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Weird performance issue after SWAP to a D15b HELP!

Discussion in 'HYBRID -> EG-EK / DC' started by hondapower1, Feb 28, 2012.

  1. hondapower1

    hondapower1 New Member

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    Here is the story:

    I installed a D15b in my 98 civic DX, here are the details, I swaped the intake manifold with injectors of the D16Y7 on the D15b, kept the D16Y7 harness, put a P28 ECU with OBD2A to OBD1 conversion a harness, plugged in the Vtec into the OBD1 harness, kept the crank pulley of the D15B (alternator belt too lose) and everything else is original D16Y7 (oil catch can, dizzy ... well everything except ECT sensors and switches that were already on the D15b). Now the knock sensor on the D15b is not connected since there were none on the D16Y7 and the crankshaft position sensor wire is not connected to the D15B since there was no bracket on the oil pump for it and anyway I was told that there would be no problem leaving it not plugged in (which is true because the engine started on the first crank of the starter and that there is no trouble code coming out).

    That being said, here's the problem, the engine started number 1 with idle a little high but nothing alarming for now. First ride, everything is good at first, Vtec kicks in and all. 3-4 minutes after the car has a hard time, at idle the RPMs go up and down non stop. Leaving form a stop, I give it gas but it does not want to go to well, it hesitates (no misfire or bucking or bogging) it goes slowly and suddenly the power comes back and it goes. In higher RPMs the problem seems to disappear, if i floor it in low RPM it doesnt want to go too good but then suddenly it goes and all of a sudden there is less power, then it comes back so basically the power comes in and out. Flooring it at high RPM seems to be less troublesome. On the highway if I keep the pedal steady and keep it at 70 mph in 5th it feels like a roller coaster, power.... low power .... power .... low power ...power. It feels like all of a sudden it pulls, and suddenly it coasts, it pulls, it coasts .... all of this happening at a steady 70 mph (+ or - 2 mph) You see the picture? No check engine light or battery ever flashed. If I recharge the battery and I leave for a ride, the same cycle starts from the beginning, the first 3-4 min are ok but suddenly everything starts over, weird idle ... etc.

    Keep in mind that the crankshaft pulley of D15B was too small so the alternator belt is extremely loose and the alternator squeals loudly at idle and occasionally at higher speed (I'll change it tomorrow for smaller one). Also the distributor is form the D16Y7 and I had to drill it to fit it and now because of the tight fit it has no play to adjust the timing. Also the knock sensor and crankshaft position sensor are not connected as previously mentioned. All that still without ever any check engine light or battery light appearing....

    Thanks in advance
     
  2. 99sidude

    99sidude Moderator Moderator VIP

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    Make sure your cam timing isn't off a tooth. Are you sure you can just swap the dizzys? Perhapse that is causing timing issues. Lastly, make sure you dont have any BIG vacuum leaks. A faulty IACV can cause this. Double check the wiring of the IACV. Some of the newer 3 wire ones need to be rewired to work with an obd-1 ecu. Check our tech library for that.
     
  3. hondapower1

    hondapower1 New Member

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    Perfect, thanks.

    As for the dizzy it seems to be working right, i just had to drill out the slots in order to make the bolts fit and to give the dizzy some play so that i can time the ignition to 16* once the idle issue settles down!
     
  4. hondapower1

    hondapower1 New Member

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    Does anyone know that using an OBD2 dizzy on a OBD1 head causes issues? If so what are they?
     
  5. hondapower1

    hondapower1 New Member

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  6. hondapower1

    hondapower1 New Member

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    For future reference the idle problem was caused by the IACV which needed to be a 2 pin type and the low RPM performance issue was due to a defective ECT switch or ECT sensor (not sure which one since I swapped them both from the old engine in the same time!) Thanks for all your help guys and if someone ever has the same problems in the future well start with that!
     
  7. josh_crewdson@y

    josh_crewdson@y New Member

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    The p28 ecu is mapped for 240cc injectors, d16y7 injectors are only 180-190 iirc...
    That's probably not what's causing your problem, but its a good place to start.
    Also make sure you didn't accidentally switch your MAP & TPS plugs..
     
  8. hondapower1

    hondapower1 New Member

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    Manifold of the D15b was installed so the injectors with it and switching the MAP & TPS prob cause a bigger problem than that!
     
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