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For years...YEARS...I have been plagued by two nagging problems. This (a '70) is my second 1800E, and the brakes on this one have never been as firm as they were on the first one. I have also have a stuttering on transistion from idle, Recently, in a private conversation with Eric (planetman), he revealed the source of the problem. The previous owner who put the big bore kit in back in the early 90's must have put in an aggressive cam. As such, idle manifold vacuum is low. So my question: Eric told m that the FI sysem needs between 17-20 in. of vacuum at idle. I'd like to put a vacuum gauge on it and record the vacuum at various RPM, under load. Can anyone give me the figues for the manifuld vacuum at various RPMs in a normal B20E.
BTW, as a temporary fix I whipped out an old VW MPS I'd picked up in a junk yard. Long ago I'd ground out all that amber around the diaphragn adjustment screw (I know, you can't just screw that in or out to make a proper adjustment) and simply screwed it in until I had a smooth idle. The car immediatley ran perfectly, but my eyes burnd from the richness at idle. So I cranked back the fuel pressure as low as possible (about 22 psi) and that helped a bit. Car still runs fantastic at all RPMs, but fuel consumptionis up a bit. Eric and I agreed that the long term solution, since I can't budge the headbolts to switch out cams, is to jerry-rig some sort of constant vacuum source at idle. I think I have that figured out. Apparently the hot-rod guys also have systems that will up the vacuum to the brake booster. The engine compartment will probably look like a steam locomotive until I'm done, but I find these kinds of seat-of-the-pants engineering projects intriquing.
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