rx7jocke

This problem just happend out of nowhere...

car runs fine during idle and low load(vacuum) but as soon as boost hits about 10psi the car runs pig rich (10afr instead of the 12 it was tuned to) and it wont boost as much as it is tuned to do...

idle is still about 13 and cruise 14-15

haltech ps1000, fpr, smartcoils, big turbo and so on

can anyone please shoot some ideas at me :-)

IRPerformance

iTrader: (41)

12 is a little lean for a turbo rotary under boost. Its safer to be in the low 11s. That being said, what changed? If the water and air temp tables weren't tuned correctly the afrs could change with the weather. You could also have a bad water or air temp sensor. An ignition problem would also make the car run richer as fuel wouldn't be burnt.

rx7jocke

water and air temps are the same and the readings are good, guess i should check my timing and spark but i did try and change sparkplugs with no succes

Vicoor

Also anything that may have altered the volumetric efficiency could cause it to run rich. like engine damage...

but I'd look at sensors/ grounding/ wiring first

rx7jocke

ok i double checked the sensors, they are fine. I also checked the battery voltage and found out that it only is 12.5 volts when the car runs and the alt is getting kinda hot....could this be teh problem?
I also tried to just lean out over all trim map by a few % but then the car runs like **** on vacuum/light load
I also ran some new ground wires and a new wire from alt to battery. No change at all.....wtf is this!

Vicoor

You may be on to something there. The injector dead time changes with voltage. There is a correction table for this. But if the corrections are not set correctly it will cause the mixture to change, possibly towards rich.

You'll be needing to find a solution to your charging problem, really before you go any further with diagnosis. That is because the engine management relies on the voltage being good to make accurate calculations.

as far as what is wrong, May just be an alternator, but could be something else, so it would be best to test before replacing.

Victor

vrx8

iTrader: (18)

Datalogs are you best friend. Get a datalog and post it.