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Thread: Engine wont go past 3500 rpm/positive boost, bogs down

  1. #1
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    Default Engine wont go past 3500 rpm/positive boost, bogs down

    ook her out today after firing it up for the first time last night, and am having some problems. I'm not sure wether it is rpm related or boost related, but at 3500-4000 rpm the car will bog down and not have ANY power what so ever, but the car also bogs down when the boost (gauge) goes positive. Since boost starts to kick in around 3500-4000 rpm i'm not sure which it is. Even when I downshift, I still cannot get the car past 3500 rpm. I can get going, but either need to keep under 3500 or under positive boost levels. The car drives fine until either of those points.

    When i'm idleing I can get the car up to redline with no problems, but once I let off the gas, the rpm's shoot waay down, enough to stall it out. If I rev it then get off the gas slowly the car will idle fine at 1500 rpm (i need to adjust the tb, so thats why its idleing high..)

    Could a vacuum line cause this. I had a bunch of things off over the winter, and could have possibly forgotten to reconnect one.

    Anything I can do to see wether it is rpm related or boost related?


    Help?

    Thanks

  2. #2
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    Default

    do you have a BOV? apparrently certain ones do that, also did you do a tune up on it yet? that was almost the same problem i had, i did the tune up and it runs perfect now.

  3. #3
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    When I got mine, I couldnt go WOT at all, did a tune up, and it ran great after.

  4. #4
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    I do have a bov. it is recirc.

    tune up consisted of plugs (.028"), wires, cap. Same rotor as before. I dont think this is the problem because it happened so instantaneous. If it was bad ign parts it would be constant.

    I was stopped at a light, and for the first 3 gears I hit full boost (10 psi) although it did seem to be pulling a bit sluggish. coming up in 3rd it started to bog (3500+), geared up to 4th, that didnt help, downshift to 2nd and same problem...

    I checked the vac lines going into the intake mani and there is one unplugged. My engine is not in an mr2 and im not 100% sure how they are configured (i think they are just turned around) but on my pass side on the back on the mani, next to the firewall there is a nipple that is unplugged. on my car it is located on the tbelt side, behind the brake booster line, and is directly on the rear of the manifold. what is that nipple for?

    Could this be tvis related? IIRC doesnt the tvis "open" up at around 3500?


    its not even WOT. I can't even slowly get past that rpm/boost level...

  5. #5
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    Get new plugs, wires, cap, rotor. Your problem will go away guaranteed.

  6. #6
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    Well I found my leak. (I hope...) One of the nuts for my bov flange came off, and made it loose. I didn't notice it at first because it was on the underside of the bov, and when I quickly checked it on the side of the road, it still seemed tight and secure. After the drive home, i noticed it was loose, and because the bov is so close to my tb I'm guessing thats how the small leak made such a big difference.

    I threw a ziptie through the flange hole and tightened it down, took it for a spin, and it seemed to have cleared things up. When I cut the ziptie off, and loosened the bov, the problem came back.

    Off to find another bolt/nut/set of washers tomorrow to secure it properly, and I guess we'll see if that was it for sure.

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