I ve had this issue since late 2008 where the cars headlights would dim out if I went WOT or heavy throttled the car in any gear. I have an interceptor gauge thats piggybacked off of my a/f ratio gauges power that is connected to the ignition harness under the steering wheel. In the same situation as stated above, the interceptor gauge will fade out and will only remain backlit, but the a/f gauge will give a consistent reading the whole time. Weird right?

Ok so this morning the highway was wide open and I opener her up in 3rd gear, near 6k rpms the backlights on the dash gauges go out, the headlight go outand the interceptor fades out, but I still get a reading from the dash gauges and keep going WOT. Past 6k rpms the car starts to have quick short bursts of missfires but the a/f ratio remained a consistent 11.6-11.8. Then the check engine light started flashing on and off rapidly. I shut it down and started crusing at 70mph and everything cam back to normal.
I checked the interceptor and the only code i was throwing was P0300 which is the missfire code...

I have 60's w/2.9, injen cai, full exhaust. I have a custom tune but I have never had missfires with it and I have ran my car harder than this without incident other than the headlights dimming out. I have had the car to the dealership for a alternator test and it passed the test np but there was alot of carbon build up on it. There has to be an explanation for this, bad ground? battery? I need to know how to fix this asap.

UPDATE!!
02/2 Power steering had cut out briefly twice when I was driving on the highway last night... I hope its a related issue to the alternator bc the power steering is a electric style system and not a seperate issue

02/3 Alternator finally shipped today, will be here friday and I plan on replacing it as soon as I can.

02/7 Got the alternator in last night, PROBLEM SOLVED! I also noticed that with the old alternator the voltage was varying rapidly between 14.8 and 15.3v. The new alternator stays at a constant 14.7 or 14.8, took her for a rip and everything worked fine, no miss fires at idle, no dimming lights and no problems at WOT. I think I might need a retune though bc my top end was a lil rough past 6500rpm consistently Also my interceptor still has the same problem but I think that has something to do with the interceptor itself.

02/11 With the miss fires happening randomly now, I decided to check the plugs and what I found scared me a bit bc I thought I might have done some damage to the piston. The #4 plug had melted away a bit and was probably one of the factors contributing to the miss fires, #2 & #3 both appeared to be fine, #1 however had a considerable amount of oil build up on it and the whole coil pack was covered in dried oil. I think this was a result of the voltage spiking from the alternator and causing the #4 plug to burn up. Here are the pics, probably get some more later of the alternator and the coil packs bc I have to re gap the plugs.




You can sorta tell the tip isn't completely there


Looking closer you can see there's been electrical corrosion and the tip of the plug had melted off pretty good.


Above average carbon and oil build up.


Above average carbon and oil build up.


You can tell the plug is covered in oil, the picture doesn't do it justice when I say this thing felt like it was the dipstick for the engine oil.

02/12 THE END IS HERE! Did the compression test tonight 210-210-210-180. Last one is weird but its all within the norms of what we know. Ran the car hard with HP tuners and nothing was wrong, car ran hard and fast. So in conclusion, I hate alternators, change your plugs and I love my baby.

 

i had the lights issue. it was the alternator

 

Only under heavy throttle this happened? If so I'm buying an alternator

 

Yea max. I had this issue aswell but it was opposite. At idle i'd have near full power. Cruising speeds 40-45 everything would dim to where I couldn't see at night. WOT i'd have full power. ABS light come on at all? Windows still roll up full power?

Unplug the batt with the car running and try going for a spin around the block. Mine held idle and took off in 1st, died as soon as I went into 2nd 2 houses down.

 

Ill try that... it will be funny to hear whinee...... click...... lol. Ive never had the abs light comeon, but idle and cruise no porblems but WOT obviously problem. Never tried rollin down or up windows at WOT lol

 

Oh yea and if you still run a stock battery, check under neath for acid. This is what led to killing my alt.

 

i checked the battery and all the connector were clean, except for very slight blueing on the ground to battery connector

 

your stock battery isnt in the trunk?

 

yeah dude its the alt. i had idling issues, light issues, all kinds of ****. Replaced it and everything was fine.

 

We have batteries?

nice thanx man, i was hoping it was something easy like this and not a bad ground or a frayed line

 

i scoured the whole car in search of a bad ground. i was dead set thats what it was cuz i did a motor swap, and this started after. but i went on ebay and bought and alt threwer on then that was it.

 

whats the replacement alternator info?

 

bump more info guys

 

The blueing seems to be an indication of overtemp. Check the connection, make sure it's not loose, at the battery, or at the ground point near the battery..

 

Alternator fixed it!

I think the internal voltage regulator went bad? Any suggestions on how to fix that or a different conclusion?

 

bump, more serious shitt

 

Hmm, looks like it broke then melted a bit. I would keep an eye on the new plugs and forget about these. They look rather old anyway.

 

I think you best richen the tune before you do in the piston in #4.
There was a rash of #4 piston blown back when these cars where first getting tuned.
Especially when it got cold out.
I just stating this from what I was reading 4 years ago.

Personally I think if you live in a warm state you can drive with the same tune all year .
If you live where it gets cold either retune when it starts getting cold or park it.

 

#4 plug caused by detonation, probably from a lean mixture. I have seen #1 caused by a plug that were not torqued correctly, but its hard to tell from the pic. Does it go up the outside of the plug boot?
tom

 

yea ur probably right on the #1, it did seem a lil loose comin out, if 4 leaned out...... thank god it didnt blow lol

 

We can do a compression test if you're worried next time we meet up.

 

might just do that, just to be sure.... the car is running fine though..... damn you cobalt gods!!!!!

 

Mine ran fine with a cracked ringland on #1..Idle was fine didn't have the subi sound until I sprayed it and took a giant chunk out.

 

.... y do u have to tell em these things lol

 

bump