Veilsideride90

Th battery was changed to a 750cc cold crank when the texas speed ls3 and t56 magnum where swapped into the car. it would turn over then die and continued to turn over then the engine would cut off. Each time we turn on the car it basically needs a remote jumper cable to spark the battery in the car. everything else including the faulty gauges in the FD have been corrected and a hollyefi was installed in the dash to combat the issue with the old instrument cluster in the car. what could be the culprit here? I'm thinking potentially the alternator?

Veilsideride90

any hints leading to a conclusion, that would get the car back on the road would be greatly appreciated hahaha

Wompa164

iTrader: (4)

Need more details man, can't even really begin to understand the problem from what you provided.

Are you able to get it started and idling or not?

Veilsideride90

something in the FD has to be consistently drawing power for it to constantly die. my guess is the alternator is bad in the car. They are only 150$ to change out so not that bad if its the issue.At this point should consider using a tachnnometer on the car?

Natey

iTrader: (19)

Don't forget that as a group we're a little bit rotarded when it comes to piston engines.

ATC529R

sounds like a bad side seal

books

iTrader: (8)

does the engine run with jumper cables connected to another vehicle?

Wompa164

iTrader: (4)

You didn't answer my question.. good luck on your car

Veilsideride90

when the key is in the ignition, the car will start up and then turn off. I did some research on ls swaps and they often point to it being a issue with the PCM on the engine(a common ls swap problem). The guys who are ironing out a few of the issues on the car for me corrected a few things on the vehicle.

1. a new battery was purchased and installed 750 cc
2. the wiring on my 93 fd rx7 was redone.
3. a Holley efi took the place of the faulty gauges on the car.
4. the engine was checked and is in great condition.

books

iTrader: (8)

You may receive more experienced swap diagnostics from norotors.com

Will the car continue to run with jumper cables attached?

If your fuel pump is running then most likely an electrical issue.

I doubt it is PCM/ECM related unless VATS is not turned off.

Could be starting circuit or ignition switch.

Veilsideride90

it does, but when the cables are removed from the battery the car shuts off. a lot of research indicates it might be the computer on the engine of the car and yeah it was bought from one of the no rotors guys. It was recently tuned and a few goodies were installed. we are aiming for 640 at the wheels which im certain the t56 magnum transmission will hold up. New heads were bought for the car. Last dyno was in the 500s.

books

iTrader: (8)

I think your first post indicates a likely culprit....the alternator; especially since it dies once the cables are removed. If you don't want to buy a new one, pull it off and have it tested at a local parts store.