Help! Video-1977 US 930 Misfire? Thoughts?
10-24-2018, 01:49 PM
#1
Help! Video-1977 US 930 Misfire? Thoughts?
Sorry for upside-down video. Tried flipping it then upload again to google drive but still upside-down?
Click for video----->https://drive.google.com/open?id=1C2...qGVKqAI0aQ2NLX
1977 US Turbo 930. Has run great since engine rebuild. This started out of nowhere after a few thousand miles. Putt, putt, putt, putt at idle and AFR goes slightly lean. Not lean enough to stall but it will stumble before clearing up when getting on throttle. Seems to rev and boost fine. Not driving it, don’t want to get stuck. When it started doing this was on my way home and I did get into boost. I did notice afr seemed to fluctuate/react faster to throttle modulation and may be going richer on boost? Wideband has data logger but haven’t used that feature yet. The video doesn’t show the sometimes quite lean condition 15-16.5 but mis sound can clearly be heard. At idle it does go away sometimes but only for a few seconds?
System Pressure: 95 psi
Volume Delivery Test: Passed
Cold Control: 20psi
Is this right? Hot Control: 35psi with wur vent vac hose plugged in(This is the reading with the engine running) (Car has run great this way the hole time?)(Only discovered this now after testing for misfire)
Is this right? Hot Control: 51psi with wur vent hose unplugged(Plugged Vac hose)(This is the reading with engine off and fuel pumps running)
New parts: Wires, Plugs, Cap/Rotor, WUR, Front Fuel Pump, Fuel Injectors, Fuel Filter, Porsche bov(Not vented to air)
Old parts: Coil, Fuel Head, Rear Fuel pump, Fuel accumulator, all other devices that come on 930
Checked for vac leaks but nothing found. Used water spray mist. Continuing to check…
Now I’m jonesing to drive! It’s like taking away drugs from an addict! Thank you all in advance.
Click for video----->https://drive.google.com/open?id=1C2...qGVKqAI0aQ2NLX
1977 US Turbo 930. Has run great since engine rebuild. This started out of nowhere after a few thousand miles. Putt, putt, putt, putt at idle and AFR goes slightly lean. Not lean enough to stall but it will stumble before clearing up when getting on throttle. Seems to rev and boost fine. Not driving it, don’t want to get stuck. When it started doing this was on my way home and I did get into boost. I did notice afr seemed to fluctuate/react faster to throttle modulation and may be going richer on boost? Wideband has data logger but haven’t used that feature yet. The video doesn’t show the sometimes quite lean condition 15-16.5 but mis sound can clearly be heard. At idle it does go away sometimes but only for a few seconds?
System Pressure: 95 psi
Volume Delivery Test: Passed
Cold Control: 20psi
Is this right? Hot Control: 35psi with wur vent vac hose plugged in(This is the reading with the engine running) (Car has run great this way the hole time?)(Only discovered this now after testing for misfire)
Is this right? Hot Control: 51psi with wur vent hose unplugged(Plugged Vac hose)(This is the reading with engine off and fuel pumps running)
New parts: Wires, Plugs, Cap/Rotor, WUR, Front Fuel Pump, Fuel Injectors, Fuel Filter, Porsche bov(Not vented to air)
Old parts: Coil, Fuel Head, Rear Fuel pump, Fuel accumulator, all other devices that come on 930
Checked for vac leaks but nothing found. Used water spray mist. Continuing to check…
Now I’m jonesing to drive! It’s like taking away drugs from an addict! Thank you all in advance.
10-27-2018, 09:56 PM
#2
Burning Brakes
Join Date: Apr 2006
Location: Central Washington State
Posts: 1,118
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had a similar Problem and replaced all the things you did , same problem ,then we replaced the green wire ,the coil, drained the fuel tank ,cleaned out the filters ,fuel lines ,put an adjustable warm up regulator and replaced the spark plug wires ,checked the voltage drop to the fuel pumps, we put new fuel pump’s and also fixed up the wiring at the fuse box and made sure the alternator was charging ,correctly it wasn’t ,we had to replace it ....after all that the car runs great