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3.4/3500 Hybrid Project Stuck at the PCM

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  • 3.4/3500 Hybrid Project Stuck at the PCM

    Let me start off with thanks to Force Firebird, RobbertISaar, and all the that have posted there experiences on 3.4/3x00 hybrids.

    I Bought a 1994 Firebird With a 3.4, and an automatic 4l60e.

    After replacing the head gaskets, I drove it for a few months. I then decided to look into adding a little more power. After a lot of searching, and reading, I decided to do the 3.4/3500 hybrid conversion. It sounded like a fun challenging project. (Project 10+ wins me about 3 wins if I round up).

    So I went to the local pick and pull and got the following parts:

    2006 Pontiac G6
    3500 heads
    3500 lower intake manifold
    3500 waterneck

    2000 Grand am GT
    Upper intake manifold
    Valve covers
    fuel rail with fuel regulator and some the extra fuel line attached (2 ft ish)
    the 22.5 lbs fuel injectors (and the pigtails there different connectors then the 3.4 firebird ones)
    pistons and rods

    I ordered the following parts:

    Fel-pro 94 firebird 3.4 firebird lower rebuild kit with oil pump and cam.
    Fel-pro 2006 G6 3500 top-end rebuild kit
    Fel-pro 2000 Grand Am upper intake manifold gaskets (metal version just because they're easier to install, and stay in shape knowing I will have to remove upper-intake a few times)
    2000 Grand Am dish pistons (wanted nice new clean ones and the measurements seemed off on the ones I bought from the salvage yard. Come to find out I swapped out good pistons with new pistons on the stock forged rods.

    Comp Cams 260H (decided to upgrade from the stock one after I ordered one in the rebuild kit)

    the secret push rods

    94 cavalier 3.1 push rods almost perfect length.

    Pacesetter headers (have to slot bolt the holes in them to get them to fit right)

    Things to make:
    throttle body adaptor to use a pull from behind throttle body to keep the stock cables.
    Ported the 3.4 firebird throttle body.
    Accessory bracket mods (recommend modding the brackets with an engine outside the car, put the valve covers on the heads, and check the alternator clearance. I created a swivel spacer thing (that’s the technical term) to move the alternator up and to the left about 1/2 inch. I didn't like the idea of grinding on the alternator.
    A lot of wire length changes due to moving sensors and other items.
    adaptor for the temp sensor to put in the lower intake manifold.
    modified 3500 water neck (Paid British conversions for the one they offer still waiting for it 9 month later. I would recommend there’s. It's a straight hose connector that would fit perfect.)

    I am sure there are a few things I left out, however, that's all the major items I believe.

    I put all the parts together, put the key in the car and guess what? It started with the stock 3.4 firebird PCM. It idles like crap, and drives just as bad. However, I got a lot further then others at this point, so I was happy.

    The problem:
    I bought tunercats V6 Y cable kit (figured I would spend the little extra and get the Y kit. I might use it on another car some day) to find that there are options missing that need to be tuned like injector size. So the answer was throw more money at the problem, pay someone to tune it, and I'll upload the file. I Used Scan9495 v6 version for data logging. (nice cool little app if you want to see what's happening in the v6 in real time, there’s an LT1 version also)

    The tuner company refunded my money due to the fact that they couldn't tune the car. They claimed my definition was wrong, and my logs were not constant with their changes.
    I took the car to a shop in Jacksonville only for them to tell me that something wasn't right also.
    I tried the P66 TunerPro definitions. They're a really nice set definitions by RobertISaar. (Contacted creator was a lot of help in explaining where I needed to start, and how to get from point a to b) I decided it's a little rough for someone's first tuning project, and I didn't understand the definitions in relation to the PCM's odd math VE tables and other odd factors created from the OBD 1.5 PCM.

    PCM swap is the next option. I have a 4L60E transmission, and just paid to have it rebuilt with corvette guts, so I would like to keep it (8.3 total miles so-far on it).

    I want to swap to an OBD 2 PCM. I have a 1997 Camaro 3800 PCM 16227797. I found that the crank sensors will create a few problems. Is there an OBD2 PCM I can use that's close to my wiring harness I can slice in that will work?

    I was thinking a 2000 Grand Am.
    Last edited by Thordac; 12-20-2014, 10:03 PM.

  • #2
    Wondering if i change the 3.4 Harmonic Balancer to a 3800 Harmonic Balancer would that change my crank signal to 18x from 24x.
    The 16227797 PCM for the 97 Camaro uses a 18x crank signal. Any ideas on how that would that effect DIS and firing order.

    Another option I was reading that is a switch option in the PCM that lets you change that to 24x being this PCM is used in the Monte Carlo 3.4. Does anyone know if that is true? (best choice in my opinion)

    If it is true does it change that pin that the reference signal is used on the PCM.

    The 3x signal i think i found the solution on Feiro website they sliced 3x high low together to get a reference (sounded kinda odd but would give the highs and lows on one output wire. I am Questionable on the outcome.
    Last edited by Thordac; 01-07-2015, 06:41 PM.


    • #3
      Solved the PCM wiring and 18X to 24X by changing the setting in the bin using Tiny Tuner. Along with the 3X reference into wiring into the PCM.

      Also solved the 4L60E PWM solenoid by tuning out the DTC 1860 in the PCM. Along with the 3-2 shift solenoid difference without having to change out the solenoid.

      Soon i will have a tuned bin file to post for a 16227797 PCM that will work with this conversation that uses OBD2 PCM letting you use MAF on and the automatic 4l60e transmission from the 94-95 Firebird/Camaro with the 3.4/3500 top end conversion. I will also post the wiring pin out needed to make the PCM this conversion from 94 automatic/manual PCM to the 97 Firebird/Camaro 16227797 PCM.

      In my research I found an interesting throttle body Conversion that's Pull from behind sold by an MG restoration/conversion site here is the link tho the throttle body

      They also sell a cable setup for the throttle body that mounts to the firewall should fit the factory hole with 2 small holes to hold to the firewall.


      • #4
        IMO just for the record that BMC throttle body is not only too small for a 3500 top end but also it won't bolt to the 3400 or 3500 upper without an adapter.
        '89 Firebird, 3500 Turbo, T56, 9-bolt/4.11
        '86 Fiero, 3500, 4-speed


        • #5
          My understanding was that the 95 3800 camaro and bird was still obd1. My current android code scanner will read my 01 3800 just fine, but it will not read any 95 3800 codes. Just a thought.

          Sent from my Verizon LG G3 sexiness via tapatalk


          • #6
            the OBD 1.5 PCM you need a scan tool that will do OBD 1 or an aldl cable and an OBD 1 reader program. Scan94/95 should scan the codes same with OBD 1 sniffer.
            You can buy a aldl cable at (little over priced i think)
            Or you can make one using FTDI FT232RL and GM 12pin to 16Pin OBD1 OBD2 SR1G and splice them together

            Items needed to make this cable
            FTDI FT232RL USB to Serial adapter module USB TO TTL RS232 Arduino Cable (Ebay)
            GM 12pin to 16Pin OBD1 OBD2 SR1G (Ebay)
            soldering iron
            heat shrink or electrical tape(cheaper choice dont look as good in my opinion).
            multi meter

            Solder on the FTDI FT232RL
            Green wire TXD, Yellow wire RTS together. (Joint 1)

            cut the obd 2 cable in half strip back the wires
            use the multi meter to figure out what wire feeds pin 9 on the obd2 plug
            solder Joint 1 to the wire that feeds pin 9
            use the multi meter to find the wire that feeds pin 5 that is ground solder the black wire to that.

            heat shrink the extra wire ends up and then use one big heat shrink to cover all wires (be sure to add heat shrink before soldering or u will have to use electrical tap instead)
            Last edited by Thordac; 02-12-2015, 01:43 PM.


            • #7
              Ok I kinda fell off the planet with this post. I ended up parking the Car because I went on a 10 month deployment.
              Some how the passenger window was cracked so interior is destroyed from weather(full of mold) but I have found a cheap car with a good body and the engine has a bad main seal. So back to do the swap over again good part is I have little experience at it this time and 90% the parts I can re-use.

              I'll post pics soon of the start and some the process.
              Last edited by Thordac; 06-27-2016, 08:57 AM.


              • #8
                I have a less aggressive cam to install should be easier to tune.
                And My new body is a 95 Camaro using same Trans setup as before 4l60e only difference is this one has a PWM solenoid. I'll have to re-enable the the PWM codes in the PCM.