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  1. #1

    Default Running a roller motor with my stock 1985 CFI setup, now have pinging issues

    Hey guys, I just recently put a roller motor from a 1987 LSC into my 1985 LTD LX with stock CFI. I just bolted on my stock intake and CFI throttle body and didn't mess with any settings on it. I set the initial timing to 10* and it runs great until I get to normal operating temp, then it starts pinging under heavy acceleration. It also stumbles a bit when I stomp on the gas. I tried going down to 8* and it stumbled worse, I tried going up to 12*, no difference. I never had this problem with my stock non-roller motor with my stock CFI, does the roller motor need more fuel or timing? Am I running too lean? I also tried 91 octane and that had no affect. I'm pretty stumped by now, I can drive the car around fine but I cannot get on the gas too much because of the pinging. Any help or would be great.
    Thanks
    Mike

  2. #2
    FEP Senior Member liv2roc's Avatar
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    dont know about the pinging but if you have the roller cam in it with a cfi distributor its going to chew that distributor gear up because the cam is hardened steel and the gear is cast steel. you need to get a steel gear on the distributor.

  3. #3

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    I'm using the original 87 LSC distributor that came with the motor. That should be good right?

  4. #4
    FEP Super Member bwguardian's Avatar
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    The first thing I would check is the damper. If original, it is possible the rubber has shrunk and the outer ring rotated thus not giving you a correct timing reading.
    HAD
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  5. #5

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    So if the balancer happened to slip, I would be getting a more advanced reading on the mark right? So if it shows 10* it could be more like 12* or more?

  6. #6

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    The damper could slip either direction. The important thing is to verify it's accuracy.

    The '88 LSC engine uses the '85 HO camshaft, which has considerably less overlap (-5 degrees)
    than the camshaft used in the CFI engines, and less exhaust duration (266º vs 274º). The former
    will affect the manifold vacuum signal curve, and both will affect the 'self-EGR' effect.

    Speed-density engines are completely dependent on the MAP sensor signal to tell the ECU how
    much load the engine is pulling, which is why they're so sensitive to cam changes.

    I don't know if the LSC used a different MAP sensor than your '85, but if so, it might be worth a
    try swapping in the one from the LSC. You might also experiment with raising the fuel pressure
    a bit. I expect your engine is running pretty lean.
    Cheers,
    Jeff Cook

    '85 GT Hatch, 5-speed T-Top, Eibachs, Konis, & ARE 5-Spokes ... '85 GT Vert, CFI/AOD, all factory...
    '79 Fairmont StaWag, 5.0, 62K original miles ... '04 Azure Blue 40th Anny Mach 1, 37K original miles...
    2012 F150 S-Crew 4x4 5.0 "Blue Coyote"... 65 coupe, 289 auto, Pony interior ... '67 coupe 6-cyl 4-speed ...
    '68 Vert, Mexican block 307 4-speed... '71 Datsun 510 ...
    And a 1-of-328 Deep Blue Pearl 2003 Marauder 4.6 DOHC, J-Mod, 4.10s and Lidio tune

  7. #7

    Default

    Thanks for the info Jeff, I do remember seeing a 87 LSC at the junks last time I was there, I'll be going tomorrow to see if I can pull the MAP sensor and give that a try. I checked the balancer and the rubber ring has no cracks or dry spots on the front end, so I'm sure the marks are accurate. I started pulling KOER codes and I kept getting a code 63 for a TPS circuit fault, I just installed a new Motorcraft TPS about 3 months ago. Can a problem with my TPS circuit cause detonation? Also, how can I raise fuel pressure on a CFI system?

  8. #8

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    TPS issues can cause all sorts of problems with CFI. I would check it. Also don't forget to check
    the wiring and connector.

    Fuel pressure on CFI is adjusted with an allen wrench after removing the black plastic plug on top
    of the regulator. Normal setting is 39PSI, and I normally wouldn't stray too far from that, but you
    don't have any other tuning options if the engine is running lean because the MAP sensor is seeing
    more vacuum than it would have with the stock CFI cam.

    One interesting thing I learned about MAP sensors when mine failed on my '85 Vert, is they are not
    all the same. I had swapped in another sensor I had from a later SEFI car, and it made my engine
    run rich across the board. At one point I had dialed the fuel pressure all the way down to 32PSI. (!)
    I ordered the correct Motorcraft DY-503 sensor, and when I installed it, the engine would barely run
    until I put the fuel pressure back to where it was supposed to be.
    Last edited by JACook; 01-10-2014 at 03:22 PM.
    Cheers,
    Jeff Cook

    '85 GT Hatch, 5-speed T-Top, Eibachs, Konis, & ARE 5-Spokes ... '85 GT Vert, CFI/AOD, all factory...
    '79 Fairmont StaWag, 5.0, 62K original miles ... '04 Azure Blue 40th Anny Mach 1, 37K original miles...
    2012 F150 S-Crew 4x4 5.0 "Blue Coyote"... 65 coupe, 289 auto, Pony interior ... '67 coupe 6-cyl 4-speed ...
    '68 Vert, Mexican block 307 4-speed... '71 Datsun 510 ...
    And a 1-of-328 Deep Blue Pearl 2003 Marauder 4.6 DOHC, J-Mod, 4.10s and Lidio tune

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