stravi757 Posted August 17, 2009 Share Posted August 17, 2009 alright so I just got my l28et swap running. It keeps running rough tho. on my boost gauge the vacuum reads at 15, and for some reason i remember it being closer to 22-25 or something. so ive been lead to believe i have a pretty big vacuum leak, but i cant figure out where. i just put the intake exhaust manifolds on with a new gasket and i know i torqued all the bolts right, and ive checked about everywhere else and i cant find anything. the only place i dont have blocked off is the egr valve(i dont know how major that is tho) when i drive the car and about 2,500 rpms and keep it there the car will jump back and fourth on me constantly(not very hard but you can feel it) ive checked my plugs they seem alright, not running lean or rich, the tps is working. the only other thing i can think of is my timming is probably off a little because i dont have a timming light(i have it set a little more on the retarted side) anyone got any ideas?! note: i bought a turbo short block and assembelled it with all turbo parts stock(heads rebuilt) Quote Link to comment Share on other sites More sharing options...
MAG58 Posted August 17, 2009 Share Posted August 17, 2009 Do you still have the EGR attached? If it's not there and there's no block off plate, that's a pretty big gaping hole that leads directly into the runners. But if that was the case, I would be surprised if the thing ran well at all. When you tightened down the bolts were the washers that touch both the Intake and exhaust mani's (bottom part of the intake manifold) at any sort of an angle? I had this problem when I did a carb swap to put the L28 in my 71. I'd tighten the bolts all to spec and there was still a big gap in the bottom allowing the intake manifold to just float around. Also, which gasket are you running? I've had a few fel-pro gaskets that have really large holes on the intake side and if it's not put on just right you can get A little bit sticking out (the hole that is) also causing a vacuum leak. Quote Link to comment Share on other sites More sharing options...
ktm Posted August 17, 2009 Share Posted August 17, 2009 Your vacuum was not at 22 or 25, most likely it was either at 18 or 20. However, I would not use a boost/vacuum gauge as a means to measuring vacuum. You should use a real vacuum gauge to measure your vacuum. when i drive the car and about 2,500 rpms and keep it there the car will jump back and fourth on me constantly(not very hard but you can feel it) Sounds like lean surging. Quote Link to comment Share on other sites More sharing options...
stravi757 Posted August 17, 2009 Author Share Posted August 17, 2009 Your vacuum was not at 22 or 25, most likely it was either at 18 or 20. However, I would not use a boost/vacuum gauge as a means to measuring vacuum. You should use a real vacuum gauge to measure your vacuum. when i drive the car and about 2,500 rpms and keep it there the car will jump back and fourth on me constantly(not very hard but you can feel it) Sounds like lean surging. well now my gauge is reading 16 1/2 on vac and it reads 18-18 1/2 on deceleration. so maybe my gauge is the problem. an on boost im at 6 psi. Also engine is no longer running rough!. I decided to change the plugs, and while i had them out i decided to do a compression test which turned out with good numbers, 130 all across. Anyways when i was taking the plug wires out i decided to take out the wire that goes to the dizzy and it turned out the connector was broken in half! i replaced it and the car runs great now, it takes off on the freeway! thanks of ur helps guys Quote Link to comment Share on other sites More sharing options...
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