NewZed

Here's the two side-by-side. Same parameters, just a better explanation.

This is interesting. Nissan rewrote the chart for 1987 MAFS self-cleaning operation. Don't know if the chart was wrong or they changed the operation parameters. I'm guessing that the 1984 chart was wrong and/or confusing. You didn't say which Z31 you had so you'll have to draw your own conclusions. Looks like the basic design is that it cleans the wire as long as three conditions are met - engine speed went above 1500 RPM, vehicle speed went above 12 mph, engine not overheating, and engine shut off normally. As soon as the engine is turned off, it waits 5 seconds and cleans for one second. So it looks like you need the speed sensor if you want the self-cleaning to work.

I think that the diagram and test description imply that the ECCS sends 1 second of power through Pin 12 of the 20 pin connector which then passes through pins C and F of the MAFS, to ground. But it may not be full battery voltage so a switch may not work. Best to let the ECCS do it for you. Basically, Pin 12 needs to be connected to either pin C or Pin F of the MAFS. That wire 33 is probably connected to one of those. But it's unclear from the chart if all three conditions need to be met or just one. Looks like all three but who knows. So your question about if you need the speed sensor is still open.

Actually there's still some figuring to do, but that should get you closer.

Should be enough in these two pictures. Either use the ECCS wire, or hook up a switch and count - one one thousand.

Works now. Take the distributor out and see if the drive shaft, bottom of the hole, is connected to the crankshaft. If it turns freely by hand, you'll have to remove the oil pump. Apparently the shaft can slip down inside the drive gear. Another Hybridz member had that happen. So you might find that the shaft won't turn, but the tang doesn't stick up far enough to catch the distributor. You might also find that your distributor is about to fall out and has lifted up out of its mount.

Tried ti reply to this before and it wouldn't post.

Actually, the guy that welded the shaft may not have tried it out. #13 - http://forums.hybridz.org/topic/112092-j30-shortnose-vlsd-into-open-longnose-r200/ Found the original too - http://forums.hybridz.org/topic/110563-nissan-vlsd-into-a-long-nose-r200-axle-options/

Can't remember who it was but a Hybridz member extended the inner portion of the shaft that needed to be long by cutting and welding on another splined section. It's all torsional inside the diff so the flexing and stress riser issues you'd see on the outside seem diminished. He said it worked fine and hasn't been back to report a failure so who knows. Welding the shafts affects the carbon content of the steel and the heat-treatment. Most shops don't like to do it so you'd probably have to waive your right to complain if you had flanges welded on the outside.

No effect. Once contact is made, the two sides are essentially one piece of metal, as far as electricity is concerned..

He said it has a Holley 390. Is that your distributor or a picture from the internet? Looks like a ZX distributor. If you can't check the timing at least make sure the triggering points are aligned in the distributor. Or about 10 degrees retarded with everything at TDC. That will give you clue about timing. I've seen Chevy small blocks pop back through the carb when a cam lobe was flat. I'd imagine a burnt/warped intake valve might pop back also. Valve lash will decrease as valves sink in to their seats from wear. The old unleaded gas problem. Focus on what the valves are doing. The sprocket problem is odd. Maybe it's on backward. Some of the aftermarket sprockets don't have the mark.

No apologies necessary. I was just pointing out how obscure your question is. In the picture I posted in #4 it shows GY (green with a yellow stripe) as a Start Circuit. I can't see why you would connect that to the blower unless you connected it to an NC (normally closed) relay that opened to cut off blower power. The GY wire is supposed to have power at Start only so you'd have to measure with a meter to know if it was working.

I see it as splitting up to two locations, one a green/blue wire. No connection to the blower motor. But the diagram is hard to follow without losing track. Regardless, you're digging in to a problem almost nobody has ever had in an area nobody really wants to browse around in - wiring diagrams. Looks to me like it should only have power at Start though, maybe it switches off instrument panel power or lights something up. Not sure what R means, if that is an R. But, a look at the Starting section of the FSM might find something.

Disconnect it and see what happens. If bad things happen, you need it.

Looks like there are several components that could kill blower power if they failed. Probably not an ignition switch problem though because that would kill power to other important things.

He said it happens with the engine not running, so no spinning of distributor parts. Weird problem. For the coil to discharge the primary coil circuit has to be broken, after being energized. It could happen either on the supply side or the ground side (ignition module side). I think that even the early ignition modules had a safety circuit designed in that would cut the power after a certain amount of time to save the coil from overheating. Not sure if happens slowly to avoid a spark or quickly, giving one spark. Maybe it's failing and not cutting off completely. Anyway, (Edit - Maybe ) it's your ignition module. You could determine if it's power supply or ignition module grounding by disconnecting the power to the coil positive and running a jumper directly to the battery positive. Turn the key on so the module is powered and see if it still sparks. If it doesn't spark anymore, (maybe) there's something cutting power on the supply side, maybe the ignition relay. If it does still spark, (maybe) there's something happening on the grounding side. Could also probably be the coil heating up and opening circuit. Try disconnecting both post wires on the coil and wiring directly to battery and ground. Don't leave it that way too long, it will get hot. If it still sparks, it's the coil. This might actually be the most likely cause.

931

930. http://forums.hybridz.org/topic/119982-2jz-overkill-z-for-sale-35k-obo/

The first could just be wide tires. I don't know what "tramline" means, but if you mean it tends to grab and follow road ruts, that's a sign of loose bearings, and maybe other steering components. Wearing out tires is also a sign of loose parts. Excessive toe will do the same. That orange boot is not stock so somebody's been in there. Either they tried to fix what you're dealing with or they caused it. I had loose bearings and a wandering, rut-grabbing car for about a year. I adjusted toe to compensate, dinked around with the rack a bit, and wore out my tires pretty quickly. Replaced the bearings and set the toe to zero and I've had the new set of tires for about 4 years (just a street car). It can be hard to tell if the bearings are worn. Mine didn't seem worn but they were. Often the bearing seats in the hubs are worn so new bearings won't properly torque down. But if you get everything right, the car will track straight over typical worn, high-volume highway grooves, and feel tight at the steering wheel. Like a normal car.

http://forums.hybridz.org/forum/90-l-series/

A dial-back timing light might help you see the advanced number. I'm just trying to figure out your words. If you can't see the marks, then how do you know it's jumping? That's where I get lost. Another clue, overall, might be - why are you looking at it? Does the engine not run right? That might offer some guidance. And the thing about spinning the cam gear still makes no sense. You might bend some valves, but the CAS is in the distributor, driven by crankshaft rotation, through a gear that spins the oil pump shaft and the distributor shaft. It's not driven by the cam shaft. You can have perfect ignition timing control as the cam gear spins randomly. Sorry, but that's the way the stock system works. Maybe your crankshaft drive gear is loose. Maybe the distributor/oil pump drive shaft has play in it.

Than you have a blockage or a bad gauge. Yes, high fuel pressure will cause the problems you described. Proper fuel pressure is the foundation for the ECU's injector control algorithm..

Seems unlikely. You didn't confirm that you saw page EFEC-67. Why would you look through the suspension chapters? Seems more like you're just not sure what you're looking at. You said you can't see anything but then implied that you can see 0 and 20. And "spinning the cam gear" doesn't have anything to do with anything really. Certainly not erratic ignition timing. Sorry, just trying to find your level. You're obviously new to engines so you're going to have to put some work in. Give some background on you, and how long you've had the car. If this is a new problem, if the engine has ever run right, did you do somehtng and this problem cropped up, stuff like that. You're just a guy who has a problem he can't describe well at this point. Good luck.

1983 is new. That's a start. 3 ECU swaps is new. That helps. How about some timing numbers? 10 to 20, 15 to 16, 5 to 25. Those would be significant. Have you looked through the manual? EFEC-67 describes what the ECU uses to adjust timing. Just trying to help. There are many reasons timing can move around. Maybe somebody will feel energetic and make a list.

There are no facts in your post except 280ZXT, crank angle sensor, and timing mark jumps around. Could be as simple as your inductive timing light pickup is too close to another plug wire. But without some details, nobody can offer anything useful.