Thanks Thanks:  0
Likes Likes:  0
Dislikes Dislikes:  0
Page 1 of 2 12 LastLast
Results 1 to 15 of 27
  1. #1
    EEvette
    Guest

    Default Very strange starting

    Hello everyone,

    I am what i like to call strange starting issues. I am by no means an expert but this problem is driving me nuts.
    First a few things ive done to try and solve the problem.
    1) New Fuel pump/filter
    2) New IAC valve
    3) New exhaust system (no restriction issues)

    Ok so this is what happens, I first turn the switch to start the car and it cranks for maybe four or five seconds and then starts. I have noticed that if I turn the switch and let go right away, at the second try it starts like a champ.

    Please help like im sure everyone here has, Ive invested quite some money on this car.....its all worth it when it runs though!

  2. #2
    Member JimBobC4's Avatar
    Join Date
    Aug 2004
    Location
    Canton Ga
    Posts
    343
    Corvette(s)
    1995 Dark Red 6spd Convertible
    Post Thanks / Like
    Rides
    0

    Default

    I think you have a fuel pressure leak down issue.

    Check pressure at the schrader valve on the fuel rail.

  3. #3
    EEvette
    Guest

    Default

    Thanks Jim

    I will do so.....I also forgot to mention that once it starts it idles perfectly.

    Oh, and I have a wet kit nitrous system on it...I have not used it yet, but the test port is connected to the fuel soleniod on the kit. I doubt this has anything to do with it but mind as well make mention of it.

  4. #4
    Very strange starting TedC's Avatar
    Join Date
    Oct 2007
    Location
    Amherst, NY
    Posts
    719
    Corvette(s)
    1989 Red Coupe
    Post Thanks / Like
    Rides
    0

    Default

    EEvette, Disconnect the injectors and measure resistance and report back. They should all be very close to each other (in the 16 ohm range). Also, is your ECM EPROM the stock EPROM or was it customized? In 1989 GM added a longer delayed start to increase the crank time, improving starting oil pressure. 1989 EPROM code is a popular base to customize from because of the higher timing advanced curves vs. prior years and the elimination of the 9th injector used for cold start.

  5. #5
    EEvette
    Guest

    Default

    TedC,

    I have an 86, as far as the ECM I personally have not modified/upgraded it. This is a recent issue so it is safe to say it is not due to an ECM upgrade. I will check the injectors' resistance as soon as I get home from work.

    I just passed emissions inspection last sunday so I know the engine is not running too rich.

    I will post the injector readings later this afternoon.

  6. #6
    EEvette
    Guest

    Default

    Ok, I read the resistance on all 8 injectors yesterday. They all read between 16.1 and 16.2 ohms.

  7. #7
    Very strange starting TedC's Avatar
    Join Date
    Oct 2007
    Location
    Amherst, NY
    Posts
    719
    Corvette(s)
    1989 Red Coupe
    Post Thanks / Like
    Rides
    0

    Default

    That is good news on the injector front. Just one bad injector (low resistance) can cause the ECM not to pulse any of the injectors. Would suggest investing in the factory service manuals. Some other suggestions... When you turn the key to run (do not start the engine) do you hear a click (fuel pump relay). I would check then make sure you are getting fuel pressure on the rail and that this pressure holds. Pull a plug wire and check for a spark during this condition. Check timing.

  8. #8
    EEvette
    Guest

    Default

    I have also checked the fuel pump and the relay. I can hear the pump activate as soon as I turn the key....might be the timing.

    I will look into getting the factory service manuals since I have the Haynes but thats not quite as good I hear.

    Thanks for all your help and I will report back if I find the problem.

  9. #9
    Member Ezmunie's Avatar
    Join Date
    Feb 2006
    Location
    Sherman,Texas
    Posts
    233
    Corvette(s)
    1986 Black Convertible
    Post Thanks / Like
    Rides
    0

    Default

    Keep us posted on what you figure out as I'm having the same problem

  10. #10
    EEvette
    Guest

    Default

    Would a bad or about to go bad ICM cause this problem?

  11. #11
    Member TWISTERUP's Avatar
    Join Date
    Aug 2008
    Location
    Powhatan VA
    Posts
    138
    Corvette(s)
    1996 LT1 Coupe
    Post Thanks / Like
    Rides
    0

    Default

    Quote Originally Posted by EEvette View Post
    Would a bad or about to go bad ICM cause this problem?
    Doesn't sound like the ICM to me
    Quote Originally Posted by JimBobC4 View Post
    I think you have a fuel pressure leak down issue.

    Check pressure at the schrader valve on the fuel rail.
    I agree with JimBobC4--Have you checked fuel pressure at the rail yet ?
    I know you've ohmed the injectors..the resistance may check OK and they could still be leaking down (not holding pressure) over time. The time lapse you feel when cranking may be the time it takes the fuel pump to build pressure back up in the fuel lines/ fuel rail and the injectors

  12. #12
    Member
    Join Date
    Aug 2002
    Location
    wilkes-barre,pa.usa
    Posts
    758
    Corvette(s)
    1988 white 4+3 coupe 99 Torch Red 6spd. coupe
    Post Thanks / Like
    Rides
    0

    Default

    That's exactly what my 88 was doing. Injectors ohms were ok. Fuel system would not hold pressure. Replaced the injectors with Bosch GenIII's and my problem was solved. Starts hot/cold, runs beautiful. I'm sure there could be other issues, but the fuel pump was changed, could be the regulator. More than likely it's the injectors leaking down and I thank all who got back to me with the solution.

  13. #13
    EEvette
    Guest

    Default

    I will check fuel pressure next....how long would I need to leave the gauge in place before I can determine if there is/isnt loss in pressure?

  14. #14
    Very strange starting TedC's Avatar
    Join Date
    Oct 2007
    Location
    Amherst, NY
    Posts
    719
    Corvette(s)
    1989 Red Coupe
    Post Thanks / Like
    Rides
    0

    Default

    You have verified injector resistance. This means that the ECM should be able to pulse the injectors properly. It is important to verify that the rail is getting pressure, and the right pressure. Injector leak down is usually a problem on a hot soaked engine. I guess it could occur on a cold engine. My 1988 had leaking injectors, and it still started like a champ when cold. Did you check for spark during cranking? This is an easy test, and can help it determining if we should be looking for an ignition issue. When you measure fuel pressure, measure first in run (do not start) and record what happens at the start and after 5 minutes. Then start the engine and measure again. Record pressure with and without the vacuum hose attached.

  15. #15
    EEvette
    Guest

    Default

    I did check for spark, I used a spark tester that I bought from a local automotive store. However, I wasnt sure to what setting to adjust the screw to. It ranged from 10 to 40 SE. On the 35 setting I got a spark upon starting and not during cranking. The spark would not jump the gap every time(engine running). Has anyone used these, what setting should I use?

    Thanks for all the help.

Page 1 of 2 12 LastLast

Similar Threads

  1. strange starting problem
    By caninelver in forum C4 Technical and Performance
    Replies: 11
    Last Post: 03-25-09, 08:57 AM
  2. 1986 (Late) Hard Starting When Hot!
    By Piratetc in forum C4 General Discussion
    Replies: 5
    Last Post: 09-22-06, 07:40 PM
  3. strange starting problem
    By novafink in forum C4 Technical and Performance
    Replies: 6
    Last Post: 03-28-05, 11:31 AM
  4. 1984 starting problem
    By ffvetteman in forum C4 Technical and Performance
    Replies: 4
    Last Post: 09-12-03, 05:27 PM
  5. Starting and electrical problems
    By 3tt3vman in forum C4 Technical and Performance
    Replies: 1
    Last Post: 05-19-02, 09:51 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •