mike13

iTrader: (27)

This has me scratching my head.

turbo ls in my 1999 Firehawk

at the track I launch the car it starts pulling building boost and than the ecm does the reset, full gauge swing, trip meter resets, etc looses power and after the reset runs fine, roll back into the throttle and does the same thing.

bad ground maybe? will the coils draw enough electrical power that would create problems if my charging system might be marginal?

mike13

iTrader: (27)

Also tried datalogging but when the ecm resets it corrupts the datalog and can't be read.

lurker1978

Sounds like a bad ground to me..

LT1RAY

iTrader: (21)

Check the grounds on the back of the heads.

mike13

iTrader: (27)

just did all the grounds are good, I'm thinking I might be getting a voltage drop when the 2nd 340 fuel pump turns on. It's set to power up in boost. Tried datalogging but when the ecm resets it corrupts the log and won't play.

I'm wondering if the alternator is marginal?

AgFormula02

iTrader: (13)

I converted to a one wire alternator which does not require PCM signal to charge. It was upgraded to 160 amps
Had it done for relatively cheap at a local shop

mike13

iTrader: (27)

the 105amp alternator upgraded to 160? same alternator?

Johnv

disconect the second pump and try a quick pull.

mike13

iTrader: (27)

The more I troubleshoot the more I'm leaning towards a marginal alternator. Today it was charging at 14v, yesterday I never saw more than 12v.

Old Geezer

iTrader: (3)

"I'm wondering if the alternator is marginal?"...
Time to check/test/verify the integrity of the entire electrical system.
What are you seeing on a data log w/o putting the boost into play?
Does it do the drop out at the same boost level, repeatedly?

nocooler

iTrader: (5)

Is the battery secure?

Mine would hit the a/c accumulator and ground out - everything would die and then come back to life.

mike13

iTrader: (27)

I agree, spent much of yesterday doing that.

mike13

iTrader: (27)

All the battery cables have been replaced this year but spent yesterday checking all the grounds, the ends of all cables, inspected for abrasion or burn damage.

The system was charging at 12v and slightly less in the staging lanes, replaced the alternator and now I see 14v, have to wait a week before heading back to the track.

I think I might get the idiot of the day award, I can't remember if your charging system is always charging at 13.6-14.2? If so it was staring me right in the face.

vwdave

iTrader: (3)

Ideally it should be 14.0.

mike13

iTrader: (27)

Is that a constant 14.0? With the engine running I should never see 12v?

Ryans99ls1

iTrader: (16)

mine did this exact thing when i would hit boost. Motor would twist when it hit peak torque and my catch cans would hit the battery terminal. covered the terminals and moved my catch cans and the problem was gone.

vwdave

iTrader: (3)

Should be over 12v. I dont like anything under 13.5 while running.

mike13

iTrader: (27)

Ya, I ruled that out right away.

mike13

iTrader: (27)

Thanks.

Ryans99ls1

iTrader: (16)

I ran around with a bad alternator for a long time. thing almost never charged at 14v. with the lights/fans on the car, it dropped reallllyyy low. Never caused any performance issues until it actually took a ****, but the car suddenly became completely undriveable at that point. It was bucking and surging like no ones business at idle. Its worth a shot to replace yours as electrical problems can be weird but i wouldnt be surprised if its something else.