DCrosby

I'm having some strange issues, for one, the car was running, and has been for over 4 Years now, on the same tune, same ECU, same Everything.

I'm on the on ramp, and mid on-ramp the car falls flat on it's face .... I put it in gear, and no power, can't start it again, and I coast to the right of the freeway/interstate.

I get a tow, back home, and nothing I can see is wrong with the car. So I start checking fuses, all are ok, and not burnt out. So I look at the coil voltage, as by my gauges I can see I'm getting Fuel, Fuel Pressure reads 40-50 PSI. So I look at my plugs, and they seem fine, nice color, nothing wrong, maybe the gap is a bit bigger than when I put them in 4 Years ago, but fine. So I look at the Pink Wires going to the coils. 8v Drivers Side and 9-10v Passenger.

And I'm thinking, that's not right it's supposed to be 12v.

The Battery Optima Red Top is Less than a Year old, and charges to 100% and roughly 13.4v.

So I check the fuses again, and I notice the fuse that goes to the switched 12V on the ECU when removed, has 12v, but when plugged in and has power it drops to 9-10v.... so I'm thinking "AHA!" And start tracing the wire, and find little to remark about, some stereo stuff that I had disconnected over a year ago, and now removed all together "Just in case", and I've been working a couple of hours a weekend on this bloody thing, and I now ordered a new ECU, just to see if it'll fire... Since it turns over just fine... just doesn't fire... most likely because of the 8V on the coils...

Oh and I also removed one of the plugs and grounded it, to see if I could see spark when I cranked it... no nothing.... and I do smell some fuel coming from that spark plug hole...
Speaking of grounding, the harness was grounded to the firewall, and secure, and I had good grounds from the fuse box...

Any Ideas, suggestions, or stories of "Oh Yeah that happened to me" are welcome, also this may be useful for someone in the future searching, and finding what I when through, and what was the ultimate solution, as I intend to update this...

And Here are some images since pictures make things seem saner than they are...

Ground Straps


Spark Plug Removed, and Grounded, as well as location of pink wires I am checking


Charger reading when battery was fully charged

shakenbake

iTrader: (16)

post this up on norotors.com. It sounds like the ecu but not sure.

TS87FC3S

was wire going to or from ecu 12v?

DCrosby

Everything Mentioned is to ECU, except the pink wire, that's from ECU to coils..

TS87FC3S

have you checked continuity to pins a and b? or just the coils ground path? it has a normal ground and a ecu ground

Ignition positive voltage - pink
Ignition Control Signal - light blue, purple, dark green, or red depending on which coil
Reference low - brown (ecu ground)
Ground - black

check continuity between brown and ground, and black and ground.

DCrosby

I'll try that, to check between a and b I have to disconnect the ECU from the harness, and it's difficult to see what clips / screws / retainers there are... I didn't wire the car, and the place that did went out of business, a while back. In hind sight I wish I'd done it myself, but it was a logistical impossibility...

I'll have some time during the weekend (I hope) and I'll check the grounds, it does sound like a Ground issue... doesn't it... I just haven't found where it originates... and the fact that the car dies in mid drive, seems very strange, either something finally ground itself through a wire, and caused a short (blown fuse) which I don't have or something burned out inside the ecu... which is why I got a spare... for $80 they're pretty cheap to come by.

-DC

DCrosby

Well the ECU Failed me, or didn't as the case may be, the replacement ECU did the same thing 8.5 v on the pink wire at the coils, on one side, and 9-10v on the other... Same Issues It Doesn't Fire...

I'm running out of ideas, other than re-wiring power to the ECU from scratch... :O

This Really Sucks, I don't understand what could have worn out / changed during driving... A Bad Rectifier or something would make sense... but this is NUTS.... I could change the battery, but unless everything is lying to me the Optima Red top with Less than 12 Mo. on it is fine...

Something could have melted together (Wires), but again, the car ran fine for nearly 4 Years... what could have suddenly changed ? With the old FD Harnesses it's a heat issue, and brittle wires, all the wires I have checked have very pliable insulation....

DCrosby

I have gone through all the advice I've gotten:
Check Pins 1 & 40 on both the Blue and Red Connector on the ECU, both (Plugs) have .01 ohms resistance and show continuity to the frame...

Check the Brown and Black Wires on the Coil Pack Plug (Pictured) and see if you get solid grounds...
Well neither side Brown Wire did show a continuity signal, the Passenger side black signal did, and I have the Picture of the Multimeter Of what it showed... (27 Ohms)


The Black Wire on the Drivers side did not show continuity but had a massive amount of resistance... (almost 1 Mega Ohm)


I'm gonna say that may not be normal....

TS87FC3S

Try running some jumper grounds. And recheck

DCrosby

To Everybody asking for better grounds, the big fat wire added to the cylinder head next to the negative probe from the multimeter... goes straight to the negative terminal on the battery.... (4AWG) and the multimeter changed very little if at all..)

shakenbake

iTrader: (16)

Thats not a good grounding point. Put that straight to the back of the head in one of the large holes. It may not fix your problem but you should have at least 2 of those on the motor.

DCrosby

It's not like I'm going to leave it there, it's in the way of all kinds of stuff... it's troubleshooting the issue... if it had fired, I'd have removed it and cut two appropriate wires and grounded the block...

jagwrjack

iTrader: (3)

Had the exact same thing happen last week. Been driving my Ls1/FD for 7 yrs.
Put in new valve springs and went for a 25 mile stop and go drive on a very hot day.
Car stalled at a stop sign. Blew the 15amp fuse for switched power. Put in another 15amp fuse. Car started, ran a while and the fuse blew again. Got towed home and began checking
everything on that circuit and found nothing.

Went to where I was working to put in the valve springs. Found nothing wrong but began jiggling the harness under the hood, especially behind the intake manifold.

Presto! It ran. I put on about 30 miles and didn't blow that fuse. Hopefully it's cured.

I'd check around the engine compartment, along the firewall where the harness pops out and
around your right side header, near the water temp. sensor.

Mine is running but my as.hole puckers up at every stop sign

froggy4life

hahaha im glad you guys are posting this stuff i'll be alot more careful on my wiring this weekend