timhill78

iTrader: (6)

I posted in the PFC section about this but I was hoping to widen the pool of help so I'm posting here as well.

My car died at a local autocross last weekend and i can't figure out what's wrong. It will turn over but die immediately. I've checked the sensor read out on the PFC and they are way out of whack.

PIM 0.03
VTA1 0.01
VTA2 0.01
VMOP 0.00

I installed the stock ECU and it fires right up and idle ok. I've removed the airpump so it's not perfect but ok.

I tried replacing the TPS in hopes that it would make some difference but it doesn't. I've also tried disconnecting the map and tps to see if the reading change and they do read that they are disconnected.

I've also took the PFC apart to see if i can find any burnt areas but I don't see any.


Any ideas?

MazdaSpeedDan

iTrader: (4)

Did you adjust the TPS or just put it right back on?

timhill78

iTrader: (6)

I couldn't get any signal close to what it's supposed to be to adjust it. I just put on the new one and it does the same thing.

MazdaSpeedDan

iTrader: (4)

Tps is the cause for alot of issue. Thats what mine is in the shop for right meow. I couldnt get numbers close to what it needed.

timhill78

iTrader: (6)

I've been playing with the TPS I can only get it to read full open or almost full closed.

MazdaSpeedDan

iTrader: (4)

Those are the 2 values you need to be concerned about. Are you saying it reads 0 all the way from closed to open?

timhill78

iTrader: (6)

Both values will go from 0.01 to '0.04 from full closed to full open. If i take off the TPS I can get the larger value to go from .01 to .05 then it jumps to 4.98. With it off the smaller value will go form .01 to .05 then it will jump to 4.98 but I can get it to stop around 2.98 if I'm really careful. It still won't stay running at that value though.

Speed of light

iTrader: (8)

Looks like the reference voltage (normally +5) supplied by the PFC is dead. There won't necessarily be any physical indication of a failure, so a visual isn't of much value here.

timhill78

iTrader: (6)

New PFC then?

DaleClark

iTrader: (55)

Could also be wiring. Pull the plug to the TPS off, one of the wires should be a 5v input. Test it with both the PFC and the stock ECU.

Dale

timhill78

iTrader: (6)

It's there with the stock but not with the PFC

Andre The Giant

iTrader: (21)

What would cause this reference voltage to not be output by the PFC? A failed transistor or driver circuit? What would cause it to fail, a short to ground that caused too much current flow through the reference voltage output circuit inside the PFC?
I'm just tossing out ideas because I'm curious

timhill78

iTrader: (6)

Progress update: Got a new (used) PFC. Installed it. Car ran great. Today coming home from work it dies again. Same thing. Same from the sensors. I put in the stock one again and it started right up.

Does this mean I have a short? I take it I need to track down the short and get another PFC? How do you go about tracking down a short?

MazdaSpeedDan

iTrader: (4)

Time and Patience