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On "Microsquirting" the Porsche 914 - Part 4, The Sensors

The Sensors - cont'd

 Return to Part 3

The box of sensors finally arrived from The Dub Shop. It wasn't too long before I was trying different locations on the engine, deciding where to mount them.

I started with the CPS. The crank position sensor is mounted behind the cooling fan shroud and needed to be in place before anything else went on. The location bothered me a bit, as failure of the CPS would likely require removing the engine to get the fan shroud off to get to the sensor; of course, there's no way it would be field-serviceable. But it's one of those "necessary evils"...so let's hope this is a hardy sensor.

The Dub Shop Crank Position Sensor
The aluminum block to the left is Tangerine Racing's
oil cooler block/thermostat for an external cooler
Installing the sensor itself wasn't that difficult; it literally just bolted in. However, it's in a tight space and took some fiddling to get it positioned correctly; you had to ensure it's in the right space radially and as close to the wheel without touching. You attach a battery and a voltmeter and spin the engine to check for signals, and loosen and move the sensor, then recheck, then loose and remove, then check...but, some fiddling later, it was installed.

It was clear, however, that some fabrication was going to be needed for the other sensors, as almost nothing else would just bolt right up.

D-Jet plenum and throttle body with Kia TPS and
GM IAT and MPS
That's where Chris Foley of Tangerine Racing came in. Chris is pretty clever with machine tools and can asses a situation quickly to fabricate a solution. Long story short, Chris quickly fabbed up a couple of mounting brackets for the TPS to mount to the stock throttle body, and for the IAT to mount in the location where the D-Jet Cold Start Valve (CSV) was. * Perfect.

So, CPS, MPS, IAT done. CLT, the "coolant" temp sensor, is actually a DubShop item, a sensor modified to measure head temperature. It slid under a screw on the sheet metal, so no biggie there. That left only the wideband sensor input - and a whole lotta wiring - to go. Chris welded a "bung" into the muffler for the O2 sensor and I was going to mount the sensor controller somewhere in the back of the car. Easy.

You may have noticed that the intake plenum is nice and shiny...that's because the powdercoated parts were done! I used the time from waiting for my credit card to roll over to start assembling the cooling sheet metal and induction. I think it turned out kinda nice...

75% done, 75% to go!

On to Part 5: "Ignition Coil, Bracket, and Injectors"

Engine, partially assembled


*3/28/22 Update: I later found that the IAT was getting heat-soaked in the plenum and not giving me a good intake air reading. I later moved it into the air filter box; see Part 11 Addendums


TDC - Top Dead Center, the firing position for #1 cylinder
CPS - Crank Position Sensor, also known as CAS, Crank Angle Sensor
TPS - Throttle Position Sensor
MPS - Manifold Pressure Sensor
IAT - Intake air Temperature sensor
CLT - Coolant temp sensor
AFR - Air-Fuel Ratio
FLAPS - Friendly Local Auto Parts Store

Comments

  1. victor brunettiJanuary 3, 2023 at 10:08 PM

    Hey Greg - Thank you so much for putting this blog together! This is amazing, and the 914 community appreciates you.

    Apologies if you've already addressed this question, but in the last photo on this page (https://1.bp.blogspot.com/-DWlgn09BhYA/XmAQY4cYI-I/AAAAAAAACEI/ZEMcQVkS3C44CuIY49q8_JoR8ZwIaq9FwCLcBGAsYHQ/s640/2020-01-18%2B17.43.53.jpg) what's behind the grommet to the left of the dizzy-plug with the red, black, and yellow wires coming out of it? Is it the Modified "Coolant" Temperature Sensor? If so, is the reason the wires are visible (and not sheathed as in the reference photos) because you are using a different connector?

    ReplyDelete
    Replies
    1. GregAJanuary 4, 2023 at 7:51 AM

      Victor, that's the pigtail for the crank position sensor. I'm actually using the OP sensor grommet to run it out from behind the front shroud; the stock OP sensor comes out of there as well.

      And thanks for the comments!

      Delete

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