RunawayRadio

iTrader: (2)

Hi everyone,

I finished a t56 swap in my 87 GTA awhile back and have everything running as good as can be. I've noticed that the SGI 5e is somewhat slow to respond when reading the vss outputting the current speed to the dash, taking upwards of 3-4 seconds to do so sometimes. At other times, it's almost instant, as long as the speed is above 5mph.

Is there a reason for this? I called Dakota and they said there should not be any delay at all, but i've also read a forum post somewhere that mentioned older SGI models (a/b/c) had a "sleep mode" on them that disengages on a set condition.

Some notes:

• i have a digitial dash and EBL Flash ('165) ECU
• The install wiring is correct and the SGI 5e is calibrated properly for the ECU, Speedo and cruise outputs
• my 700r4 vss output reading was instantaneous from 1kph
• I've rarely seen the sgi 5e read below 10kph on slow acceleration or contant speed. Sometimes it doesn't read until 15-20kph.
• The sgi 5e sometimes doesn't read until 40 kph under hard acceleration
• The sgi5e usually reads below 10kph on deceleration, but seems to struggle with maintaining that speed reading, dropping to 0 intermittently
• There is ALWAYS a noticeable delay in updating the dash speed to the speed of the car after the SGI 5e is working properly
• the two support techs I spoke with at Dakota Digital say the SGI should not have a delay at all.

I've been wondering if there was too much resistance in the signal wires or if there was another issue that could cause the discrepancies but would rule that out, considering the responsiveness of the dash to the 700r4 vss. It seems odd that a converter box would struggle this much to convert a magnetic pulse to a sine wave. With 17 teeth on the t56 reluctor, it will receive tens of pulses in the first 10 feet the car moves in 1st gear, which should be more than enough to calculate the converted speed. Why would it take as long as 3-4 seconds to process it?

Am i missing something in how i'm looking at it?

RBob

iTrader: (1)

The VSS pickup may be bad, sending an intermittent signal. When the speedometer is delayed does this also affect the ECM's MPH reading?

RBob.

RunawayRadio

iTrader: (2)

Hi Rbob, thanks for the quick reply. I want to say yes, since i did notice similar behaviour off the ECM's reading on the flash WUD. A snowstorm came into town nov 20, forcing me to put the car into storage before i could double check and be sure. I'll have to follow up in April when it comes back out.

When i put the car on jackstands for storage, however, I did notice that ATF was leaking out around the VSS, but the rest of the transmission was dry. Don't know if that's related to the pickup being slow, but may mean something is going on there.