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Sluggish throttle response / Injector issue?

Discussion in '308/328' started by royriccomini, Mar 6, 2010.

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  1. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
    Full Name:
    Roy Riccomini
    #1 royriccomini, Mar 6, 2010
    Hello

    I have read all Birdman’s great right ups on clogged injectors. I have been have a lot problems with my 1983 308 2V. It has almost zero throttle response and based on Birdman’s write ups, I thought I found the root cause.

    I replaced my injectors today and got the car to run for a couple of minutes, but the throttle response problem still exists. I’m not sure what to do now. Aggravation is setting in :/ Any help would be greatly appreciated
     
  2. miketuason

    miketuason F1 World Champ
    Owner Silver Subscribed

    Feb 24, 2006
    15,783
    Cerritos, CA.
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    Mike
    #2 miketuason, Mar 6, 2010
    I'm not an expert on this but it sounds like the butterfly under the air filter might be sticking which explain the slugish and lag as to almost no respond.
     
  3. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #3 royriccomini, Mar 6, 2010
    The butterfly (flow plate) seems to move freely. I also checked if the engine was running on both banks by pulling one coil plug wire at a time before starting the car. I got the car to run momentarily on one bank at a time. I did not want to run it too long due to possible catalytic converter fire.

    I did have a mechanic adjust the fuel/air ratio with a CIS injector system ( not sure what this CIS injector system is but that is what they used) before I installed the new injectors. Should I readjust the fuel/air ratio again? How?
     
  4. wazie7262

    wazie7262 Formula 3

    Feb 13, 2008
    2,357
    Temecula, CA
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    Scott
    #4 wazie7262, Mar 7, 2010
    How do you have an '83 2V??
     
  5. st@ven

    st@ven F1 Rookie

    Aug 4, 2008
    3,307
    Netherlands
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    Steven
    #5 st@ven, Mar 7, 2010
    are you sure the car is running both cilinderbanks? check your ingnition
     
  6. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #6 royriccomini, Mar 7, 2010
    Last edited by a moderator: Sep 7, 2017
  7. Iain

    Iain F1 Rookie

    Jan 21, 2005
    3,309
    UK
    #7 Iain, Mar 7, 2010
    Last edited: Mar 7, 2010
    CIS refers to the injection system on your car. If you have fitted new injectors you absolutely should get the micture checked again & you can only do it with a gas analyser.

    Not a good idea to disconnect the coils like that - I think you can start frying (expensive)things if you are not careful.

    If you put a timing light on all 8 plug leads & they are all firing then your ignition would seem to be fundamentally sound.

    As to the plugs. 1 & 2 on the rear looks a bit lean while 3 looks a bit rich. 1 on the front does;t look great either - have you checked all the plug extenders for cracks/shorts/breaks?

    One thing you might look for is air leaks. If you had your CIS mixture set and there was an air leak in the system it will be all wrong. Check Vacuum pipes & also the pipes that run around the warm start system (AAV & warm up reg etc). The CIS will not work right if its not airtight.
     
  8. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #8 royriccomini, Mar 8, 2010
    Iain thanks for the reply.

    I'll check vacuum leaks. I will take a video of the car starting up so everyone can see and hear the problems I’m having to make sure it’s just a fuel ratio problem. I have this funny feeling its something else.
     
  9. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #9 royriccomini, Mar 8, 2010
    Here is the video of me trying to start the car. It seemed to start better when it was cold. Once i got it started everytime the pushed the gas peddle it would not repond and die.

    I had the unreposive throttle before i replaced the injectors, but now its worse.

    http://www.youtube.com/watch?v=5euM7g-Rllw
     
  10. Davvinci

    Davvinci Karting

    Dec 11, 2009
    162
    California
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    DavidoSpeedo
    #10 Davvinci, Mar 13, 2010
    After listening to your start-up, I would next pull the connector from the cold start injector at the end of you intake manifold. It sounds like you start up and then flood out. This will tell you if the injector is stuck open or a signal relay is causing it to stay open. My problem was hard starting and I cured the problem by disconnecting it. But still haven't found the cause. I think mine are O2 sensors and cats that have gone bad but I don't think you have this problem with the Euro version in this year.
     
  11. Davvinci

    Davvinci Karting

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    #11 Davvinci, Mar 13, 2010
    After thinking about the start-up video, I might have another quick check you can do. It sounds like you are flooding but a quick check to see if it is starving is to disconnect the wire going to your fuel distributor while the key is on and the engine off. If you are getting the proper fuel pressure from your fuel pump, you should hear the gas flowing back into your tank from the overflow. If it does this, your fuel pressure is fine and you're not starving out. More simple checks to come. Let me know any results, please.
     
  12. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,345
    #12 Paul_308, Mar 13, 2010
    The fuel pump voltage has a different path when ignition switch is in start and when in run, controlled by the fuel pump relay. Sounded like while in start it ran ok but when released back into run it would guit.

    Change the fuel pump relay (lowest leftest relay). If that doesn't help and if you have a fuel pressure gauge, now is the time to use it.
     
  13. fletch62

    fletch62 Formula Junior

    Mar 8, 2004
    333
    Fairhope, AL
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    Larry Fletcher
    #13 fletch62, Mar 13, 2010
    Roy,
    If you help with the injection system contact me. I can send you testing info and procedures.
    Larry Fletcher 251-929-3771
    CIS Flow Tech
     
  14. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #14 royriccomini, Mar 15, 2010
    Davvinci, Paul,

    Thanks for the reply!

    It’s a Euro car, but I have O2 sensors. The local smog test station said they were working when the car was running a few months ago. How do I check them myself?

    Any easy way to check fuel/air mixture at home? Car is not running, so I can’t bring it anywhere without a tow. Is there a low cost fuel/air ration device I can buy?

    I pulled the cold start injector connector, but the start/idle problem still occurred. I'm thinking on pulling the cold start injector and seeing if it is sticking open or not working at all.

    Things I've checked and seem to function properly:

    Fuel plunger/Flow plate - It moves freely....no sticking.
    Ignition test – Tested with Timing gun.
    Vacuum leaks - Can't find anything visually.
    AAV - Open closes properly.
    Fuel pump relay - I swapped the headlight motor relay and fuel relay for the test considering the headlights seem to function properly...should I buy a new one anyway and do the test over?

    Things I’m going to check:

    Fuel delivery volume - I’m going to test this by disconnecting the fuel tank return line from the regulator and connecting a banjo union with hose. The hose will go into a container where I can measure the volume output (spec says 1000cm^3 per 30sec).
    Fuel pressure test – I need to buy a CIS fuel pressure test gauge set, but I’ll try to do this test this weekend.
    WUR – I have not searched the FC site yet on a WUR test procedure, but I should ensure this is functioning as well. Any advice on how to check its operation?
    Cold Start value – I put this further down the list because it had no effect when I pulled the connector
    Vacuum limiting device – need to check this as well.

    I welcome all the advice you guys can give me…thanks in advance
     
  15. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #15 royriccomini, Mar 15, 2010
    Larry,

    Thanks for the offer!!

    Checkout my de-bug process above. Let me know what you think.

    I think the fuel volume test will determine if I have a fuel pump or fuel blockage issue. Pressure test should help in determine if I’m leaking system pressure prematurely. Any thoughts on how to test if the fuel accumulator is function properly?

    I found a system pressure test for a 1988 328 CIS system. I'm assuming it’s the same for my car (1983 308 GTSi 2V)
     
  16. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
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    Roy Riccomini
    #16 royriccomini, Mar 27, 2010
    Conducted a fuel delivery volume test this weekend, and I only got 500cm^3 per 30sec. I believe I should get 1000cm^3 per 30 sec.

    I also conduct a fuel pressure test even though the results would not mean much because of the insufficient fuel volume the system is producing:

    Cold control pressure = 20psi (1.4bar)
    Warm control pressure = 40psi (2.6bar)
    System pressure = 59psi (4bar)


    Do I need a new fuel pump?
     
  17. royriccomini

    royriccomini Rookie

    Feb 10, 2010
    19
    Saratoga Ca USA
    Full Name:
    Roy Riccomini
    #17 royriccomini, Apr 6, 2010
    Got the car running. The root cause of the problem was the fuel pump. I would like to thank Larry at CIS Flow Tech for all his help.

    Larry-you have a customer for life
     

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