When I got my Mini SPI (with A/C), it had been horribly neglected (mechanically) by the P.O. After resolving the most immediate issues (seriously leaking water pump, fuel sender unit inop, dead radio, and intermittent A/C) I could turn my attention to the engine.
From the beginning, the car would sometimes be hard to start, frequently would die at idle, and suffered from occasional diminishing of power at higher rpms.
I decided to spring for the Android-based Mems_Diag, available on Google play. I went ahead and bought the "paid" version, since it was only about $8 US and I thought the developer deserved a few bucks for his efforts.
To make the Mems_Diag work with your Android device, you need the APP, the special 3-pin SPI diagnostic cable (with standard USB on the other end), and then an inexpensive adapter to convert the "old-style) USB plug to match the USB jack on your phone/tablet. If you have the MPI system with the OBDII-style plug under the dash, those cables are also available, just do a search on Google or eBay. There are also online schematics showing you how to wire up the 3-pin SPI connector, but I figured by the time I acquired the parts, and interjecting another variable into the system, I was better off purchasing a ready-made cable (seems like it was about 40 GBP)
To be honest, I really wasn't expecting any results from this system, and, in fact, when I first hooked it up, all I got was an "unable to connect" message. I emailed the developer (Pawel?) and he suggested I check that I had selected the correct MEMS version in the software. Turns out, my system is version 1.6, and the default setting is version 1.9. Soon as I changed that, Eureka! I started getting all sorts of real time data. There is an error code section, and I discovered the ECU was complaining about no Intake Air Temp (IAt) signal.
I dutifully pulled out the sensor (underneath the air filter), cleaned it good with carb cleaner, reinstalled it, and the error code went away!
Then Pawel suggested I make a small tweak to the idle timing adjustment and one other since-forgotten parameter.. Damn, that car is running perfectly now. The idle does now automatically adjust when the A/C engages (it would kill the engine before), and all seems well.
I should mention that I have replaced those 3 vacuum pipes that the MEMS depends on, and that perhaps contributed to my success as well.
I can't say enough good things about Mems_Diag and the support I've received from the developer!
Edited by pauldridge, 29 August 2017 - 01:12 PM.
