Quagmire Posted July 20, 2015 Share Posted July 20, 2015 My plenum doesn't have that extra pipe your red hose is connected to... Odd. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 20, 2015 Share Posted July 20, 2015 What Quagmire said, blanking that IAC hole is just the "mounting" for it, and the red hose is (IIRC) a crank breather vent. The IAC itself lets air bypass the throttle plate through the inlet, this is how I blanked mine off (I added a plate to cover it up as well, obviously): Quote Link to comment Share on other sites More sharing options...
Tanuki Posted July 21, 2015 Share Posted July 21, 2015 One thing to check is the routing of the HT leads; the RV8 is known for "crossfiring" - if the plug leads run close to each other then some of the spark energy intended for one cylinder can couple across to another cylinder's plug-lead enough to cause a spark on that cylinder's plug. If that cylinder happens to be on the intake-stroke the stray spark can be enough to cause ignition of the ingoing fuel/air mixture and you get a backfire-through-the-intake-valve. I had experience of this on an ancient RV8 where the backfire was enough to blow the oil out of the dashpot of the L/H Stromberg. Rearranging the plug leads gave a total cure, though like you I'd spent ages faultfinding and replacing other parts before I found out what the real cause was. Quote Link to comment Share on other sites More sharing options...
Fatboy Posted July 25, 2015 Author Share Posted July 25, 2015 I checked the plugs leads and they were fine Tanuki... That would have made sense though! Blocked the internal ports off with a snug fitting lump of silicon hose.. That sorted the high idle out and I adjusted it using the throttle stop as advised. Now got it to a nice 900rpm.. Reconnected the PWM valve and the idle went back up so I decided to try and live without the PWM for now until I make some progress on basic running... I reloaded Nige's basic 4.6 map because I suspect with all of the rich running, the adjusted previous map would be garbage. It is running a lot smoother now!! I'm using TunerStudio, and the following day, when the engine was cold, decided to try and autotune the warm up.. Now, here is todays mystery that i can't fathom out. During this exercise, the display is telling me that the O2 is "Out of Range" but it is from the "Rear Bank". Yet if I go to the main Gauge Cluster, it is giving me a different reading on the "Front Bank" ---> Note that this photo of the gauge cluster wasn't during the warm up attempt (That photo was fuzzy!) but it does show the different labelled O2.. I've had a good look about in the various menu's but cannot see anywhere where I can confirm where it is getting the data from. Could it be picking up a rogue signal from somewhere? My exhaust only has one Lambda sensor, on the single pipe beyond the Y. I read somewhere that that might be tricky because the exhaust is getting cooler there, and I do have tubular manifolds but they are thermotec wrapped.. When I took it out for a quick run, and tried autotune, the O2 quickly went out of range so I guess its back to the manual to see if my various settings are correct. If anybody has any thoughts or suggestions, please feel free to chuck them at me. (and if I've made any howling errors or assumptions in my scribblings, please point them out too ). Every day is a school day... Thanks. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted July 26, 2015 Share Posted July 26, 2015 You can change what the gauges are showing by right clicking on them, have a look around for the different AFR gauges. Could be that the rich running has killed your lambda sensor.. Do a search on here on how to confirm if it is alive. Is it a heated sensor? Quote Link to comment Share on other sites More sharing options...
Quagmire Posted July 26, 2015 Share Posted July 26, 2015 Oh and good job on getting the idle down You are right to eliminate as much as possible in these early stages and just fix one thing at a time. Quote Link to comment Share on other sites More sharing options...
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