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New fuel delivery (?) issue?
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Fri Jul 17, 2020 2:14 am    Post subject: Reply with quote

Thanks for the advice guys. Sounds like I have a bit of fun in front of me.

The only reason I was trying to bypass the valve was to test my theory that that was the source of my vacuum leak. Basically, I didn't want to do this job unless I had to. But I think I have to now...
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Sun Jul 19, 2020 7:56 am    Post subject: Reply with quote

Ugh. It looks to me like I'm going to have to remove the water pump to get the motor-side cover off. I got the outside cover off relatively easily, but the piston presses up against the side of the car, no room to get it out. On the other side, it appears that the top rear bolt does not have clearance to unthread all the way...the water pump is in the way. My cunning plan was to remove all the other bolts (done, after creatively combining tools to get at all the bolts) and then swing the cover to the side so I could replace the seal, but I'm doubting myself at this point. I don't suppose anyone who has done this remembers if they had to remove the water pump?

If I can clamp the "guts" off the popoff valve so it's compressed and inside the housing, I may be able to do what I need to do, but I don't want to damage anything.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Mon Jul 20, 2020 10:07 am    Post subject: Reply with quote

OK, well I was wrong, I did not have to remove the waterpump. There is an article in the tech section here that described some techniques, although I couldn't get the piston to clear the bore of the valve so I had to do some extra wrestling to get the inside cover back on. Anyway, I spent the better part of two days removing 8 bolts, and then putting them back. End result: No change Typical.

So now I need to do another smoke test, to see if I fixed the vacuum leak but something else is going on, or I didn't fix the leak. For what it's worth, those popoff valve seals were not good. One was broken in a couple places, and the other...well I could barely find any of it. God only knows where it's gone. So no matter what else, I at least have new seals in there.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Wed Jul 22, 2020 6:23 am    Post subject: Reply with quote

Well, I may have just done a bunch of unnecessary work. Looking more closely, I see smoke wafting out from around the ends of the compressor output-to-AFM bellows. The clamps were actually a bit loose, so I tightened them down. No change. Removed the bellows, and damned if there's not a split in the rubber under the top clamp.

So the bad news, of course, is: Where do I get one? If I understand it correctly, it's NLA, and I'm not sure I want another 30+ year old used one. I found a thread on here somewhere where someone used a 2.5" 45 degree silicone hose elbow, cut to fit. I'm going to order one of those, unless someone has a better idea.

I think I'm just going to go with "there were many small leaks, and I totally fixed one by replacing the pop-off valve seals." It will make me feel better
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2002
Location: MI

PostPosted: Wed Jul 22, 2020 9:53 am    Post subject: Reply with quote

I'd take it to the auto parts store with the biggest stock that you know of, tell them that you need to look at all the rad hoses in the back to find something that matches it, find a hose, cut the chunk out that you need, use it..
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1987
Location: Somerset, UK

PostPosted: Wed Jul 22, 2020 8:31 pm    Post subject: Reply with quote

1st choice is a genuine intake which has ribs and metal to avoid it collapsing in vacuum. Second choice is using a short ally elbow and silicone joiners, but will be tricky to make a good fit that is vibration proof from coming undone
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Thu Jul 23, 2020 7:05 am    Post subject: Reply with quote

By "genuine intake" do you mean somehow find one of these NLA parts? I am sure there are some somewhere, but no idea where or how much such a thing would cost, unless it were simply a used one, and then I'll be in the same boat again. Or did you mean there is some kind of "generic" intake piece that could be used? I looked a bit for a spring I could shove into the silicone elbow, but I wasn't really finding anything appropriate.

Carrera RSR wrote:
1st choice is a genuine intake which has ribs and metal to avoid it collapsing in vacuum. Second choice is using a short ally elbow and silicone joiners, but will be tricky to make a good fit that is vibration proof from coming undone

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2002
Location: MI

PostPosted: Thu Jul 23, 2020 7:25 am    Post subject: Reply with quote

I'd be back running the same day with a rad hose..

If their is enough vacuum to collapse a regular hose between the turbo and AFM then I'd thing you really need to clean your air filter or something..


Also remember this connection moves.. The engine is on soft motor mounts and the fuel distributor it connects to is mounted to the body.. FD does not move/vibrate with the engine..

So.. If you want to use a hard 45 and 2 silicone couplers, leave some length of silicone in it to give it something to move on.. IMO
It's a flexy connection..


My AFM-Turbo boot ripping was the catalyst that made me install an intercooler and redesign that whole thing..

My connection there is currently 2 45 hoses and a straight 2.5" hard pipe with a 1" bung in it in the middle of it for the recirculating bov setup that I don't use.. My compressor has just a straight inlet on it though..
Has never failed..
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80 Turbo - Slightly Modified


Last edited by Fasteddie313 on Thu Jul 23, 2020 7:32 am; edited 1 time in total
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Thu Jul 23, 2020 7:32 am    Post subject: Reply with quote

Yeah, I want to avoid hard parts here I think. What I've ordered is a 4-ply silicone piece that I should be able to trim slightly and fit it. If it ends up collapsing too easily I'll have to find something else, but it was $20, it will be here by Saturday and at the very least I can verify that the leaks are gone.

Fasteddie313 wrote:
I'd be back running the same day with a rad hose..

If their is enough vacuum to collapse a regular hose between the turbo and AFM then I'd thing you really need to clean your air filter or something..


Also remember this connection moves.. The engine is on soft motor mounts and the fuel distributor it connects to is mounted to the body.. FD does not move/vibrate with the engine..

So.. If you want to use a hard 45 and 2 silicone couplers, leave some length of silicone in it to give it something to move on.. IMO
It's a flexy connection..

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1987
Location: Somerset, UK

PostPosted: Thu Jul 23, 2020 6:09 pm    Post subject: Reply with quote

bureau13 wrote:
By "genuine intake" do you mean somehow find one of these NLA parts? I am sure there are some somewhere, but no idea where or how much such a thing would cost, unless it were simply a used one, and then I'll be in the same boat again. Or did you mean there is some kind of "generic" intake piece that could be used? I looked a bit for a spring I could shove into the silicone elbow, but I wasn't really finding anything appropriate.

Carrera RSR wrote:
1st choice is a genuine intake which has ribs and metal to avoid it collapsing in vacuum. Second choice is using a short ally elbow and silicone joiners, but will be tricky to make a good fit that is vibration proof from coming undone


Find a used AFM to turbo connecting tube.......lots of parts cars in USA. Put a wanted ad on here. Search t'internet. Don't bodge it........fix it!
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Fri Jul 24, 2020 2:58 am    Post subject: Reply with quote

My concern there is it's 40 year old rubber, just like the one that failed.

Carrera RSR wrote:
bureau13 wrote:
By "genuine intake" do you mean somehow find one of these NLA parts? I am sure there are some somewhere, but no idea where or how much such a thing would cost, unless it were simply a used one, and then I'll be in the same boat again. Or did you mean there is some kind of "generic" intake piece that could be used? I looked a bit for a spring I could shove into the silicone elbow, but I wasn't really finding anything appropriate.

Carrera RSR wrote:
1st choice is a genuine intake which has ribs and metal to avoid it collapsing in vacuum. Second choice is using a short ally elbow and silicone joiners, but will be tricky to make a good fit that is vibration proof from coming undone


Find a used AFM to turbo connecting tube.......lots of parts cars in USA. Put a wanted ad on here. Search t'internet. Don't bodge it........fix it!

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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View user's profile Send private message
bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Mon Jul 27, 2020 1:07 am    Post subject: Reply with quote

Well that wasn't so hard. I just found a used tube/bellows/whatever that is reported to be in good condition. The same guy I bought the bracket for the lower pressure pipe had one. I'll probably go ahead and make my "work-around pipe" when the elbow gets here (it's late ) as a back-up.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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View user's profile Send private message
bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Tue Aug 04, 2020 8:10 am    Post subject: Reply with quote

Never say "that wasn't so hard." It's a curse.

The silicone elbow is lost in the ether, over a week late. But no problem, because I found a used part! Well, it looked fine, it seemed in better overall shape than my old one. But you have to manhandle it a bit to get it on*, and OF COURSE, it split right where it goes over the pipe, just like the original. Almost 40 year old rubber is just not the answer.

*Do you guys remove the fuel dizzy to fit these? That seemed like a lot of effort to fit a flexible (ish) pipe, but in retrospect that is the only way to do it gently.

I think I am going to try the random radiator hose option, as was suggested previously by FastEddie313.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 281
Location: South Florida

PostPosted: Wed Aug 05, 2020 8:29 am    Post subject: Reply with quote

I'll go ahead and answer my own question: YES! Just loosen the fuel dizzy, it makes it MUCH easier.

That being said, NO CHANGE in the car's behavior. I re-smoke tested it, and from what I can tell, I'm not seeing smoke. Given how obvious it was when I had the leaky intake tube, it seems that the silicone elbow, which FINALLY arrived, is working, for now. But I still get tons of stumbles and lean spikes on my AFM when I give it just a bit of gas trying to get going.

Idle is great. At least from before, when this first started, full throttle worked fine. Light throttle...no bueno. It's just very hard for me to accept that I had this problem that is indicative of a vacuum leak, I tested and found the vacuum leak, I fixed (apparently) that leak, and I still have this problem. I'm suspicious, I just don't know about what. I can start fixing random things, but I hate doing that. What else would likely cause those symptoms?
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2002
Location: MI

PostPosted: Wed Aug 05, 2020 11:49 am    Post subject: Reply with quote

Will your smoke tester create any pressure?

Can you seal it pretty good on top of the AFM and plug the exhaust pipe to make a bit of pressure?

Could be a vacuum only leak..
Try spraying around with carb cleaner?

I thought your original description sounded more like a post-TB vac leak..
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