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New fuel delivery (?) issue?
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Fri Sep 04, 2020 7:17 am    Post subject: Reply with quote

I saw the video...yeah, at no/light load, you're getting very lean with no misses. Interesting...I may have been chasing the wrong stuff all this time. Wouldn't be the first time!

I did set to 9 BTDC initially, and it didn't seem to be loose or anything when I was poking around before but I will definitely go through all of that stuff.

I was actually thinking a misfire would show rich, because of the unburnt fuel, but I keep forgetting its an OXYGEN sensor, so unburnt fuel also has unburnt oxygen. Doh! Good stuff guys, thanks for the assistance. I will report back with what I find when I go through the ignition system. If I can't find anything obvious and it's still timed as it should be I will likely just replace the coil to rule it out, if nothing else. I have some store credit at FCP
_________________
-----------------------------------------
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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kondzi  



Joined: 02 Jul 2018
Posts: 110
Location: MZ/Poland/EU

PostPosted: Sun Sep 06, 2020 6:05 am    Post subject: Reply with quote

Doesn't look to me like misfires causing lean reading.
What controller you have? I see Innovate Gauge, what you have LC-1, LC-2?
Had a faulty LC-1 (Innovate support stopped responding to my claims) that was behaving similar as yours, and then dropped to low 8's. Did you calibrate the o2 controller with o2 sensor out in fresh air?
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)
'74 Ford Capri 1.3 (factory specs)
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Sun Sep 06, 2020 2:16 pm    Post subject: Reply with quote

It's a Zeitronix controller, which uses a Bosch 5-wire wideband sensor. No calibration required. This is definitely NOT a wideband gauge/sensor/controller problem. There are some weird things I have to do to get the gauge to work, but that's a different story. This is a driveability issue, which the wideband has nothing to do with. It's just an observer...I'm not using the narrowband emulation, which is the only means it might have to actually influence things.

kondzi wrote:
Doesn't look to me like misfires causing lean reading.
What controller you have? I see Innovate Gauge, what you have LC-1, LC-2?
Had a faulty LC-1 (Innovate support stopped responding to my claims) that was behaving similar as yours, and then dropped to low 8's. Did you calibrate the o2 controller with o2 sensor out in fresh air?

_________________
-----------------------------------------
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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chuck21401  



Joined: 20 Feb 2005
Posts: 261
Location: Annapolis, MD

PostPosted: Tue Sep 15, 2020 10:11 pm    Post subject: Reply with quote

So I noticed some odd readings on my A/F meter before blowing the fuel pump fuse and then finding low voltage to the fuel pump. Have you checked the voltage at the pump?
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1981 Porsche 931
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Wed Sep 16, 2020 1:24 pm    Post subject: Reply with quote

I was going to do that until I went down the ignition path. Which, I'm happy to report, was correct! I ordered a replacement ignition coil, because that's the one piece of the ignition puzzle that I hadn't touched, and it arrived today. I don't think the old one was original actually, but it certainly wasn't a Bosch. Put the new one in, and it's back to driving like it should. Very pleased

Thanks to everyone who helped me get here!

chuck21401 wrote:
So I noticed some odd readings on my A/F meter before blowing the fuel pump fuse and then finding low voltage to the fuel pump. Have you checked the voltage at the pump?

_________________
-----------------------------------------
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: 2038
Location: MI

PostPosted: Thu Sep 17, 2020 4:11 am    Post subject: Reply with quote

Congrats!!!

I was worried about you..
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Thu Sep 17, 2020 1:41 pm    Post subject: Reply with quote

Honestly, me too! I still can't believe it was the coil. That just seems too easy. I could have saved myself a lot of trouble had I tried that first, but in the long run, I'll be better for having fixed all those small vacuum leaks, etc.

Fasteddie313 wrote:
Congrats!!!

I was worried about you..

_________________
-----------------------------------------
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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Mike9311  



Joined: 14 Dec 2004
Posts: 877
Location: Chicago-ish

PostPosted: Thu Sep 17, 2020 11:15 pm    Post subject: Reply with quote

bureau13 wrote:
Honestly, me too! I still can't believe it was the coil. That just seems too easy. I could have saved myself a lot of trouble had I tried that first, but in the long run, I'll be better for having fixed all those small vacuum leaks, etc.

Fasteddie313 wrote:
Congrats!!!

I was worried about you..


Few years ago while prepping for 92Forty, the 82 had issues starting and running right after starting. We were out of our minds late into the night when the coil finally started smoking. I installed the coil from my 80 and instantly everything was fine. Craziness

Really cool that you have it all sorted out
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Fri Sep 18, 2020 2:25 pm    Post subject: Reply with quote

Smoking would have helped diagnose it! I drove it tonight, ran perfectly. To be honest, it's never really run right until I removed the weird homebrew ignition setup and replaced it with the Mittelmotor, but I barely got to enjoy it when the coil went.
_________________
-----------------------------------------
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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Mike9311  



Joined: 14 Dec 2004
Posts: 877
Location: Chicago-ish

PostPosted: Fri Sep 18, 2020 10:43 pm    Post subject: Reply with quote

I wonder if you are the only one in the US with the Mittelmotor ignition?
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Sat Sep 19, 2020 8:53 am    Post subject: Reply with quote

That's an interesting question. I never see them discussed here, even in Porsche clubs most people just get a blank look on their face.

I have seen some US-centered discussions of the 123ignition gear, mainly as a retrofit for muscle cars I think.

Mike9311 wrote:
I wonder if you are the only one in the US with the Mittelmotor ignition?

_________________
-----------------------------------------
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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kondzi  



Joined: 02 Jul 2018
Posts: 110
Location: MZ/Poland/EU

PostPosted: Sun Sep 20, 2020 4:27 am    Post subject: Reply with quote

bureau13 wrote:
I was going to do that until I went down the ignition path. Which, I'm happy to report, was correct!
[...]
Thanks to everyone who helped me get here!


You're welcome
_________________
---
Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)
'74 Ford Capri 1.3 (factory specs)
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bureau13  



Joined: 07 Sep 2017
Posts: 310
Location: South Florida

PostPosted: Sat Sep 26, 2020 9:07 am    Post subject: Reply with quote

OK, someone explain this to me: The problem is back

At first it was pretty subtle...just a slight stumble around 2500-3K. I tweaked my ignition map to take some advance, no real change. It seems subsequent drives during the day get worse, although the car isn't really hot.

Earlier today I took it for a drive to try to characterize it a bit better, and it was really not bad. A bit of a stumble with light throttle around 2500-3K. If I gave it a bit more throttle it would stumble initially (AFR would go to maybe low 15s...possibly just misfire related as it seemed before) then richen up as the WUR saw boost (I'm guessing this is why) and everything would be fine.

An hour or two later, I went to drive, and it's bad like before. The slight stumble is a fairly violent bucking.

I don't get it. When I replaced the coil it seemed fine. It certainly wasn't doing this. And when I had problems the first time around, it was fine, then the slight stumble appeared, and then it got bad. Same exact thing. But why did replacing the coil "fix" it for a a bit? It's a Bosch coil, btw. I didn't get some off-brand crappy one.

I also have a hard time believing it's an ignition map issue. I've been doing the math to see what sort of advance numbers I'm getting under the conditions its happening, and I've pulled a bunch of timing out to see if it would make a difference, but it didn't.

This is doubly annoying because my other car is also having weird problems as well. I'm getting it from both ends
_________________
-----------------------------------------
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: 2010
Location: Somerset, UK

PostPosted: Sat Sep 26, 2020 9:46 pm    Post subject: Reply with quote

Take it to a dyno assuming they have K Jet knowledge and let them work it out. Then you can try and replicate it on the rollers under any load, speed, rpm and measure fuel pressures, boost and timing all at the same time.......they will either find the fault or it will be tuned so no further issues.
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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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peterld  



Joined: 10 Dec 2006
Posts: 783
Location: Noosa Heads QLD Australia

PostPosted: Sat Sep 26, 2020 10:14 pm    Post subject: Reply with quote

+ 1 above.
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