{"id":2208,"date":"2017-09-16T19:30:29","date_gmt":"2017-09-17T05:30:29","guid":{"rendered":"https:\/\/blog.familjenjonsson.org\/blog\/?p=2208"},"modified":"2017-09-16T19:30:29","modified_gmt":"2017-09-17T05:30:29","slug":"plenum-intermission","status":"publish","type":"post","link":"https:\/\/blog.familjenjonsson.org\/blog\/2017\/09\/16\/plenum-intermission\/","title":{"rendered":"Plenum intermission"},"content":{"rendered":"

With the vacuum leak fixed<\/a>, I was excited to try another test run. But first, a small side track.<\/p>\n

The “RDAC” box that connects all the engine sensors to the MGL Enigma comes in two flavors, one that has a manifold pressure sensor and one that does not. The one in N132EA does not, but from reading the manuals (and looking at the pitot-static connections on the Enigma itself) I had a sneaky suspicion that the MAP sensor used was the same Freescale sensor that I used for the MAP sensor on the NC30. The manual said it was a 0-250kPa range sensor, and coincidentally I happen to have a spare MPX4250AP. Opening the RDAC box up, sure enough, there were unused solder pads where the MAP sensor should be, although only 5 and not 6 pins like the MPX. However, I determined that the pinout was compatible (only 3 pins are used on these particular models) so I soldered it in, reconnected the RDAC and fired up the Enigma.<\/p>\n

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The RDAC, now with MAP sensor. I only had to solder the Freescale sensor in and drill a hole in the lid.<\/p><\/div>\n

I was extremely pleased to see a MAP reading that matched the atmospheric pressure reading within a kPa, and sucking on the MAP hose made the reading go down. Perfect, now we have a MAP sensor (and the sensor is only $15 compared to the $65 or something MGL charged extra for the MAP version.)<\/p>\n

After drilling a hole in the plenum (two holes, actually, I also mounted an LM355 temperature sensor so we can read manifold temperature) and 3d printing a small hose barb that I epoxied into the hole, I could hook the MAP sensor hose up to the plenum.<\/p>\n

Re-mounting the plenum and connecting the intake runners didn’t take long, so it was time for a test run. However, when I pressed the starter button, all I got was a “click”… The starter relay was definitely kicking in, but the starter did not turn. I wondered what could be causing that connection to not be made when I noticed the main battery lead to the starter coming out of the lug at a peculiar angle.<\/p>\n

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The lug on the lead to the starter was not crimped real well, it was more “crushed” than a real crimp.<\/p><\/div>\n

Apparently the wiggling of the plenum in and out had been enough to pull the lead out of the crimp in the lug. Now, this should just not be possible, I should be able to hang<\/em> from a properly crimped #4 AWG lead, but the crimp was not a proper hexagonal crimp but rather looked like someone had stamped a cross in the copper lug.<\/p>\n

A proper crimp squeezes the lug from all directions and actually cold welds the strands and the lug together into a single piece of metal. Luckily I happen to have a few lugs I got for the NC30 #6 AWG battery wire which actually fit the #4 AWG starter wire too. I also have up a cheap hydraulic crimper I picked up on eBay, so I could replace the lug easily.<\/p>\n

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The new, properly crimped lug. Note how the entire perimeter of the lug has been compressed into the wire.<\/p><\/div>\n

After that small delay, it was now time for the test run. That’ll be in the next post.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

With the vacuum leak fixed, I was excited to try another test run. But first, a small side track. The “RDAC” box that connects all the engine sensors to the MGL Enigma comes in two flavors, one that has a manifold pressure sensor and one that does not. The one in N132EA does not, but …<\/p>\n

Continue reading ‘Plenum intermission’ »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[2,31],"tags":[],"class_list":["post-2208","post","type-post","status-publish","format-standard","hentry","category-airplane","category-sonex"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/posts\/2208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/comments?post=2208"}],"version-history":[{"count":4,"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/posts\/2208\/revisions"}],"predecessor-version":[{"id":2216,"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/posts\/2208\/revisions\/2216"}],"wp:attachment":[{"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/media?parent=2208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/categories?post=2208"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.familjenjonsson.org\/blog\/wp-json\/wp\/v2\/tags?post=2208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}