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Thread: Installed valve height

  1. #21
    Join Date
    Mar 2018
    Posts
    35

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    Update: Got everything back together and reinstalled. I'm now trying to get my CIS dialed in and it's a learning curve because I've never owned or worked on a K-jet equipped car. The 308/328 WSM doesn't have much info but I have a copy of the 1983 Mondial QV WSM and it has a pretty good section on the fuel injection that I'm assuming is identical. So I've been using those charts and pressures for my troubleshooting. The engine fires right up but has a really rough idle. The auxiliary air and cold idle and electro-valves seem to be working, it will idle a bit over 2000 until the yellow light on the instrument cluster goes out at which point I can see the high idle control valve close and it drops to about 1200 - still really rough though. If I press on the air metering plate very slightly with my finger it idles perfect so I was convinced I just had an intake leak but I can't find any. I've used starting fluid and a smoke generator to try find one but no indications. I don't want to mess with the mixture adjustment until I have exhausted all other possibilities. It ran perfect when I took it apart and I didn't really mess with anything but the injectors did sit in a box for a year so they might be suspects.

    Anyway if any CIS gurus have tips or advice I'm all ears. I put the car on non-op status with the DMV last year and I really can't operate it until after August 5th without having to pay the entire 2018-2019 license fee so I've got a few weeks to get this sorted out. I have driven it around the block a few times, it runs good but the idle seems to be way too lean. The plugs are chalky white.

  2. #22
    Join Date
    Sep 2009
    Location
    In the big house
    Posts
    7,134

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    Quote Originally Posted by kcabpilot View Post
    Update: Got everything back together and reinstalled. I'm now trying to get my CIS dialed in and it's a learning curve because I've never owned or worked on a K-jet equipped car. The 308/328 WSM doesn't have much info but I have a copy of the 1983 Mondial QV WSM and it has a pretty good section on the fuel injection that I'm assuming is identical. So I've been using those charts and pressures for my troubleshooting. The engine fires right up but has a really rough idle. The auxiliary air and cold idle and electro-valves seem to be working, it will idle a bit over 2000 until the yellow light on the instrument cluster goes out at which point I can see the high idle control valve close and it drops to about 1200 - still really rough though. If I press on the air metering plate very slightly with my finger it idles perfect so I was convinced I just had an intake leak but I can't find any. I've used starting fluid and a smoke generator to try find one but no indications. I don't want to mess with the mixture adjustment until I have exhausted all other possibilities. It ran perfect when I took it apart and I didn't really mess with anything but the injectors did sit in a box for a year so they might be suspects.

    Anyway if any CIS gurus have tips or advice I'm all ears. I put the car on non-op status with the DMV last year and I really can't operate it until after August 5th without having to pay the entire 2018-2019 license fee so I've got a few weeks to get this sorted out. I have driven it around the block a few times, it runs good but the idle seems to be way too lean. The plugs are chalky white.
    So, the variable is the new injectors....
    Pressing on the sensor plate enriches the mixture
    White plugs-Check

    Running cold and running hot require different pressure from the WUR. If those pressures are in specs AND the sensor plate height is correct (see WSM), adjust the mixture. O2 sensor if equipped, disconnected. Righty ->rich Lefty->lean. Turn the mixture screw 1/8 turn and wait for the engine to respond. Remember that you need to plug the hole (for the mixture screw) whilst your evaluating the effects of your adjustments. Go slow, as a little goes a long ways.
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

  3. #23
    Join Date
    Mar 2018
    Posts
    35

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    To clarify - they are not new injectors, they are the same ones I took out. They're brass so not sure if they are the original ones or if they were replaced at some time in the past. Anyway I took them all out yesterday and stuck them into 8 empty water bottles which happen to fit perfectly onto the threaded mounting bosses. I did a quick visual of the spray patterns and they seem to be pretty even but I couldn't do an actual measured flow test or open them up full pressure because they fit so well I'll need to poke or drill some vent holes. But that is why I've been reluctant to mess with the mixture adjustment since all of the components are the same and it ran fine before I took it apart. I did however replace all of the polymide fuel lines.

    So I think today I'll go ahead and make those vent holes and do a more thorough test throughout the entire range as well as recheck the cold and warm pressures on the WUR with and without vacuum because thinking back I forgot to bleed the air out of my gauge line the first time I did it. If everything checks out I'll put it all back together and try adjusting the mixture.

    One other thing I wasn't sure about is the idle air bypass needle valve. I didn't find anything in the WSM but read somewhere to start with it 4 turns out from fully closed and the throttle stop screw a half turn past where it just catches a sheet of paper between it and the arm lever. So that's where they are right now.

    I'll snap a couple of photos today and come back with a report. Thanks for the tips.

  4. #24
    Join Date
    Mar 2018
    Posts
    35

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    Update: After extensive tests and observations I'm pretty sure my injectors are the problem. Two of them don't do anything but dribble until I have pressed the plate down about a half inch and at least three of them continue to drip after shut off. My warm pressures at the WUR are 2.5 without vacuum and and 3.3 with vacuum which are at the low end but within spec. My cold pressure looks to be okay as well even though I don't have a thermometer to tell me exactly what temperature it is in the garage (I'm guessing it's about 75 deg) Watching the injectors throughout the range, I can see why my idle was so bad. I could try make up a pressure pump to clean them but I got a pretty good deal on a whole set of new ones on Amazon ($163)
    Attached Images Attached Images

  5. #25
    Join Date
    Jun 2007
    Location
    Massachusetts
    Posts
    13,495

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    Love the water bottles!! Pretty clever way to observe the individual injectors. Sounds to me like a replacement set of injectors is a good idea. I'm sure you have seen my tutorial on cleaning them. Super easy to clean if you acquire the apparatus.
    Birdman308 for parts and tutorials!

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