This car is a 4wd Mazda 323. It is stripped with a cage, 2 seats, steering wheel, shifter, pedals and not much else. The powerplant is a B6T (internally stock) with a number of external modifications. One of my tasks in this project was to re-wire the engine system and give it a complete engine management system.
MembersPage/MichaelRichards/Projects/TonyGTX/Wiring has details on how the wiring is done.
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Problems.
I've got most of the sensors wired up. Missing only the fan relay and IAC valve. These shouldn't have an effect as the idle throttle is trimmed to not need the IAC valve.
The trouble is in the MAP sensor. I am using a GM 3 bar MAP. At atmospheric pressure the MAP reads 1.57v and the display shows 102kpa.
Settings are as follows:
kpafac=96
kpaoffs=64
Whenever I attempted to start the car it would go through the cranking just fine, fire up then immediately die. I noticed that the MAP reading was all over the place so I added a DVM. I raised the cranking threshold so it would idle and think it was still cranking. I used this to measure the MAP sensor output. At idle it reads 0.95v but the "P" value was anywhere from 20 to 0.
So I shut the engine down and attempted to debug the MAP problem. I used a vacuum pump to pull about 15" of vacuum. As soon as it dropped below that the P reading would go to 0. As I continued to pull more vacuum the numbers began to randomly change.
Have I screwed up a setting or is it possible that my pulldown resistor is messing things up? If anyone can recally I added a pulldown resistor so a disconnected MAP sensor would result in a 0 pressure reading.