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EZ EFI 2.0 Throttle Body System Vehicle #2 - An '81 GMC

Discussion in 'FAST Support Forum' started by A A, Jun 5, 2016.

  1. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    After installing the new rear speaker box, while waiting for the new interior, I've noticed some slight strangeness with my EZ EFI2.0 F/A in the GMC. I've been running only mid grade fuel instead of regular for a number of months now. A plug check showed some light ceramic sooting, but still looking good. The engine was running slightly rougher at cold start until it warmed, and I noticed exhaust was no longer looking as clean as it had in warm engine WOT acceleration. I had also begun getting sporadic 003 IRM readings.

    I changed WOT from 12.6 to 12.5 and the exhaust during WOT acceleration immediately cleaned back up. Since the cold start appeared rich, I took the idle F/A to 14.5 - leaving the enrichment setting where it was. Cold start has now settled to a smoother idle again. I also changed cruise F/A to 14.8 and accel fuel enrichment to "0". Timing and heat range still looks correct at the plugs, and the plug ceramics have only returned to a clean white coloration. The IRMs have gone back to the 000 readings I had grown accustomed to. I'm hoping this strangeness isn't signaling the O2 sensor going bad. Maybe there was just some carbon buildup somewhere in the old engine that is going away.
     
  2. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Seating and dash parts for this GMC are arriving tomorrow. Naturally, the weather here is miserable constant rain and expected to remain so throughout next week. As a result, I haven't been able to get the truck ready for a quick install of the new interior. Of course, the carpet and sound deadener supplies are also shipping last - just my luck. At least the truck is running sweet on the new settings.
     
  3. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Lol. As usual the weather forecasts were dead wrong - it snowed this morning. It was biting cold, but I took delivery of the dash, seat, and seat bracket. I'm hoping the rest of the LMC parts will still come FedEx tomorrow. I have the GMC in my heated garage, so I will install the dash today - along with a new heater core. Of course, when I drove the TA out of the garage last night, I put the car cover on front to rear in the dark. So, I still get to play in the cold as I turn the cover around.

    Edit: Of course, after I assembled the seat and left it sitting in the truck bed, life had to take a twist. As I began getting ready to install the new dash, I found they sent a red stitched dash instead of white. Now I have to wait for the correct dash.
     
    Last edited: Nov 15, 2018
  4. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Installed the glove box today and took out the old rotten headliner. Don't know how that headliner was looking as well as it did. I'll give GM the bird on their '81 truck glove box latch design - It was a PITA to get apart without damaging anything. I decided to repaint the interior metal after the cleanup. But, I'm undecided on black or royal blue. The royal blue will probably give some needed contrast with the black interior - although the white stitching already helps. Should have the new headliner installed in the next few days - then, on to installing new the carpet and seat. The weight of the new seat has surprised me - it's heavier than the old one. I'll also be replacing the rest of the plastic trim parts. They're just too brittle - even though they still look new.
     
  5. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Got my interior paint yesterday, but I've been running my Kubota loader filling in and leveling a steep area in my orchard while the rain is holding off. Planted a few new fruit trees as well - and was promptly visited tonight by four deer. Good I also put wire fencing around the trees.

    I've been told the replacement white stitched dash should come next week. I have the truck inside my heated garage now, so there's no real hurry other than I'm not getting to enjoy driving it.:(

    The new door panels look great, but I've got to do some creative metal work to fit the Infinity door speakers high in the panels. I don't want them low where they can be hit by shoes getting in and out of the truck. I'm also thinking the small Infinity tweeters might look and work better in the rear pillar moldings.
     
    Last edited: Nov 21, 2018
  6. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    As Al Jolson would say,"Hot diggity dawg!". My correct dash is arriving tomorrow!
     
  7. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The new white stitch TMI dash from LMC and new dash trim looks great! I still need to weld in some new custom metal work for my door speakers before finishing the interior.
     
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Haven't had time to work on the truck lately. I found some very small rust throughs at the outer floor board areas near the doors. I could have easily covered that up, but knew I would never be satisfied with other than a perfect repair. So, I'll be cutting and forming some small replacement panels to weld in for an invisible repair after cleaning the welds up and painting. Once I complete this welding and the changes to the inner door steel, I'll install the new interior. I'm itching to drive the truck again with the new interior installed.
     
  9. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Raining again here today, but I intend to start welding in some small pieces of metal in the floorboard for an invisible repair. Once in and painted, the insulation and carpet will be installed along with the new TMI custom seat. I have already installed the new headliner and the matching TMI dash pad.
     
  10. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Still haven't welded the rust through places up in the floorboard, but no matter, I still needed a few new pieces of trim. I purchased those today along with two new Vibrant 17930 resonators. The more I listened to the exhaust of my GMC, I decided there was some drone at 2450-3000 - and I would probably like to tone down the volume some. I'm going to do a before and after video of how adding these new 18" long, 5" diameter bottle type resonators, behind my PYPES MVR-13 Race Pro mufflers, changes the sound of my 2 1/2" dual exhaust. I could have saved myself $80 by using the 4" diameter 1793 resonators, but I believe the larger diameter 17930s will give additional silencing and allow me to hear the engine better. I have an idea the addition will also make me happier with the windows down, and stop some of the nuts always trying to street race me while I'm enjoying my GMC. Hey, with all the new custom interior, my GMC might end up being quieter than my all factory Silverado.

    Edit: Thought I had bought all the trim pieces. I did, but I forgot to get the new door gaskets. Can't install much trim until the door gaskets are in. Arrrr! Now, I'm just not in much of a mood to get the gaskets very soon.
     
    Last edited: Dec 28, 2018
  11. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Received the new Vibrant 17930 resonators today and boy do they look good. Just need to install them now.
     
  12. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Here's the before video



    Using a Google phone meter dB app., under the exact same conditions shown above, idle dB averaged 79.0 with an average of 79.5 dB at 3000 RPM. The app. rated this as a normal level for a metropolitan street. Actual conditions are backed into a garage with the garage door open, and sitting in driver seat with driver door wide open.

    By comparison, my new single exhaust Silverado, sitting outside with the drivers door wide open, averaged 63.5 dB at idle and at 3000 RPM.

    1/05/19
    I installed one of my Vibrant 17930 resonators into one side of my PYPES dual Race Pro 2 1/2" exhaust today. I started the engine and noted all idle rasp and cackle was gone from the side with the newly added resonator. Standing at the exhaust end with the resonator, engine idling, I could hardly hear the exhaust note at that side for the side still without a resonator. Did I just get the exhaust too quiet? Stay tuned. I may have only needed the cheaper Vibrant 1793 resonators. The proof will be the dB meter app. reading with the resonators added to each side..

    I finished the exhaust and my new average dB levels are 74.6 at idle and 77.1 at 3000 RPM. All rasp and cackle at idle is totally gone now, and the '81 GMC sounds like a completely different truck - plus, it still sounds really healthy. Most of the drone the exhaust previously had at 2350 is now gone. and I doubt it will ever be heard now in actual driving. Overall, the truck no longer sounds like a street rod and now has a more sophisticated depth I like.

    And here is the after video with resonators added. A profound difference with no added exhaust restriction.
     
    Last edited: Jan 11, 2019
  13. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    In my second video, with the added resonators, you may have noticed the IAC was at 005 (effectively turned off) at idle. This was due to my replacing the two year old NGK UR4 sparkplugs with new NGK UR5 plugs. While the engine sounded the same and didn't sound like it was missing, those old plugs were weak and needed replacement. They didn't even look bad when I pulled them, but the need for a slightly colder plug was visible. The engine then needed IAC adjustment to get it back to an IAC of 20. The tipoff here of needed plug replacement was the previous unstable IAC at idle in the prior video. Although I knew the plugs needed replacement, I had forgotten about it until I saw the IAC floating more than normal. So, just a heads up on plug state with the EZ EFI 2.0. This unit can and will mask many things to continue good operation.
     

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