Quote Link to comment Share on other sites More sharing options...
capt_furious Posted May 22, 2009 Author Share Posted May 22, 2009 It's instant. Only when I stab the throttle and not when I baby it, if I carefully ease onto the throttle and ride the clutch, it'll sputter but it won't stall. And it's not constant, it comes and goes. Once it starts it won't go away for quite a while. I haven't had any trouble for about a week, but last week while driving to Oakland, it started having trouble on the Richmond Bridge and wouldn't stop until I got home late that night(with a good 6 hours in a parking lot in between). Fired it up the next day and drove around with no problems at all. I'm wondering if I need to put in a stronger pump. Quote Link to comment Share on other sites More sharing options...
Canadianz Posted May 22, 2009 Share Posted May 22, 2009 Theres two things here that came to my mind reading this: first, figure out what that blue and red wire is that is running to the ignition box, because as I remember usually your ignition wires in the early s30s are black with a white stripe. Secondly, I had a problem like this with a carbed 280 (without the problem with the ignition switch) where the car would randomly cut in and out, stumble and lose spark entirely... then run fine an hour or so later. What it turned out to be was a brand new condenser that had gone bad, so thats something to think about. Hope that helps Rob Quote Link to comment Share on other sites More sharing options...
capt_furious Posted May 23, 2009 Author Share Posted May 23, 2009 The red & blue wire is stock for the wiring harness. My Haynes manual shows this in the wiring diagram for the '74 260. It's been spliced into - not cut - and a new wire run to the run signal on the box. As for the condenser, where is this located? I know there's a small one on the back of the alternator, not sure what it's for. I've had trouble in the past with coil condensers on other cars, auxilary know about this. Quote Link to comment Share on other sites More sharing options...
Canadianz Posted May 24, 2009 Share Posted May 24, 2009 You can usually find the condensor either on the side of the distributor or attached to the ballast resistor, its easy to check and rule out of the equation at least. Another thing I just thought of is when you have this issue, check with a multimeter to see if youre losing voltage on certain wires or if there's any way to track down what exactly is happening. This way you can get an idea of whether to look at the wires before the ignition module or whether its something after it. Quote Link to comment Share on other sites More sharing options...
srgunz Posted May 25, 2009 Share Posted May 25, 2009 Did your 260z come with the transistor ignition set up that was on the inside kick panel? I thought they all did. If so do you have this isolated now or removed? Also, where is there a 260Z wiring diagram posted? Anybody know? Quote Link to comment Share on other sites More sharing options...
RUZN Posted May 26, 2009 Share Posted May 26, 2009 how about this. Re do the ignition get rid of Chrysler Parts as they are Made in Mexico. Nissan with Chrysler.. gawd I'll toss my car in the bonfire if that ever mergers. I worked for chrysler their product is down right shiiiitz so. Anyway after all ignition stuff is redone simpl by following where wires go to =-) Put in Stock 300zx NA ECU even even better results and slightly newer system. OH but after check your O2 if you have one =-) Quote Link to comment Share on other sites More sharing options...
capt_furious Posted May 26, 2009 Author Share Posted May 26, 2009 Let me handle this point by point here: Condenser: Nothing of the sort anywhere near the coil or ballast resistor. Never removed anything like this, either. There is one on the alternator, but I have no idea what it's for. Stock transistor ignition setup: Never seen anything like this on the car, or evidence of it having been there. It's a very early 260, I'm willing to bet it predates such a setup. Ditch the Chrysler box: Much as I'd like to, I have absolutely no idea where to start with this. The harness has been hacked to pieces by some numbnut several owners ago and there's no telling what's right and what's wrong. If I could find the person responsible, I'd beat them to within an inch of their life for causing me so much grief. Put in Stock 300zx NA ECU even even better results and slightly newer system. OH but after check your O2 if you have one =-) The who what now? It's an L28 with L24 SUs. No ECU or O2 sensor to speak of, and a VG30 ECU certainly won't help on an L28, carbed or not. aux has got me thinking I've got fuel delivery issues and it may not even be the ignition at this point, anyway. I'm fine with it running(sort of) in accessory mode if by fixing my suspected fuel issue, the problem is solved. Again, the problem has been resolved down to intermittently stalling when coming off idle too quickly. Roll on the throttle slowly, and it might sputter a bit on accel, but it wont' stall. Restart is instant after a stall. Let it sit for an extended period(usually overnight) after the problem arises and it goes away. Quote Link to comment Share on other sites More sharing options...
Canadianz Posted May 29, 2009 Share Posted May 29, 2009 Well at least you have something fairly easy to rule out now. Since the problem has steadily gotten worse, that could relate to junk from the tank plugging up the lines... How recently have you checked the fuel filters? what kind of a pump are you running? have you checked the float bowls in the carbs to see if there is any sediment in there? and lastly, have you checked the overall condition of the carbs, ie. checking for enough oil in the dashpots etc. When you're sure that the fuel system is running properly, then you can narrow things down a bit. hope that helps. Rob Quote Link to comment Share on other sites More sharing options...
capt_furious Posted June 1, 2009 Author Share Posted June 1, 2009 I've swapped the fuel filters a number of times in the past year. I just changed out the one in the engine bay and broke open the old one, nothing in it. The is one at the tank before the pump that is fairly new. I'm running a Carter electric fuel pump at the tank on the stock wiring, I believe it is this unit. I had this feeding to the stock mechanical pump, which failed within one day of installing the new electric pump - the gasket between the two halves blew and the pump was spraying fuel all over the engine bay. I disconnected it and I'm now running off of the Carter only. I assumed - perhaps incorrectly - that the pressure was too high for the mechanical pump and that's what blew out the gasket. Maybe it was just time for that pump to go. How do I determine the oil level in the dashpots? One carb piston definitely has more resistance than the other. I can see oil on the 'plunger' when I pull it, but I can't see any oil level by looking down the top of the carb with it out. Quote Link to comment Share on other sites More sharing options...
capt_furious Posted June 3, 2009 Author Share Posted June 3, 2009 Interesting: Symptoms: The main symptom of improper damper oil level is an off-idle/low-speed stumble in acceleration. This happens because' date=' with oil levels that are too low, the distance between the oil level and the damper allow the piston to flutter up into the bore. This premature lifting of the piston disrupts the metered air and fuel flow into the engine and gives you a stumbling/lean acceleration. Upper rpms are not affected because the piston has raised enough to cover the damper in the remaining oil.[/size'] Ignoring my previous ignition problems which may be solved at this point (I haven't had issues with getting spark since replacing the ballast resistor, ignition module and cleaning up connections), this description sounds very similar to the problem I am having. I checked the damper oil recently and cannot see any oil level while looking down them. DUH. Not only that, but when checking, the thumb nut on the dome was loose! Hello, McFly! Hello!? Quote Link to comment Share on other sites More sharing options...
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