Code 56 and while I was in there...

[fletchusmc]

I haven't had anything to share here in quite some time as I haven't had really any issues but I do login and read what others have been doing.

With that being said, a few weeks ago I got a code 56 on my 95. The FSM wasn't much help but after searching through here and some of Marc's information I found out it could be the differential pressure sensor. I want to thank Jerry for supplying the sensor, gaskets, and new PCV hoses.

While the plenum was off I wanted to replace the plastic weatherpack connector housings to the TPS, DPS, and MAP because the locking tabs had snapped off. The TPS housing was no problem to find except all I could find were black and not the orange color as original. The other 2 were a bit more difficult. The local parts stores had pigtails for $20-$25 each, but I didn't want to buy those just to remove the terminals and wires just for the $1 housing. Some of you might know of a better place, but I was able to find the correct color and indexing for the MAP and DPS from a company called Raffenday in the UK. For 6 housings (gotta have spares) and shipping came to $32. Shipping was $25...

Since I was waiting on those to show up I went ahead and blocked the throttle body coolant, added a PCV oil catch can, and removed the secondary vacuum parts and safety wired them open. Everything I've read on here was helpful in that and I want to thank Marc for the upgraded calibration chip. I had everything ready to go and the chip showed in the mail today. Got that put in and have only had a chance to drive a few miles and not really open roads. It's been a while since I've driven her but I plan to change that in the next few days!

Again, thanks to all of you who have provided information on here!

[secondchance]

I had code 56 about 3 years ago and the fix was pressure differential sensor.
Now that you have disabled staged secondaries, you will notice secondary intakes staying clean like the primaries. Reduced vacuum spider makes it a lot easier to service under the plenum also.

[Z51JEFF]

TERMINAL SUPPLY and MOUSER has pretty much all of the OEM connectors and housings for GM.

[XfireZ51]

You can also fix a Code 56 by eliminating the secondary throttle mechanism all together.

[fletchusmc]

Jeff, I checked those sites for these particular connector housings. The dark green for the map sensor has a minimum order qty of 750 and a lead time of 12 weeks from mouser. Could not find the gray one for the differential pressure sensor on their website. Terminal supply only shows one 3 terminal weatherpack and it is correctly indexed for the TPS but not the MAP or DPS.

Xfire- was told by Marc that removing the secondaries would not fix a code 56 as this sensor remains connected electrically.

[XfireZ51]

I was being somewhat facetious. But the calibration can be set so it doesn't matter what the sensor reads for all practical purposes.