Dyno Day Gone BAD - Can't stop without dying

[annie4rb20]

So this is kind of long, I'm telling the WHOLE story so that way if you guys catch anything I goofed on, you can let me know.

I dynoed my pretty stock RB20 yesterday. My base run was awesome (203hp at the tire, 196ft/lbs of torque), but after that run the car sounded like it was misfiring. So we checked to make sure it wasn't anything else first, took out the ECU and checked for codes, looked for maybe any boost leaks just anything...

*I changed the spark plugs, took it for a run to make sure it wasn't doing it anymore, and it seemed to fix the problem.

After getting on the dyno again and tuning:



So everything was working fine after we left, and it wasn't until we stopped on our way back home (home's 2hrs away from dyno) that it started doing what it's doing now.

*While we were stopped, I took my center console apart since at one point the screw to bolt in the e-brake went AWOL and it was driving me nuts. *My SAFC-2 (wired Tuesday) sits below my radio. *At this point, the ECU was still exposed from when we checked for codes.

The Problem:

I started the car, and the temp needle shot WAY up. Past the big H and beyond. No unusual noises from the motor. I turn the headlights on, and the gauge cluster goes dim. The temp gauge always seemed weird, and I always thought it was faulty, (since its reading is usually different from when the key is in the on position and from when it's actually started and sometimes when I drove I'd see it jump) so I kept going for a second and the minute I hit the brakes, it started to sputter, and the car died. So after a while, I figured I could try and limp it back, but after shifting once, it sputtered, and no power.

So: The car starts to die when I push on the brakes, or the headlights are on. When the brakes are first engaged, the radio cuts out, and then turns back on, still while the brakes are engaged. The temp needle shoots up also when the brakes are pushed and the headlights are on. The e-brake works fine.

What we tried:

We stopped, I popped the hood and the intake mani felt a unusually hot (not terribly), but I don't think it should've been as hot as it was. So we sat and let it cool. I tried again , and still the same thing.

The SAFC-2 shows if the alternator is doing OK, and it seemed fine, it was reading 13V I think. So we tried to see if it was the battery, so I took out mine, and was going to try someone else's but there's wouldn't fit, so they just tried mine on theirs and it seemed OK.

I looked around my center console, but I'm not really sure what I'm looking for, as I don't know anything about wiring. I tried to see if there were any wires I might've pinched or if anything looked weird... There was never a smell of melting wire.

What happened:

Car got towed back home, and now it's in the driveway. I tried messing with it again, checking where I was working and I'm really at a dead end.

Some background:

Car used to be an automatic.The guy who did the wiring harness did a crappy job.

Any ideas on what I should try and do now? I'm REALLY in a bind, and don't know much about wiring. Thinking about getting a new harness.
Modified by annie4rb20 at 5:32 PM 8/17/2006

[gawdzilla]

sounds like it might've overheated? did you not have any other way to judge your water temp at the time?

[annie4rb20]

No other way... I'm driving it around today, and it drives fine, as long as I don't press on the brakes long enough for it to die. I'm pretty sure it's electrical, but I have no idea where to start looking for the problem.

[Kansei240sx]

Sounds like a fuse shorted out or some wire connections somehow touched grounding themselves out depending on the harness job.

MAKE sure all your grounds are stuck to a non painted metallic surface.

[nizmo zilvia]

"The guy who did the wiring harness did a crappy job."

I think thats your problem right there.

[Shocker]

check your alt fuse. i blew mine partially a while back and it created some weeirrddd headaches.

[jrb92se]

did it +boil over into the reserve bottle?

[USMCgetsome]

OK HER MOTOR DID NOT OVERHEAT! She is showing an electrical problem for sure. You lose power when you turn on the head lights or hit the brakes. You need to ensure you grounds on the head lights are good and brake lights. Also, the negative terminal of the battery is outstanding. The alternator at 13vdc when running is a lil low. when you put the lights on what does it drop down to? Also, check the wiring to the dash board plug that is wired into the gauge cluster. Could be the ecu as well.

top 3 things to check!

alternator i.e. plugs fuses wiring to the ecu and main fuse boxcluster gauge

[Chaos the Xile]

I agree that sounds like a shorted fuse or a terrible wiring problem.

[annie4rb20]

OK... so I was messing with it this morning, and with the SAFC unpluged, it idles REALLY rough, but the brakes and the headlights don't make the car die anymore... It just sounds terrible though... I think that kind of narrowed it down?

I'm guessing I might've accidentally kicked something around the ECU area when I was putting the center console back together.. GR!

[Yellow4g63]

IF you unplug the afc you need to connect the maf back since it's in the AFC harness. So plug the maf wires back together and see if it makes a difference with the AFC off.

[240z4u]

Annie, I had an alternator crap out on me too. Showed good voltage at the output signal, but the amperage was like 8 amps or something like that. Take your car somewhere where they can do a test on your alternator such as autozone or whatever. Usually still on the car.

Check grounds too, how much is your voltage dropping when you step on the brakes?

Its definitely electrical. Did you fuse your AFC etc? A wire could be partially shorted. I have seen that in a couple cars in the past.

Good luck! - Evan

[USMCgetsome]

did u fix the IN OUT setting of the safc? also check the maf wire. Last but not least check for a busted wire to the safc.

[nissanman04]

sounds exactly like mine when i had a loose alternator connection

[Dano]

I told Aaron to get that alty checked...

Do wat these guys said, plug in the maf to with the afc unplugged to make sure its in the afc wirig, it probly is, but after seeing that wiring in person, I wouldn't rule out anything electrical related... It might even be a combination of things...

-Dan

[OKRB20DET]

that sux annie...hope you get it worked out

courtney b.!