Powerstroke Diesel IDM mod
I thought I might put this on a seperate page for eveyone to read. First lets start with som FAQs
What is an IDM?
IDM stands for Injector Driver Module. It acts sort of like an amplifier for a stereo. You couldn't hook up 18" house speakers to a walkman right? The IDM and injectors work similar, injectors require a lot voltage to start up quickly enough and 12V from the battery doesn't cut it.
Where is it located?
The IDM is located on the driver's side fender wall below the hood hinge on 94-97 trucks. 8mm bolts hold the IDM in place and a 10mm bolt holds the connector on. On the newer style trucks, they are hidden in the drivers side wheel fender just inside of the F-#50 decal. You need to remove the plastic fender wall to reach the IDM. 10mm bolts hold the bracket and a 10mm bolt holds down the connector.
How does it work?
Injectors are very inductiove loads, similar to light bulbs. When you trun on a light bulb, it does not turn on right away. it takes time for current to flow through the bulb. Time here is in millionths of a second (us). By changeing some parameters on the IDM, i turn on the injectors faster and therefore keep them on longer since the PCM does not know it has happened. With a stock IDM, the injectors take 560 us to fully turn on (see below), with the IDM mod, injectors turn on in 440us (see below).
What sort of improvements will I see?
A while ago some friends of mine dynoed this mod and got improvements of 20hp/60ft-lbs. I will eventually post them, but for now email me and i will send them to you. I finally got around to placing my truck on the dyno. Peaks did not change much but the graph shows areas of improvemnt of over 100 ft-lbs. See the dyno graphs below.
What negative side effects will this create?
I spent 3 months with an oscilloscope and temperature sensors on my truck to find out if componets get over stressed with this mod. I did not find a single component that would warm up and hotter thatn stock. Also, I found that the IDM has electronics on it to limit the current to the injectors to about 7.5 amps rush in, 3.5-4 amps holding current.
The guys operating the Mustang dyno on my truck messed up the calibration of RPM. I redid the RPM and horspower calculations.
My dyno with IDM mod
My dyno without IDM mod
Stock injector rise time
Modified injector rise time