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Old 10-12-2006, 05:31 PM   #1
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Default hmm lumpy idle after friend touched throttle

hey, i was idling perfect at 850-860rpm, just about to set my timing and my friend hops in the seat and taps the gas, now the idle is really lumpy. up-down-up-down and such. I have emb, 305 cc injectors, afpr, ****'s IC. On the emb i have the injectors set at 205/230 since ive heard that was the most normal idle. can you help? what might i be missing?
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Old 10-12-2006, 05:32 PM   #2
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You took the jumper out of the diag box? I would look for vacuum leaks as well. Do you have a wideband?
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Old 10-12-2006, 05:35 PM   #3
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Friends shouldn't let friends...........
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Old 10-12-2006, 05:41 PM   #4
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You took the jumper out of the diag box? I would look for vacuum leaks as well. Do you have a wideband?
no wideband, i dont went over the vacuum hoses and didnt see any problems. It started doing the lumpy idle before i put the jumper in the box.
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Old 10-12-2006, 05:44 PM   #5
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arent you supossed to transverse the 205/230? I thought I read about people doign that somewhere.


I'd check for vacuum leaks. Wideband?
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Old 10-12-2006, 05:50 PM   #6
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arent you supossed to transverse the 205/230? I thought I read about people doign that somewhere.


I'd check for vacuum leaks. Wideband?
I dont have wideband. I dont see any problem with any vac hoses... ill go over it again. So your saying i should put in 230/205 instead of 205/230? also for the emanage im using phillips 8psi map.
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Old 10-12-2006, 05:52 PM   #7
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I'd check for vacuum leaks. Wideband?
I like how you think
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Old 10-12-2006, 05:56 PM   #8
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Originally Posted by penpen989 View Post
So your saying i should put in 230/205 instead of 205/230? also for the emanage im using phillips 8psi map.

You can try it....I remember reading about problems with the 305cc idling.

Here's the post:

https://www.miataturbo.net/forums/sh...ighlight=305cc
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Old 10-12-2006, 06:26 PM   #9
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i tried reversing it from 205/230 to 230/205 and it helped a little bit. but after taking off the filter and putting my hand on the end of the afm it doesnt seem to have any suction at all, and very little when we hit the throttle. maybe a leak?
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Old 10-12-2006, 06:41 PM   #10
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I'd can't remember off hand exactly what I set the correction at. I tuned it at idle with a WBO2. I'm using the 310cc injectors and an RX7 AMF. I had to richen it up significantly to get it to idle properly I think I ended up something like 260/205 or maybe it was 280/205. Either way idle and cruise are perfect. AFR under boost seems to be nice as well.

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Old 10-12-2006, 06:45 PM   #11
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hmm, i dont have an RX7 AMF or WBO2 but i guess ill try that 260/205 or 280/205. The thing is even off of idle its surging between 600-900rpm... when i gave it some throttle it would come back down and then stall. When i tried 310/205 which gave me ~1.3xx it seemed to be a decent idle but then after giving it some throttle it would stall...
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Old 10-12-2006, 07:04 PM   #12
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try going back to 205/205
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Old 10-12-2006, 07:14 PM   #13
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Sorry I should have been more clear. With just the 310cc injectors I ran 205/230. Once I added in the RX7 AFM I had to go change it to 260-280/205.

Sorry about that.
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Old 10-12-2006, 07:19 PM   #14
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You you have a BOV not rerouted? Maybe its being pulled open at idle?
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Old 10-12-2006, 07:22 PM   #15
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you really need to put a vacuum gauge on there
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Old 10-12-2006, 07:28 PM   #16
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duct tape the bitch closed to see
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Old 10-12-2006, 07:47 PM   #17
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alrite, i set the injectors to 205/305 which gave me .672 and it idles! its right around 850 give or take, doesnt sound the greatest but its there. the problem now is when i give it some throttle it seems to hang around 1100 before coming back down to idle... any suggestions?
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Old 10-12-2006, 07:59 PM   #18
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also upon revving it it seems to hiccup, it will go up and then bog and then go up again. same surging like when it was idling but now it only does it if i hit the throttle, it seems to rev up to about 2000 then gets cut then revs again and gets cut. over and over and over.....

Last edited by penpen989; 10-12-2006 at 08:18 PM.
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Old 10-12-2006, 10:20 PM   #19
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You have a vacuum leak. Check the nipple on the firewall side of the intake manifold. Also check the PCV hose. I think you have air getting in somewhere after the throttle causing the revs to go up. The ECU commands the IAC duty cycle down and the Revs drop to normal levels. THe Ecu commands the IAC to run at normal duty cycle again since normal idle and throttle position are seen. Its a vicious cycle.
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Old 10-12-2006, 10:28 PM   #20
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And check that BOV
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