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i don't know much about Nissan electrical systems, but if it uses a Jetronic, your ECU, should be fine, your electrical gremlins, could come from a defective alternator, i came across this particular problem with Toyota's 1MZ-FE with VVT.
the alternator was damaged and produced AC current, instead of DC. symptoms are: flickering lights, misfiring, battery dead even after a good recharge, and fuses that keep burning up.

thank god you don't have a regina system, trust me, you would have commited suicide by now....

I HATE REGINA ECUs

Nope, its definitely the ECU plug, determined 100% today... when I broke down again. I was furious, because I would have to wedge something in between the plug and the wall to keep it at "the right angle", and somehow it still worked itself loose. So I removed the one screw holding the cover on the plug and exposed the back of the plug where the wires go in to the terminal end. because it was supported by ONE f*cking screw, and because the wires had been softened at the end from being plugged/unplugged a bunch of times, the actual plug was not seating right, and going on loosely at an angle. Chalk it up to another case of Nissan half-assing things (J and BMWneo, eat your heart out). With the cover off, I'm able to fully press the plug into place.

However, as I learned on the way back from my gf's house after midnight, because the cover is off the plug it has no way to retain itself to the ECU and will eventually work its way off due to running vibrations. Its kind of funny, on the highway the car began to sputter a few times and all I had to do was lean forward and push firmly on the plug and the sputtering would stop. What a pain, I hate this f*cking thing. Can't wait to install megasquirt.

On a side note I also stopped by a Napa Auto today that actually had a set of old NGK sparkplugs in stock, much better than the champions I was running. However, I'm still a bit miffed about my performance. My car has absolutely no balls below 2500rpm, especially accelerating from a stop. I blame the headers.

This post has been edited by Oddmanout84 on May 8 2009, 10:56 PM

hmmm... try checking your fuel calibration, also replacing your coil pack is a good idea. i had the same problem with Ford's Cosworth V6, that thing needed to be revved to get power. not enough fuel or too much, bad spark is the main cause of no power at the bottom end. headers have nothing to do with it unless it doesn't start nicely, because that means you don't have backpressure

bwahahahahahahaha, Demon Z strikes again.

The S30's run an early Bosch Fuel Injection btw.

Unplug your TPS, leave it unplugged and tell me how it runs. Low end, Better or worse? High end, better, worse or no change?
(If it runs a hell of a lot worse at idle or in low end, then stop and plug it back in)

BTW, Zip ties for the ECU/Main harness conection.







P.S. I have yet to consult the 800 page FSM, but I will depending on the results of the disconnected TPS

This post has been edited by TexasDemonZ on May 9 2009, 12:43 AM

Trust me on this one, since I know them personally... they realize 100% that Nissan half-asses shit. Ask them sometime about how FUN the R32 has been.

Interesting, though... I've been having some random bogging things going on with my 280Z, too. We figured it was bad injector clips because pushing on them seemed to help. Guess I should check the ECU connector as well just in case.

280Z/ZX ECU were made by Hitachi IIRC. they changed to Mitsubishi components, I think in the 300zx or the 240sx .


Well while you are dealing with the Z's temper tantrums, you can gather parts to do a 300zx efi system conversion on the L28

Coilpack LOLWUT. I wish I had coilpacks!

Well I did get a new coil near the beginning of the project, its a Crane Cams Fireball. It doesn't look like it would be the problem and I still have a pretty good spark going, though if anything the bottleneck is at my spark plug wires now, they're a bit on the cheap side. The reason I've been blaming the headers is because they're attached to a free-flowing exhaust with glasspacks. My back pressure has been reduced IMMENSELY with the removal of the smaller stock 1.5" piping + muffler + cat. Headers are almost supposed to narrow your power band in most cases, but I'll be trying some other things before I give up.

I feel as though I have been ignored.
So I will restate my earlier comment.


Yes, I was right about the ECU plug.




Now, for the low end problem.
Unplug your TPS, leave it unplugged and tell me how it runs. Low end, Better or worse? High end, better, worse or no change?
(If it runs a hell of a lot worse at idle or in low end, then stop and plug it back in)

DONT BLAME THE EXHAUST.
It's not the problem.
I had the 3-2-1 header into the twice pipes on an L24, and had KILLER low end power still.

Follow my directions at the of this post and let me know what happens.

This post has been edited by TexasDemonZ on May 9 2009, 10:47 AM

DONT BLAME THE EXHAUST.
It's not the problem.
I had the 3-2-1 header into the twice pipes on an L24, and had KILLER low end power still.

Follow my directions at the of this post and let me know what happens.

No, you haven't been ignored. I just got back up from testing the TPS. No change at idle, but the engine doen't like to rev beyond idle, very rough.

Well shit.

hmmm... That sometimes works.... but since it didnt, I'm gonna have to go dig out the FSM later tonight and start looking at some things.

I'm 75% certain it's still wiring

Yeah, I was pretty sure at most I could have installed the TPS at the wrong angle, but double checking proves otherwise. It tested good on circuit checks a while back as well. So maybe....

1. I could try advancing the timing on the distributor, it should be set at 0 degrees now.
2. The fuel pump is OEM and old, could trying installing a Walbro sooner rather than later.
3. EGR is gone, btw, and the hole is sealed via gasketed blockoff plate that I made.
4. My injectors are old.
5. My clutch is old... but it doesn't feel like its slipping.

I could also try installing the ECU the car came with, maybe this "new" one I've been running sucks.

I say check your AFM. About 60% of the electrical problems I've had working on most of the S30 in alaska have been a connection problem with the AFM.

The AFM, TPS and O2 sensors are really the only sensors the ECU actually reads.





Coil pack? whats that.... lol

L24, L26, L28E the spark was controlled mechanically controlled, separate from the ECU. The L28ET (version 2) Was when they actually started doing spark control from the ECU. Even then, they didn't go to coil pack system.

This post has been edited by AK-Z on May 9 2009, 01:18 PM

Maybe check the injector plugs for corrosion. I just fixed a dead miss on my buddy's Shelby Lancer that was due to that green looking corrosion that sometimes builds up on them. Also, his dad had similar seemingly fuel problems on his SRT, turned out to be the connections at both the computer and the injectors.

whatever the case... WIRE BRUSH lol

Checked it multiple times, even cracked it open to fix a flab binding issue. Electrically sound.

Well how about some emotional support would that work

Swap the ECU's and recheck the pins when you do.

Also, set her to about 5-10 degrees advanced if the ECU doesnt seem to make a difference.

My best diagnosis's are usually done in person, and require hearing, smelling, feeling (and occasionally tasting)
How does she smell when she's idling? a little rich?

If it was a fuel pump issue, I'd be expecting more high end problems rather than low end... But I could see either injectors periodically sticking open, or a worn out Fuel pressure regulator causing the problem if it winds up not being electrical.


If it was a clutch, you'd feel slippage in 4th.




The reason I told you to disconnect the TPS is semi complicated, but we have a few S30's here that are semi built NA motors which actually run better when the TPS is not connected. I wanted to see if your TPS was confusing the ECU.

Have you tried checking the rotor and cap? and also the coil (not pack lol).

does it stall out or just dies? symptoms?

Oh, no. The stalling/dying problem was fixed (sort of, or at least the source was discovered), it was a loose fitting ECU plug.

So far the lack of power issue hasn't caused me to stall out at all, its just that especially from a stop, when the car is below 2500rpm the engine has no get up and go. No matter how hard you stomp on the gas with the car in gear, the car feels like it just doesn't want to accelerate. Even if I rev the engine before getting off the clutch. But once you get to 2500 its like VTEC JUST KICKED IN YO and the engine screams to life, rocketing to the redline. Its not the brakes dragging, because I can push the car with the ebrake disengaged. And when the clutch is out, or the car is in neutral, the engine has no problems revving at all. its just like at the lower rpms I feel like I have absolutely NO torque.

I don't think the car's running lean, I've had no problems with temps and even at high RPM I don't have any pinging. The only thing that bothers me is that the headers orange VHT paint too almost no time to burn white and start flaking off, but I think that might be that I didn't prep the surface enough. If anything it might be running a bit rich, although its not so bad as to cause any visible smoke (it was at one point, last year). The crackle/popping sound while engine braking should just be a normal thing for the headers.

I'll try advancing the timing, but probably not today since its mother's day and writing this is all I really have time for.

Yeah sounds like it needs more timing, not enough definitely makes an engine lazy.

derp derp.... manual says 10 degrees BTDC... mine's at 0...

EDIT: make that about 5 degrees, now that I have a flashlight to see the marks better.

EDIT: I'm really just eye-gauging it. I should really just grab myself a timing light and do it right.

This post has been edited by Oddmanout84 on May 10 2009, 09:13 AM

have you tried messing with the adjustment screw (I forgot it is was on the AFM or the throttle body. haven't worked on my engines in like a year ) to raise idle RPM?

I'll be messing with it in conjunction with the distributor and timing light later so I can do it right. But since the car's been running I really haven't found the need until now. The Z idles at about 800rpm on its own, where it should be.

Then I am lost as to what to look at next at the moment .

BTW, you removing the EGR shouldn't affect anything really. Hell, one of my L28 didn't come with one stock (FED model

This post has been edited by AK-Z on May 10 2009, 04:07 PM

LOL dude you can't set timing w/ a flashlight and guesswork, come on man