Engine stumble when the gas pedal is nail ..
07-28-2012, 02:01 PM
#19
Three Wheelin'
Thread Starter
07-28-2012, 03:12 PM
#20
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I have something similar going on with car, though it is an L-jet. I also think I have a small hole in the exhaust before the O2 sensor. So I want to see if my O2 is giving back bad info to the brain. Might explain the pops some are having. Please keep in mind, I dont really know what I am talking about.
07-28-2012, 03:54 PM
#21
Racer
Join Date: May 2012
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Very possible...According to the previous owner the MAF was replaced twice. He had a bunch of shady mechanics work on the car as was very obvious to me judging by the sloppy work in which I had to repair/replace things as a result. The previous owner was not mechanical at all. If you are not mechanically inclined and are not willing to get dirty, you are in for a friggin ride with these cars.
07-28-2012, 06:31 PM
#22
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07-28-2012, 08:55 PM
#23
Three Wheelin'
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07-28-2012, 10:07 PM
#24
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I had stumbles on acceleration, popping overrun and a deterioriating miss as things heated up . Checked everything and my thoughts were going to MAF failure. The symptoms disappeared after changing my engine mounts!!! 
Car has run perfectly ever since the first startup after the mount change and this had me really scratching my head. Replacement of the mounts includes removing the main engine ground and I had disconnected that ground and given it a thoroughly good cleaning.
Main engine ground is my best guess anyway for what solved my problem and might be an area to look.
Good luck.
Car has run perfectly ever since the first startup after the mount change and this had me really scratching my head. Replacement of the mounts includes removing the main engine ground and I had disconnected that ground and given it a thoroughly good cleaning.
Main engine ground is my best guess anyway for what solved my problem and might be an area to look.
Good luck.
07-29-2012, 06:20 AM
#25
Rennlist Member
Either send it to Injection Labs or to my agent Louie Ott who can check it out.
He has a calibrated flow jig.
http://www.performance928.com/cgi-bi...&pass_parent=0
He has a calibrated flow jig.
http://www.performance928.com/cgi-bi...&pass_parent=0
04-24-2013, 03:47 PM
#26
Three Wheelin'
Thread Starter
04-25-2013, 04:15 AM
#29
Burning Brakes
Maybe it's the first time ii can help here...it's a common problem on bmws with l-jetronic and early motronic:the throttle switch is out of place or you need a new one.
move throttle link where all accelerator and cruise control cables are attached on the intake manifold, move throttle slightly, as soon as you move it you could hear a click,if the throttle moves some millimeters before hearing that click you need to adjust, or the ecu will think the engine is still idling when you instead are presssing accelerator pedal...on bmws the throttle switch is calibrated on the travel or working angle of the throttle,so the porsche lhjetronic is,bear in mind that of you need to move 4 millimeters the throttle to hear that click sound from the switch,this means also that the throttle is full open but the throttle switch has a "delay" of 4millimeters to switch on again and tell the ecu you are running flat out...and the ecu will never give you full power.
Hope this helps and hope you understood anything with my poor language.
move throttle link where all accelerator and cruise control cables are attached on the intake manifold, move throttle slightly, as soon as you move it you could hear a click,if the throttle moves some millimeters before hearing that click you need to adjust, or the ecu will think the engine is still idling when you instead are presssing accelerator pedal...on bmws the throttle switch is calibrated on the travel or working angle of the throttle,so the porsche lhjetronic is,bear in mind that of you need to move 4 millimeters the throttle to hear that click sound from the switch,this means also that the throttle is full open but the throttle switch has a "delay" of 4millimeters to switch on again and tell the ecu you are running flat out...and the ecu will never give you full power.
Hope this helps and hope you understood anything with my poor language.
04-26-2013, 10:02 AM
#30
Maybe it's the first time ii can help here...it's a common problem on bmws with l-jetronic and early motronic:the throttle switch is out of place or you need a new one.
move throttle link where all accelerator and cruise control cables are attached on the intake manifold, move throttle slightly, as soon as you move it you could hear a click,if the throttle moves some millimeters before hearing that click you need to adjust, or the ecu will think the engine is still idling when you instead are presssing accelerator pedal...on bmws the throttle switch is calibrated on the travel or working angle of the throttle,so the porsche lhjetronic is,bear in mind that of you need to move 4 millimeters the throttle to hear that click sound from the switch,this means also that the throttle is full open but the throttle switch has a "delay" of 4millimeters to switch on again and tell the ecu you are running flat out...and the ecu will never give you full power.
Hope this helps and hope you understood anything with my poor language.
move throttle link where all accelerator and cruise control cables are attached on the intake manifold, move throttle slightly, as soon as you move it you could hear a click,if the throttle moves some millimeters before hearing that click you need to adjust, or the ecu will think the engine is still idling when you instead are presssing accelerator pedal...on bmws the throttle switch is calibrated on the travel or working angle of the throttle,so the porsche lhjetronic is,bear in mind that of you need to move 4 millimeters the throttle to hear that click sound from the switch,this means also that the throttle is full open but the throttle switch has a "delay" of 4millimeters to switch on again and tell the ecu you are running flat out...and the ecu will never give you full power.
Hope this helps and hope you understood anything with my poor language.
If you nail the throttle, the idle switch will be open at virtually the same instant, regardless of where it actually is triggered (well, mostly)?!
Does anyone know how much travel of the bowden cable (after taking out any play) to the throttle is OK before the idle switch clicks?
_________
Kurt
90 S4
satin black metallic