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Old 02-20-2017, 10:56 PM
86911TLCAB 86911TLCAB is offline
Tito
 
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Default Injector question: 328is

My 328 is running very rich. I pulled the codes today and came up with quite a few:
0300 general misfire
0155 o2 heater bank one sensor 1
0135 o2 heater bank two sensor 1
0301 cylinder 1 misfire
0303 cylinder 3 misfire
0306 cylinder 6 misfire.

Will check the heater circuit fuses (if there are some) tomorrow.

I had pulled the injectors and put plastic bags on all 6. When I turn the car on, without starting, I get a good quantity of fuel coming from injector 1 and 3. Then it stops flowing. No expert but I don't think this is supposed to happen. Does this mean the injector is no good? Can it be repaired or is it toast? Not sure on 6, but will pull that one and see if I get any flow through it using carb cleaner. Any thoughts on this appreciated. Thanks. Tito
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82 911 SC with 3.2
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99 328is
97 Lexus SC300 Manual

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  #2  
Old 02-20-2017, 11:49 PM
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cmartin cmartin is offline
 
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Check fuel pressure. Also, double check you have the coils and vac lines back together. You can swap things around to issolate a coil or cylinder too.

Fuel pressure check...

Quote:
The injection rate is precision-adjusted by means of the injection time; the injection time is controlled by the DME.
The partial vacuum in the intake manifold serves as engine load information for pressure regulation. The diaphragm of the pressure regulator is actuated with this partial vacuum.
A partial vacuum builds up in the intake manifold during idling operation or in overrun mode. Depending on the partial vacuum value, the fuel pressure decreases starting out from the nominal value. The nominal value is stamped in the fuel pressure regulator housing.
At full load, the partial vacuum in the intake manifold is approximately equal to zero. The fuel pressure regulator regulates the fuel pressure to the nominal value stamped in the housing.

Description of operation: fuel pump
The control function of the fuel pressure regulator must be ensured in all operating states. The fuel pump must therefore always be able to generate a higher fuel pressure than the pressure regulated by the pressure regulator.

Description of operation: fuel return line
When the engine is at a standstill and the ignition key is in position 0, the fuel return line after the pressure regulator is at zero pressure.

Description of operation: pressure retaining function
The pressure regulator closes when the engine is at a standstill and the ignition key is in position 0. The fuel pressure in the delivery line is retained over an extended period. A non-return valve closes in the fuel pump. These measures help to retain the fuel pressure in the fuel system. Extended starting times are thus avoided.

Complaint: drive characteristic faults, lack of power
Run engine at idle speed and measure fuel pressure. In order to simulate "full load" state:
Disconnect vacuum hose from fuel pressure regulator and measure fuel pressure.

The measured value must increase by 0.4 to 0.7 bar depending on the engine. Note down measured value.
If the measured value does not increase: Replace vacuum hose and measure fuel pressure again
If the measured value still does not increase; Replace pressure regulator
Measure fuel pressure again and note down measured value.
Compare the measured value with the nominal value stamped in the pressure regulator housing.
If the specified measured value is still not achieved, you must carry out the following checks depending on the measured value.

If the measured value is less than the nominal value -0.2 bar :
The cross-sections in the fuel feed line are contracted or the fuel filter is clogged, or
the fuel pump voltage supply is not O.K., e.g. due to high contact resistance (corrosion) in the plug connection between wiring harness and fuel pump
If the measured value is greater than the nominal value +0.2 bar :
Switch off engine and then observe measured value.
If the measured value drops to the nominal value, the cross-sections in the fuel return line are contracted or clogged.
Check the fuel lines for kinks. If no kinks are visible:
Replace return lines. If the measured value remains too high, the pressure regulator is most probably faulty.
CAUTION!
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Old 02-21-2017, 09:27 AM
86911TLCAB 86911TLCAB is offline
Tito
 
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Thanks...I will check the fuel pressure. I have verified the vacuum lines are properly connected and hose clamped. all 6 coils are in the engine...I didn't remove them.

Fuel pressure should be the same for all injectors across the rail. so if it is a little high, would it cause an injector to go bad?

Have been trying to find some good reading on injectors and how they function. When the car is off, the injectors I presume are closed. When you turn the car on, and the fuel pump kicks on, I would think the injector should remain off, and should still not be allowing fuel into the cylinders. Once you turn the key to start should be when the ecu (I suppose) should begin to cycle power to the injectors telling them to spray fuel in time with the ignition sequence.
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82 911 SC with 3.2
73 RSR project
97 328is
99 328is
97 Lexus SC300 Manual

86 TL (gone)
993 (gone)
75 911S (gone)
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  #4  
Old 02-21-2017, 10:25 AM
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cmartin cmartin is offline
 
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Basically yes, at least thats my understanding. Several variables including lamda reading. I'm far from an expert on this system, just worked on it a bunch.
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Old 02-21-2017, 10:32 AM
86911TLCAB 86911TLCAB is offline
Tito
 
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OK...so at a minimum I have two injectors that are allowing fuel to flow when the system is initially pressurized. There was about 2-3 tablespoons of fuel in the Ziploc bags each time I tried this...so that much raw fuel could easily cause the misfires.

Plus if that is what they are doing when they aren't supposed to be open, who knows how much fuel they are putting out when they get a signal to open. suppose there is a way to check that. that plus the o2 sensor failure is clearly a likely cause of all the fuel in the exhaust.

Lets see...got a couple of injectors coming as well as o2 sensors...so I can take the next step...plenty of other things to do while I await the parts...thanks for the feedback.
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Tito

82 911 SC with 3.2
73 RSR project
97 328is
99 328is
97 Lexus SC300 Manual

86 TL (gone)
993 (gone)
75 911S (gone)
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  #6  
Old 02-24-2017, 10:00 PM
86911TLCAB 86911TLCAB is offline
Tito
 
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Swapped out the injectors..seem to be working fine. All codes cleared.
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82 911 SC with 3.2
73 RSR project
97 328is
99 328is
97 Lexus SC300 Manual

86 TL (gone)
993 (gone)
75 911S (gone)
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