Announcement

Collapse
No announcement yet.

FI Problems stil...Running very rich.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • FI Problems stil...Running very rich.

    Ok here goes. MSD 6 Offroad and Holley Duraspark hybrid distributor:-) Using the MSD 8920 Tach adapter to send the signal to the computer and the tach per MSD.
    The TPS is adjusted and works.
    IAC moves when I crank it then moves back when I shut the key off. Both of the above items have been checked against others that are known to be good.
    CTS reads 421 ohms at 180 deg F.
    If I unplug the injectors they do NOT drip or bleed fuel when cranking.
    FP is at 12Psi steady.
    MAP has the same readings as it did new.
    Changed the computer...twice, I have 2 spares. Even tried a chip from a Astrovan with a smaller motor and it didn't lean it out.
    Engine will start cold but idles very rough until the IAC seems to be able to compansate when cold. Engine will idle for 1/2 hour at least just fine, sounds rich but not excessive. Once I shut the engine off it is all over. You can't restart the engine without holding the throttle wide open then it is flooded when starts and I can clean out the cylinders until the engine smooths out but it will not idle it is so rich. Engine won't run below 1500 rpm at this point.
    Tiiming is 10 DBTDC..same place it has been for years. I do have spark..and a HOT spark at that.
    I have 3 books on FI systems but none tell you how to troubleshoot the problem I have.
    I am at the end and not sure what else to check, replace or pray over.
    From the time I first noticed something wasn't right to the point it is now is less than 1 1/2 hours engine time.
    I have no engine code faults.
    Any ideas?????
    Thanks
    Darrell Tuxworth

  • #2
    Is there a chance the msd is still sending multiple pulses to the ecm, making it think the ignition is firing more times then it really is?
    You didn't have any problems until you changed distributors and added the MSD.
    Is there a stock dist you can borrow to run the eng just to verify the rest of the system is still good? If the only wire you moved was the from the neg side of the coil then it has to be ign related.
    What concerns me is you even had to buy a special timing light just to check the timing due to the multiple sparks.
    When you checked the timing was it advancing smoothly as you accelerated?
    Any chance a ground wire got pulled loose?

    Some additional tech.
    MSD magnetic pickup distributor

    Rotor Phasing
    Based on diagram #2 where do you have your ECM wire hooked up to? If you originally were using the neg side of the coil to trigger it, then I would try the gray tach wire. From all I have read I dont see the need for the Tach filter you have.
    diagram

    Tach adapter
    Last edited by Bill usn-1; 12-12-2003, 07:57 PM.
    Bill USN-1

    COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
    HAMILTON FUEL INJECTION
    May be the answer to all your fuel injection needs!
    Learn to do it right.

    Comment


    • #3
      Is there a chance the msd is still sending multiple pulses to the ecm, making it think the ignition is firing more times then it really is?

      That would explain things for sure but the tach is connected tot he same place and it reads correctly.


      You didn't have any problems until you changed distributors and added the MSD.
      Is there a stock dist you can borrow to run the eng just to verify the rest of the system is still good?

      I might be able to talk someone into taking their dizzy out and letting me borrow it.


      If the only wire you moved was the from the neg side of the coil then it has to be ign related.

      Yup so you would think.


      What concerns me is you even had to buy a special timing light just to check the timing due to the multiple sparks. The multiple sparks go to the spark plugs not to the tach lead and then on to the ECM or tach otherwise my tach would also be wiggin out.


      When you checked the timing was it advancing smoothly as you accelerated?
      Yes timing moves nicely

      Any chance a ground wire got pulled loose?

      Could be but not sure where. I have looked.


      It really acts like the pulse width of the injectors has been increased by 2 or so. Both injectors are havint the same problem or I could get the engine to run on 4 cylinders. The one question I have that no one has been able to answer is what type of signal does the GM ECM require? The MSD unit puts out a 20% square wave, wich the ECM ran off of but ran about the same it is now but the tach didn't work so the MSD tech said I needed an Adapter for the tach and it would cure the ECM problem as well. The signal to the tach "should" be the problem since, like you ointed out, is the only item related to the FI that has been altered. Do you have any idea what sort of signal the ECM requires??? This is probably my problem but not knowing what to use to correct it I am dead in the water....
      Darrell

      Comment


      • #4
        You replied while I was editing/adding some links from the MSD site.

        If I understand you correctly, you are using the gray tach wire to trigger the ECM.

        The MSD billet dist uses the same magnetic pick up as we use from the ford dist. so it has to be a simple wiring problem.

        I'll see if I can find the input signal spec.
        Bill USN-1

        COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
        HAMILTON FUEL INJECTION
        May be the answer to all your fuel injection needs!
        Learn to do it right.

        Comment


        • #5
          Bill.
          I can't thank you enough for helping me out here. That must have been a very good trip up Blanca for you to help me out this much after knowing me for such a short time.
          Any way here is what I have found out...at least I "think" I figured out.
          Contrary to the MSD tech you can't run the GM ECM from the purple wire on the 8920 tach adapter, You Can however run the ECM off of the grey tach lead wire coming from the 6 box. But I still needed the adapter to run my tach. Now I just need to find out which one will work with the cruise control.
          I changed the ECM to the grey tach wire and it fired up and ran. It also refired after shutting it off. It does seem to take more cranks to get it to fire but it will fire and idle now....No idea what was going on but I MIGHT have found the cure, keeping fingers crossed on this one.
          Thanks Darrell

          Comment


          • #6
            That's what I thought.
            I couldn't understand why it wouldn't work if you were using the tach lead.
            I just assumed you had it on the tach lead already.
            So you still need the tach adapter for your tach?
            Bill USN-1

            COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
            HAMILTON FUEL INJECTION
            May be the answer to all your fuel injection needs!
            Learn to do it right.

            Comment


            • #7
              And yes I had a great time on the trip up and down Mt Blanca.
              BTW I will email you my address for the tape. Just let me know how much.

              I'm planning to be back this year. May be my last outing before tranferring overseas.
              Bill USN-1

              COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
              HAMILTON FUEL INJECTION
              May be the answer to all your fuel injection needs!
              Learn to do it right.

              Comment


              • #8
                Yup still need the adapter for the tach. NOT the ECM per MSD TECH SUPPORT. Confusing thing is that the tach and ECM both were attatched to the "-" coil terminal and both worked from that signal but now they need different signals????? The engine still idles low upon initial startup for the first 10-15 seconds and takes longer cranking to get it to fire ...I think these two might be related and this was the first symptom I noticed that made me thing that the ECM needed a different signal to work properly. Oh well I think I am making progress any way and it will be ready for RMIHR...hopefully for MOAB too.
                Darrell

                Comment


                • #9
                  Were you running the tach and the ecm on the same wire out of the tach adapter?
                  The purple wire.
                  That would be odd that your tach would work right but the ECM wouldn't.

                  When are you planning Moab?
                  Bill USN-1

                  COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                  HAMILTON FUEL INJECTION
                  May be the answer to all your fuel injection needs!
                  Learn to do it right.

                  Comment


                  • #10
                    Yes, I was running both off of the purple wire. Now the tach off of the purple wire and the ECM on the grey.
                    Moab is usually the 2nd or 3rd week in April. right around tax time.
                    Darrell

                    Comment


                    • #11
                      Sweet IRS money

                      Something I've been thinking about with your idle.
                      You don't have ignition control so the ecm can't bump your timing for cold starts like it does with mine.

                      I'll take a look at the temp tables and see where I might be able to help it out.
                      I still have a copy of the last Bin I burned for you so I can work with that.

                      With the new ignition and hotter spark you need to build that cable and log some data for me. The fuel table will probably need tweaked again!
                      Bill USN-1

                      COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                      HAMILTON FUEL INJECTION
                      May be the answer to all your fuel injection needs!
                      Learn to do it right.

                      Comment


                      • #12
                        Amazing!

                        Multiple signals to the ecm. Did it think it was running at twice the RPM it really was? Or did ya have a 16 cylinder?

                        I have only been around a couple MSD ignition systems and the reason being they were acting up. What is the selling point behind the system? Yall have talked about multiple and hotter spark, is that it? Benefits? Is cost /gain worth it?

                        I have never been into the hot rod/speed parts so I am in the dark about the MSD.

                        Looks like yall have about fixed it. Amazing!!!

                        Maybe I will be ready to follow you both up a mountain in CO this coming July.
                        My "Disasterpiece"
                        1970 800A 4X4,HFI'd,304,B/W,27,44,3:73,28's.
                        The rest are in my 25 year plan!

                        My "Ruedh"
                        FREE 1972 1110 4x4,V8(?)727,205,44 drum/60/3.54's,small cheap tires.
                        LOOOOADS-O-RUST!! Donor body located. Not!! JY owner played the "crusher value" card. : angry:
                        NON-working rear window. Need info!!!

                        www.northtexasbinders.com

                        Comment


                        • #13
                          Multiple signals to the ecm. Did it think it was running at twice the RPM it really was? Or did ya have a 16 cylinder? >>>>>

                          I don't think it was getting multiple signals exactly, after all the tach reads correctly, I think it was getting the wrong signal with the wrong wave or duration....I don't really know tho and as much fuel as it was getting it was like it was trying to feed an engine 2-3 times the size of the 345. I don't know exactly what the ECM was thinking.


                          I have only been around a couple MSD ignition systems and the reason being they were acting up. What is the selling point behind the system? Yall have talked about multiple and hotter spark, is that it? Benefits? Is cost /gain worth it? >>>>>

                          Their were a few other events that led to me ending up with the MSD, not that I just wanted it, which I didn't really. My Prestolite fried, couldn't get new parts so I built a Holley Duraspark then found out that the Duraspark wouldn't fire the coil so I needed an ignition module and wanted something good so I ended up with the MSD since it would also be a performance gain.
                          I didn't realize my timing light wouldn't work with it, many do mine didn't, and then the tach wouldn't work so I had to buy a tach adapter from MSD to correct that. If I had known all of the problems and expense I was going to have to go through to get it running, and it hasn't been on the street yet so I don't know if it will work right or not, I would have just picked up the Ford control module from the salvage yard and been done with it for much less money.
                          One of the problems I believe I still have is something is governing the engine at 4K RPM or so( the MSD or ECM????) the tach didn't work origionaly, and I thought the governing would be fixed by the tach adapter since that is what the MSD"pro" told me. I will have to see if I still have the limiter affecting the motor and where it actually is.
                          One thing I can say for the whole system is that the engine sounds stronger in some way when it is running. I can't pin point why it sounds stronger it just does....I will just have to see and if I can get the wiring all routed and it runs right by the weekend after Christmas we are going to do some wheelin and I should be able to tell something more then about how this system has changed the performance/economy of the motor.

                          Darrell Tuxworth

                          Comment


                          • #14
                            ECM goes to tach on MSD not coil

                            It looks like you all have the answer that you are looking for here. Sorry I did not get on here any sooner to help out. We are dealing with some health issues in our family and have been out for a bit.

                            We have done a lot of fuel injection units with the MSD module. You always need to connect the wire that would normally be signal in from the distributor to the tach lead of the MSD and not the "-" side of the coil. The "-" side of the coil like Bill said is giving out multiple pulses making the ECM think it is running faster than it really is.

                            As for your starting issue do you have the crank wire connected to the crank side of the ignition switch or starter relay? If not this could be an issue.

                            Also you need to have the "base air" adjustment correct for the throttle body. Meaning just as a carburetor (yes I said carburetor) the throttle plate needs to be adjusted for a minimum amount of air flow to work with the IAC valve. If you are depending to much on the IAC you can have the same issues. You can go to our website under troubleshooting and #10 will tell you how to adjust this. If there is a plug over the adjustment screw you will need to remove the plug to adjust this. Here is the link and hopefully this will help you out. http://www.affordable-fuel-injection...jection.htm#10

                            Comment


                            • #15
                              Thanks Norm,
                              We are still dealing with a couple of issues.
                              He said he is only getting 3800 RPM with it hooked up on the tach lead but if he hooks it back up to the tach adapter he can get 4800. But it just loads the motor up with fuel and dies below 1500 rpm from being flooded.
                              I have him verifying the rotor phasing and the correct magnetic pick up wiring.
                              My initial thought was the PW of the signal or some RF interference from the adapter is sending the false signals to the ECM causing it to think the motor is running faster than it really is.
                              Which in turn is causing the tach to read higher.
                              He said when he hits 3800 that the inj stop firing. So...is the ECM shuting down like a rev limiter or is the signal from the ignition shuting off and the ecm stops firing the inj?
                              There's nothing I have seen in the bins that can work like a rev limiter have you?
                              I know guys use the TCC signal for a shift light!!!
                              Any way that's where we are at.
                              It will run fine and idle now but he said it wont get past 3800rpm.
                              He is in the process of rechecking all of his setting now.

                              He has put scope on the tach output and verified the amplitude and pw.
                              It's 12v and 20%.
                              Do you know what the GM input signal is?
                              Thanks
                              Last edited by Bill usn-1; 12-14-2003, 07:45 PM.
                              Bill USN-1

                              COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                              HAMILTON FUEL INJECTION
                              May be the answer to all your fuel injection needs!
                              Learn to do it right.

                              Comment

                              Working...
                              X