DcMaN

iTrader: (13)

I installed my 791xv 2 years ago or so, but recently i changed the computer in my car from the Geforce ecu, back to stock, now whenever i remote start the car it starts up but drops immediatly and when i try to relearn tach it wont flash blue. Anything that can be done ? It won't even stay running if i start the car, press the * twice, and remove the key it just shuts off once the key is removed from the ignition. The lights flash as if it were gonna work but it doesnt.

kpr10is

iTrader: (9)

Where did you tap? Whats the voltage the wire is reading?

DcMaN

iTrader: (13)

green white @ ecu. I soldered connection i know its ok.

mendon99

iTrader: (15)

im not familiar with the process on tach learn on the 791's, but perhaps check your other connections that have to do with learning the tach (during programming)?

...ie: I have to hold brake while the tach learns on my units. If the brake line is disconnected for whatever reason, obviously the programming wont work..


Other that, confirm you have a tach signal at the brain

DcMaN

iTrader: (13)

yea its all there, the only thing i can think of, is the rpm switch for the variable intake is hooked up to the same tach signal @ the ecu. Maybe thats throwing it off ?

mendon99

iTrader: (15)

cut it and rule it out.

DcMaN

iTrader: (13)

i did still didnt work lol, im stumped.

mendon99

iTrader: (15)

bad brain?

JSMax

iTrader: (13)

check fuses in the brain. I have a compustar and it was acting weird. I took it in and from the problems I was describing, the installer thought it might be a bad brain. He checked the fuses and one was no good.

I don't know anything about your system, but that is something that I think could get overlooked.
goodluck
hope that helps.

mendon99

iTrader: (15)

the tach signal doesn't run through a fuse.

DcMaN

iTrader: (13)

im gonna unplug the main harness for a bit, even though i know the dei alarms store the info even if there unplugged :\

mendon99

iTrader: (15)

if it turns out to be the brain, run it tachless. If your car is in decent shape you should be okay.

cheaper than getting a new one..

DcMaN

iTrader: (13)

might just toss in the towel an dgetthe 5900 sst its all plug n play i think isnt it ?

Pearl96Max

iTrader: (151)

Had the same issue months back when I threw in my UTEC, went tachless and never had a problem since.

DcMaN

iTrader: (13)

hmm ill swithc over to voltage sense and give it a shot.