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I've been running an 87na 5spd fed ecu in my 84T, 5spd turbo for a month or so
and had no problems other than an unstable idle which was minimized by adjusting the
idle set screw on the TB and unplugging the AAC valve. It would idle high ~1200 with the AAC plugged in,
and the instability would drop it to 500 sometimes and other times smoothly at 700.
Today after work i go to start it and notice a high pitched constant whine from the fuel
pump. The car starts up fine, but now in addition to the whine, It has a rough irregular idle,
revs rough and belched blueish rich smoke out the back. I also do not hear the audible
click of the fuel pump relay from the passenger B pillar. I always listen for that.
After unplugging a few things and replugging them in with no change (AFM, O2 FPR) I am
about to give up. As an after thought, i plug in the original ECU. It starts up fine and the
noise from the fuel pump is gone. The car gets me home but with the same problems that
running the 84T ECU had, hesitation, acceleration doesn't feel as smooth as with the 87na ECU.
Also the AAC is plugged in and the 84T ECU doesn't jack up the idle.
I'll check the codes later tonight.
I hate this shit…
Any ideas?
84 AE/Shiro #683/Shiro #820/84 Turbo -
that is odd… one ecu makes the pump whine, the other doesnt. but otherwise they operate the same? -
The 84T ECU, when installed, causes the car to hesitate on acceleration where you can feel it kind of holding back when compared to the 87na.
It also will only start on the 3rd try. It could be related to this http://z31performance.com/showthread…ECU-pcb-repair
I haven't really dug down deep into troubleshooting as i've been focused trying to get the other SS running before fall.
But i did bring the ECU into my lab this morning and found a fair amount of water damage to the PCB. I would suspect that the corrosion and rust
could be causing intermittent shorting which may be the problem with the erratic idle and now the fuel pump issue. My employer builds industrial
high power UV LED lightsources that replace arc lamp technology in large format printers. It's a pretty harsh environment and I see a fair amount
of returned demo units where it looks the whole lamp assembly was dipped in something caustic.
Sorry for the quality, my lab camera is over 7yrs old..
84 AE/Shiro #683/Shiro #820/84 Turbo -
that'll do it. lol -
Brush it away and apply a coating of polyuretane to the affected area.Cha iro
enjoy building it yourself.
if it fails, fuck it.
at least you gave it a whirl. -
wouldn't even bother with it. some of those components can be damaged, but still functional to a certain degree. -
That's a really dumb idea, it's already rustingAugustus Maximus;343351 wrote: Brush it away and apply a coating of polyuretane to the affected area. -
Seriously, this can work. I've done it on mixers and old power amps (though those were usually intended to be somewhat serviceable, which I don't think the ECU is.) If any of the components that actually provide logic were damaged the thing would probably just be a brick. Sometimes damaged connections or traces will work fine if they can be kept absolutely dry. Or you could get in there and start trying to replace corroded jumpers and caps/resistors. I have seen much worse boards on audio gear brought back from the dead.G-E;343357 wrote: That's a really dumb idea, it's already rusting
However, given what an ECU costs and the fact that you apparently have a leak into your ecu compartment, I would try to fix the latter first and just get a different ECU. There's no sane argument for trying to fix a rusted PCB in this case if you actually want a running car anytime soon -
I most likely bought it like this. I can clean it up using tools at work, (we see corroded PCB's a lot) and conformal coat it but
i dunno if i would trust it. That's why i kept the stock ECU behind the seats…insurance.
84 AE/Shiro #683/Shiro #820/84 Turbo -
Is this the one you just got from me?
1988 300ZX Turbo, Shiro Special #760
1988 300ZX Turbo Automatic (wife's car)
1991 Hard-body 2WD
http://zccw.org/zccw/?page_id=1215 -
Tim, it was another one that i was using when this happened.
I attributed the failure to the corrosion i found and installed yours this morning before work.
I made it to work fine, idle was still bottoming out at ~500rpm before stabilizing at 700
Other than that it ran great.
However, after work, it tried to cut out and started sputtering again with the ECU i got from you.
Luckily i was really close to home and nursed it the rest of the way.
I noticed a commonality, both times it happened was immediately after i was aggressive on the throttle, under boost.
First 87na ECU,
The first time it cut out a few days ago was just after lunch and i was accelerating into a turn to beat a light.
I noticed it slightly trying to cut out before i parked it but didn't think anything of it until after work when the pump whined
and it wouldn't stay running.
Second 87na ECU,
Gave it some gas and was under slight boost when i felt the cutting out happening again. I pulled into the side street and it
kept sputtering, trying to die. I had to keep the rpms up and california stop a stop sign to make it home, that's where i noticed
the whine of the fuel pump again.
What the hell (I park the car and go inside to drown my sorrows in Minecraft for a few hours)
EDIT:
So before posting the above, i think "i should check the codes on the 87na ecu"…(z31.com "did you check the codes before posting" flashbacks)
I go out to the car and I get this:
1 long Green
3 quick Red and Green
4 quick Red and Green
5 quick Red and Green
1 quick Red and Green
1 quick red and Green
1 slow red and Green.
This makes no sense.
And the car doesn't start, no fuel pump whine anymore when it primes and the B pillar relay turns it off like normal.
Okay, plug in the 84T ECU, same thing… relay works, pump comes on with no whine..still no start, cranks but doesn't even try to catch.
What the diddly?
Hmm..I can smell raw fuel smell from the exhaust pipe.
I pop the hood to see what i can see and casually pull the vac tube from the FPR.
Gas comes out of it. DUN DUN DUUUUNNNNN!!
Okay, my stock FPR (replaced in 1995) took a shit, boost probably pooched the dying diaphragm.
But what then would cause the fuel pump whine? (forgot to mention it's a Walbro 255, tank is 3/4 full of midgrade)
Does the fuel circuit in the 87na drive the pump differently/harder than the 84T or something (i don't see why it would)
I'll start with replacing FPR i guess (hooray for stockpiling spare parts, i have 2 spare fprs…somewhere)
84 AE/Shiro #683/Shiro #820/84 Turbo -
Last night I replaced the FPR with a spare and had to crank it for 10-15 seconds but it finally started and chugged for a few minutes
before coming to a stable idle using the 84T ECU. There was some smoke coming from the drivers side exh manifold area for awhile.
I got under it but couldn't see where the source was. My motor is really clean so it should have been easy to find.
I'm thinking the fuel that was sucked into the intake thru the leaking FPR got to the exhaust manifold gasket and burned off.
I couldn't see under the manifold shields so i'm hoping that theory is correct.
I did an oil change just to be sure and afterward it idled much smoother. I'm sure a fair amount of gas made it into the oil.
Drove it around the neighborhood and it ran fine. Checked for smoke under the hood and found none.
I think I'll try the non-corroded 87na ECU tonight.
I'm hoping all of this was just a bad FPR and i can go back to the 87na ECU.
I'm still confused by the weird ECU code thing though.
84 AE/Shiro #683/Shiro #820/84 Turbo
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