280z turbo, bad afm?

[jhill]

So I finally got my l28et to fire. WOOO! . It starts, then dies out a few seconds later. If I manually hold the door on the afm open it will idle like a dream, if I keep pushing it in and give it some throttle it picks up great, but for some reason it won't control the door on its own. Now, the car is still being put back together as I want to make sure everything is in working order before I put it back so the afm is not attached to the rubber boot to the turbo, is that my problem? Does it need to be hooked up directly? I would have thought it would be able to at least idle this way. Until I figure out a way of mounting the afm I can't attach it to the boot(suggestions welcomed ). Or is the afm bad?

 

Let me know what cha thinkin'

 

Thanks

[ComicArtist]

The AFM DOES have to be directly connected to the intake of the turbo. I did a N/A to turbo conversion so I just used the rubber boot going from the AFM to the air filter box on my N/A engine to connect the AFM to the turbo.

 

I ended up fabbing a mount to the frame rail out of a piece of sheet metal.

[NewZed]

So I finally got my l28et to fire. WOOO! . It starts, then dies out a few seconds later. If I manually hold the door on the afm open it will idle like a dream, if I keep pushing it in and give it some throttle it picks up great, but for some reason it won't control the door on its own. Now, the car is still being put back together as I want to make sure everything is in working order before I put it back so the afm is not attached to the rubber boot to the turbo, is that my problem? Does it need to be hooked up directly? I would have thought it would be able to at least idle this way. Until I figure out a way of mounting the afm I can't attach it to the boot(suggestions welcomed ). Or is the afm bad?

 

Let me know what cha thinkin'

 

Thanks

 

No offense intended, but you should really browse through the Engine Fuel section of the Service Manual. It is easy reading and very informative. The AFM is just one input of many to the ECU that determines how long to leave the injectors open, to supply the proper amount of fuel to the engine. The AFM flap is suppoed to be "moved" by the air that flows by it, not vice versa. When you moved the AFM flap by hand, the ECU supplied more fuel to the motor, because the AFM signal was showing that the throttle was opening.

[jhill]

Ok I did some researchin' and some troubleshootin'. I don't get it, I tried it a bunch, won't idle. Then one time I turn the key and it idles with basically no problems, I mean it was a little low but it was idling pretty strong and for at least 60secs. It still didn't want anything to do with throttle, as soon as I touched it it died. Then I started it like 10 more different times after I fiddled with different things and its back doing the same thing as before, won't stay running.

 

I know all the components put out because like I said in the original post I can manually open the afm door and all is well, turbo even spools great. Could it be vaccum? It doesn't sound like theres a leak but I don't know maybe. Could it be that its just not getting baseline FP from the FPR? What confuses me is why sometimes it will act perfect (minus dying the instant you even look at the throttle). Also if I hit the AFM it kinda rattles like there is something inside, could it still be an AFM prob?

 

I'm so close to getting her on the road!!!! Ugh

[NewZed]

Ok I did some researchin' and some troubleshootin'. I don't get it, I tried it a bunch, won't idle. Then one time I turn the key and it idles with basically no problems, I mean it was a little low but it was idling pretty strong and for at least 60secs. It still didn't want anything to do with throttle, as soon as I touched it it died. Then I started it like 10 more different times after I fiddled with different things and its back doing the same thing as before, won't stay running.

 

I know all the components put out because like I said in the original post I can manually open the afm door and all is well, turbo even spools great. Could it be vaccum? It doesn't sound like theres a leak but I don't know maybe. Could it be that its just not getting baseline FP from the FPR? What confuses me is why sometimes it will act perfect (minus dying the instant you even look at the throttle). Also if I hit the AFM it kinda rattles like there is something inside, could it still be an AFM prob?

 

I'm so close to getting her on the road!!!! Ugh

 

Sounds like you don't have the boot hooked up yet, re ComicArtists' suggestion.

 

So you're running the motor's exhaust through the turbo but without the inlet hooked up so no boost, just spinning things to see if everything works? If the AFM boot is not connected to the turbo inlet, what is it connected to? And what is the turbo intake connected to, both sides? Is it just blowing air? Are you basically running an N/A motor through a turbo exhaust?

 

I'm not a turbo guy (could be eventually) but this sounds interesting...

[jhill]

Actually I did figure out how to mount the afm so it is hooked up to the boot, nice and tite. I just cut and crushed the old AFM mount and the turbo one fit in there great, looks almost stock. Ok, let me clear some stuff up, It is a turbo engine all turbo compenents, AFM is now hooked up. Everything is hooked up the way it should be just not in its final resting place (i.e. need to tuck wiring away etc). Car still doesn't wanna stay running. .