Stillridin Posted August 1, 2019 Share Posted August 1, 2019 On my '03 injected Bird, adjacent to each fuel injector are two vacuum ports. The right ones for each cylinder join to supply vacuum for the evap canister. The left ones for each cylinder join to supply vacuum (manifold pressure signal) to the MAP sensor. I have installed an aftermarket cruise control which requires a vacuum source. I hope someone can confirm whether the vacuum ports feeding the evap canister and those supplying the MAP signal are all interchangeable or whether the left and right ports are somehow different, making one a preferred source to tap for the CC? Thanks much for sharing any wisdom. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted August 2, 2019 Share Posted August 2, 2019 If no one knows, maybe you could tee a vacuum gauge in and start it to see if they act the same. Quote Link to comment Share on other sites More sharing options...
Furbird Posted August 2, 2019 Share Posted August 2, 2019 I haven't installed a vacuum cruise control since 1997 because even back then the world was going with full electric cruises. I don't even know if you can pull enough vacuum on a bird to do a vacuum cruise?!? Quote Link to comment Share on other sites More sharing options...
Stillridin Posted August 2, 2019 Author Share Posted August 2, 2019 Thanks for the replies. I'm hoping someone who's done head or intake work knows definitively whether all 8 vacuum ports are the same. For the record, I had this aftermarket cruise control laying around for years and finally decided to install it on the Blackbird. I can tell you it works well but acknowledge vacuum is insufficient for it to maintain speed on significant hills. Riding at high elevation recently I experienced a stumble transitioning from neutral to light throttle. While investigating that I began wondering if it might be better to tie the cruise control into the evap canister vacuum instead of the supply for the MAP sensor. It may be the 8 vacuum ports are all the same but the fact that separate ports and hosing was designed for the two purposes suggests there may be some unseen difference. I'd still appreciate hearing from anyone who knows. Thanks again. Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted August 2, 2019 Share Posted August 2, 2019 I don't remember which port I used. I do remember that you must have a check valve installed in the vaccum line between the port and a accumulator canister. I ended up with a large canister to get the cruise to work right. I started with a ball cock float, and it was too small. I built one of pvc pipe. It was about the size of a 32 oz sport drink. A safety question? Your installation does use the ball chain? If not. Please install it. People who didn't experienced some exciting run away. Also, on my 01, the vacuum lines started cracking after ten years or so. I googled and replaced them with silicon lines. Quote Link to comment Share on other sites More sharing options...
SwampNut Posted August 2, 2019 Share Posted August 2, 2019 11 hours ago, Furbird said: I don't even know if you can pull enough vacuum on a bird to do a vacuum cruise?!? Certainly not going to be able to hold 170. Quote Link to comment Share on other sites More sharing options...
XXBirdSlapper Posted August 3, 2019 Share Posted August 3, 2019 12 hours ago, SwampNut said: Certainly not going to be able to hold 170. If it's ported vacuum it would. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted August 3, 2019 Share Posted August 3, 2019 I'd avoid using the MAP vacuum source, that could fuck with what the sensor sees. Quote Link to comment Share on other sites More sharing options...
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