Tony D Posted July 7, 2013 Share Posted July 7, 2013 Your friend is misleading you somewhat on the mechanics of how it might be running rich, but if it's caked up with gunk, indeed it will not allow the proper flow of air to the engine for the calibrated throttle position and flow through the AFM and THAT will make it run rich. There gets to be a point (Hot Idle) that the AFM Flapper is near CLOSED, and the air bypasses around the AFM---this should be close to the requirement of the engine at hot idle. That valve, screwed all the way out...should allow a speed of 2,500. I'd get some throttle body cleaner, and start there with your idle speed problem before chasing electrical stuff any further! Clean the T/B good as well, it can get gunked up and cause problems as well. Then get a vacuum gauge on that manifold and see where your hot vacuum is at proper curb idle. Incidentally, if someone has played with the AFM bypass and the rpms slow enough....the switch can open, killing the fuel pump and stalling the engine. When in doubt "IDLE UP" until you get it all figured out and adjusted properly. I have seen cars with 8" Hg vacuum and bad timing from a slipped balancer pulley that wouldn't run at all. Bought for a song and within an hour under a tarp in Orange adjusting the valves, timing and other basic items from the FSE Engine tune up, the car was strongly running and drove to Phoenix that evening. People just let the basics go because the rest of the stuff compensates so well. The old systems default RICH, and that always aids drivability, meaning people don't perceive a problem until it's WAY down the road to being out of proper adjustment. It's why the OBD Systems these days throw codes. They run so well, you will never know when something goes 'bad' unless you have sophisticated instrumentation and know to look for it! Quote Link to comment Share on other sites More sharing options...
ISPKI Posted July 7, 2013 Author Share Posted July 7, 2013 That is going to be my next step. I have cleaned up/replaced/upgraded a ton of electrical on this car already (Replaced all the harness connectors, AFM, TPS etc, removed and cleaned manifolds, injectors, replaced all the seals, redid the fuse wiring with maxi fuses etc, cleaned and replaced and in some places added grounds). Unfortunately my alternator on my honda civic just kicked the bucket so I had to skip removing the throttle body and cleaning it this weekend. The bypass screw on the AFM does not seem to have been tampered with, it appears to still be sealed up from the factory. We will see what happens with the TB bypass. Quote Link to comment Share on other sites More sharing options...
ISPKI Posted July 30, 2013 Author Share Posted July 30, 2013 (edited) Wow, took me three weeks to get the time to test this. I picked up a new vacuum fitting and got the gauge installed. When the vehicle first starts (which is when it seems to Idle pretty good) the vacuum gauge bounces between 15 and 16. After about 30 seconds, it dropped down to being extremely rough. At that point, the vacuum gauge was bouncing between 6 and 8. When I pull the idle set screw completely out (so there is just a giant hole right into the intake) the vacuum gauge bounces up to 17ish and stays relatively stable at that level. This behavior makes me wonder if there is simply no air getting in at idle and that is starving the engine completely. It seems to me that, when the idle screw is removed, shouldnt the vacuum pressure drop rather than increase? That is, unless there is absolutely no air coming in and the engine is just slowly dieing. Edited July 30, 2013 by ISPKI Quote Link to comment Share on other sites More sharing options...
ISPKI Posted July 30, 2013 Author Share Posted July 30, 2013 (edited) Edited July 30, 2013 by ISPKI Quote Link to comment Share on other sites More sharing options...
ISPKI Posted July 31, 2013 Author Share Posted July 31, 2013 So, I was reading a page from Atlanticz's techtips about this. One of the possible causes that they list is that the exhaust could be too restricted which it is (the pipe immediately after the manifold is crushed). I am going to try and get that off until I can find some other ideas to look into. I cant find a vacuum leak anywhere, and it isnt behaving like it has a leak IE: creating a leak makes it run better and GAIN vacuum. My issue follows the details from atlanticz pretty closely (low idle that gradually drops and then dies). Quote Link to comment Share on other sites More sharing options...
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