Battery / Electrical problem
 

I am having some sort of problem with my battery electrical system. I disconnected my negative battery last night to change out my coils. The car started up fine, actually much better with the new coils. I took it for a test drive, but as soon as I put the car into neutral and let off the throttle the car died. After that I could start the car but it would die soon after.

I had the same thing happen last year when I replaced my battery. I bought a new battery (duralast redtop) and the car would start but the car would die if I did not give it any throttle. I bought a better battery (duralast gold top), connected it and did not have any issue. I assumed that the first battery was not strong enough. Otherwise I didn’t have this problem at any other time.

Could this be a connection issue? The terminal has some corrosion, I tried to clean off a bit. I need to get a battery brush. But the stock terminal looks pretty weak, so I might try getting a better terminal. Anyone have any other thoughts as to a potential cause?

Make sure all the plug wires are securely plugged into the coils. Also make sure that the spark plugs are securely plugged into the wires, you might have disconnected it while moving the plug wires around when you were changing out your coils.

make sure you ground connections are ok too.

If you have any modifications which cause your fuel trims to be at one extreme or another your RX8 is going to have idle issues.

As an example, prior to the accessPORT I had around +19% LTFT. The problem was when I would reset the PCM the car had a really hard time idling after a hot start. I had to stay on the throttle until the PCM added enough fuel to keep the car running.

Coil performance would be an issue everywhere not just at idle. Give the car a couple drive cycles and it will probably straighten out.

The Battery / Electrica issue is gone.

Basically here is what I experienced.

If I disconnected the battery and then tried to drive with the headlights on the car would start the first time and then die as soon as I let off the gas. After that the car would only start if I give it gas as soon as I start it and hold the rpms at about 2000 giving it a little throttle.

Now if I disconnect the battery and drive it with the headlights off, the car will almost die when the RPMs drop in neutral. The car gets to about 500 RPMS almost bogs down. I'll give it some gas and save it. It does this for a few drive cycles and then the problem goes away.

Now my theory (which is probably wrong since I do not understand electricity or computers) is that there is something in the compter memory that gets erased when I disconnect the battery and the car goes to a default mode and then takes some time to relearn that there is a problem or condition with my particular car that requires more electricity at low RPMs. Does this seem plausable or do I just have electrical gremlins that like to F with me?

I'm gonna say a big fat no on that one.

To me it sounds like you unplugged a vacuum line and forgot about it or there could be a semi loose connection on your wires.

double check your work and get back to us.

yes

yes

no, the computer re-learns the fuel-trim adjustments particular to your engine. Don't drive around with the battery disconnected.

Thanks Nubo.

I didnt drive around with the battery disconnected, but when I disconnect it and then reconnect it my car will do this for about 10-20 minutes of drive time and then its back to normal. It lasts a bit longer than the traction control light takes to go out after reconnecting the battery.

I disconnected it again last night to reset a check engine code after a patched a vacuum leak. Same issue. Drove around for 10 minutes last night, died at ever light or stop sign I got to.

It is the normal ECU disconeect and the unit relearning.

OK, same problem, not going away this time.

Didnt drive the car for about 3 weeks, battery completly died. jump started it, and had the same problem. If I let off the gas in neutral or clutch in the car dies. In gear it works fine. This time it wont go away. It started a week ago, drove over 100 miles and is still happening.

Found some other threads about bad idle problems, could dirty/bad MAF sensor be the problem. Other sugestions?

Engine starts and running but no electrical power
 

This question would be more appropriate for a Ford forum. However, did you check the fusible link?

i apologize, this is the forum that i found so far, anyways, where can i find the fusible link , is this the fusebox found under the hood? i dont know what specific fuse should i look into, coz it seems like a general POWER off.. but my engine can start, and runs good... no annoying sounds can be heard. IS there such a MAIN fuse for the car?