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I found some pictures from long ago that have the vacuum ports labeled so everyone can figure out where they go. Here they are.
[attachment=1:250woqrw]map-sensor-location.jpg[/attachment:250woqrw]
[attachment=0:250woqrw]TBI-ports.jpg[/attachment:250woqrw]
What model is this, a 220, a 300 or a 700, didn't think it looks like a 220 (that's what I have), but then again I have never pulled mine off!
I'm not really sure what model. Most look identical, even the one barrel looks identical except it's only half.Quote:
Originally Posted by mudbuggy
The Model 220 is the 2 bbl TBI, while the Models 300 & 700 were the 1 bbl (single point) TBIs used on the 2.5L. Those pics have two injectors, as in EagleMark's picture. The Model 700 TBI has a horizontal FPR, while the Model 300 had a vertical FPR, similar to the Model 220.
http://myfiero.oceanmoon.com/wp-cont.../clip00011.jpg
Model 700 TBI with the horizontal FPR (as viewed from above).
Thanks MadJack for the picture! :wtg:
Sorry it took so long to get it approved? We usually don't look for first posts anywhere other than Introductions. Everyones first post needs to be approved by a moderator, this way our guests and members never see SPAM! But anyway I found it! Thanks! :thumbsup:
Resurrecting this old post... Anyone know if there is a difference between the MAP port on the back of the TBI and straight manifold vacuum pulled off of the intake manifold? I was poking around and noticed my MAP sensor is hooked to manifold, not this port. I'm using this port to run my heat/AC vents and stuff.
That port is designed for the MAP sensor by GM, so why go anywhere else with the most important sensor on a Speed/Density system?
Straight manifold vacuum should be the same thing, but where is it in manifold? I looked at a data log once and saw a jumpy MAP signal? Asked where his MAP was hooked up and it was in number eight runner so it was not a steady vauum reading. GM went out of there way to give MAP what it needs, why change it? Run your heater to other one, it's not a sensitive device and won't know difference.
I'm going to change it, just trying to understand if it matters. Right now MAP sensor is plugged in to the manifold right behind the throttle body. Same place the brake booster is connected.
If it's a clean steady engine vaccum probably not. But if it shares a fitting with a brake booster then every time you hit the brakes it drops to fill booster. When it drops the MAP thinks there's a load on engine and adds fuel. Like above in a fitting on number eight intake runner pulsed with intake stroke of that cylinder.
Every GM EFI vehicle I have seen is a designated MAP sensor vacuum port for a true uninterupted intake manifold vacuum source. So GM thought it mattered.
Wow!!! I just had a smack in the face... I never thought about this being an issue, until now. Thanks Mark! this could be a major reason why when i come to a quicker stop the thing wants to stumble and die. I'm using a tee fitting for the booster and for the MAP, pulled from the manifold like Mastiff. Now i feel like a complete moron. I will be changing this setup as soon as i can.Quote:
Originally Posted by EagleMark
No reason to fell like a moron, now if you did something stupid maybe, but this is a common issue with conversions.
Learn and share, learn and share! :happy: