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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 12-14-2006, 07:57 PM   #1
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Question I've got an odd one for you...

I narrowed my oil consumption down to a leak at the drain line. So I pulled the turbo off and modified a few things.

I put all back together and tried to start it up. Turned over right away, idled for a few seconds....now the odd part.

It gradually started losing vacuum untill it died. Tried again same thing. Questioned the AFM and put it in Diagnostics mode (Gnd & 10) to no avail. Holding the throttle open just ever so slightly keeps it running. Then I noticed on the WB that it's running super lean while this is happening before it cuts out. Also tried keeping the fuel pump running (Gnd & F/P) to no avail.

Not sure what the problem is...on top of that I made the oil leak worse.
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Old 12-14-2006, 08:27 PM   #2
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Is your fp staying on, your relay migth be ****** up. I would take of the back pannel or put the gauge on to see whats going on.
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Old 12-14-2006, 08:31 PM   #3
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It might be time to redo the jb weld maybe it got jostled and broke the seal.
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Old 12-14-2006, 08:51 PM   #4
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Would leaking oil slowly cause a loss of vacuum? No FP gauge at the moment, might have to wait till this weekend.
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Old 12-14-2006, 08:58 PM   #5
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i dont think it would unless you have a blown cylinder or sticking valve not letting the oil drain properly so it has to go somewhere. I have had my fp relay stick before and not let the pump come on you might pull the battery cable to reset everything and check the relay and fuse if all this doesnt work i would cut the wires to the afm and wire it together for constant on if this works you can keep it like that or put a new afm in place.
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Old 12-14-2006, 09:54 PM   #6
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I know I'm getting fuel pressure, If I clamp down on the return it reacts like it would normally, i can hear it build pressure. I can try swapping the AFM, but it just seems really weird.

It was running perfectly fine yesterday, I pulled the intake as a whole, unbolted the downpipe, removed the oil lines, and pulled the turbo. I didn't touch anything else. And went over my work like 20 times trying to figure it out.
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Old 12-14-2006, 10:08 PM   #7
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Maybe you nicked, disconnected, or grounded your o2 sensor wire somewhere when you removed the DP? I'd also check to make sure that the o2 sensor was screwed in all the way into the bung.
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Old 12-14-2006, 10:37 PM   #8
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I'll check.
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Old 12-14-2006, 11:43 PM   #9
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maybe you have a vacuum leak?

er I mean... did you disconnect any air passages while you were working that you might have forgotten? can you do the carb cleaner trick?

ah anyway.
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Old 12-15-2006, 12:07 AM   #10
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Quote:
Originally Posted by y8s View Post
maybe you have a vacuum leak?
That's what I originally thought, I'm no mechanic though...
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Old 12-15-2006, 12:12 AM   #11
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yeah i can try that, but its hard to keep it running and spary **** at the same time....i went through all my vacuum lines, and none are disconnected, ran compressed air into a few to listen for leaks but couldn't hear any. I still think it may just be a AFM issue.
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Old 12-15-2006, 12:44 AM   #12
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At least it starts.
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Old 12-15-2006, 09:19 AM   #13
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Man, WTF.

No clue...AFM, I guess? I mean, these things are getting old at this point. Were you running the RX-7 AFM or Miata one these days?
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Old 12-15-2006, 09:42 AM   #14
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you're telling me...I've taken the turbo off at least 10-15 times now and this has never occured. It's the OEM AFM currently. I'm going to swap the RX7 one back on just to see how it reacts. I mean unless I somehow punctured the coupler off the turbo outlet I don't see what I could have done to it.
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Old 12-15-2006, 10:49 AM   #15
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it almost sounds like a bad AFM connection. but i dont know what the vacuum looks like in that case.
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Old 12-15-2006, 10:55 AM   #16
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Yeah I dunno, from prior forgetfulness I've noticed the car won't crank over at all without the AFM. But a swap with another unit will be able to narrow that one down really fast.

Going to try disconnecting the o2 sensor incase I did somethign with that signal.

It wasn't throwing a code, but I'll try to pull any stored ones to see if that doesn't point me in the right direction.

Otherwise if that results in no change I'm going to rip the turbo out again and try again after I fix the oil leak...again.
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Old 12-15-2006, 11:56 AM   #17
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Don't worry about the O2 sensor. On a cold engine it does absolutely nothing. NB sensors need to get up to 600* F before they create a signal, so they are not looked at until the engine is warmed up.

To check the AFM, look for varying resistance between the blk-light green and red-green wires going into the AFM as you move the flapper door.
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Old 12-15-2006, 11:59 AM   #18
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the car will crank with no afm it just wont run if the conection is loose it will run like **** due to no fp operation. Ive been there.
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Old 12-15-2006, 12:03 PM   #19
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I'm betting on bad afm.
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Old 12-15-2006, 12:09 PM   #20
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yeah, that was always my first thought. I'll see whats going on with it in a bit.
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